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  CB Radio Accessories

MD-1  Modulator


CP-1 Compressor

Installation instructions
and list of compatible radios.

MD-1 Instructions
CP-1 Instructions

The following text is from the manufacturer:

"Now the same Top Gun Modulator MD-1 and Compressor CP-1 circuits used in the new Magnum radios are available for most other 10- meter and many CB radios. Full tone, clear, high swing audio (AM) modulation is achieved with the addition of these two fully assembled micro circuit boards. While the Top Gun Modulator works only in AM, the Top Gun Compressor works in AM, FM, and SSB keeping the modulation at peak performance in all these modes. Installation is accomplished with the removal of up to 3 resistors and the connection of 7 to 9 pre stripped and tinned wires.

Instructions are included for current and past production compatible radios. Additional Web support is available at These circuits work with or without the modulation limiter. For the purest, the limiter can be adjusted for excellent forward swing without any square wave audio. Without the limiter the compressor maintains high-level audio without severe squaring of the audio signal. It is the squaring of the audio peaks that create the distortion and splatter of adjacent frequencies.

On 30-50 Watt radios, the dead-key or carrier can be set to 2 Watt or less with a modulation swing to the full output potential of the radio transmitter. The modulator can be switched to normal swing with the installation of an optional SPST or SPDT switch. Even in the normal swing mode, the Top Gun Modulator is still working to keep the audio clean at all power levels.

200mv P-P 1KHz Sine Wave At Mic Input


AM Modulated Signal With The Top Gun Modulator In The OFF Position Same Modulated Signal With The Top Gun Modulator In The ON Position


Bird 43P

Bird 43P

Bird 43P

Reading 2-Watt Carrier

 Reading Peak Power
With Top Gun Modulator OFF

Reading Peak Power
With Top Gun Modulator ON

50-Watt Slug

50-Watt Slug

50-Watt Slug

All text on this page written by the manufacturer and Bells CB makes no claims of the same performance. :

... MD-1 Modulator... $20.00

... CP-1 Compressor... $15.00


Let me further explain the purposes of the MD-1 and CP-1. They CAN both be used in the same radio. The MD-1 is primarily an AM device that allows very low dead key and still have high peak power without severe overmod that normally would occur when there is such a deadkey to peak ratio, So people like to use it when driving an amplifier that has low deadkey requirement and want maximum peak values from it. It also increases the RMS peak power and makes guys with BIRD meters happier. The CP-1 is primarily effective when talking on SSB. It's job is to amplify the low level audio without amplifying ALL the audio, so soft spoken parts of speech would get louder and create a higher PEP output on SSB. It doesn't really assist in AM so much.
























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