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Re: Topband: Signal source and distance from antenna?

To: topband@contesting.com
Subject: Re: Topband: Signal source and distance from antenna?
From: "Dan Zimmerman N3OX" <n3ox@n3ox.net>
Date: Sun, 5 Oct 2008 18:30:40 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
What do YOU guys use to determine which antenna works better or if you've
> made an improvement in gain, null, signal strength, etc. during the
> daytime, -and- how far away does this source have to be?  (I don't like the
> thought of driving a mile down the road, installing a 30' vertical antenna
> on my analyzer (so it can be heard a mile away), then leaving it unguarded
> for someone to swipe, HI HI !)
>

I use a TTL can oscillator that runs at 1.843 MHz.    I'd probably recommend
a self-contained antenna apparatus... little magnetic loop, maybe, or a
short dipole type to help stabilize things, though as long as you do direct
A/B between the antennas you're comparing that should wash out variations in
signal strength.

I also think you need to be out more than a wavelength or so.  100-200 feet
is too close.  Try 500-600.  The cheap can oscillator may make you feel
better about that ;-)  I end up leaving mine out in a public park for hours
at a time, so I'd worry too... but if I've got a cheap homebrew circuit out
there, who cares? ;-)

73
Dan
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