Tube kv power amplifier. IRF630 Power Amplifier for HF Radio Remote Control

tube, transistor

As practice shows, few of the radio amateurs work with QRP, while most sooner or later begin to dream of increasing the transmitter power. That's when and the question arises of preference for a lamp or a transistor. Long-term practice of operating one or another has shown that tube amplifiers are much easier to manufacture and less critical to operating conditions, and the weight of anode transformers is practically offset by the weight of heat sinks needed to cool powerful transistors, which are more capricious in operation, especially to overloads, so experiments with them are expensive. It is easier to make a power supply with a power of 2 kW at 2000 V at a current of 1 A than 20 V at a current of 100 A. The presence of small-sized electrolytic capacitors designed for high voltage and large capacity makes it possible to create small-sized high voltage sources for tube amplifiers directly from the network without using power transformers.

The power amplifier is one of the main attributes of the radio set of the contestman and DX-men. Depending on his choice results in competitions and ratings.

HF tube power amplifiers, transistorized HF power amplifiers

The output amplifier (power amplifier - PA) is an amplifier loaded on the antenna. The output amplifier consumes most of the power. The operation of the PA mainly determines the energy performance of the entire radio station, so the main requirement for the output stage is to obtain high energy performance. In addition, good filtering of higher harmonics is very important for the output amplifier.

A good modern HF power amplifier is a rather complex and time-consuming device, as evidenced by world prices for branded PAs, at least in relation to the cost of middle-class transceivers manufactured by the same companies. This is explained, firstly, by the high cost of the lamps themselves used in UM, and secondly, also by the high percentage of manual labor in their manufacture.

ACOM-1000

The ACOM 1000 HF power amplifier is one of the world's finest HF power amplifiers. The output power of ACOM 1000 is at least 1000 W on all amateur radio bands from 160 to 6 meters.

Without antenna tuner

The amplifier performs the functions of an antenna tuner with SWR up to 3:1, thus allowing you to change antennas faster and use them in a larger frequency band, saving tuning time.

One output lamp 4CX800A (GU-74B)

The amplifier uses a high-performance ceramic-metal tetrode manufactured by the Svetlana plant with an anode dissipation power of 800 W (with forced air cooling and grid control).

Specifications of the ACOM 1000 Power Amplifier:

• Frequency range: all radio amateur bands from 1.8 to 54 MHz; extensions and/or modifications upon request.
• Output power: 1000W peak (PEP) or push mode, unlimited operating modes.
• Intermodulation Distortion: Better than 35 dB below peak power rating.
• Hum and noise: better than 40 dB below peak power rating.

Suppression of harmonics:

• 1.8 - 29.7 MHz - Better than 50 dB below peak power rating.
• 50 - 54 MHz - better than 66 dB below peak power rating.

Input and output impedance:

• nominal: 50 ohms, unbalanced, UHF connectors (SO239);
• input circuit: wideband, SWR less than 1.3:1 in the continuous frequency band 1.8-54 MHz (no need for tuning and switching);
• pass-through SWR is less than 1.1:1 in the continuous frequency band 1.8-54 MHz;
• Output Matching Capabilities: Better than 3:1 or greater SWR at reduced power level.

• RF Gain: 12.5dB typical, less than 1dB frequency response (with 50-60W input for rated output).
• Supply voltage: 170-264 V (200, 210, 220, 230 and 240 V taps, 100, 110 and 120 V taps on request, tolerance +10% - 15%), 50-60 Hz, single phase, Consumption 2000 VA at full power.
• Meets EU safety and EMC requirements and FCC regulations (installed on 6, 10, and 12m).
• Dimensions and weight (in working order): 422x355x182 mm, 22 kg
• Requirements for environmental parameters during operation:
• temperature range: 0...+50°С;
• relative air humidity: up to 75% at +35°C;
• altitude: up to 3000 m above sea level, without deterioration of technical parameters.

ACOM-1011

The ACOM 1011 power amplifier is based on the well-known ACOM 1010.

The outstanding performance of the latter has been noted by many radio amateurs around the world.

At the WRTC championship in Brazil, the teams used the ACOM 1010 amplifier and it was found to be the best for both stationary use and DXpeditions.

The main differences between the two amplifiers are:

• The ACOM 1011 uses two 4CX250B tubes, currently manufactured by many of the most well-known tube manufacturers, to provide the same power output as a single GU-74B tube.
• Lamp warm-up time reduced to 30 seconds.
• The tube panels are commissioned by ACOM and designed specifically for this amplifier.
• The ACOM 1011 uses a new fan designed and manufactured specifically for ACOM based on the well-known and proven fans used in the ACOM 1000 and ACOM 2000 models. It uses similar components, which provides better cooling and quieter operation of the amplifier overall compared to the ACOM 1010.
• ACOM 1011 has some differences both outside and inside. The stronger metal construction improves its performance during transport and DXpeditions.

ACOM-2000

The ACOM 2000A Automatic Power Amplifier is the most advanced HF amplifier in the world of amateur radio amplifiers. The ACOM 2000A is the first amateur radio power amplifier to combine a fully automated tuning process with sophisticated digital control capabilities. The new advanced amplifier design produces the maximum permitted power in all modes and operates on all HF amateur radio bands.

Advanced technology has improved the classic amplifier design

Fully automatic tuning

The automatic tuning functions of the ACOM 2000A are a real breakthrough in HF power amplifier design. No need to think about using an antenna tuner with SWR up to 3:1 (2:1 on 160 meters). The process of matching the actual impedance to the optimum lamp load is fully automated. In time, this process lasts no more than one second and does not require much experience.

QSK - full duplex mode

Full duplex (QSK) operation is based on a built-in vacuum switch. The switching sequence from transmit to receive mode is provided by a dedicated microprocessor.

Remote control

Near the operator it is necessary to place only the remote control. The amplifier itself can be placed up to 3 m (10 ft) away. GLE features include: LCD amplifier status, control of all functions, measurement and/or monitoring of the twenty most important parameters of the amplifier, operational technical information, troubleshooting suggestions, recording of operating hours, password protection.

Protection

• Continuous monitoring and protection of such parameters and functions as:
• all lamp voltages and currents,
• supply voltage,
• overheat,
• pumping on the input signal,
• insufficient amount of cooling air,
• internal and external RF sparks (in amplifier, antenna switch, tuner or antennas),
• switching sequence from transmit to receive T/R,
• switching the antenna relay during transmission,
• the quality of matching with the antenna,
• reflected power level,
• saved data,
• inrush current of the supply voltage network,
• lid lock for operator safety.

Specifications of the ACOM 2000A power amplifier:

• Output power: 1500-2000W push mode or SSB mode - no time limit. Continuous beam mode - 1500W output power - no time limit when using optional cooling fan.
• Frequency range: all radio amateur bands from 1.8 to 24.5 MHz. 28 MHz band with modification for licensed radio amateurs only.
• Ranging/Tuning: Initial output matching is done in less than 3 seconds (typically 0.5 seconds). The process of retuning to previously agreed settings / range switching takes less than 0.2 seconds to change to another section of the same range, and less than 1 second to change to another range.
• Non-volatile storage device (memory) tuning up to 10 antennas per frequency segment.
• Drive power: typically 50W at 1500W output power.
• Input impedance: 50 Ohm nominal. SWR<1.5:1.
• Output Tolerance: Up to 3:1 VSWR (2:1 on 160 meters) at full output power before energizing the high SWR protection circuit. Higher SWR values ​​are matched at lower output power.
• Harmonics: At least 50dB below peak at 1500W.
• Intermodulation: At least 35dB below peak at 1500W.
• Transmit to receive (T/R) switching and keying: Vacuum Relay: Capable of full duplex (QSK) operation.
• Output tubes and circuits: 4CX800A/GU74B tetrodes (2 pcs.), resistive grid, PI-L output circuit with negative RF feedback. Adjustable screen grid tension.
• Automatic Level Control (ALC): Negative grid voltage control, -11V maximum, rear panel adjustable.
• The remote control unit provides monitoring of all operating parameters of the amplifier.
• Protection: control and screen grid current limiting, on power surges (soft start is possible), shutdown on excess of the reflected power value, in case of sparking in the RF circuit, access is protected by a password if necessary, correction of the alternation of switching transmission and reception modes (T / R), removal of cooling air from the lamp, blocking and grounding of the high voltage circuit when the cover is opened.
• Fault diagnosis: remote control display, plus indicators, plus "INFO Box" information device for the last 12 events. Computer interface (RS-232), plus remote telephone interrogation line function.
• Cooling: Full forced airflow inside the case. Rubber insulated fan.
• Transformer: 3.5KVA with Unisil-Ha strip core.
• Power supply requirements: 100/120/200/220/240 volts AC. 50-60 hertz. 3500 VA single phase at full power.
• Dimensions: HF unit: length 440 mm, height 180 mm, depth 450 mm, remote control unit: length 135 mm, height 25 mm, depth 170 mm
• Transported in two cardboard boxes, total weight 36 kg.
• Lack of controls on the HF unit, except for the ON/OFF switch.

