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Reviews Categories | Amplifiers: RF Power - 6M/VHF/UHF+ | Gonset 903A ... 2 Meter SSB/CW Amplifier Help


Reviews Summary for Gonset 903A ... 2 Meter SSB/CW Amplifier
Gonset 903A ... 2 Meter SSB/CW Amplifier Reviews: 1 Average rating: 5.0/5 MSRP: $(missing—add MSRP)
Description: 2 meter amplifier using a 4CX150 or 4CX250B tube for 350 to 375 watts output with 3-5 watts drive.
Product is not in production.
More info: http://
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You can write your own review of the Gonset 903A ... 2 Meter SSB/CW Amplifier.

N8FVJ Rating: 5/5 Jun 20, 2018 03:01 Send this review to a friend
Solid Built Amplifier  Time owned: 0 to 3 months
The Gonset 903A is a well designed and solidly built amplifier for 2 meter SSB or CW. It would likely perform on FM but not sure of the safe power output or if it even tunes on 2 meter FM frequencies. I would reduce drive to 250 watts output on FM. On SSB or CW I get 375 watts out with 5 watts drive. The amp has input tuning for low SWR and a handy relative power output reading on the meter. This handy power out function eliminates buying an expensive high power 2 meter Watt/SWR meter.

Due to the age of this amplifier I replaced the high B_ voltage and low B+ voltage capacitors. The HV board is perfectly suited to securing snap-in type capacitors. 5x 450 volt capacitors are used for the high voltage. I used 220uF 450 volt replacements. The screen low voltage uses 40uF @ 250 volt capacitors. I used two 40uF 450 volt axial lead capacitors. Higher capacitance is not needed due to the regulated screen voltage that reduces AC ripple.

The amplifier does not have antenna relays, but the amp I purchased had two Dow Key antenna relays mounted on the back panel. A 1/2 wave rectifier & capacitor was added of off the tube filament for low voltage keying.

The way I see this amp is a low cost alternate to more modern amplifiers that use very expensive ceramic tubes and likely more power in the 800 watt to 1500 watt range. These are $1500 to $2000 amplifiers used.

The Gonset 903A makes enough power to get over that 10 watt to 50 watt 'wall' for long distance weak signal contacts. I would make up the difference in lower power using a very high gain 2 meter antenna. Of course, a 1500 watt 2 meter amplifier is best for moon bounce, but that mode is rare and requires a huge array if antennas.

The Gonset 903A is available for $400 to $600 used. I consider it a bargain, but is rather rare. One or two come up for sale yearly on ebay or ham classified sites. Highly recommended.
 


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