[TenTec] AM Ouput Level 2.037j

[Ron Castro]

I just did some AM tests looking for carrier level and found that with the 
PWR set at 45%, I get 10 W out with no modulation.  Running 1 kHz sine wave 
at a level that just makes the ALC light come on, the carrier increases to 
15-17 W.  12.5 Watts AM carrier is all I need to drive my linear to 1500 W 
PEP with 100% modulation.

Running modulation right to where the ALC starts to light seems to be 
consistent with 100% modulation, which appears to be DSP controlled.  The 
good news is that if you take a long pause during a transmission, or reduce 
modulation for a long time, the transmitter drops power, saving on heat 
generation from your linear.

Also the speech processor is no longer available for AM, which is probably a 
good thing.

Ron N6AHA


----- Original Message ----- 
From: "Grant Youngman" <nq5t at comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Sent: Tuesday, September 12, 2006 8:18 PM
Subject: Re: [TenTec] AM Ouput Level 2.037j


> To follow up, now that the amp is cabled.
>
> As I suspected.  I've never had a problem driving my amp to the legal 
> limit
> on AM (arguably 375W carrier with about 1500W peak out).  I now 
> effectively
> have a 250W+ AM transmitter.  With no modulation the thing puts out around
> 200W carrier. Output peaks run about 1200W, so there's obviously some
> positive carrier shift going on.  That's on 40M.  On 20M, the most I can 
> get
> out of the radio with no modulation drives the AL-1200 to a measly 130W
> resting carrier and a maximum of 1000W on peaks.
>
> One could argue that the dB's are a nit, but this wasn't really a positive
> change.  The early v1 AM transmit DSP code was very very good.
>
> BAD Andy!
>
> Max Orion II output power seems ok, but now I can barely make 1500W on any
> band.  Used to do it with PWR set to around 90, now even at 100 I'm lucky 
> to
> see 1300 watts out of an AL-1200.
>
> Grant/NQ5T
>
>
> -----Original Message-----
> From: Grant Youngman [mailto:nq5t at comcast.net]
> Sent: Tuesday, September 12, 2006 9:13 PM
> To: 'Discussion of Ten-Tec Equipment'
> Subject: 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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