Alpha-9500

The Alpha-9500 is no ordinary linear amplifier, but the culmination of over 40 years of design and engineering.

The Alpha-9500 is an advanced technology, the auto-tuning of the linear amplifier easily delivers 1500W of output power with a minimum input power of only 45W.

SPECIFICATIONS:

All amateur bands from 1.8 - 29.7 MHz

• Output power: 1500 W minimum, on all bands and modes
• IM 3rd order:< -30 дБн
• SWR allowed: 3:1
• Power input: 45-60W to achieve rated apparent power
• Tube: One 3CX1500/8877 high power, high performance triode with 1500W dissipation delivers advertised power over all frequency ranges, all modes, all duty cycles.
• Cooling: Forced air from two fans
• Antenna Outputs: Comes standard with 4 SO-239 connectors, but can be changed to Type N on the rear panel by removing 4 screws.
• Antenna selection: Internal 4-port antenna switcher with 1 or 2 band outputs
• Calibrated Wattmeter: The Bruene Wattmeter allows you to simultaneously measure forward and reverse power and display this information in an easy-to-read bar graph on the front panel. It also uses the information to simultaneously control the amplifier's gains.
• Protection mechanisms: high-voltage blocking and power blocking.
• Bypass Mode: There are two "ON" power switches on the front panel of the ALPHA-9500.
• "ON1" activates the wattmeter and antenna switch without turning off power to the amplifier itself, and sets the amplifier to "bypass" mode.
• The amplifier itself is turned on with the "ON2" button.
• Input: Standard SO-239 BIRD connector, but can be changed to BIRD N type
• Tuning/Ranging: Automatic plus manual override
• Power supply: 100, 120, 200, 220, 240 V AC, 50/60 Hz, automatic selection. At 240 VAC, the amplifier draws up to 20 amps.
• Interface: serial port and USB. Full remote control function.
• Protection: Protection against all common faults.
• Display: The display shows bar graphs of power, SWR, grid current, anode current, anode voltage and gain all at the same time. The digital instrument panel can display input power, anode current, anode voltage, grid current, SWR, filament voltage and PEP output.
• Tx/Rx Switching: Two Gigavac proprietary vacuum relays allow QSK to operate on QRO.
• Output power: 1500W.
• Weight: 95 pounds
• Dimensions: 17.5"W X 7.5"H X 19.75"D

Ameritron AL-1500

Ameritron AL-1500 is one of the most powerful linear amplifiers covering all RF and WARC bands.

It uses a manually tuned amplifier that is designed around a single 3CX1500/8877 ceramic tube and has an efficiency of at least 62-65%.

With an input power of 65 watts, it delivers the statutory maximum power by a large margin, up to 2500 watts.

The amp features a Hypersil® transformer, two backlit fixtures, adjustable ALC, delay time adjustment, current protection and more.

Price (approximately in Russia) = $3650

Ameritron AL-572X

The Ameritron AL-572 amplifier is made on four 572B tubes according to a common grid scheme. The Ameritron AL-572 amplifier uses tube capacitance neutralization, which improves performance and stability on the HF bands. The lamps are installed vertically, which significantly reduces the risk of interelectrode short circuits

To match the input of the Ameritron AL-572 amplifier with the output of the transmitter, separate P-circuits are installed at the input for each of the operating ranges. Using the configured input equalizes the load on the output stage of the transceiver and allows you to get an SWR close to 1 on all bands. Additional contouring is possible through holes in the rear panel of the amplifier.

The anode power supply is assembled according to a voltage doubling transformer circuit and uses high-capacity electrolytic capacitors. The anode transformer is wound on a prefabricated steel core made of plates with a high temperature resistant silicone coating, which provides high power density with low weight. The anode open circuit voltage is 2900 volts, at full load about 2500 volts. To reduce the temperature inside the Ameritron AL-572 case, a low-speed computer-type fan is used to circulate air at a low noise level.

Details of the Ameritron AL-572 output circuit (frameless coils made of thick wire, an anode capacitor with ceramic insulators and a large gap between the plates, a range switch on a ceramic dielectric) ensure reliable operation and high efficiency of the oscillating system. The handles of variable capacitors are equipped with verniers with deceleration and indication of the position of the rotors.

The Ameritron AL-572 amplifier also has an ALC system, a mode and bypass switch, an indication of transmission operation, and instruments for measuring the voltage of the anode power supply / anode current and the magnitude of the grid current. Both measuring instruments are illuminated. For QSK operation, it is possible to install an additional QSK-5 module.

Price (approximately in Russia) = $2240

Specifications

• Peak output power: SSB mode 1300 watts, CW mode 1000 watts
• Excitation power from the transceiver 50-70 watts
• Lamps: 4 lamps 572B with neutralization in inclusion with a common grid
• Food: from a network of 220 volts
• Dimensions: 210x370x394 mm
• Weight: 18 kg
• Production: USA

Ameritron AL-800X

Tube Power Amplifier for HF Transceivers

Operating frequency range: from 1 to 30 MHz

Output power: 1250 watts (peak)

Built on a 3CX800A7 lamp

Price (approximately in Russia) = $2900

Ameritron AL-80BX

The Ameritron AL-80B linear power amplifier is made on a 3-500Z lamp according to a common grid scheme. The lamp is installed vertically, which significantly reduces the risk of interelectrode short circuits.

To match the input of the Ameritron AL-80B amplifier with the output of the transmitter, separate P-circuits are installed at the input for each of the operating ranges. Using the configured input equalizes the load on the output stage of the transceiver and allows you to get an SWR close to 1 on all bands. Additional contouring is possible through holes in the rear panel of the amplifier.

The Ameritron AL-80B anode power supply for the Ameritron AL-80B amplifier is assembled according to a voltage doubling transformer circuit and uses high-capacity electrolytic capacitors. The anode transformer is wound on a prefabricated steel core made of plates with a high temperature resistant silicone coating, which provides high power density with low weight. The anode open circuit voltage is 3100 volts, at full load about 2700 volts. To reduce the temperature inside the case, a low-speed computer-type fan is used, which provides air circulation at a low noise level.

Details of the Ameritron AL-80B amplifier output circuit (frameless thick wire coils, an anode capacitor with ceramic insulators and a large gap between the plates, a range switch on a ceramic dielectric) ensure reliable operation and high efficiency of the oscillating system. The handles of variable capacitors are equipped with verniers with deceleration and indication of the position of the rotors.

The Ameritron AL-80B amplifier also has an ALC system, an operation and bypass switch, an indication of transmission operation, and instruments for measuring the voltage of the anode power supply / anode current and the magnitude of the grid current. For QSK operation, it is possible to install an additional QSK-5 module.

Price (approximately in Russia) = $1990

Specifications

• Operating ranges: 10-160 meters including WARC
• Peak output power: SSB mode 1000 watts, CW mode 800 watts
• Excitation power from the transceiver 85-100 watts
• Lamps: Lamp 3-500Z with neutralization in inclusion with a common grid
• Input and output impedance: 50 ohm
• Food: from a network of 220 volts
• Dimensions: 210x370x394 mm
• Weight: 22 kg
• Production: USA

Ameritron AL-811

The Ameritron AL-811 HX linear power amplifier is made on four 811A lamps (a complete analog is the G-811 lamp) according to a common grid scheme. The lamps are installed vertically, which significantly reduces the risk of interelectrode short circuits.

To match the input of the amplifier with the output of the transmitter, separate P-circuits are installed at the input for each of the operating ranges. Using the configured input equalizes the load on the output stage of the transceiver and allows you to get an SWR close to 1 on all bands. Additional contouring is possible through holes in the rear panel of the amplifier.

The anode power supply is assembled according to a transformer bridge circuit and uses high-capacity electrolytic capacitors. The anode transformer is wound on a prefabricated steel core made of plates with a high temperature resistant silicone coating, which provides high power density with a low weight (8 kg.). The anode open circuit voltage is 1700 volts, at full load about 1500 volts. To reduce the temperature inside the case, a low-speed computer-type fan is used to circulate air at a low noise level.

The amplifier also has an ALC system, an operation and bypass mode switch, an indication of transmission operation and devices for measuring the voltage of the anode power supply / anode current and the magnitude of the grid current. For QSK operation, it is possible to install an additional QSK-5 module.

Price (approximately in Russia) = $1200

Specifications

• Peak output power - SSB mode 800 watts, CW mode 600 watts (excitation power from the transceiver 50-70 watts)
• Input and output resistance - 50 Ohm
• Operating ranges - 10-160 meters, including WARC
• 4 lamps 811A in inclusion with a common grid
• Adjustable ALC output
• Mains voltage 240 volts, it is possible to switch
• taps for mains supply 100/110/120/210/220/230 volts
• Weight 15 kg

Ameritron AL-82X

The Ameritron AL-82X linear power amplifier is made on two 3-500Z tubes according to a common grid scheme. The Ameritron AL-82 amplifier uses tube capacitance neutralization, which improves performance and stability on the HF bands. The lamps in the Ameritron AL-82 amplifier are installed vertically, which significantly reduces the risk of interelectrode short circuits.

