With a picture perfect antenna, dipole with coax running 90 degrees from the
radiator, placing a balun or choke (basically same - same) at the feedpoint
is a WASTE OF MONEY. For all practical purposes there is not cmc being fed
back into the coax. I HAVE MEASURED AND ASURED THIS!
Placing a choke at the house (end of the feedline, just before entering the
house) is always a good idea.
I ALWAYS do it.
I have measured data to support my claim.
If you have not measured it yourself, you are speculating.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Bob McGraw
- K4TAX
Sent: Sunday, June 01, 2014 8:01 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Trading radios
OK so with a center fed dipole fed with coax we have a balanced antenna fed
with an unbalanced feed. A 1:1 common mode choke is suitable to be placed
at the antenna feed point.
Now, since the antenna radiates, and the coax will be in the near field,
thus the shield will have some amount of RF induced on the outside or
shield. Therefore one needs some form of Common Mode Choke at the radio.
If one chooses to use only one Common Mode Choke or Line Isolator, best
first placed at the radio.
73
Bob, K4TAX
----- Original Message -----
From: <k4elo@fastmail.fm>
To: <tentec@contesting.com>
Sent: Sunday, June 01, 2014 11:42 AM
Subject: Re: [TenTec] Trading radios
> Disagree Bob. Put the choke at the feedpoint of the antenna or your
> coax will be radiating rf all the way down to the rig. If you can't
> move the antenna, this is the most effective rfi fix.
>
> 73
> Wayne
> K4ELO
>
>
>
>> For starters, as to RFI issues, yes antenna to radio spacing, increasing
>> same, will usually improve the issue. Be sure all equipment is each
>> bonded to a common point such as the PS ground. Omit the external
>> ground but keep 3rd pin ground intact. Use a common mode choke on the
>> output of the radio.
>>
>> 73
>> Bob K4TAX
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
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