[TowerTalk] TA-33 Jr. SWR curve

[Keith Dutson]

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 at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Neal Sacon
Sent: Tuesday, June 14, 2005 8:52 AM
To: towertalk at 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 


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