To match the input of the Ameritron AL-82X amplifier with the output of the transmitter, separate P-circuits are installed at the input for each of the operating ranges. Using the tuned input of the Ameritron AL-82 amplifier equalizes the load on the output stage of the transceiver and allows you to get an SWR close to 1 on all bands. Additional contouring is possible through holes in the rear panel of the amplifier.

The Ameritron AL-82 anode power supply is built according to a voltage doubling transformer circuit and uses high-capacity electrolytic capacitors. The anode transformer is wound on a prefabricated steel core made of plates with a high temperature resistant silicone coating, which provides high power density with low weight. The anode open circuit voltage is 3800 volts, at full load about 3300 volts. To reduce the temperature inside the Ameritron AL-82 amplifier case, a low-speed computer-type fan is used to circulate air at a low noise level.

Details of the output circuit (frameless thick wire coils, an anode capacitor with ceramic insulators and a large gap between the plates, a range switch on a ceramic dielectric) ensure reliable operation and high efficiency of the oscillatory system. The handles of variable capacitors are equipped with verniers with deceleration and indication of the position of the rotors.

The Ameritron AL-82X amplifier also has an ALC system, an operation and bypass switch, an indication of transmission operation, and instruments for measuring the voltage of the anode power supply / anode current and the magnitude of the grid current. Both measuring instruments are illuminated. For QSK operation, it is possible to install an additional QSK-5 module.

Price (approximately in Russia) = $3000

Ameritron AL-82X Amplifier Specifications

• Operating ranges 10-160 meters including WARC
• Peak output power: SSB mode 1800 watts, CW mode 1500 watts
• Excitation power from the transceiver 100 watts
• Lamps: 2 lamps 3-500Z lamps with neutralization in inclusion with a common grid
• Input and output impedance 50 ohm
• Mains power 220 volts
• Dimensions 250x432x470 mm
• Weight 35 kg
• USA production

Ameritron ALS-1300

Ameritron introduces its new ALS-1300 solid state amplifier.

The output power of the amplifier is 1200W in the frequency range 1.5 - 22 MHz.

The amplifier does not require time to rebuild, FET 8pcs MRF-150 are used as output transistors.

The amplifier uses a fan whose rotation speed is controlled by temperature sensors to ensure minimal noise.

The ALS-500RC remote control can be used together with the ALS-1300 amplifier

Ameritron ALS-500M

The amplifier uses four powerful bipolar transistors 2SC2879

The amplifier is made without the use of vacuum tubes, so it does not require preheating

The amplifier does not need to be tuned. Switching ranges from 1.5 to 29 MHz is carried out with one knob

The amplifier monitors the load resistance and, if it deviates more than the permissible norm, a “bypass” is activated

The amplifier has a built-in current consumption indicator that allows you to control the collector current of the output transistors

In order to work "bypassing" the amplifier, it is not required to disconnect it. You just need to switch it to the "off" position.

The weight of the amplifier is only 3.9 kg with dimensions of 360x90x230 mm

When operating the amplifier in stationary mode, it is recommended to use a power supply with an output voltage of 13.8 V and an operating current of at least 80 A.

Price (approximately in Russia) = $1050

Specifications of the ASL-500M Power Amplifier:

• Frequency range: 1.5 - 30 MHz
• Output Power: 500W Peak (PEP) or 400W CW
• Drive power: typically 60-70W
• Supply voltage: 13.8 V, consumption 80 A
• Harmonic suppression: 1.8 - 8 MHz - better than 60 dB below peak power rating, 9 - 30 MHz - better than 70 dB below peak power rating
• When operating the amplifier in stationary mode, it is recommended to use a power supply with a maximum output current of at least 80A.

Ameritron ALS-600

No setup, no fuss, no worries - just plug and play

Includes 600W output power, 1.5-22MHz continuous frequency range, instantaneous band switching, no warm-up time, no bulbs harmful to children, maximum SWR protection, completely silent, very compact.

The revolutionary AMERITRON ALS-600 amplifier is the only linear amplifier in amateur radio applications that uses four rugged RF power TMOS FETs to deliver unsurpassed solid-state quality with no tuning required. The price includes a non-configurable FET amplifier and a 120/220 VAC, 50/60 Hz mains power supply for home use.

You get instant range switching, no setup required, no warm-up time, no fuss! The ALS-600 provides a maximum envelope output of 600W and 500W in CW mode over a continuous frequency range of 1.5 to 22 MHz

The ALS-600 amplifier is completely silent. The low speed, low volume fan is so silent that it is difficult to detect its presence, unlike the noisy blowers used in other amplifiers. The ALS-600 amplifier has small dimensions: 152x241x305 mm - it takes up less space than your radio! Weighs only 5.7 kg.

Two-needle SWR and power meter with backlight allows you to read SWR, maximum power of the incident and reflected waves simultaneously. The Operate/Standby switch allows you to operate in low power mode, but you can instantly switch to full power mode if needed.

You get the ability to control the ALC system from the front panel! This unique AMERITRON system allows you to adjust the power output on a convenient front panel display. In addition, you get LED indicators for transmission, ALC and SWR on the front panel. DC 12V output jack allows you to power low current accessories. Enjoy 600 watts of non-tunable solid-state amplifier power. A pair of RJ45 remote control jacks on this amplifier allow the ALS-600 to be controlled either manually with the compact ALS-500RC remote control or automatically with the ARI-500 auto range switch. The auto range switch reads the band data from your transceiver and automatically changes the bands of the ALS-600 when you change bands on the transceiver.

Price (approximately in Russia) = $1780

Expert 1K-FA

Fully automatic transistor linear amplifier with a power of 1 kW.

Built-in power supply and automatic antenna tuner. Dimensions: 28x32x14 cm (including connectors).

Weight about 20 kg.

The Expert 1K-FA amplifier uses two processors, one of which is designed to automatically adjust the output P-loop. (C.A.T.s System) More than 13,000 software elements provide a unique set of technical features not found in other models.

Easy connection to all models of Icom, Yaesu, Kenwood transceivers, automatic antenna tuner, antenna characteristics control, immediate broadcast. Similar results when working with models from other companies and homemade equipment. The operator's functions are limited to turning the frequency knob in the transceiver.

From 1.8 MHz to 50 MHz including WARC bands. Fully transistorized. 1 kW PEP in SSB mode (passport value). 900W CW (nameplate) 700W PEP on 50MHz (nameplate).

Automatic full/half power selection on operator command in CW and SSB modes, for digital modes of operation and providing automatic amplifier protection. Does not require warm-up time.

Amplifying elements are not subject to aging (CMOS transistors are used). Built-in automatic antenna tuner. It is possible to match antennas up to SWR values ​​of 3:1 on HF, and 2.5:1 on 6 meters. Switching up to 4 antennas (SO239 connectors). Switching bands, antennas and all adjustments are carried out in 10 milliseconds. When working only from the tuning transceiver, switching of bands and antennas is carried out in the "waiting" mode. Having two entrances. SO 239 connectors used.

Power buildup 20 watts.

Continuous monitoring of temperature, current and voltage overloads, SWR level, reflected power level, maximum RF voltage of the tuner, "pumping" of input power, imbalance of amplifying stages. Full duplex mode (QSK). Low noise operation. The amplifier and transceiver can be turned on and off independently. The large LCD display shows a lot of information.

Connection via RS 232 port for PC control. For easy portability, the amplifier is placed in a small bag. It is possible to work in the "field day" and DXpeditions.

BLA 1000

The RM BLA-1000 is a new transistor amplifier with an output power of up to 1000W, which implements all the most advanced achievements in amplifier design. The output stage of the amplifier is made on two super-powerful field-effect (MOSFET) MRF-157 transistors. A 2-stroke bridge amplification circuit (Push-Pull type) operating in AB2 mode provides high gain and good amplifier efficiency while maintaining high linearity.

For the convenience of covering all operating ranges, 2 antenna ports are provided on the rear panel of the amplifier. For example, you can connect HF antennas to one port, and low-frequency antennas to the second port.

To control the linearity of the amplifier, there is an ALC input on the rear panel. The possibility of both automatic control of the ALC level and from the transceiver is implemented. The ALC parameters can be adjusted manually with 2 resistors. The release time of the transmission relay (RX-delay) can be adjusted in the range of 0…2.5 seconds in steps of 10 ms.

Switching the "Receive / Transmit" mode can be carried out both from the transceiver and automatically (Int. VOX). To do this, there is an RC-connector - “PTT” on the rear panel of the amplifier.

The amplifier is powered by its built-in switching power supply. The high output power of the amplifier is obtained by feeding the transistors with a high voltage of 48 volts. In this case, the current consumption at the peak of the signal can reach 50 amperes.

One of the interesting features of this amplifier is its ability to operate in a fully automatic mode. In this mode, it is not necessary to switch not only the “Receive-Transfer” mode, but also the operating range of the amplifier. The frequency meter built into the microprocessor will automatically determine the transmission frequency and select the desired low-pass filter. This feature will be especially useful for the application of the amplifier in "unattended areas" or "closed rooms" of industrial radio communication structures.

