Topband
[Top] [All Lists]

Re: [TowerTalk] Fabricated common mode chokes and their impedances

To: "Tod" <tod@k0to.us>, <topband@contesting.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Fabricated common mode chokes and their impedances
From: "Jim W7RY" <jimw7ry@gmail.com>
Reply-to: Jim W7RY <jimw7ry@gmail.com>
Date: Sun, 28 Aug 2011 20:35:07 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I notice the holding bolt is steel. Do you think this had any effect on your 
measurements?  I know that if you use this method on L-coil or the PI coil 
in a linear amplifier, the bolt heats considerably.

Thoughts?
73
Jim W7Ry


--------------------------------------------------
From: "Tod" <tod@k0to.us>
Sent: Sunday, August 28, 2011 3:51 PM
To: <topband@contesting.com>; <towertalk@contesting.com>
Subject: [TowerTalk] Fabricated common mode chokes and their impedances
> This probably has a limited audience but I do know that there are some
> readers on this list interested in fabrication of high impedance common 
> mode
> chokes for their stations.
>
> I built and measured 18 of this type of choke during the past week. There 
> is
> a write-up on my web site which shows how they were fabricated, how they
> were measured and the measurement results. I used Fair-Rite 2.4 inch
> diameter type 31 toroidal cores and small diameter [RG 59 size} coax. I
> measured the magnitude of the impedance for each of the chokes on the 160,
> 80, 40, 20, 15 and 10 meter bands. There are also attenuation values for
> each choke [specific to the 50 ohm measurement circuit]. The results are
> shown as a series of graphs for two cores, three cores and four cores with
> 3, 4, 5, 6, 7 and 8 turns on the core bundle.
>
> These graphs should provide guidance to those fabricating their own common
> mode chokes.
>
> The site is
> http://www.k0to.us/HAM/ham.htm
>
> The article is under Experiments & Measurements
>
> "Measurement of Chokes made using type 31 material cores"
>
>
>
> My work is an extension of material found in the excellent paper on this
> subject written by Jim Brown, K9YC, which has been mentioned here before.
>
> Tod Olson, K0TO
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk 

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>