[TowerTalk] CM Choke Cookbook

Wayne Kline w3ea at hotmail.com
Fri Sep 22 19:52:18 EDT 2017


I also use M-17 - RG 400  MIL-17-G   v  on my  Balun , line isolators and all  in shack coax.


It's Double Shield ,stranded Center Cond  and Silver-plated    TFE   insulation and jacket.


I had made a few  20 years ago open construction on Plexiglas  .250 thickness..... the Plexiglas fell apart from WX and UV  but the  Balun hung  by it's connection wire to the beam and the coax RG214  ( it's now inside a  PLASTIC NEMA box... )


Wayne W3EA


________________________________
From: TowerTalk <towertalk-bounces at contesting.com> on behalf of Stan Stockton <wa5rtg at gmail.com>
Sent: Friday, September 22, 2017 7:21 PM
To: Grant Saviers
Cc: towertalk at contesting.com; jim at audiosystemsgroup.com
Subject: Re: [TowerTalk] CM Choke Cookbook

RG-400 is way better in my opinion because of stranded center conductor.

Stan, K5GO

> On Sep 22, 2017, at 6:01 PM, Grant Saviers <grants2 at pacbell.net> wrote:
>
> I've made 20+ with RG142 using the "cookbook" smaller coax turns and core counts, 160 to 10.  Measured with my VNWA the L & R values are near the expected.   The TFE is UV resistant and some chokes are in PVC junction boxes and some not.  At 6m the RG142 is at its QRO limit, below that it is fine QRO+.  My 142 is the double braid silver plated version, it comes both ways with the same obsolete RG unless it is MIL marked as mine is.
>
> Grant KZ1W
>
>> On 9/22/2017 13:48 PM, Jim Brown wrote:
>>> On 9/22/2017 8:16 AM, David Needham wrote:
>>> I have made several full power CM chokes for 80m and 160 m using RG213 and
>>> Mix 31 toriods per your articles. Do the number of cores or turns count
>>> change if I use RG142 for lighter weight?
>>
>> Dielectric and o.d. of the coax both affect resonance. I have no data for RG142, but I suggest that you start with the guidelines for RG59/RG8X.
>>
>> 73, Jim K9YC
>>
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