Price (approximately in Russia) = $4590

RM BLA-1000 Power Amplifier Specifications

• Frequency range 1.5-30 and 48-55 MHz
• Supply voltage 220-240 Volts; 15.5 A
• Input power 10-100 watts
• Output power 1000 watts
• Impedance Input/Output 50 Ohm
• Dimensions 495 x 230 x 462 mm
• Weight 30 kg

BLA 350

New, inexpensive amplifier RM BLA-350. The ideal solution for the beginner or intermediate radio amateur who decides to amplify the signal of his transceiver or protect the output stage for little money. Due to the built-in powerful power supply, the amplifier takes up little space on the table.

The output stage of the amplifier is made on two powerful field-effect (MOSFET) SD2941 transistors. A 2-stroke bridge amplification circuit (Push-Pull type) operating in AB2 mode provides high gain and good amplifier efficiency while maintaining high linearity. Additional purity of the output signal is provided by 7 low-frequency band filters of the 7th order, which is an important parameter for basic amplifiers.

Thanks to microprocessor control, full automation of the control of the amplifier operating modes is carried out and control of temperature, SWR and input power is implemented. It is possible to flexibly configure protection and alarm parameters when threshold values ​​are exceeded.

Switching of the “Receive-Transmit” mode can be controlled both from the transceiver and automatically (Int. VOX). To do this, there is an RC-connector - “PTT” on the rear panel of the amplifier.

One of the interesting features of this amplifier is its ability to operate in a fully automatic mode. In this mode, it is not necessary to switch not only the "Receive / Transmit" mode, but also the range of the amplifier. The frequency meter built into the microprocessor will automatically determine the transmission frequency and select the desired low-pass filter. This feature will be especially useful for the application of the amplifier in "unattended areas" or "closed rooms" of industrial radio communication structures.

Price (approximately in Russia) = $1090

RM BLA-350 Power Amplifier Specifications

• Frequency range 1.5-30 MHz (including WARC bands)
• Modulation types AM/FM/SSB/CW/DIGI
• Supply voltage 220-240 Volts; 8 A
• Input power 1-10 watts
• Output power 350 watts
• Impedance Input/Output 50 Ohm
• Dimensions 155 x 355 x 270 mm
• Weight 13 kg

Elecraft KPA-500

The power amplifier is designed to operate on all HF amateur radio bands from 160 to 6 meters (including WARC bands) in all operating modes. The KPA-500 automatically tunes to the frequency of your transceiver.

A 500W all-solid-state amplifier powered by high-power FET transistors, has the same dimensions as the Elecraft K3 transceiver and fits perfectly into the Elecraft K3 line of devices.

The amplifier has an alphanumeric display, a bright LED indicator, and a reliable, powerful built-in power supply. The unit works with any transceiver using a grounded PTT output. When pumping or increasing the SWR, the power automatically decreases by 2.5 dB, when the problem is eliminated, it returns to nominal.

The amplifier delivers ultra-fast, noiseless QSK through a high-power PIN diode switch. The unit has a six-speed temperature-controlled fan. With the optional KPAK3AUX cable, enhanced integration with the K3 transceiver is possible:

• manual control buttons on the KRA500 panel control the ranges and buildup level on the K3;
• range switching data is transmitted from K3 before transmission begins;
• PTT is transmitted by cable, no separate control is required;
• K3 determines the current state of the amplifier and adjusts the drive level according to one of the two memory states on each band.

When the Internet is connected, the presence of new firmware versions is automatically detected from the company's server via the RS232 port.

HLA-150

Price (approximately in Russia) = $520

• Input power: 1 - 8W.
• Output power: 150W CW or 200W PEP in SSB.
• Supply voltage: 13.8 V.
• Maximum current consumption: up to 24 A.
• Dimensions: 170x225x62 mm, weight 1.8 kg.

HLA-300

The amplifier has a microprocessor control, a frequency range of 1.5-30 MHz, LED indicators for output power and operating range, automatic TX / RX switching. Range switching can be done automatically or manually. The amplifier has band output filters that are switched manually when changing the band.

The protection system in case of a malfunction of the amplifier or antenna-feeder system, an increase in the level of spurious radiation will automatically turn off the amplifier and / or connect the transceiver to the antenna directly (“bypass” mode). To manually turn on the "bypass" mode, just turn off the power to the amplifier.

Input power 5 - 15 W.

Power output 300W CW or 400W PEP in SSB.

Supply voltage 13.8 V.

Maximum current consumption up to 45 A.

Dimensions 450x190x80 mm, weight 3 kg. Price (approximately in Russia) = $750

OM Power OM 1500

Linear power amplifier for operation on all amateur bands from 1.8 to 29 MHz (including WARC bands) + 50 MHz with all types of modulation. Equipped with ceramic tetrode GS-23B.

Specifications:

Operating frequency range: amateur bands from 1.8 to 29.7 MHz, including WARC bands + 50 MHz.

Output Power: 1500+W SSB & CW on HF, 1000+W SSB & CW on 50MHz, 1000+W RTTY

Power Input: 40 to 60 W typical for full power output.

Input impedance: 50 ohms at SWR< 1.5: 1

Gain: 14 dB, Output Impedance: 50 Ohm, Maximum SWR: 2:1

High SWR protection: automatic transition to STANDBY mode when the reflected power is more than 250 W

Intermodulation distortion: 32 dB of rated output power.

Harmonic suppression:< -50 дБ относительно мощности несущей.

Lamp: Ceramic tetrode GS-23B. Cooling: Centrifugal fan.

Power supply: 1 x 210, 220, 230 V - 50 Hz. Transformers: 1 toroidal transformer 2.3KVA

Peculiarities:

Antenna switch for three antennas

Memory for errors and warnings - easy maintenance

Automatic Anode Current Adjustment (BIAS) – no adjustment required after lamp replacement

Automatic fan speed control based on temperature

Full QSK with silent relay

Smallest size and weight of any 1500W amplifier on the market

Dimensions (WxHxD): 390 x 195 x 370 mm, Weight: 22 kg

OM Power OM 2500 HF

The Russian-made GU84b tetrode is used to obtain an output power of up to 2700 watts.

The amplifier uses a GU84B tetrode according to a grounded cathode scheme (the input signal is fed to the control grid). The amplifier shows excellent linearity in stabilizing the control grid bias voltage and the screen grid voltage. The input signal is fed to the control grid using a broadband transformer with an input impedance of 50 ohms. This input scheme provides an acceptable SWR value (less than 1.5:1) on all HF bands.

The output stage of the amplifier is a Pi-L circuit. The variable ceramic insulator capacitor for loop tuning and load matching is divided into two parts and designed specifically for this amplifier. This allows you to fine-tune the amplifier and easily return to previously tuned positions after a band change.

The high anode voltage consists of 8 voltage sources of 300V/2A each. Each source has its own rectifier and filter. Safety resistors are used in the anode voltage circuit to protect the amplifier from overload. The grid voltage is stabilized by the IRF830 MOSFET circuit and is 360V/100mA. The voltage of the control grid -120V is stabilized by zener diodes.

Main Specifications of OM2500 HF Power Amplifier

• Output Power: 2500W CW and SSB, 2000W RTTY, AM and FM
• < 2.0: 1 входное - 50 Ом при КСВ < 1,5:1
• RF gain: not less than 16 dB
• Protection nodes: with an increase in the SWR, anode and grid currents, with an incorrect setting of the amplifier, providing a soft start to protect the fuses, blocking the inclusion of dangerous voltages when the amplifier covers are removed
• Dimensions and weight (in working order): 485x200x455 mm, 38 kg

OM Power OM2000HF

The power amplifier is designed to operate on all HF bands from 1.8 to 29 MHz (including WARC bands) in all operating modes.

High frequency block:

The amplifier uses a GU-77B tetrode according to the scheme with a grounded cathode with excitation applied to the control grid. The amplifier has excellent linearity because the control grid bias and screen grid voltage are well stabilized. The input signal is applied to the control grid through a broadband matching device with an input impedance of 50 ohms. This solution ensures that the input of the amplifier is matched with an SWR of at least 1.5:1 on any HF band.

Power node

With the help of a node made on a relay and powerful resistors, a powerful rectifier is soft-started. The high voltage unit is made up of eight sections providing 350 volts at 2 amps, each with its own rectifier and filter. Safety resistors are installed in the anode voltage circuit to protect the amplifier from overload.

Amplifier Protection

Main Specifications of OM2000 HF Power Amplifier

• Frequency range: all radio amateur bands from 1.8 to 29.7 MHz;
• Output power, not less than: 2000 W in CW and SSB modes, 1500 W in RTTY, AM and FM modes
• Intermodulation distortion: no more than -32 dB from the peak value of the rated power.
• Suppression of harmonics: more than 50 dB of the peak value of the rated power.
• Wave impedance: output - 50 Ohm, for an asymmetric load, at SWR< 2.0: 1 входное - 50 Ом при КСВ < 1,5:1
• RF gain: not less than 17 dB
• Supply voltage: 230V - 50Hz, one or two phases
• Transformers: 2 toroidal transformers, 2KVA each
• Dimensions and weight (in working order): 485x200x455 mm, 37 kg

OM Power OM2500 A

The power amplifier is designed to operate on all HF bands from 1.8 to 29 MHz (including WARC bands) in all operating modes. The OM2500 A automatically tunes to the frequency of the transceiver.

