[TowerTalk] 2 element 20m beam resonates too high in band

Doug Snowden dougn4ij at gmail.com
Mon May 31 19:28:51 PDT 2010


I am curious about this:  I am experimenting with a 2 element beam for
20 meters.
It is driven element - director arrangement. I haveit near the ground
with the director
near the ground and the driven up about 10 ft off the ground, in other
words forward
direction is into the ground.. In looking at the resonant point, it is
resonant around 14.6 mhz.  The boom is about 9 ft long. I would expect
it to be lower than the design freq than higher. Could it be some
strange interaction witht eh ground since it is de/dir ?
I know it is recommended that with e reflector you have the reflector
on the ground when doing inital testing.  I'll try and elevate it to
see what is going on, but it seems
strange to me.  I am using a beta type match, so I can tune it, but the lowest
swr is at 14.6.

Anyone seen this sort of thing before?

Doug, N4IJ


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