[VHFcontesting] Amps in the Attic

[Les Rayburn]

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
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