High frequency block

The amplifier uses a GU-84B tetrode according to the scheme with a grounded cathode with excitation applied to the control grid. The amplifier has excellent linearity because the control grid bias and screen grid voltage are well stabilized. The input signal is applied to the control grid through a broadband matching device with an input impedance of 50 ohms. This solution ensures that the input of the amplifier is matched with an SWR of at least 1.5:1 on any HF band.

The Pi-L circuit is turned on at the output of the amplifier. Each of the variable capacitors designed to adjust the circuit and the load is made on ceramic insulators and is divided into two sections. This solution allows you to more accurately tune the amplifier and easily return to the previous settings after changing the range.

Power node

The amplifier is powered by two two-kilowatt toroidal transformers.

With the help of a node made on a relay and powerful resistors, a powerful rectifier is soft-started. The high voltage unit is made up of eight sections providing 420 volts at 2 amps, each with its own rectifier and filter. Safety resistors are installed in the anode voltage circuit to protect the amplifier from overload.

The voltage for the screen grid is provided by a parallel regulator assembled on high-voltage transistors of the BU508 type, which provides a voltage of 360 volts at a current of up to 100 mA. The offset for the control grid (-120 volts) is also stabilized.

Amplifier Protection

The device provides continuous monitoring and protection of all circuits in case of violations in the operation of the amplifier. The protection node is located on the control board installed in the sub-panel.

Main Specifications of OM2500 A Power Amplifier

• Frequency range: all radio amateur bands from 1.8 to 29.7 MHz;
• Output power, not less than: 2500 W in CW and SSB modes, 2000 W in RTTY, AM and FM modes
• Intermodulation distortion: no more than -32 dB from the peak value of the rated power.
• Suppression of harmonics: more than 50 dB of the peak value of the rated power.
• Wave impedance: output - 50 Ohm, for an asymmetric load, at SWR< 2.0: 1, входное - 50 Ом при КСВ < 1,5:1
• RF gain: not less than 17 dB
• Manual or automatic tuning
• Tuning speed on the same range:< 0.5 сек.
• Tuning speed when changing to another range:< 3 сек.
• Supply voltage: 230V - 50Hz, one or two phases. Transformers: 2 toroidal transformers, 2KVA each
• Protection nodes: with an increase in SWR, anode and grid currents, with incorrect amplifier settings, providing a soft start to protect fuses, blocking the inclusion of dangerous voltages when the amplifier covers are removed
• Dimensions and weight (in working condition): 485x200x455 mm, 40 kg

OM Power OM3500HF

The OM3500 HF power amplifier is designed to operate on all HF bands from 1.8 to 29 MHz (including WARC bands) in all operating modes. The amplifier is equipped with a GU78B ceramic tetrode.

The amplifier uses a GU78B tetrode according to a grounded cathode scheme (the input signal is fed to the control grid). The amplifier shows excellent linearity in stabilizing the control grid bias voltage and the screen grid voltage. The input signal is fed to the control grid using a broadband transformer with an input impedance of 50 ohms. This input scheme provides an acceptable SWR value (less than 1.5:1) on all HF bands. The output stage of the amplifier is a Pi-L circuit. The variable ceramic insulator capacitor for loop tuning and load matching is divided into two parts and designed specifically for this amplifier. This allows you to fine-tune the amplifier and easily return to previously tuned positions after a band change.

The power supply of the amplifier consists of two 2KVA toroidal transformers. The soft start mode occurs with the help of relays and resistors.

Amplifier protection:

Constant monitoring and protection of anode and grid voltages and currents is carried out if the amplifier is incorrectly configured, a soft start mode is implemented to protect fuses.

Specifications of the OM3500 HF Power Amplifier:

• Frequency range: all radio amateur bands from 1.8 to 29.7 MHz;
• Output power: 3500W CW and SSB, 3000W RTTY, AM and FM
• Intermodulation Distortion: Better than 36 dB below peak power rating.
• Harmonic Suppression: Better than 55 dB below peak power rating.
• Wave impedance: output - 50 ohms, for asymmetric load, input - 50 ohms at SWR< 1,5:1
• RF gain: typically 17 dB
• Supply voltage: 2 x 230V - 50Hz, one or two phases
• Transformers: 2 toroidal transformers, 2.5KVA each
• Dimensions and weight (in working condition): 485x200x455 mm, 43 kg

RM KL500

Amplifier RM KL500 HF band (3-30) MHz, input power 1-15 W, output 300 W with electronic switching technology and polarity reversal protection. It has six levels of output power and a 26 dB antenna preamplifier.

Frequency: HF

Voltage: 12-14 Volts

Current consumption: 10-34 Amps

In. power: 1-15W, SSB 2-30W

Ex. power: 300W Max (FM) / 600W Max (SSB-CW)

Modulation: AM-FM-SSB-CW

Six power levels

Fuses: 3×12A

Size: 170x295x62mm

Weight: 1.6 kg Price (approximately in Russia) = $340

YAESU VL-2000

High power combined with high reliability.

8 massive VRF2933 type CMOS FETs in a push-pull circuit provide the necessary output power in the range from 160 to 6 mA. Two large fans with a continuous speed control system effectively cool the PA and low-pass filter unit, and provide years of reliable and silent operation.

Two large dial gauges.

The left instrument shows the output power or SWR. Right - consumption current and supply voltage.

The monitoring system provides reliable and fast troubleshooting of the system.

In high power devices, monitoring of mains voltage fluctuations, temperature violations, high SWR levels and exceeding the level of the RF input drive signal is monitored.

The built-in automatic high-speed antenna tuner matches your antenna to an SWR level of 1.5 or better in less than 3 seconds (according to the passport).

Two input and four output connectors allow integrated selection of the transmitter and desired antenna.

For example, two input connectors allow you to connect to the first (INPUT 1) HF transceiver, and to the second (INPUT 2) a 6 m transceiver. In this case, the output connectors can be connected to various antenna switching devices available at the station. Automatic selection of the correct antenna can be done for a transmitter connected to INPUT 1, often eliminating the need for additional antenna switches. When the DIRECT toggle switch located on the rear panel is turned on, the amplified input 2 (INPUT 2) signal is fed directly to the ANT DIRECT connector, bypassing the output switching system. Besides, PA VL-2000 can be used in SO2R system.

Automatic range switching for fast transitions.

Most modern Yaesu transceivers allow the exchange of data on the current range between the transceiver and the VL-2000 PA, which allows you to automatically change the range in the PA when you change the latter in the transceiver. For automatic band changing when using other types of transmitters, the VL-2000 PA has an automatic ranging function using the built-in frequency counter, which ensures an immediate band change when the RF signal is first applied to the PA input.

Specifications

• Range: 1.8-30; 50-54 MHz
• Antenna Switch: ANT 1-ANT 4, ANT DIRECT
• Power: (1.8-30MHz) 1.5KW, (50-54MHz) 1.0KW
• Consumption: 63 A
• Supply voltage 48 V
• Operations: SSB, CW, AM, FM, RTTY
• Range switching: manual / automatic
• Output transistor: VRF2933
• Output stage operation mode: Class-AB, Push-pull, Power Combine
• Spurious emissions: -60 dB
• Input Power: 100 to 200W
• Temperature: -10 +40 C
• Dimensions 482x177x508 mm, Weight: 24.5 kg
• Power supply: Output voltages: +48 V, +12 V, -12 V. Output current: +48 V 63 A, +12 V 5.5 A, -12 V 1A,
• Dimensions: 482x177x508 mm. Weight: 19 kg

tagPlaceholder Tags:

The lamp kv power amplifier is assembled on 4 GU-50 lamps. Connected in parallel according to the scheme with common grids, and is designed to operate in the ranges of 80, 40, 30, 20, 15 and 10 m. The maximum output power of the amplifier is 350 - 400 W. Two power transformers are used to power the amplifier. The outputs of the rectifiers on diodes VD1 - VD4 and VD5 - VD8 are connected in parallel and loaded on a capacitive filter (electrolytic capacitors C1 - C3). A high-resistance resistor and a small capacitor are connected in parallel with each rectifier diode. This increases the electrical “strength” of the rectifiers and reduces the output voltage ripple. The anode voltage is approximately 1000 V.
Amplifier

A constant voltage of +15 V is obtained at the output of the VD9-C4 half-wave rectifier and is used to power relays and LEDs that indicate the operating mode of the amplifier.
The filament voltage is supplied to the lamp heaters through the choke Dr6.
At the input of the amplifier, a C6-L1-C7 low-pass filter with a cutoff frequency of about 30 MHz is installed. However, given that the input impedance of the amplifier is quite low and varies with the range. It is desirable to install a matching device between the amplifier and the transceiver. An amplifier well matched to the transceiver with a low excitation power (about 50 W) allows you to get an output power of 400 W (and even more!). And it provides a spectrally pure signal at the output (of course, if the transceiver and amplifier are in good condition and operate in nominal modes).

