Those new to broadcast V/UHF may be surprised to learn that you can sometimes see “over” a hill or mountain using knife edge refraction.
I am amazed I get deep fringe channels from my location north of Toronto, on the “ blocked side” of the Oakridge Moraine (a high landform that separates Lake Ontario and Lake Simcoe- like the Great Divide ). Toronto and Buffalo are also in the low Lake Ontario basin .
Even worse, I am also in a very low valley and completely blocked to the south - towards the signals of Toronto and Buffalo.
Yet, with my 60 ft tower and yagi with corner reflector (gleaned from a vhf-uhf deep fringe ant) I get most UHF channels from Buffalo ! (and Toronto- tnx to the CN Tower)
It sometimes depends on WX, but I believe it is more due to knife edge refraction off the newmarket hilltops ( top of the valley) and/or the Morain , and NOT Tropo.
Give it a try if your buried in a low valley or on the backside of a high landform.- u may be surprised.
I haven’t bothered trying it on lowband VHF- I don’t have a suitable antenna (or room on the tower) I’d love to get channel 7 - WBBZ.
Note: This effect is also used on VHF radio communications -with 10 Watts and short boom yagi I can talk to Ripply NY and Erie PA
Knife edge refraction!
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Re: Knife edge refraction!
Well, I'm just outside of Toronto (near Lake Ontario) and I've got two pairs of bow-tie feeds at the convergence region of my 12' c-band dish and I can pickup up all 1st-edge, 2nd-edge and most Tropo signals from Peterborough, Mid-Western Ontario, Rochester, Buffalo, Erie, Hamburg and a few others. It helps to have your dish motorized (azimuth, elevation, skew), so you can scan the whole sky.
I've scanned nearly 150 "local" channels (the norm for Toronto with a standard 8-bay antenna is about 50 channels if you are lucky) into the ZGemma and I'm sure there are hundreds more. You just need a really narrow-beam and pin-point accuracy to pull them in. Most Tropo signals have a signal-to-noise ratio that can vary by 10-15 dBs over a few hours as atmospheric conditions change dramatically. You'd be surprised whats "up" there...
I bet a motorized 14ft or 16ft parabola could potentially scan over 300 channels from places as far away as Detroit and Cleveland, even Chicago, NY and Montreal. Got to try it someday.
Who needs local spot beams from DTV and Dish when you got your own TVRO.
I've scanned nearly 150 "local" channels (the norm for Toronto with a standard 8-bay antenna is about 50 channels if you are lucky) into the ZGemma and I'm sure there are hundreds more. You just need a really narrow-beam and pin-point accuracy to pull them in. Most Tropo signals have a signal-to-noise ratio that can vary by 10-15 dBs over a few hours as atmospheric conditions change dramatically. You'd be surprised whats "up" there...
I bet a motorized 14ft or 16ft parabola could potentially scan over 300 channels from places as far away as Detroit and Cleveland, even Chicago, NY and Montreal. Got to try it someday.
Who needs local spot beams from DTV and Dish when you got your own TVRO.
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http://www.tek2000.com
#1 Supplier of TVRO Satellite Equipment in North America
[email protected]
(I am not on this forum often and don't check forum PMs, so please email me for faster service)