Topband: Thanks!

[ZR]

> On 5/21/2013 1:18 PM, ZR wrote:
>> Are you now claiming that the thousands of bead choke baluns in use for 
>> decades at HF and 6M dont work?
>
> I have published extensively on this, first in 2005 in a peer reviewed AES 
> paper, and later in my RFI tutorial. All of this work is on my website. 
> W1HIS published his work on this in 2006. A few years ago, an engineering 
> supervisor at CIA sent me work from an US Army research group prepared in 
> the 70s reaching the same conclusions as I had.  And literature searches 
> for my AES paper found references (in a European ferrite manufacturer's 
> applications notes) to the importance of resistance in chokes as far back 
> as the 50s.


You didnt answer the question and anybody can write papers and create a 
website with a lot of readily available data plus new items that isnt open 
to peer review.

Ive also mentioned to you and others several times over the years of my 
actual involvement with the CIA/DOD Tempest program. There were contributors 
nationwide, companies and individuals, that all created the results that you 
appear to have "discovered" later.


>
>> I suspect that those who have been happy with the results in mimizing 
>> feedline radiation would heartily disagree....
>
> Many people believe many things that are not true.

That is a typical response to criticism or simply asking a question. It 
serves no useful purpose altho it is rather common on Topband.


 Many false beliefs
> are based on a grain of truth. The generalized assumption in ham 
> literature has been that 500 ohms choking Z is sufficient to prevent 
> pattern distortion caused by feedline radiation, but W1HIS showed that 
> increasing choking Z to the range of 5,000 ohms can significantly reduce 
> receive noise.

More nonsense as well over 1000 Ohms, was recognized by the late 70's among 
the serious contesters. While this is Topband, ferrite use isnt limited to 
it and you show broadband graphs.
My own Mosely TA-33 kits did wonders to stop feedline radiation and were 
soon popular with Hy Gain, KLM and others.


 When I saw his paper, I immediately tried multi-turn
> chokes on an antenna that was picking up a lot of noise. The choke reduced 
> the noise by nearly 10 dB. Since I published my work, hundreds of hams 
> have told me they have had similar results.

I thought it was you or maybe Tom that belittled that paper

>
> 73, Jim K9YC

In any case 43 mix large beads and 2.4" toroids did well until 31 came along 
and it still has its benefits.

Has anyone asked Fair-Rite about producing the 2.4" and large beads in 73 
mix?

The following older paper with update should be read by all considering the 
authors 35 year involvement with Fair-Rite. Dont be surprised if some of the 
data and text is already familiar..

http://www.incompliancemag.com/index.php?option=com_content&view=article&id=739:using-ferrites-to-suppress-emi&catid=26:design&Itemid=130

Carl
KM1H
Topband operators do not require adult beverages, just wire ones.