Sent from my iPhone
> On Jun 23, 2016, at 6:27 AM, Edw McCann <edwmccann@aol.com> wrote:
>
> 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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