"DJboutit" wrote
want to get stations at least 100 to 150 miles away.
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VHF basically is a line-of-sight service, although favorable propagation
conditions can extend that range at some times of the day and seasons of the
year, for some receiving locations. When those conditions exist, it doesn't
take much of a receiving antenna. When they don't, no practical receiving
antenna will work well.
For an FM station radiating 100kW from a 1,500 foot height above average
terrain, at a 93 mile range the FCC's f 50,50 curves predict a field
strength of about 75 microvolts/meter at a receiving antenna height of about
30 feet above ground. And that only occurs for "uncluttered" paths to 50%
of locations at that distance, 50% of the time. Urban clutter and/or lower
rx antenna height will reduce those fields strengths considerably.
As a cal point, my situation with St. Louis FM stations parallels the
conditions above. Using a McIntosh MR-73 tuner with a Wineguard CH6065
10-element FM antenna (10dB gain), they are received with reasonable stereo
quality about 1/2 the time.
RF
Visit
http://rfry.org for FM broadcast RF system papers.