[TowerTalk] Pattern Distortion caused by faulty balun?

[Tony]

All,

Jim Browns paper on baluns and chokes is very informative. It's written 
so even a layman (like me) can get the gist of what a choke is supposed 
to do.

As far as I can tell, the pattern on my M-Squared 5 element mono band 
Yagi seems fine. I use the  calibrated s-meter on my Flexradio to check 
the antennas pattern. It measures signal strength in dbm as well as 
s-units and the front-to-back varies between 18 to 24db (sometimes a bit 
more). The overall pattern seems fine.

That said, I'd still like to check the to see if the M2 balun is 
isolating the feed line from the antenna. It's not exactly tower work 
weather here in the northeast so I was wondering if there's a way to see 
if the balun is doing it's job from inside the shack?

HNY...

Tony, K2MO
> On 12/30/2011 10:25 AM, Tony wrote:
>> I'm told there
>> are better baluns available and was wondering if you could recommend one
>> that has greater isolation capabilities -- or at least one that's known
>> to work well.
> Sure. I've done a lot of research in that area, and published the
> results in
>
> http://audiosystemsgroup.com/RFI-Ham.pdf
>
> I don't recommend any commercial products because nothing I've tested is
> very good or even worth the cost, and because it's VERY easy to make
> your own VERY GOOD one by winding turns of coax through some ferrite
> cores. Specific recommendations are in the Choke Cookbook chapter of the
> above reference. Appendix One lists part numbers for the ferrite cores
> and some recommended places to buy them at reasonable prices.
>
> 73, Jim Brown K9YC
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