I'd say that's a relatively expensive and potentially dangerous item to
leave outside in the snow.
I want to be near enough to observe the amplifier's operating
characteristics and be aware of any funny sounds, smells, smoke, bright
flashes, or meter excursions. At some cost these observations could be
remoted with the appropriate sensor and automatic protection circuitry.
I can more easily consider putting a high power auto tuner out there and
running feedline with reasonable SWR so that the coax losses aren't great,
but keep the amp in the shack.
Just personal preferences. What you propose is certainly possible. I would
assume that there are commercial and military equipment that does this...
Dick, K6KR
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of van wd8aam
Sent: Tuesday, April 13, 2010 12:16 AM
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Coax Question
In regards to long runs of coax, has any thought EVER been
given to RG213 to a remote tuned high power amplifier
at the base of the tower. I've thought about it, and for
costs, it might be cost effective. I'm sure someone has this
working for them somewhere. What do you guru's say to this?
van
wd8aam
At 06:04 4/13/2010, you wrote:
>On Mon, 12 Apr 2010 21:07:25 -0400, Steve Bagley wrote:
>
> >I am putting up a tower and will need to run about 500 feet of coax.
>
>http://audiosystemsgroup.com/Coax-Stubs.pdf
>
>500 ft is a LONG run. You can easily burn half your TX power (3dB) in the
>coax. Many of us try to keep feedline loss under 1 dB. 500 ft of LMR400 is
>3.3 dB on 10M, 2.3 dB on 20M. Half-inch heliax is 1.1 dB on 20M, 1.6 dB on
>10M. To get under 1 dB on 10M you'll need 7/8-inch Heliax. :)
>
>Another option to consider is CATV hardline. It's pretty low loss, it is 75
>ohm cable, so there will be a bit of mismatch, but that's why God made
>antenna tuners. It's often possible to get it free or cheap. You'll have to
>buy or scrounge connectors and a tool.
>
>Study the data on W3LPL's and K1TTT's website and save your pennies.
>
>73,
>
>Jim K9YC
>
>
>
>
>
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>
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