If a tube HF power amplifier is to be operated with a transceiver,

at the output of which a P-circuit is installed. Then, when using a short connecting cable between these devices, a matching device is not required. A traditional P-loop is installed at the output of the amplifier, but since The “anode” capacitor of variable capacitance C11 has a small initial and maximum capacitance; capacitor C12 is connected in parallel to it in the range of 80 m.
When the contacts of switch S2.1 are closed, relay K1 is activated, using the contacts of which the output of the transceiver is connected to the input of the amplifier. The output of the amplifier to the antenna, and the cathodes of the lamps VL1 - VL4 - to the common wire (through the resistor R2).

The anode choke Dr7 is wound on a 40 mm ribbed ceramic frame and contains 30 turns of 0.5 mm wire.
Resistor R2 consists of two 1 ohm resistors connected in parallel.
Coil L1 - frameless, wound with 0.1 mm wire on a 12 mm mandrel and contains 11 turns, coil L2 - 9 turns of 3 mm silver-plated wire wound on a ribbed ceramic frame. The position of the taps is selected when adjusting the SWR at the output of the amplifier should not exceed 2. In addition, it is recommended to connect the antenna to the amplifier through low-pass filters, and for long-term operation in transmission mode, use forced cooling.

The scheme in Splan format can be downloaded

HF power amplifier on two lamps GI-7B.

The amplifier using two GI-7B lamps is made according to the traditional scheme. Despite the fact that this lamp is designed to operate in pulse mode with anode modulation, when the excitation voltage is applied to the cathode of the lamp, and using only the left side of the anode-grid characteristics and taking additional steps to match the cascades in resistance, it is possible to obtain a satisfactory amplification linearity due to the effect of the occurrence of automatic current feedback.

Amplifier block.

The design of the amplifier is simple and does not require additional explanations. Figure 1 shows the electrical circuit diagram of the power amplifier unit. When designing the amplifier, an attempt was made to halve the equivalent resistance of the tubes at a frequency of 29.7 MHz. In view of the fact that the obtained equivalent resistance of the lamps is quite high, it is not possible to implement an inductor with a sufficiently high efficiency for a range of 10 m. For this, two additional inductors were used - L2, L3. The input impedance of the cathode part of the amplifier at the maximum input signal is 43 ohms, that is, close to 50 ohms. However, contrary to popular belief, it is impossible to do without additional matching of the output stage of the transceiver with the input part of the amplifier.

Electronic vacuum devices are a reactive load. And this means that the input resistance of the lamp changes with a change in the level of the excitation voltage and, accordingly, with a change in the current flowing through the lamp. Those. at the maximum excitation voltage to the cathode, a negative half-wave of the signal, the minimum input resistance will be obtained, equal in this case to 43 ohms. At the minimum voltage level, the input resistance of the lamp becomes extremely large, due to the quiescent current and the static parameters of the lamp. When the level of the excitation signal changes to a positive half-wave, the input resistance of the lamp tends to infinity and will, in practice, be determined by the interelectrode capacitances and the frequency of the excitation signal.

Under such conditions, neither the use of matching transformers, nor the automatic antenna tuners of modern transceivers are able to match the transceivers with the output stages. Ignoring the need to take additional measures to match the transceiver with the amplifier leads to a violation of the linear operation of the output stage of the transceiver and the occurrence of an increased level of intermodulation distortion in the amplifier itself.

The main parameters of the lamps in the amplifier used:

• Lamp anode voltage, V ………………….. 2500
• Heating voltage, V ………………………. 12.6... 13.2
• Maximum anode lamp current, A…………..0.7
• Quiescent current, mA……………………………………50

High voltage power supply.

Figure 2 shows the electrical circuit diagram of the high-voltage power supply. The high-voltage power supply is made in a separate housing, with the minimum possible number of components. To limit the charging current of the filter capacitor, the inclusion is performed according to a two-stage scheme. High voltage from the power supply to the amplifier is supplied through the coaxial connectors and coaxial cable. For added security, the cable shield is connected to the power supply and amplifier case. The power of the transformer for operation only in SSB mode must be at least 1 kW.

If it is intended to use all types of modulation, the power of the transformer must be at least 1.5 kW. The output voltage of the power supply must be at least 2500 V at a given current of 50 mA (amplifier quiescent current). To reduce the risk of overvoltages, at the output of the power supply associated with transients during the operation of the amplifier and the idling of the transformer, a load resistance R4 is installed at the filter output. Short-term overvoltages can be significant and cause arcing inside the lamp housing.

When putting the amplifier into operation, it must be remembered that when installing a new lamp or if it has not been used for more than 3 months, it is necessary to start using it at a reduced generated power. Only after making sure that the tubes have restored the vacuum and are stable, you should switch to using the amplifier at maximum output power. Practice has shown that the first time when putting lamps into operation, it is recommended to use them for some time at about 50% of the output power. After that, gradually, if no electrical breakdowns occur, the lamps are introduced at full rated power. The most responsible during this period is the moment of tuning the output circuit into resonance with the help of KPI from the side of the anodes of the lamps, because this corresponds to the occurrence of the maximum total voltage at the anode. The control of the lamp mode is carried out using a milliammeter in the power supply circuit of the control grids.

With circuit resonance and sufficient excitation power, the maximum amplitude of the alternating voltage at the anode occurs, and therefore the residual voltage at the anode becomes lower than the minimum allowable voltage, as a result, the effect of interception of the electron flow by lamp grids occurs. This process is controlled by a timely increase in power transfer to the load using the output variable capacitor of the Pi-circuit or by adjusting the excitation power of the amplifier. Both lead to a decrease in the alternating voltage at the anode and, at the same time, to a decrease in the current of the control grids.

Control scheme

The amplifier control unit is made according to a simplified scheme, and does not have any features. Figure 3 shows the electrical circuit diagram of the control unit. The +27V stabilizer is made on the KREN12A IC. To select the operating point of the lamps, a circuit based on transistors VT2, VT3 was used. Fuse FU2 prevents damage to lamps and semiconductor devices in the cathode part of the lamps in the event of a discharge inside the lamp housing. The transistor VT4 has a current protection circuit for the control grid of the lamp. The cutoff current is chosen to be less than the maximum current of one lamp, since it is initially intended to use only the left side of the anode-grid characteristics of the lamps. This measure will also ensure the protection of both lamps for grid currents.

The elements of the switching relay control circuit on the transistor VT1 provide the necessary relay switching sequence. When the current protection of the grid of lamps is triggered, the "reset" function is performed by switching off and on again the S3 "Standby" switch. Relay K1 reduces electrodynamic loads on circuit components and filament lamp circuits. The delay is 1...2s. Neon lamps installed in switches are non-linear elements that remove the resulting overvoltages in circuits due to transients.

Matching the amplifier with the load

The matching of the amplifier with the load does not differ from the typical one. An excitation signal is applied to the input of the amplifier, approximately 30% of what is necessary for full excitation. With the Pi-circuit capacitor rotor fully inserted from the antenna side, by rotating the Pi-circuit capacitor rotor from the side of the lamp anodes, the resonance of the circuit system is found. The resonance is determined by the maximum current of the control grids. If there is no grid current or there is a reverse current, then it is necessary to increase the excitation power.

Having received the maximum grid current, which should not exceed the maximum allowable, it is necessary to remove the capacitor plates from the antenna connection side, thereby supplying the power stored by the circuit to the load. In this case, it is necessary to control, by some method, the power given to the feeder. When the maximum energy transfer to the feeder is obtained, the screen grid current will tend to a minimum. After that, you can increase the excitation power again and repeat the procedure. This is done until the maximum anode current is obtained with the minimum current of the control grids and the full power in the feeder.

Having determined the required maximum excitation power, you can set the ALC threshold with resistor R7 located in the amplifier unit.

Details

The following switching relays were used in this amplifier. Relays that were used in the high voltage power supply:

• K1 RPU-OUHL4 220/8A;
• K2 RPU-OUHL4 24-27/8A;

Relays that were used in the control circuit:

• K1 RES9 passport RS4.529.029-00;
• K2 RES22 passport RF4.523.023-00;
• KZ RPV2/7 passport RS4.521.952;
• K4 REV14 passport RF4.562.001-00;
• K5 RES9 passport RS4.529.029-00;

The main parameters of the amplifier on two lamps GI-7B

When calculating, the binding was made to the voltage at the anodes of the lamps (2500 V) and the quiescent current for two lamps (0.05 A). The calculation of the linear amplifier was carried out using the program "RF Amplifier" s Developer 2001 ".

