[TowerTalk] To get a truly balanced antenna feed

[Edward McCann]

Sent from my iPhone

> On Jun 23, 2016, at 7:10 PM, Edward McCann <edwmccann at yahoo.com> wrote:
> 
> 
> 
> Sent from my iPhone
> 
>> On Jun 23, 2016, at 6:27 AM, Edw McCann <edwmccann at 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 at 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
>>> 
>>> 
>>> _______________________________________________
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk