[Elecraft] [TenTec] Tx IMD and Purity

[amsctalx at comcast.net]

And 1.5 watts, through a decent antenna system, now becomes the equivalent of a nice QRP station - covering up that DX station, when propagation is right, that you were trying to work. Those of you with P3s shave probably already seen it in your waterfalls - "walls of noise" up to 9/10 kHz wide. Those that haven't should; it's a real eye-opener. 


Mike Alexander - N8MSA 

amsctalx at comcast.net 

----- Original Message -----
From: "Jim Brown" <jim at audiosystemsgroup.com> 
To: elecraft at mailman.qth.net 
Sent: Tuesday, July 2, 2013 3:06:36 PM 
Subject: Re: [Elecraft] [TenTec] Tx IMD and Purity 

On 7/2/2013 11:10 AM, george fritkin wrote: 
> Nobody can even hear -30 distortion products. 

WRONG! 30 dB down from 1.5kW is 1.5 watts. If that 1.5 watts is your 
neighbor a few miles away, he's 30 dB over S9 and the trash is on top of 
the S9 station you're trying to copy, you damn well WILL hear it, and 
you'll be thinking about putting pins in his coax if he doesn't clean it 
up. 

While I agree that AUDIO distortion IN THE PASSBAND at 30dB down does 
not matter, the SPLATTER it produces matters a LOT. And that's for ham 
radio. If you're listening to acoustic music and you're not deaf, you 
CAN hear some kinds of distortion products in the -60dB range, depending 
on the nature of the distortion. 

73, Jim K9YC 
Fellow, Audio Engineering Society 
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