[TowerTalk] Fwd: Antenna to Shack Ground Connection

[Roger (K8RI) on TT]

The tower doesn't even have to be close.  The idea of tying all grounds 
together is to have all equipment to rise (and fall) to the same 
voltages at the same time.

As for induced voltages, a strike a mile distant can induce as much as a 
thousand volts per meter into a piece of wire, so imagine one in the 
neighbor's yard.  Signal strength falls as the square of the distance, 
so what's a 100 yards compared to 1700 @ 1000 volts/meter.  That's a 
ratio of 170:1.  or  a strike in the neighbor's yard could induce as 
much as 28,900 times as much voltage in a meter of wire.

Sounds like a good reason for a good grounding system and why most 
damage is from nearby strikes.  There's a lot more nearby strikes than 
direct hits.

73

Roger  (K8RI)


On 1/30/2015 10:17 AM, john at kk9a.com wrote:
> Even with no connection, if the tower is close to the house everything
> inside will be vulnerable due high voltages induced into electrical system
> from a lightning strike.
>
> John KK9A
>
>
> To:	Towertalk <towertalk at contesting.com>
> Subject:	Re: [TowerTalk] Fwd: Antenna to Shack Ground Connection
> From:	Bill Turner <dezrat at outlook.com>
> Date:	Wed, 28 Jan 2015 17:36:56 -0800
>
>
> At the risk of starting a flame war (wouldn't be the first time), I
> have to question the purpose of running a ground wire from the tower
> to the shack.
>
> What is it you are trying to accomplish?  Or putting it another way,
> what current are you expecting to flow between your tower and your
> shack?
>
> If your tower takes a direct lightning strike, won't a small
> percentage of the strike find its way into this ground wire, and since
> the wire to earth connection is not zero ohms, some of the strike will
> find its way into your shack?
>
> Even if you disconnect your coax and rotator cables during a storm,
> this ground wire leaves your shack vulnerable, doesn't it?
>
> Does not sound good to me but if there is a good reason, I want to
> hear it.
>
> Bill W6WRT
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk


-- 

73

Roger (K8RI)


---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com