The results of calculating the parameters of the anode circuit of the amplifier for one lamp

• Lamp anode voltage, V ………………………………………………………………….. 2500
• Maximum allowable grid voltage, V ……………………………………………… 80
• The anode current of the lamp in the bearing mode, and ……………………………………………… 0.35
• Lamp quiescent current, A…………………………………………………………………………… 0.025
• Anode current cutoff angle, deg…………………………………………………………….. 96.41
• Maximum anode current, A ………………………………………………………………….. 1.034
• Maximum anode current of the first harmonic, А…………………………………………. 0.531
• Lamp amplification at minimum residual voltage………………………………. 4.308
• Voltage coefficient of the lamp mode………………………………………………….. 0.904
• The amplitude value of the alternating voltage generated by the lamp anode, V……… 2260
• Minimum residual voltage at the anode, V………………………………………….. 240
• Maximum amplitude of the total voltage at the anode, V………………………….… 4160
• Vibrational power at the lamp anode, W………………………………………………….. 600.03
• Coefficient for SSB signal taking into account peak factor (p-4) ………………………………… 0.35
• Average oscillatory power of the SSB signal, W ………………………………………... 73.504
• Maximum power supplied to the anode, W………………………………………… 875
• Average lamp efficiency for SSB signal…………………………………………………………..0.23
• Average power supplied to the anode, W…………………………………………………… 319.583
• Lamp efficiency …………………………………………………………………………………… 0.686
• Maximum power dissipated on the anode, W ……………………………………… 274.97
• Average power dissipated at the anode, W …………………………………………… 246.079
• Power dissipated on the anode at quiescent current, W …………………………………… 62.5
• Equivalent resistance of the lamp anode circuit, Ohm………………………………… 4256

Parameters for the second harmonic

• Peak anode current of the second harmonic, A ………………………………………………….0.194
• Vibrational power of the second harmonic, W……………………………………………. 219.22
• Equivalent anode resistance for the second harmonic, Ohm …………………………. 11649

Parameters for the third harmonic

• Peak anode current of the third harmonic, А………………………………………………… 0.032
• Vibrational power of the third harmonic, W……………………………………………. 36.16
• Equivalent anode resistance for the third harmonic, Ohm ………………………… 70625

When determining the main parameters for two lamps, the selected parameter must be increased or decreased by 2 times based on mathematical logic.

Table 1.

Frequency, MHz	1,85		7,05	10,12	14,15	18,1	21,2	24,9
Cin, pF
L, µH	19,03	9,78	4,99	3,12	1,63		0,73	0,53
Cout, pf	2251	1157
				13,6	19,1	24,6	28,0

The inductor is made of a silver-plated copper tube with a diameter of 6 mm. The design requirement is a high quality factor of an unloaded inductor. The results of calculating the values ​​of the elements of the anode P-circuit of the amplifier for the ranges of 160 ... 12 m (for two lamps) are shown in Table 1.

Table 2.

Frequency, MHz		1,85				7,05		10,12		14,15		18,1		21,2		24,9		28,6
L, µH		17,43		8,18		3,39		1,49				0,58		0,32		0,12		0,43
L, µH +20%		20,92		9,82		4,07		1,79		1,44				0,38		0,14		0,52
Frame diameter, mm
Wire diameter, mm
Distance between coils, mm
Number of turns				16,5

The parameters of the output P-circuit of 3 inductors connected in series are given in Table. 2. The effect of metal chassis elements on the inductors was taken to be 20%.

The results of the calculation of the anode P-circuit of the amplifier for the range of 10m (for two lamps)

• Frequency, MHz ………………………………………….29.7
• Capacitor capacitance Сinp pF ……………………… 30
• Coil inductance, μH ……………………….0.43
• Capacitor capacitance Couf pF ……………………… 352
• Q received………………………………………….19.1

In this case, the following initial data were used:

Table 3

Frequency, MHz	1,85		7,05	10,12	14,15	18,1	21,2	24,9	29,7
Cin, pF	2677	1355
L, µH	3,69	1,89	0,97	0,67	0,48	0,38	0,32	0,27	0,23
Cout, pf	2838	1458

The results of the calculation of the input matching P-circuits of the amplifier are given in Table. 3. In this case, the following initial data were used:

Table 4

Frequency, MHz	1.85		7.05	10.12	14.15	18.1	21.2	24.9	28.6
L, µH	3,69	1,89	0,97	0,67	0,48	0,38	0,32	0,27	0,24
L, µH + 20%	4,43	2,27	1,16		0,58	0,46	0,38	0,32	0,29
Inner diameter L, mm
Wire diameter L, mm
Distance between turns L, mm
Number of turns L		11,9
Q loaded
efficiency	0,91	0,93	0,94	0,94	0,94	0,94	0,94	0,95	0,95
Overlap, kHz		1200	2350	3373	4717	6033	7067	8300	9533

In table. 4 shows the parameters of the inductors of the input P-circuits for each range. The influence of the metal parts of the chassis on the inductors was taken to be 20%. Despite the large frequency overlap, especially in the upper ranges, real impedance matching is possible only within the same range. When using one filter for two or more ranges, complex eleptic filters must be applied.

Download power amplifier circuits - zip 730kb.

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Perhaps the main role in resolving this issue will be played by the choice of amplifier.
Function
The amplifier is responsible for the quality and power of sound reproduction. At the same time, when buying, you should pay attention to the following designations, which mark the introduction of high technologies in the production of audio equipment:

• Hi fi. Provides maximum purity and accuracy of sound, freeing it from extraneous noise and distortion.
• Hi end. The choice of a perfectionist who is ready to pay a lot for the pleasure of distinguishing the smallest nuances of his favorite musical compositions. Often hand-assembled equipment falls into this category.

Specifications to pay attention to:

• input and output power. The nominal value of the output power is decisive, since edge values ​​are often unreliable.
• Frequency range. Varies from 20 to 20000 Hz.
• The coefficient of non-linear distortion. It's simple - the smaller the better. The ideal value, according to experts, is 0.1%.
• Signal-to-noise ratio. Modern technology assumes a value of this indicator in excess of 100 dB, which minimizes extraneous noise when listening.
• dumping factor. Reflects the output impedance of the amplifier in relation to the nominal load impedance. In other words, a sufficient damping factor (more than 100) reduces the occurrence of unnecessary vibrations in equipment, etc.

It should be remembered: the manufacture of high-quality amplifiers is a laborious and high-tech process, therefore, a too low price with decent characteristics should alert you.

Classification

To understand all the variety of market offers, it is necessary to distinguish the product according to various criteria. Amplifiers can be classified:

• By power. Preliminary - a kind of intermediate link between the sound source and the final power amplifier. The power amplifier, in turn, is responsible for the strength and volume of the signal at the output. Together they form a complete amplifier.

Important: the primary conversion and signal processing takes place precisely in the preamplifiers.

• According to the element base, tube, transistor and integrated PAs are distinguished. The latter arose in order to combine the advantages and minimize the disadvantages of the first two, for example, the sound quality of tube amplifiers and the compactness of transistor ones.
• According to the mode of operation, amplifiers are divided into classes. The main classes are A, B, AB. If class A amplifiers use a lot of power, but produce high quality sound, class B is exactly the opposite, class AB seems to be the best choice, representing a compromise between signal quality and sufficiently high efficiency. There are also classes C, D, H and G, which have arisen with the use of digital technologies. There are also single-cycle and push-pull modes of operation of the output stage.
• By the number of channels, amplifiers can be one-, two- and multi-channel. The latter are actively used in home theaters to form the volume and realism of the sound. Most often there are two-channel, respectively, for the right and left audio systems.

Attention: the study of the technical components of the purchase, of course, is necessary, but often the decisive factor is the elementary listening to the equipment according to the principle of sounds or does not sound.

Application

The choice of amplifier is more justified by the purposes for which it is purchased. We list the main areas of use of audio frequency amplifiers:

1. As part of a home audio system. Obviously, the best choice is a tube two-channel single-cycle in class A, also the best choice can be a three-channel class AB, where one channel is defined for a subwoofer, with Hi-fi function.
2. For car audio system. The most popular four-channel amplifiers are AB or D class, in accordance with the financial capabilities of the buyer. In cars, the crossover function is also in demand for smooth frequency control, which allows you to cut frequencies in the high or low range as needed.
3. in concert equipment. Higher demands are reasonably placed on the quality and capabilities of professional equipment due to the large space for the propagation of sound signals, as well as the high need for intensity and duration of use. Thus, it is recommended to purchase an amplifier with a class not lower than D, capable of operating almost at the limit of its power (70-80% of the declared one), preferably in a case made of high-tech materials that protects against negative weather conditions and mechanical influences.
4. in studio equipment. All of the above is true for studio equipment. You can add about the largest frequency reproduction range - from 10 Hz to 100 kHz in comparison with that from 20 Hz to 20 kHz in a domestic amplifier. Also noteworthy is the possibility of separate volume control on different channels.

Thus, in order to enjoy clear and high-quality sound for a long time, it is advisable to study all the variety of offers in advance and choose the option of audio equipment that best suits your needs.

