[Towertalk] Coax ground at tower

n4kg@juno.com n4kg@juno.com
Thu, 25 Jul 2002 09:10:09 -0600


With a 115 ft coax run, the maximum loss in RG213  will be
around 1.5 dB at 28 MHz and 1.0 dB at 14 MHz.

Low Loss Coax will save you at most 1 dB (for 0.3 dB /
100 ft cable) and only 0.5 dB for 0.6 dB/100 ft cable at 28 MHz.

Tom  N4KG

On Thu, 25 Jul 2002 01:10:17 -0400 "David" <k4zzr@bellsouth.net> writes:
> Hello...  My transmitting equipment will be between 1.5-50Mhz fed 
> with 50ohm
> LMR-400 coax cable using UHF-PL259 connectors.   According to 
> Polyphaser, I
> need to know exactly which product do I use at the top of the tower 
> and the
> bottom of the tower to provide the ground to my coax shield?  I've 
> seen
> websites showing the use of  "cable grounding kits" but not sure 
> where and
> what kind I should get?  I've seen what appears to be the coax 
> attached to a
> UHF bulkhead splice connector with a clamp on it that's attached to 
> a ground
> wire connected to the tower leg.  I guess I need some specific 
> product
> numbers if any of you have done this successfully.  This will be on 
> a US
> Towers HDX-555 crankup galvanized tower.  Incidentally, I'm already 
> using
> ICE lightning arrestors on a copper SPG bulkhead.
> 
> Another question....the total run from shack to antennas will be 
> about
> 115'.....should I use LMR-400 up to the top of the tower and then 
> use
> LMR-400UF (ultraflex) for the remainder to the antennas so there's 
> less
> twisting stress to the coax around the rotator?   Or should I just 
> stick
> with RG-213 for the whole length?
> 
> And finally, which product do I use to attach my copper ground 
> radials to
> the galvanized tower legs?
> 
> Thanks for any advice,
> David, K4ZZR
> 
> 
> _______________________________________________
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