As you'll recall, I have a "stack" of VHF/UHF Yagi's mounted on a small TV
rotor and tripod in my large open attic. All the antennas are currently fed
with 1/2" Andrews Hardline, with the run length for each antenna being about 70
feet. Currently, I have RF sensed mast mounted pre-amps installed at the
antennas. Running low power of no greater than 120 watts on any band. Less on
432 and 1.2ghz.
It occurred to me that I could consider installing additional "brick" power
amps along with an Astron power supply in the attic right next to the antennas.
My thinking is that I'd save some power loss that I'm experiencing in the
feedline now.
Also, I think I'm correct that if I did a path of antenna>rotor loop>power
amplifier>short hardline jumper>RF Sensed Pre-amp>long 1/2" feedline back to
the radio, then I could avoid sequencers (The expense, and I'm unfamiliar with
how they work)
So, VHF Guru's...my questions are the usual:
A. Any problems I'm not thinking about with this plan? If I mount the pre-amp
near the antenna, but after the power amp, I still gain most of the advantages
of a true mast mount pre-amp, and have the convenience of a "in shack" pre-amp
which a lot of folks seem to resort to once power amps are involved. Am I right
about that?
B. I'm thinking that I'll add a 300 watt brick for 2 Meters, and a 300 watt amp
for 432. 220 watts for 222. Nothing on six meters. And nothing on 1.2ghz (have
you priced power amps for that band!??? Wow.)
I assume this isn't done more often because most folks would have to struggle
with getting power to the tower, and weatherproofing the amps. In my case,
neither is a problem.
As usual, thanks for all the advice. I'd be lost without you guys!
73,
Les Rayburn, N1LF
EM63nf
Les Rayburn, director
High Noon Film
100 Centerview Drive Suite 111
Birmingham, AL 35216-3748
205.824.8930
205.824.8960 fax
205.253.4867 cell
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