Some Notes on RFI

21 Sep

The PDF that this article points to has been removed as I had an error in my data. In actual fact I miscounted turns in the series chokes (Not the Binocular one). Inasmuch as the miscount is propagated into captured screen shots from my AIM 4170 I will need to rerun the data to insure it is correct. This may take some time. I apologize for the error and any inconvenience.


I recently attended a club meeting where a fellow asked about making a choke for his 20 Meter antenna. During that conversation I focused mostly on a two snap-it constructed choke as it is simple, works for the general 1-30 MHz range that HF ops are mostly interested in and can be repeated along a transmission line or interconnect cable to great advantage. In my case I use four such chokes along my transmission line between my amp and antenna.

The subject of how to wind these chokes came up and so I found that intuitively, I thought I knew the correct answer but I had not done the physical construction and measures to cement my thoughts. Therefore I undertook to make the measures and so have collected a lot of data that I would like to make available here. To that end Ive made a PDF and included some links to other data set pdfs so that you can manually go through the information should the graph provideĀ  insufficient detail.

Anyway, I trust this may be of some use to Hams with RFI issues.

The document can be found here.

Thanks for reading my Blog. Best, Chas W5PG

1 Comment

Posted by on September 21, 2011 in Radio, RFI


One response to “Some Notes on RFI

  1. Paul PC4T

    September 21, 2011 at 7:42 pm

    Hi Chas, I always use a RF choke. I make such thing intuitive. The info you publish is very useful, thank you. I hope everything is okay with you, take care, 73 Paul


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