|[AMRadio] AM Transmitter Advice??|
w5omr at satx.rr.com
Sun Feb 19 02:55:22 EST 2006
John E. Coleman (ARS WA5BXO) wrote:
>I have heard rumors of a citation or two but only in extreme cases such as
>10 or 20 KW PEP and I don't know if the rumors are true.
>As I understand it the trick, that the FCC was to prevent, and someone was
>trying to get away with, was to run a 304TL with about 100 Volts on the
>plate in a GG configuration. Forward bias it to a high plate current like 1
>Amp, so that it acts like a switch that is on. Then drive it with 5 KW PEP.
>It may have been some other some scenario as this but I think you get the
>An Now, For Something Completely Different.
> Then there was the trick that a gentleman up in 3 land, I think, was
>going to run the high level double sideband reduced carrier generator type
>rig but he was not reducing the carrier just increasing the SBs via an extra
>upside down tube, as it was commonly called. The sideband power would
>continue to go up without distortion (if copied on a proper synchronized
>product detector) after the first tube was over modulated in the negative
>direction. The voltage and power would be diverted to the upside down tube
>where sideband power would continue. There was trouble with the specific
>rule interpretation at the time in the FCC. Of course any of us today, would
>be able to see that the upside down tube's audio plate current and audio
>voltage must also be counted as part of the input power. But the FCC was
>having trouble deciding, at least as I understand it. At any rate, I think
>they got him for being outside the 40 meter band limits. You may remember
>more of the specifics on this Don.
Fred, I believe. W3PHL.
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