Larry,
If it's the same kind I have, (I don't have my Fair catalog here at work
with me) I have the vhf version 100-225 Mhz. Mine used a single 4x150A which
I replaced with a 4CX250B for more power. I'm guessing yours is the same,
except for the physically shorter cavity. One cavity is tuned for the
input, the other for the output, with an output coupling control, right?
I stripped the front panel and frame off and bolted it in a standard 19" rack
mount chassis which is nearing completion. I added metering, blower, relays,etc.
It makes building a single tube amp real easy.I am building an external
power supply so I can have about 1200-2000VDC on the plate. I just hope the
wiring holds up. That might be something I have to change. On a test bed I
checked mine out with a Heathkit HP-23A power supply and got about ~100
watts out with 800V on the plate. They are very efficient amps. I also
checked mine with a network analyzer and have found that my cavitys have
definite resonance points at 432 Mhz, even though they are only designed for
100-225 Mhz. So, I'm really hoping I have an amp that is continous from
100-440 Mhz! (on the ham bands) Linear conversion should be straight
forward, just add bias. You really can't beat
the price!
Later,
Walter
At 08:16 AM 12/23/97 -0600, you wrote:
>I just purchased a surplus AM-1178 400-600 Mhz amplifier from Fair Radio
>Sales.
>Two beautiful cavity circuits using 4X150A tubes. I would appreciate any
>information from anyone who has converted one of these units for 432 Mhz
>linear operation or as a 426 Mhz ATV amplifier.
>
>Thanks...
>
>
>
>
>
>Larry Bush, W5NCD
>359 Arrowhead Point
>Waco, Texas 76712
>Tel 254-848-5155
>
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>FAQ on WWW: http://www.contesting.com/ampfaq.html
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>
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