Re: [TenTec] AM Output Level 2.037j

["Ron Castro" <ronc@sonic.net>]

I used it on 75 meters the night before last and got good reports but I did 
notice the "upward modulation" effect you saw.  Looking at sine wave on a 
regular oscilloscope, it looked like standard 100% AM, but I saw the 
wattmeter move up as the modulation increased.  I think I remember this 
being detailed somewhere (maybe in Doug Smith's writings) about a DSP AM 
design that automatically corrects the carrier level to accommodate the 
amount of modulation applied, and I think that design is incorporated in the 
Orion firmware.
What I did learn the other night was that you need to cut the bass and 
increase the treble to get the AM response flat enough to not sound muddy.
Ron N6AHA

----- Original Message ----- 
From: "Grant Youngman" <nq5t@comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Tuesday, September 12, 2006 7:12 PM
Subject: [TenTec] AM Output Level 2.037j


> Has anyone figured out what's going on with AM transmit with the new
> release?
>
> I get a resting power out level in the 10+ watt range, with upward carrier
> shift with modulation (erratic with around 25% peak positive shift on a
> Belar mod monitor).  The peak output with 100% modulation is running 70+
> watts, or there 'bouts, which on average might imply the carrier is moving
> up to something shy of 20 watts under modulation, give or take the side of 
> a
> barn.
>
> This isn't all that terrific, if it's working the way it appears to be --
> behavior more like a controlled-carrier modulation scheme (albeit with a
> relatively slow time constant).  And given the output levels, it's
> questionable whether this new version is going to fully drive my AL-1200.
> Haven't put it on the air yet on AM, so don't know if it's going to play 
> at
> the other end like a loud DX-40 or what :-)
>
> I almost think a bit of downward modulation might be a better answer 
> rather
> than the way it was 'fixed" in the new release.
>
> Then again, maybe I'm just missing something ...
>
> Grant/NQ5T
>
>
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