Re: [IRCA] More on noise suppression
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Re: [IRCA] More on noise suppression



Mine are made using RG174 coax on a FT140-77 core:

http://www.quebecdx.com/P1010201.JPG

http://www.quebecdx.com/choke.JPG

Sylvain Naud
Portneuf, QC


Le 2011-08-01 14:02, Chuck Hutton a écrit :
I would not recommend using RG58 to wind a choke. You just can't get enough turns of RG58 (even with a big core) to make a good choke. That's why receiving applications usually use a box with connectors, a big core, and have windings made with a small coax such as RG187, 188 or 316. You'll easily get 3 times as many turns and therefore 9 times the impedance. Unless you live on top of a silver, copper or gold mine you'll get a lot of benefit from the higher impedance.

Chuck


From: Mark4@xxxxxxxxxxxxxxx
To: neilkaz@xxxxxxxxxxxxx; irca@xxxxxxxxxxxxxxxx
Date: Mon, 1 Aug 2011 08:38:00 -0500
Subject: Re: [IRCA] More on noise suppression

Photo sent off-line. It's really easy to do if you have the right size
rings (as id'ed below) and your connectors aren't too big.

Regards,

Mark Durenberger

--------------------------------------------------
From: "neilkaz"<neilkaz@xxxxxxxxxxxxx>
Sent: Sunday, July 31, 2011 10:07 PM
To: "Mailing list for the International Radio Club of America"
<irca@xxxxxxxxxxxxxxxx>
Subject: Re: [IRCA] More on noise suppression

Please forgive my ignorance here as I remain quite confused. How does one
wind rather thick coax or CAT5 around small toroid rings. A picture or
link will be worth a thousand words here.

http://www.dxing.info/equipment/coax_leadin_bryant.pdf is an article where
Dr. Bryant (RIP old friend) was able to make a choke winding tiny coax
many turns, but I can't see how this is possible with something link RG58
unless I don't understand how to make a choke.

Following Dr. Bryant's guidelines, I unhooked my BOG from the xfmr and was
getting S5 to S6 on the super strong close Chicago superpowers and a few
semi-locals also were still audible, some barely moving the S-meter. So I
have some work to do.

73 KAZ


-----Original Message-----
From: Mark Durenberger<Mark4@xxxxxxxxxxxxxxx>
Sent: Jul 30, 2011 3:43 PM
To: Mailing list for the International Radio Club of America
<irca@xxxxxxxxxxxxxxxx>
Subject: [IRCA] More on noise suppression

Here's a paper that Fair-Rite publishes on core materials. It's pretty
much
agreed that their Material # 31 is overall best for MW/SW noise
suppression.
The recommended toroid rings are Fair-Rite # 2631803802. An effective
noise
choke can be realized with 9 to 14 turns of the lead-in (coax or Cat 5)
wound around 5 of these toroid rings.

http://www.fair-rite.com/newfair/pdf/CUP%20Paper.pdf


Regards,

Mark Durenberger



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