Message-Id: <7.0.1.0.1.20100901090820.0188dc40@magma.ca>
Date: Wed, 01 Sep 2010 09:40:38 -0400
To: rsgb_lf_group@blacksheep.org
From: Bill de Carle <ve2iq@magma.ca>
In-Reply-To: <4C7C52CC.7000506@telus.net>
References: <4C7C52CC.7000506@telus.net>
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Subject: LF: Re: VE7TIL TX Loop tests continue.............
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Conditions here (FN15) not so good last night.  The usual morning 
"bright-up" was less pronounced today.  Discernable on-frequency 
traces for several hours and after daybreak enough of Scott's signal 
was visible to confirm his DFCW keying signature (I'm familiar with 
it by now) - but cannot say a complete ident was received.  Nothing 
seen from John this morning.

I am unsure just what role high QRN plays in determining whether or 
not reliable copy is possible.  The static crashes are continuous on 
LF these summer nights - I had around S9 on the meter just from QRN 
so it must be doing quite a number on my front-end gain.  I tried 
turning off the AGC for a while but had to manually cut the RF gain 
so much to avoid clipping it didn't seem like a good idea.  With the 
AGC on at least there is some possibility of weak-signal energy 
getting through between crashes if there are QRN-lulls here and 
there.  I'm wondering if some adjustable-threshold hardware clamping 
before the signal goes into the radio would be effective?  Given the 
improvement in VLF weak signal detectability when applying software 
clamping (Spectrum Lab) - would a symmetrical hardware clamp work 
too?  Anyone tried it?

73,
Bill VE2IQ