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Re: U band getting into S band



On Tuesday 26 February 2002 19:29, Jeff Hite wrote in "[amsat-bb] U 
band getting into S band":
> I have just finished assembling a mode U/S station and tried some CW
> transmissions for testing purposes. I am hearing my 70cm signal
> directly on the 13cm receive...
> Any suggestions on where to start troubleshooting?

Well, I was going bats trying to discover why I wasn't able to run full 
duplex crossband V/U to a local repeater here without creating 
horrendous audio feedback, even with my station audio system (PC 
soundcard and stereo amp speakers) down the chain powered down, and 
monitoring the recived signal on headphones.

After a while I determined that the UHF RF was getting into an 
amplified auxiliary speaker (even when it was not powered on!), and 
feeding back into my station mic. Relocating the speaker and its audio 
line solved the problem. 

I guess what I'm saying is: don't assume that the crosstalk is 
happening outbound of the RF stages...rule out other stupid stuff too. 
Full duplex operation will reveal paths you'd never notice with 
half-duplex.

 73 de Maggie K3XS  

-- 
-----/___.   _)   Margaret Stephanie Leber    / "The art of progress  /
----/(, /|  /| http://voicenet.com/~maggie   / consists of preserving/
---/   / | / |  _   _   _    `  _AOPA 925383/ order amid change and /
--/ ) /  |/  |_(_(_(_/_(_/__(__(/_  FN20hd / change amid order."   /
-/ (_/   '  K3XS  .-/ .-/    ARRL 39280   /___ --A.N.Whitehead ___/
/____ICQ 7161096_(_/_(_/__AMSAT 32844____/ <maggie@voicenet.com>

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