[Elecraft] Balanced solution for KAT500 tuner?

[Jim Brown]

On 9/29/2012 11:26 AM, Robert G. Strickland wrote:
> Is there anything to be gained in putting a 1:1 "balanced isolator" at the feed point
> of an antenna that is fed by a "parallel wire" feed line? Does such an arrangement
> achieve feed line isolation while preserving the ability of such an antenna to be
> driven on various bands other than its resonant frequency? Thanks for your input.

Phrases and words like "balanced isolator" and "balun" are not only 
confusing, they are used to separate people from their money.  The 
chokes described in my RFI tutorial can be built for the price of a 
single #31 core, a few yards of THHN wire, and a couple of connectors. 
You can put it in a box if you like, but it's only cosmetic.  These 
chokes will handle legal power IF the antennas are not badly 
unbalanced.  Off-center feed creates massive imbalance, and will fry 
even the best of chokes.  The relatively small imbalances created by 
surrounding objects will not -- they simply couple noise.

#31 cores cost about $4.50 in 1,000 lots, about $7 if you buy 100, and 
$15 from the rip-off vendors who advertise in QST.  It's become fairly 
common for ham clubs to get together and make a group purchase. Over a 
period of about 8 years,  I've been part of several at the 1,000-piece 
level.  There are guidelines in Appendix One of the tutorial about how 
and where to buy.  It's worth buying in quantity, because these 2.4-in 
diameter cores are almost universally useful for RFI suppression.

73, Jim K9YC