[TowerTalk] Station Ground

[Gary Schafer]

What I described is Polyphaser's recommendations. :>)

73
Gary  K4FMX


K8RI on Tower Talk wrote:
> The station equipment is all on the same main, but the arc was between 
> two coax cables, both tied to the main grounding bulkhead.
> 
> I think I'll follow Polyphaser's recommendation on the grounding point. 
> It's worked so far and the tower gets hit on an average of 3 times a 
> summer.
> 
> 
> Roger Halstead (K8RI, EN73 & ARRL Life Member)
> N833R, World's Oldest Debonair (S# CD-2)
> www.rogerhalstead.com
> 
>>
>> To be completely properly done, the AC power should also come in 
>> through your bulkhead "ground window" with power line protectors at 
>> the ground window. It doesn't take much of an impedance difference 
>> between lines coming in to let the voltage rise very high.
>>
>> If you can't get the power in through the window, the next best thing 
>> is to run the feed for all the power in the shack over to the ground 
>> window and place protectors there and then feed the shack from that 
>> point only.
>>
>> 73
>> Gary  K4FMX
>>
>>
>>> In that case, explain this:
>>>
>>> My cables come in through a bulkhead. Each cable goes through a 
>>> PolyPhaser (bulkhead connector type) in that bulkhead.  The radio 
>>> station is on a large desk that sets against the West wall.  To the 
>>> left of that desk is a computer desk with the computer that serves as 
>>> control, packet, and sometimes logging.
>>>
>>> I had the cable to the 440 array disconnected from the Alpha-Delta 
>>> coax switch for the UHF/VHF antennas.  The end of the cable with the 
>>> PL-259 attached was laying on the desk top, below and a bit to the 
>>> side of the antenna switch for a total distance of about 10 inches.  
>>> Both duo-band 144/440 rigs set on top of the hutch above the antenna 
>>> switch.  The switch was in the 144 MHz position.
>>>
>>> Remember, all these cables and others go back through that grounding 
>>> bulkhead.
>>> I was at the computer keyboard on the main computer which is on a 
>>> desk against the South Wall which is directly to the East of the 
>>> other computer desk. Both Duobanders (the second connects to a 
>>> colinear vertical side mounted low on the tower) and the 756 Pro were 
>>> operating as well as all 4 computers on the Cat-5e (hard wired) network.
>>>
>>> Lightening struck the tower and there was a briliant flash from a 
>>> very bright arc accompanied by a lound "bang" from the end of that 
>>> cable up to the antenna switch.
>>>
>>> Other than Both UPSs resetting and the network reconnecting there was 
>>> no indication that anything had happened.
>>> However it's only 8 feet at most back to where the cable laying on 
>>> the desk and the cable tied to the switch connect together.  There 
>>> was no damage to any polyphaser.
>>>
>>> It must have been a very rapid rise time to that strike, but with all 
>>> rigs bonded together externally as well as through the cables there 
>>> was no damage.
>>>
>>>>
>>> Maybe that low inductance ground doesn't do anything, but after that, 
>>> I will certainly continue using them in all my installations.
>>>
>>> Roger Halstead (K8RI, EN73 & ARRL Life Member)
>>> N833R, World's Oldest Debonair (S# CD-2)
>>> www.rogerhalstead.com
>>>
>>
>>
>> _______________________________________________
>>
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>>
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> 
> 
> 
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