On Sun, 31 Jan 1999 13:07:43 EST Radio WC6W <wc6w@juno.com> writes:
>
>Happy Sunday everyone,
> An interesting power amplifier just popped out of the "time
>closet".
>
> It is an AM-912/TRC with a frequency range of 100-225 MC; love
>those
>old units! :-)
>
> The amp utilizes a 4X150, which is operated at 750 volts, to output
>all of 100 watts. The construction is excellent with identical
>crank-knob tuned silver plated cavities on both the grid & plate.
>
> Does anyone have any experience with this unit?
Yep, W1QXX ran one on 220 mHz CW in the 60's and I spent a fair amout of
time on it.
As is you can fit a 4CX250R for better IMD if you tightly regulate the
screen and bias for SSB. We did not do that back then since it was only
used on CW.
The air flow for the old glass 150 is more than adequate for 250-300W
from a 250R but I would limit the HV to about 1700V or so. I vaguely
remember some problems with arcing but dont 'member the details. We did
run 1500V when it all worked fine.
There was a similar amp that ran the 4CX150G for 225 to 400MHz that works
quite well on 222 or 432.
For bottom line low bucks RF at 144, 222 or 432 MHz the AM-6154/6155 are
almost impossible to beat since they are complete amps that after a few
mods just plug in to the wall and crank 350-400W with 10W or less drive.
I run one on 432.
73 Carl KM1H
.
Have fun on VHF/UHF.
73 Carl KM1H
>
> Specifically with updating it to a more modern tube and upping the
>plate voltage?
>
> & what is the best tube that would fit the foot print? The 8930
>is not an option due to the existing plate collet. What about a
>4CX350FJ/8904 or does that suffer too much above 100 MHz?
>
> Thanks in advance for any info!
>
>73,
> Marv WC6W
>
>
>
>
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