Tom:
This is a well-known issue in the Orions, and as recently as this past
weekend, I have been adding to my understanding of it. I performed W2AJI's
adjustment and noted that the internal ALC now works as you would expect it
to, but only if running 100% power. When the radio runs less than that, my
observation is that there is no ALC action, only some AGC in the audio
section that holds the power generally where you set it, but only on very
occasional peaks. The AGC will never let you run more power than the CW
power for that setting. Most other radios offer ALC compression at all
power level settings, causing the average power, and the apparent drive
power, to increase a couple of dB.
Theoretically, not engaging the ALC in the final should result is less
splatter and a cleaner sounding signal if your peaks are below 100%, but it
does look like you're running much less power. The way around it is to run
the audio levels up high (ALC light---which is not really an ALC light!---on
most of the time), and increase the power control to whatever level makes
your linear happy.
A more precise approach would be to reset the internal ALC level to keep the
power at 35-40 Watts, or put a 4 dB pad in the line to the linear. Neither
of those sound like good solutions, but they would probably work well.
Ron N6IE
www.N6IE.com
----- Original Message -----
From: "Tom" <sail8@verizon.net>
To: <TenTec@contesting.com>
Sent: Monday, February 08, 2010 2:28 PM
Subject: [TenTec] Problem with Orion 2 driving an Ameritron 811H Linear
>I have found that my Orion 2 (w/ model 709 TT mike) will drive my linear to
>a max. output of 300 watts while providing 40 watts of drive. My IC765 (w/
>the model SM20 mike) will drive the same linear with 35 watts to an output
>of 500 watts. I have switched coax leads, etc. to try to account for bad
>hardware, etc.
>
> As per suggestions from TenTec, I tune the rigs and adjust the linear
> settings using only the CW mode, tried some compression, adjusted the mike
> gain and even increased the
> TX EQ (from zero to -12 ) and nothing increased the ability of the Orion 2
> to provide more than a max. output of 300 watts. Meanwhile, the "good old"
> IC765 cooks along yielding 500 watts for a drive of 30 watts. What 'am I
> overlooking? The only variable I can see is the rigs/mikes. Has anyone run
> into a similar problem or do you have any suggestions as to what I should
> try next?
>
> Will appreciate any input you could provide.
>
> 73, Tom N3XQ
>
>
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