I have a simular story on unexplained propigation. I helped build a repeater
that is operated in Tularosa, NM and is sited on the floor of the Tularosa
Basin which encompasas the White Sands Missle Range. It uses a Comet 17 ft
dual bander on a 50 ft tower but it's coverage includes the whole of Hwy 70
from the Mescalero Apache Indian Reservation to the Oregon Mountains, near Las
Cruces NM. Running 20 watts to the antenna and a stock GE Repeater with .35 uV
sensitivity with no preamp, we have no explanation for this coverage. Sierra
Blanca Mountain rises to 12,500 ft behind the repeater site, and is about 20
miles away. The repeater ground level is about 5000 ft. The Oregon Mountains
are about 60 miles from Tularosa, and the repeater can be copied at several
sites on the other side of the Oregon Pass in Las Cruses NM. I have worked the
repeater from my motorhome about 20 miles west of Las Cruces on I-10, a
distance of around 100 miles.
Is the big mountain behind it reflecting the signal over the pass to the south
west? We have found this propigation consistant for the last 3 years the
repeater has been on the air at this site. Some smaller hills are within 5
miles of the site to the east, but the ground gradually rises to a 7800 ft pass
on US Hwy 70. The repeater is in and out to the top of the pass on the west
side, but is solid coverage to the Apache reservation. Coverage drops off
rapidly to the north of the repeater site, as would be normally expected.
73 - Jim w5ZIT
Nate Duehr <[EMAIL PROTECTED]> wrote:
We have a Sinclair SD212 at a 8000' MSL/roughly 2000' AGL site that just
rocks the boat, seriously.
I have no idea what kind of a bounce we're taking, but that site is down
in a valley, and the signal from that machine climbs right out of the
valley (Boulder, CO) and into Denver since we switched from Sinclair
4-bay to the 2-bay.
(Site owner needed us to move tower spots, and the new spot needed a
shorter antenna.)
The current theory is that the "backdrop" of the Front Range mountains
are reflecting the signal with the wider vertical beamwidth of the
2-bay... similar to using a 1/4 wave on mobiles in mountainous terrain
with the repeaters up above them, instead of 5/8 wave antennas.
But no matter how it works, it does! It really booms out of "Boulder
Hole" as we call it, since the antenna switch. I would happily
recommend any Sinclair antenna product.
.
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