[R-390] TV Balun for R-390A

[Charles Steinmetz]

Roy wrote:

> I can’t easily locate discussions of the past about using a TV coax to twinned balun on the (balanced) RF input to my R-390A.

Hi Roy,

The lower boundary of the traditional (US) TV broadcast band was 44MHz, 
so most TV baluns are specified only for VHF and UHF and do not do well 
at HF.  (Actually, most commercial TV baluns are not really "specified" 
at all, at least as far as published data is concerned, or they are 
"specified" so sparingly as not to be useful.  Even a quality 
manufacturer like ChannelMaster does not give *any* frequency response 
data for its CM9444 and CM3203 baluns.)

listings of some commercial baluns:
<https://www.amazon.com/s?k=baluns&i=electronics&x=13&y=21>

It is probably best to stick to Mini-Circuits and similar manufacturers 
who provide real technical data. 
<https://www.minicircuits.com/WebStore/Transformers.html>  (Enter 
Frequency Low = 0.01MHz, Frequency High = 50MHz, and check "Single-Ended 
to Balanced" to get a manageable list of HF balun candidates.)

Or, wind your own -- it's easy.

tutorial:  <http://vk5ajl.com/projects/baluns.php>

Best regards,

Charles