Although somewhat effective, tuning a Yagi by placing the reflector on the
ground and pointing up will yield inaccurate VSWR and resonance readings.
Basically, the reflector is being replaced by the lossy ground and the
pattern is skewed. Most Yagi antennas will give good readings from about 15
feet elevation, and the resonance will be 10-20KHz lower than typical .5 wl
install height.
73, Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Neal Sacon
Sent: Tuesday, June 14, 2005 8:52 AM
To: towertalk@contesting.com
Subject: [TowerTalk] TA-33 Jr. SWR curve
Thanks to all who replied on this - I'll get busy with all the suggestions.
One question - why does placing the antenna vertical with the reflector a
few feet off the ground change the result? This would actually put the
driven element lower (or about the same) at the same height it is when the
antenna is horizontal on the ladder (it's a 12 foot ladder).
73 Neal N7RX
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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