Any suggestions how to apply this concept to ladder line/open feed?
Ed McCann
AG6CX
Sent from my iPhone
> On Jun 23, 2016, at 12:48 AM, Ian White <gm3sek@ifwtech.co.uk> wrote:
>
> VE7RF wrote:
>
>> ## Ian mentions the current. If that’s the case, why not just
>> measure the current with a clamp on ammeter.... at say
>> several random places on the coax feedline ?
>
> That is exactly what I try to do - see my website: "Clamp-on RF Current Meter
> - *the* most useful tool for RF interference troubleshooting."
> http://www.ifwtech.co.uk/g3sek/clamp-on/clamp-on.htm
>
> A perfectly functional instrument can be thrown together in half-an-hour. The
> passive diode detector will typically read from about 25mA up to 1A. It is
> also possible to build a much more sensitive log-scale instrument based on an
> AD8307 detector chip (or similar) which will read down to 1mA, but with
> reduced resolution.
>
>> Then we have yet another issue to deal with, and thats
>> what if the coax braid is bonded to the top of the tower ?
>> If a lousy CM choke balun is used at the ant feedpoint,
>> and braid also bonded to top of tower, we can then have
>> a case where CM current is now flowing down the tower.
>
> Well jes' don't do that! Don't use a lousy CM choke at the feedpoint, use a
> good one; and if in any doubt, use another CM choke (which doesn't have to be
> so good) just above the point where the braid is bonded to the tower.
>
> Or best of all, measure the CM current both before and after.
>
>
> 73 from Ian GM3SEK
>
>
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