Good point! My chart shows 7/8" Heliax to have about 0.44 dB loss per
100 feet at 2m, so the 1,000 feet of hardline has about 4.4 dB of loss.
When you consider that a PD220-2 Super StationMaster antenna has 4.85 dB
gain, you literally have minimal return (less than 1/2 dB) on your
investment! This fact is in the "fine print" of the RFS/Celwave
catalog; all PD220 antennas below 150 MHz have 4.85 dB gain, not 5.25 dB
as shown in the specs.
So, the antenna could be dropped 900 feet lower on the tower, away from
all of the big boys upstairs, and perform much better. I assume that
the tower is already on a hilltop, so the height of the 2m antenna on
the tower is not that great an influence on its range. I agree with
Derek that an important goal is to put some vertical separation between
the 2m antenna and all of the other antennas.
73, Eric Lemmon WB6FLY
"Derek B. McIntyre" wrote:
...Finally, 1000 feet of 7/8 has what, 3 or 4 dB of loss on VHF if the
cable is good. You'd probably never know the difference if you
eliminated the whole run.
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