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Re: Topband: Ticked over intentional interference on top band

To: "topband@contesting.com" <topband@contesting.com>
Subject: Re: Topband: Ticked over intentional interference on top band
From: "Shoppa, Tim" <tshoppa@wmata.com>
Date: Sat, 21 Jan 2012 13:31:15 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
> Jack's keying may well be a tad on the hard side, but his signal HARDLY
> emits "...key clicks out to over 1 KHz from his carrier frequency",
> IMHO...and I've copied him at some 30 db.+ over S-9 here, too, so if
> he was, indeed, "clicky", I think I'd know...

Many receivers (I try to indict DSP rigs below but really pure analog 
mulitconversion receivers can show this too) can have AGC pumping causing 
perceived clicks, especially when the incoming signal is in the roofing 
filter's passband but outside the later tighter filters passband.

If everything inside the AGC chain were perfectly linear you'd think this could 
be remedied by going to slow AGC, but no, for very loud signals with most AGC 
chains there is still a fast response/decay component even at slow AGC settings.

Turning RF gain down all the way helps. Attenuator helps. Turning off AGC helps.

Someday they will do a good job putting forward AGC into DSP radios. I swear 
that almost all the parts are in a DSP radio already.

Tim N3QE
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UR RST IS ... ... ..9 QSB QSB - hw? BK

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