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[TowerTalk] lightning arrestor's..for coax + rotor's + misc relays'.

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Subject: [TowerTalk] lightning arrestor's..for coax + rotor's + misc relays'.
From: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 18 Jun 2010 06:37:09 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Ok

What kind of lightning arrestors'  are folks using... and where do they get 
installed ?? 

I'm going to run LMR-1200DB  from basement to base of new  HDX-689 tower.   At 
that point, I have to interface
with smaller, flexible coax.. like T-com 600-UF  [or RG-393] .    Since they 
don't make double female connector's
for 7-16 DIN's... I only have a few options.    You can buy female  7-16 dins.. 
that will fit on coax.   Then with a 
male on big coax.. and  a female on small coax.. the two just mate together.  
That also becomes  a 
'demarcation point'.   It also requires interseries gender changing when 
inserting test gear.. and looking up the 
tower.. or back towards the radio gear. 

I thought perhaps a lightning arrestor, installed at base of tower,  would kill 
abt 3 x birds at once.  It would
serve as a lightning arrestor  [ gas discharge tube, etc, between  center 
conductor and grnd].  It would also
allow easy bonding/grnding of BOTH coax cable braids  to grnd.    It would also 
act as an interface between
large and small coax cables.   

ALL coax braids will be bonded to top of tower [ via 1 in, 6 out remote switch 
box.] 

3 x 8' long grnd rods are jack hammered in at base of tower... and cad welded 
aprx 6"  below the grnd. 
Each rod has 2 ga  RW-90  coming off the cad welds... and over to the base 
plate for the tower... where
compression lugs are used. 

Also... 2 ga bare stranded wire.. was C clamped onto one of the 3 x grnd rod 
wires... and run abt 4"  into the dirt...
down the side of the house... and terminated on a  4 th grnd rods  [also cad 
welded]  just outside the basement
entrance point  from my coax, etc.    2 ga RW-90  from this 4th grnd rod comes 
into the basement.. and terminates
onto a huge grnd buss  thick AL plate. 

Here's the kicker.  My  3/4"  copper water line  cracked.. and sprung a leak 
last year.. and was ripped up.. and replaced
with 1"  plastic 'pex pipe'.   The 30' of cu was removed... and replaced with 
30'  of pex pipe... from  water meter  in front yard 
[in a concrete tub 1' below grnd]... all the way to basement wall.. new hole in 
wall... [ 2' below grnd]  and morphed back into
the 3/4"  copper line.. that runs all over the house. 

Problem is... there used to be a 6 ga wire [ inside BX cable sheath]   running 
from 3/4"  copper pipe inside house.... going  over
aprx 20' .. to main 200A panel.    Sure, it's still bonded to the 3/4"  cu 
pipe.... but there is No more buried copper pipe grnd in
front yard... since it's all been replaced with pex pipe !    There is mickey 
mouse 'back door'  path  via the 4" diam cast iron sewer
pipe down at the other end of the basement.  

So what do I use to dirt grnd the 200A main panel ??     I'm seriously thinking 
of running a short length  of 1-0 RW-90... from 
200a panel.... over to my  station grnd  [ aprx 17'] .... inside the basement.  
  At least the station grnd is  a 2' square 
piece of  1/4"  thick  6061-T6 plate mounted on the wall.  The cad welded 8'  
grnd rod... sit's just 3' away from this plate..
on the outside of the house.  [ grnd rod #4] .... which of course.. is tied 
back to base of tower... via 40'  of buried, BARE, stranded
 2 ga copper. [ and tied into the 3 x cad welded rods at base of tower]

Where does the lightning arrestor for the rotor cable.. + misc relay cable go 
??    I could mount it on the huge AL plate in basement
OR I could mount it at base of tower..or both. 

As a side note... I still have yet to run 120 vac [20 A circuit]  to base of 
new tower... to run the 1.5 HP motor for extending the tower. 
The previous owner terminated the UST control box  with a 4'  120 vac cord + 
plug. [ 3 way plug, hot/neutral/grnd] 
 The plug could simply be removed from the water proof new  120 vac receptacle, 
when not in use.   Then less chance of 
lighting getting back into the house... via the grnd/neutral of the new 120 vac 
circuit. 

Although I have the  UST remote switch box [ which allows raising/lowering]  
from the basement shack... I'm not going to use it.
All raising/lowering will be done from base of tower.   The breaker  for the 
new 120 vac circuit outside will be shut off..when 
not in use. 

Am I on track here ?? 

later.......... Jim   VE7RF          
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