On Wed, 2007-10-31 at 17:04 -0400, Rick Denney wrote:
> Gary Hoffman writes...
>
> > Both make good points. Obviously many hams have no idea these days
> > how to use an amp.
>
> Okay, let me check my method with you guys, since I'm relatively new,
> particularly to amp usage.
>
> I have an Omni V and an 811A. I use the relay output of the 811, but I
> did not attempt to connect ALC (I'll set aside for the moment that
> there is no ALC connector on the V that I've seen). I tune my antenna
> tuner (a TT 229A) using an MFJ 259 in place of the exciter in my RF
> chain before switching back to the Omni V as the exciter. Then, I tune
> the amp into a dummy load (or use my recorded settings), using the
> TUNE button on the V. I set the RF output on the exciter to peak
> output of the amp. The power meter on the Omni V is reading about 50
> or 55 watts, usually, with the full-power key-down operation of the
> TUNE button. I set the exciter below the point where increasing it
> yields no increase in amp output power.
>
> Then, I just switch to the antenna and use the radio. I usually read
> 600 watts or so key-down (with TUNE), but in SSB will rarely se
> anything near to that on my relatively cheap meters. I'm quite sure
> my meter does not have an accurate peak-reading capability, but even
> when I whistle into the microphone I don't see quite as much as with
> the TUNE button. And I whistle loud, heh, heh.
Most ham power meters are average reading, not peak reading so on SSB
you always see a lower value that you had the carrier. Trying to achieve
an average reading to match, even with a whistle, fails because the SSB
envelope of the whistle is not like having a single tone
>
> Seems to me that method will keep the SSB peaks below the acceptable
> exciter PEP of the amp.
>
> If I want more so-called talk power, I can use the processing in the
> exciter, which I understand keeps the peak envelope power the same but
> increases the average power. That's the same effect as ALC, it seems
> to me, but designed for that purpose instead of as a safety measure.
> If the exciter stays within its own envelope, it seems to me it won't
> push the amp outside of its envelope.
Processing works at a fractional syllabic rate, ALC fast attacks and has
a slow recovery so it works at a much slower multiple syllabic rate,
prevents overdrive but doesn't compress.
>
> Nobody has complained that I splatter, but maybe they are just being
> nice.
>
> Rick, KR9D
>
73, Jerry, K0CQ
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