M.O.P.A. 207 Watt Amplifier


The M.O.P.A. is now 20 Megahertz capable with a variable built in carrier frequency from 2.2 MHz to 3.8 MHz and is 1930's/1950's replica. When connected to the GB-4000 it is capable of outputting 8 Frequencies Simultaneously.


The M.O.P.A. or Master Oscillator Power Amplifier uses the gas filled tube radiant method of outputting frequencies from 1 to 20 million Hertz. Many people ask what are the benefits of the M.O.P.A. over the SR-4 amplifier? First: The M.O.P.A. uses the gas filled tube method. The gas filled tube method allows for a greater power output of 207 watts peak power compared to the SR-4's 30 watts peak power. Second: the M.O.P.A., for the first time since the 1930's, allows for the use of high frequencies directly output through the gas filled tube. This has been a long sought after feature that many have been asking for. If you are wanting to use the more powerful, versatile 1930's/1950's radiant method, then the M.O.P.A. amplifier is the instrument you will want to own.

When it comes to power the GB-4000, SR-4 and M.O.P.A. should be considered as good, better and best. If your budget only allows for the GB-4000 then you have the one of the best frequency generators you can purchase. If your buget allows for the GB-4000 and SR-4 amplifier then you move up to the next level of performance. If you can afford the GB-4000 and M.O.P.A. amplifier then you know you have the very best gas filled tube system on the market today. You also have the only system that can output both the 1930's/1950's frequencies through a gas filled tube. Only purchase what you can afford because you can always add the SR-4 or M.O.P.A. amplifier at a later date.

Why should you purchase the GB-4000 and M.O.P.A?

When the GB-4000 is combined with the M.O.P.A. the ability to run up to eight frequencies through a gas filled tube up to 40,000 hertz is possible. No other instrument has this 8 frequency capability.

The M.O.P.A. is the only original vacuum tube gas filled plasma tube instrument with the ability to use a variable frequency from 1 to 20,000,000 million Hertz. It also has a variable built in carrier frequency which goes from about 2.2 to 3.8 MHz.

We use the superior high voltage low current design over the low voltage high current design.

We can usually ship within 24 to 48 hours after receiving your purchase agreement.

Both the GB-4000 and M.O.P.A. come with a one year parts and labor warranty.

We not only give superior support but give technical support by phone for as long as you own your instrument.

  • Fabrication: Built by hand and tested for quality assurance with one year parts
    and labor *limited warranty.

  • Proven design: Solid state combined with vacuum tube technology used for over 80 years.

  • Amplification method: Original vacuum tube amplification.

  • Amplification voltage: High voltage (1130 volts).

  • Amplification current: Low current (30 to 280 milliamps).

  • Vacuum tube vs Solid state amplification: Modern solid state uses low voltage and high current designs. The M.O.P.A. uses the high voltage low current design.

  • Milliamp meter: Built in.

  • Waveform: Harmonic sine wave producing harmonic sidebands in the same manner as the original equipment.

  • Sine wave: Analog.

  • Frequency Counter: Built in for accurate reading of the carrier frequency.

  • Carrier frequency: Variable.

  • Built in Carrier frequency range: Approximately 2.2 MHz to about 3.8 MHz. Once the carrier frequency is set using the frequency counter the carrier frequency will stay on that carrier frequency until it is changed to a new carrier frequency.

  • Carrier frequency tuning: Variable tuning capacitor.

  • Power output: Variable average un-modulated of 103 watts RMS at 280 milliamps (280 milliamps Max).

  • Peak power: When gated or modulated 207 watts peak power when using
    a square wave waveform.

  • Frequency input method: Designed to work exclusively with the GB-4000 frequency generator through a BNC connection.

  • Frequency output modulation: GB-4000 audio frequencies up to 400,000 Hertz square wave when using the "Audio Mode" @ 100% AM modulation.

  • Maximum frequencies output: When connected to the GB-4000 it can transmit up to 8 frequencies simultaneously.

  • New maximum frequency range: When using the "RF Mode" 1 Hertz to 20,000,000 Hertz.

  • Gating or pulsing: 1 to 40,000 hertz using the GB-4000.

  • Frequency delivery: Gas filled tube (*Sold by another company. Limited warranty applies only if another type of plasma tube is used, then there is no warranty)

  • Tube ignition: instantaneous.

  • SWR meter: None. The gas filled tube is connected directly to the RF tank coil requiring no SWR (standing wave ratio) meter. This method, unlike the SWR meter systems, delivers almost 100% power output to and through the plasma tube.

  • Useful range of 30 feet using gas tube. Due to the laws of physics there are limitations to gas filled tubes and metal antennas that need to be understood. Both are very efficient and about 100% of the energy that you put into them comes out. But for every foot that you move away from these antennas you lose 75% of the power they output. To illustrate we will use the standard loss with metal antennas as the power loss ratio for a plasma tube. With a 207 watt output at one foot away from the plasma tube you will only get 51.75 watts.  At two feet away you only have 12.93 watts and at 3 feet you only have about 3.23 watts. Because of the law of physics it is important to be as close to the gas filled tube as you can get if you want the greatest amount of the energy that comes out of it. One to six feet distance away from the gas tube would be the best choice. The closer the better.

  • Suggested range: 1 inch to 6 feet when using gas filled tube. Because there is no 1 foot to 3 foot null zone (non-effective range) it is not necessary to stay 3 to 6 feet away from the gas tube because it outputs the same as the 1930's/1950's equipment that was used within 6 inches of the target area.

  • Size: Compact design - 10.5" Wide X 17" Long X 10" High.

  • Power used: Can be built for use with 110/120 volts AC or 220/240 volts AC.

  • Power usage: 240 watts. When connected to the GB-4000 265 watts.

  • Weight: 19 pounds.

For those who already own a GB-4000, the 207 watt M.O.P.A. amplifier is priced at $2495.00. This price includes shipping in the USA. ($250 restocking fee on M.O.P.A only) (Order here)

The M.O.P.A. with GB-4000 is priced at $4220.00) and includes shipping in the USA. (Order here)

(Please note: The gas filled tube including copper collars with wires and gas tube holder with new reflector are sold separately from another company for $333.00 plus shipping. We can give you the phone number for that company so you can order it when you order your M.O.P.A. This gas filled tube is made of Pyrex and is a 2" inch round by 14" inch long Helium, Argon or Helium/Argon filled tube. It is guaranteed to handle the power output of the M.O.P.A. (*The M.O.P.A. comes with a one year warranty but if any other plasma tube is used there is no warranty)


The Frequency Counter is now built into the M.O.P.A.