Rice. 17
A KPI with a split stator can be used as an anode capacitor in a P-loop and ensures its optimal tuning, provided there is a sufficient distance between the plates (so that it does not break through with RF voltage. There is another method for reducing the initial capacitance of the anode KPI. By connecting this capacitor to the tap from the P-loop coil, we achieve a decrease in the capacitance introduced into the circuit and reduce the influence of the KPI on its tuning frequency - UA9LAQ).
Air Dielectric and Vacuum Capacitors: Air dielectric capacitors are easier to find and less expensive, but have some of the disadvantages outlined above. Vacuum KPIs are expensive, they are not so easy to find, but only they sometimes provide the P-circuit with everything that we want to get from it without the use of additional switched fixed capacitors. Another advantage of these capacitors is high operating voltage, insensitivity to environmental pollution and changes in humidity and pressure, and can carry high RF currents. I have never heard of any vacuum capacitor being shot or arced. The average vacuum-type capacitor used in a HF amplifier can pass through itself RF currents many times higher than those that a real RA can produce. Most vacuum capacitors change the capacitance from minimum to maximum by turning the control axis (multi-turn). The design of the vacuum KPI allows you to install various reading devices with reset and installation in a certain position required for individual ranges. Limiters at the beginning and end of the adjustment of the KPE capacity are also provided to avoid damage to it. Installation of vacuum KPIs may or may not be a problem, as most of these KPIs also include mounting hardware, if not provided, then they are easy to manufacture. Vacuum KPI can be mounted in any position: vertically, horizontally, suspended.
For a truly powerful amplifier, the best choice would be to use vacuum KPIs, which do not flash even at very high powers supplied to them. Yes, they are not cheap, but the miser pays twice ... (The entry of a small part of the air during storage, transportation or operation makes such KPIs absolutely unusable due to the occurrence of discharges in them. Before operation, it is necessary to check the KPI for leakage using a high-voltage tester and protect them from deformation and shock during operation - UA9LAQ).
One moment: the higher the anode voltage used in the amplifier, the more difficult it is to find a suitable air-dielectric CPI that can withstand the constant anode voltage plus RF and not cause arcing or capacitance flashover problems. With a voltage at the anode of the RA lamp (s) of 3 kV, it is still possible to allow the use of KPI with an air dielectric, the problems of using them at an anode voltage of 4 kV or more increase exponentially. (The author, apparently, has in mind the direct connection of the KPI to the anode of the lamp without a separating capacitor, but, being switched on after the separating capacitor, the anode capacitor with an air dielectric in the P-circuit must have an increased distance between the plates: with an increase in the anode voltage, the output impedance of the lamp increases, and, therefore, the RF voltage also increases, which means that the risk of breakdown of the gap between the plates of the KPI increases - UA9LAQ).
When buying vacuum KPIs, pay attention to the condition of the electrodes (plates) inside the glass case. If they have lost their shining copper appearance, it means that the vacuum is most likely broken in the KPI. If, when the adjusting screw is completely unscrewed, there is no resistance provided when the plates are separated, then most likely the KPI is broken. In general, the movement of the plates inside the KPI should be accompanied by resistance (force required), and the inside of the KPI should shine, as if they had just been cleaned. Otherwise, better bypass this KPE side!
Range switch: Don't skimp on this important part of RA. Buy yourself the best one you can get. Otherwise, you'll just regret it! Very decent switches are made by Radio Switch Corp. Their model 86 switch is good, however, the top model 88 switch is the best. This switch is rated for 13 kV and 30 A. Even a 5 kW transmitter will not be able to "arc" this switch. For P- or L-circuits, this switch will require at least two sets of contacts, but three is better. A group of contacts must be provided for each range used. circuits (i.e., when switching the PA ranges with one knob). If resistors are used at the PA input (non-configurable input), then, of course, there is no need for an adapter. There is still the possibility of using separate switches at the input and output of the amplifier, but in order to prevent the switches from being set to the wrong inappropriate position, it is necessary to apply some kind of blocking: mechanical or electronic.
On Fig. Figure 17 shows a switch configuration that will help the novice designer understand the requirements for a P-loop on the 160 to 10 meter bands. Hunt for similar switches at fairs, markets, and also look on the Internet, serviceable used ones will also go.
Incandescent chokes: A choke in the filament circuit of a lamp with a direct filament cathode is absolutely necessary; with heated cathodes, like in lamps of the 8877 type, you can do without such a choke. A direct filament cathode can be found in almost all old high-power glass bulb lamps, which use thoriated tungsten as the filament and cathode. On such a cathode, both a large current and a large RF voltage are present, which must be decoupled from penetration into other circuits, so powerful chokes are installed here. Such a choke is usually bulky, it is wound with a double wire, turn to turn on a ferrite rod and contains a number of turns sufficient to completely remove the RF after the choke. Decoupling capacitors are usually placed immediately after the inductor on the side of the heating voltage supply from the power supply, to the case. This type of inductor has a very large inductance, while it provides the passage of large currents through itself. I also tried the use of a toroidal inductor and was satisfied with it, especially since this inductor had small dimensions.
In lamps with heated cathodes, such a cathode is an oxidized "sleeve" dressed on a filament, which heats it up to obtain electron emission. Cathodes of this type require lower filament currents than the first ones discussed above and do not allow the propagation of RF, since the cathode "sleeve" has a constant shielding effect (the outer side, according to the skin effect, radiates and is drawn into the RF current operation circuit, the lower It is not subject to RF currents and serves as a closed screen, here you can also remember about Foucault currents - UA9LAQ). Nevertheless, it is necessary to include chokes in the heating circuit in order to prevent even an accidental RF emission from entering the supply complex. The filament inductor in circuits with lamps having heated cathodes should no longer be large, bulky, have a large inductance, since the RF currents acting in the filament circuit are small. The inductor is small in size, wound with a double wire of sufficient cross section to pass the filament current in rubber or Teflon insulation, winding is carried out on a small ring or rod ferrite core. The inductance of the choke for operation on the ranges of 160 ... 10 meters should be 30 ... 300 μH. Decoupling capacitors are connected from both filament wires to the amplifier case at the point of connection to the inductor on the side of the power supply. Also put capacitors between the filament wires on the side of the lamp base and the cathode. The connection of the HF filament with the cathode will help to equalize the RF potentials on both. This will prevent various kinds of inhomogeneities in the signals: flashes, lumbago, crunches, breakdowns on the filament, will equalize both edges of the filament in RF, which will eliminate fluctuations in the filament voltage.

Rice. 18
On Fig. 18 shows a typical circuit for switching on a heated cathode lamp with a conventional incandescent choke.
ALC: This scheme is a must. You can do without it only if you use a lamp that can be driven by the full power of the existing exciter. An example is the 3CX1200A7 lamp, which can be driven up to and including 120W. However, whether you are using an 8877 or a 3CX800A7 lamp, 120 watts of power is enough to systematically destroy grids. The ALC system prevents this, but if you "like" changing tubes more often than necessary, don't do any ALC. The best point to tie the exciter to the amplifier is between the input transmit/receive relay and the input tunable device.
The ALC circuit detects a small portion of the exciter's input RF signal in the amplifier. This rectified signal is negative polarity and can vary from -1 to -12 V. The negative signal is fed back to the exciter, which biases the power amplifier in the exciter, which in turn reduces the output power of the exciter and thus prevents the final PA from pumping.
The procedure for setting the ALC threshold is as follows:
1. Set the amplifier to full output power.
2. Adjust the ALC threshold setting potentiometer to such a level that a barely noticeable decrease in its power appears in the output signal.
3. Everything. Installation completed.
After setting the ALC threshold, the RF drive level can be increased or decreased, but the maximum output power of the amplifier, set with the ALC control, will no longer be exceeded.
The location of the ALC system adjuster can be either on the rear or on the front control panel, but in any case, it is well marked. The installation adjustment justifies itself in practice, since it cannot be accidentally knocked down (for adjustment, you need to take a screwdriver and even climb under the cover, removing a possible lock). Once set, the ALC threshold adjustment rarely changes.
On Fig. 19 shows a typical diagram of an ALC system, simple and effective.

Rice. 19
Adjustments: The most visible part of the amplifier is the control panel, and it is also the most complex. There are many ways to position and control the apparatus. How simple the control panel will be depends on the developer and manufacturer.
There are ready-made boards that can be purchased and installed in an amplifier, but this is a little different, because creating an amplifier from scratch yourself is much more interesting, however, for a beginner, this is a way out. Remember, the more complex the machine, the more difficult it is to operate and repair. Simplicity and reliability - that's what you need to proceed from when developing an amplifier. If a designer wants to create a fully automated amplifier and feels that he can cope with the task, then the flag is in his hands ... It will be difficult, and there will be problems, problems ... For beginners, I advise you to build the simplest, most reliable, no-frills amplifiers. After you build it simpler, there will be more complex devices, more elegant.
Look at the problem like this: “You are a development engineer, you decided that you would make a device, no matter how much time and effort it takes!”
Afterword: In this day and age, when it's easy to buy and operate amateur gear the way you want, it's easy to forget the satisfaction of making it yourself. Anyone who buys and then plays with an expensive toy will never experience this feeling. For those who, nevertheless, want to test it, put their own hands and head and make their own RF amplifier, as our predecessor colleagues did in their time, this article is devoted to. It is impossible to describe in words that feeling of completion, duty done, satisfaction from the experience gained. And you will also get something new in the process ...
If you have any questions, I will gladly share my knowledge and experience with you, if you sincerely desire it.
73 de Matt Erickson, KK5DR
Free translation from English: Viktor Besedin (UA9LAQ) [email protected]
Tyumen November, 2003