Date: Wed, 05 Aug 2015 20:06:30 -0700
From: Grant Saviers <grants2@pacbell.net>
To: Steve Maki <lists@oakcom.org>, towertalk
<towertalk@contesting.com>
Subject: [TowerTalk] surge arrestors or good grounding?
I'm wondering what commercial practice is re surge arrestors?
I note the max power ratings for DIN connector arrestors is 250 watts at
least at Tessco. Many are frequency selective. PolyPhasers claim 2500
watts 1.5MHz to UHF.
With top and bottom tower bonding to a ground rod grid and 125' to tower
in a trench with the shack entry plate feedthrough grounded to a 200'
perimeter footing Ufer, to center pin arrestors do anything useful?
Tower and trench coax is all DIN terminated hardline, so it would make
sense to connect to a DIN connector arrestor (if useful), but no such
QRO animal seems to exist.
Grant KZ1W
## I use the HOFFI german brand of lightning arrestor.
These are 7-16 DIN type..and female din at each end.
Model LP 7756. Rated for 10 kw into 3:1 swr.
And 20 kw into a 1:1 swr. Peak V is 1400 V. 20K amps.
Dc up to 2.6 ghz.
http://www.arraysolutions.com/Products/hofi-lp.htm
Hoffi arrestor specs catalog
http://www.arraysolutions.com/images/1_Ueberspannungsableiter.pdf
These things are a thing of beauty. I use one at base of tower as a
demarcation point, and where the LMR-1200DB
changes to the smaller RG-393 coax. A 2nd one is located at the SPG. The
gas discharge tube is field replaceable.
Use a lower rated peak V unit, just in front of the Xcvr, for better RX
protection.
Array solutions still sells them, + all the other HOFFI lightning arrestors.
Jim VE7RF
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