Topband: Question on common mode chokes

[James Rodenkirch]

Tnx, all, for the comments...learning more and more.... 
 
> From: charlie-cunningham at nc.rr.com
> To: k6uj at pacbell.net; topband at contesting.com
> Date: Wed, 3 Jun 2015 21:57:27 -0400
> Subject: Re: Topband: Question on common mode chokes
> 
> I agree.  We really  don't want the coax shield to be part of the antenna,
> regardless of whether the antenna is vertical or horizontal. If the coax
> shield is part of the antenna, it can seriously distort  the resonance and
> the driving point impedance - hence the need for some common-mode isolation.
> 
> Regards,
> Charlie, K4OTV
> 
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Robert
> Harmon
> Sent: Wednesday, June 03, 2015 4:21 PM
> To: Top Band Contesting
> Subject: Re: Topband: Question on common mode chokes
> 
> Jim,
> 
> It will be interesting to see what others say but my take on this is that
> the tuner function is to provide an impedance match to the vertical and
> doesnt provide any choking.  You still should have the choke.
> 
> 73,
> Bob
> K6UJ
> 
> 
> 
> > On Jun 3, 2015, at 9:42 AM, James Rodenkirch <rodenkirch_llc at msn.com>
> wrote:
> > 
> > I seem to recall, while reading up on common mode chokes, where I wouldn't
> need one if I employ an autotuner at the base of the antenna...is that
> true/factual?
> > 
> > I have an LDG Z11ProII autotuner right at the base of my vertical - I did
> add a common choke at the input to the autotuner (21' of my LMR-400 coax
> wound around a piece of 4.5" PVC for the low bands) but wonder if that is
> really necessary.  
> > 
> > 72, Jim Rodenkirch K9JWV
> > 
> > 		 	   		  
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