Thread: Effects of TOA
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Old April 15th 07, 11:43 PM posted to rec.radio.amateur.antenna
Jimmie D Jimmie D is offline
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First recorded activity by RadioBanter: Feb 2007
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Default Effects of TOA


"Richard Clark" wrote in message
...
On 13 Apr 2007 16:41:25 -0700, "JIMMIE"
wrote:

I have observed that a halfwave vertical dipole
will communicate to different areas than a 1.25wl vertical monopole


Hi Jimmie,

A low halfwave operates best at 16 degrees; a quarterwave works best
in the 20s of degrees; while a 1.25 wavelength antenna works best in
the high 50s of degrees.

This presumes the last two are both ground mounted. Given that any of
these presumptions are at best a guess, then the numbers are merely
for guidance as reality may be vastly different (you really haven't
given us enough information). Actual physical size and elevation help
considerably. Also, as this is 10M, was some of the traffic from the
neighborhood (within 20 miles)?

73's
Richard Clark, KB7QHC


These are ground mounted monopoles and I am only talking about
skip reception. The antennas were mounted on the ground in an attempt to
eliminate as much local reception as possible. I am not too interested in
the local 10M chatter.not that there is very much but have noticed that the
two antennas talk into completely different areas on occasion. I first
noticed the phenmena back in the late sixties when I bult a 1.25 wl antena
for 11m believing that longer was always better. It was an interesting
antenna sometimes allowing me to work into canada from S Ga even when
others in the area werent even experiencing skip conditions. I was about 16
at the time but I do seem to remember that hering an opening on this antenna
meant that an opening would soon happen for the area. I was wondering if I
could duplcate the effect by tilting a yagi to a high angle. The more I
think about it I dont belive this would not be practical even if it was
possible. Not only would I have to have the antenna tipped at the right time
I would also have to have it pointed in the right direction. I would be
interested in knowing if others have experienced this effect using unually
long vertical antennas on the higher frequencies.