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Re: Topband: OT - disconnecting coax and rotor/control cable

To: Gary@ka1j.com
Subject: Re: Topband: OT - disconnecting coax and rotor/control cable
From: Richard Schmiedt <schmiera@bellsouth.net>
Date: Sat, 8 Sep 2018 00:36:21 -0400
List-post: <mailto:topband@contesting.com>
I’ve been hit twice, in SC where we have lots of lightning.  I gave up on 
proper grounding techniques during a lightning storm. My shack is now optimized 
to ISOLATE all station equipment from the antennas, AC mains, and grounds 
coming into the shack when I’m not around. All the stuff coming from the 
outside, like antenna transmission lines are directly grounded to a buss going 
to outside grounding rods, this includes all rg6 lines from RX antennas. 
Rotator cables are detached with 8 pin cinch-jones plugs which are unplugged, 
and the outside ends are tied around the grounding strip to the outside. The 
mains for both 120 and 240V lines optimized for quick disconnect from their 
sockets (including the computer).  Finally the station ground is removed. All 
station equipment and leads are at least 2-4 feet from the ant outside inputs 
to the shack. 

Switches don’t work even with just nearby strikes. Isolation means no grounds 
around for lightning to seek. For a direct strike, all bets are off no matter 
what you do. 

It takes me less than 2 mins to completely isolate my equipment. I have had no 
problems (knock on wood) with my radio equipment over 15 years where I’ve had 
other TVs and electronics in the house blown up by nearby strikes. 

There are many examples of coaxial grounding strips you can use. For the F 
connectors I use slip on connectors. For coax, slip ons are good for low power, 
but I prefer to screw them on for high power.  The KISS principle is your 
friend ...

Good luck and my 2 cents. 

Rick
W4GE

Sent from my iPhone

> On Sep 6, 2018, at 7:14 PM, Gary Smith <Gary@ka1j.com> wrote:
> 
> Don't know where best to post this and I 
> respect the knowledge base here so I'll 
> ask with the OT in the subject line. I'm 
> getting to the point I want to do less 
> effort and still do things right. I had 
> lightning damage to a K3 and don't want to 
> do that again. 
> 
> What enters the house are: 
> 
> - RX antenna controller cables One with 5 
> wires, one with 6.
> - Antenna rotor cable 6 wires. 
> - The remote coax switch 7 wires.  
> - Two coax going to the amplifiers.
> - Two RG-6 coax going to the Rx antennas.
> 
> I would also like to separate the 120 V 
> strips at the same time
> 
> What I would like to do... is have one or 
> two switches to flip that will allow 
> disconnect of all of this. 
> 
> As it is now, I have to unscrew each coax 
> each time I close the shack and re-attach 
> the next time I'm in the shack. I made 
> molex connectors for the Rx controller 
> cables, have not yet done that with the 
> rotor cable nor the remote coax cable. I 
> unplug the power to the terminal strips
> 
> I was thinking of perhaps using relays (I 
> have a lot of SS relays but don't think 
> they would be usable in this endeavor. 
> Maybe relays like in the old SB-220 where 
> there were many individual relays 
> activated at the same time, would work for 
> control/rotor cables. But I wonder if the 
> air gap in such a relay would be 
> sufficient to be a barrier come another 
> lightning issue. 
> 
> I have several vacuum & heavy contact air 
> gap relays that could do the job for the 
> coax. I also have some substantial relays 
> I could use for the power cords involved.
> 
> If I were to have all this in one 
> enclosure, it would be nice to get up, 
> flip a few switches and walk away knowing 
> my station is truly disconnected. At this 
> point I have time to do anything, and I 
> like making things, but only if it's worth 
> the time.
> 
> Thoughts?
> 
> 73,
> 
> Gary
> KA1J
> _________________
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