All of my equipment is connected back to a common point on the power supply
which is as described by Bob so the station fundamentally is setup correctly
including external station where I do have PolyPhaser lightning arrestors
located. I think most of us know that direct hit and close-in hits can overrun
our best efforts but best efforts have been made and when we know of a
potential situation brewing, as much as possible is simply disconnected.
Back to the switches, ALPHA DELTA recommends external grounding their switches
to the station ground. And of course these switches contain Arc-Plug's which I
believe are gas filled. The switch-active position is protected by these.
The "COM" position is also protected by the Arc-Plug. I mean the COM position
does NOT short to ground when rotated to this position as represented by the
label, at least not until a high energy situation occurs and the energy passed
through the Arc-plug to the station ground or attempts to get to ground through
the '259 connectors and coaxial braid.
Non-active switch positions are indeed shorted to the frame of the switch
housing which includes the barrel-threads of the SO-239 connectors.
Have I opened a big can of worms here? I hope everyone will consider this
thread a relevant topic to our investments in T-T equipment as well as our
personal safety. Ok…and other gear too.
Gene / K7TXO
On May 3, 2012, at 6:19 AM, GARY HUBER wrote:
> I second Bob's last comment. Better to provide a LOW impedance path to
> ground outside with gas tube or arc gap low impedance paths to ground
> outside, then high impedance (to the AC component of lightning) paths via
> drip loops and choke sleeves to the inside as commonly executed in
> commercial antenna entrance cable protection installations.
>
>
> 73 ES DX,
> Gary -- AB9M
> -----Original Message-----
> From: Bob McGraw - K4TAX
> Sent: Thursday, May 03, 2012 7:51 AM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] TEN-TEC shack photos [flat braid; antenna switch]
>
> The method suggested by Bob McGraw is to have each piece of equipment on the
> desk connected to a common point, preferably the station power supply ground
> terminal. I use #10 AWG automotive primary wire for this application. Lugs
> on each end are crimped and then soldered. One jumper for each piece of
> equipment to the common point or ground lug on the station supply.
>
> On lightning protection, this should be outside of the house using devices
> such as Alpha Delta systems, Polyphaser or arc gaps and these should be
> applied to all feedlines and rotor control cables. Be sure the ground
> system for the station or tower is bonded back to the AC mains ground and
> this should be done outside of the house.
>
> NEVER invite lightning into the house with the idea of running it to ground.
>
> 73
> Bob, K4TAX
>
>
>
>
>
> ----- Original Message -----
> From: "Gene Story - Earthlink" <gfstory@earthlink.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Thursday, May 03, 2012 1:57 AM
> Subject: Re: [TenTec] TEN-TEC shack photos [flat braid; antenna switch]
>
>
>> My picture does not show where the braid connects and others might like to
>> know the rest of the story. I am definitely interested in feedback.
>>
>> While I want to insure optimum path for a potential lightning hit, I did
>> have some worries that bonding these switches directly to my station
>> ground would be more of a hinderance as a ground loop path. Presently
>> that large flat braid goes to a small bar with two automotive spark plugs
>> threaded on it. The tip-caps of these spark plugs connect to my station
>> ground.
>>
>> The idea is that I have not set myself up with a potential ground loop,
>> rather I have a high impedance situation with the spark plug gap under
>> normal circumstances. An abnormally high energy situation may jump the
>> plug-gaps, in the hopes of shunting what could otherwise be damaging to
>> equipment through other paths.
>>
>> I admit not having enough theoretical background to know if what I
>> assembled is a sound idea. I put this together because the parts were
>> at-hand/easily fabricated, and this went together in a jiffy. But in the
>> interests of performing reasonable protection for equipment and operator
>> inside the station, have I set myself up for more negative than positive
>> results with the spark gap? And if this is plausible, would it be better
>> for each switch to have individual (direct or spark-gapped) paths as I
>> have with each piece on the desktop back which is patterned after Bob
>> McGraw's recommendations for grounding?
>>
>> Gene / K7TXO
>>
>>
>> On Apr 29, 2012, at 10:29 AM, Merschrod wrote:
>>
>>> The shack photos are interesting all right. I liked the flat braid
>>> ground
>>> straps into an antenna switch cabinet.
>>>
>>> BUT what is that neat little paddle under OZ1BII's Eagle? I can't make
>>> out the manufacturer's name.
>>>
>>> Kris KM2KM
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|