Topband: To Balun or not to Balun that is the question.

[Herb Schoenbohm <herbs@vitelcom.net>]

After reading Tom's (W8JI) excellent work on baluns, which he prepared 
while the rest of us were enjoying SP 2003,  I have his e mail and 
radiation distribution information in a 3 ring binder collection of some 
of the best of 160 tech data. (Most of the really great stuff is from 
this reflector.)  Another item is that there is never really 100% 
agreement on anything and new discoveries on building better mouse traps 
come out almost weekly. I have come to the conclusion that it is better 
to radiate than to dissipate. This is based on the unrefutable 
presumption that "what works best, works."

My question is why use baluns on low bands at all, especially on 
antennas like low dipoles or inverted vees, when feedline radiation 
probably does more for you in the DX department.  Isn't this all the so 
called Carolina Windom claim to fame amounts to, an amount of unbalance 
and radiation from the vertical down lead of an antenna that normally 
would be a sky warmer. (There may be some RFI issues that baluns may 
help avoid  but you could also hang a dummy load at the end of the feed 
line like the infamous Matchcom balun which claimed to allow a single 
wire dipole to work from 2 to 30 with a VSWR below 2 to 1! (I understand 
the vendor of this item now sails his luxury yacht in the Caribbean.  
Apparently he sold enough of these to "balun crazy" amateurs who thought 
the world would be better by hanging something special the end of their 
coax. 

Stew Perry, W1BB made a big point about feedline radiation about 50 
years ago ( long before everyone felt compelled to terminate their coax 
with one of these ferrite rod things).  He stressed the importance of 
when feeding a top band center fed zepp, of adding provisions of  a 
knife switch to actually ground one of the open wire feed wires for 
better low angle radiation. (In the case of a shortened flat top 
connecting both wires together to form a marconi against ground was also 
an option that seemed to work well.) Some years ago an article was 
written, I believe in Ham Radio of adding a third wire in the open wire 
downlead and connecting a phasing device to actually control the TOA as 
required from the ham shack for even better DX results. (I have a copy 
somewhere and will dig it out if anyone is interested.).

I do not use baluns below 10 Mhz. On the higher band I only use the 6 
turn coil recommended for feeding my 204BA and other yagis. On yagis a 
reasonably balanced feed is important for pattern symmetry.  The reason 
to stay away from  a standard voltage balun for me was to avoid a 
breakdown point in the system during contest operation.  One mistake on 
the antenna selector switch during a contest was sometimes all it took 
to destroy standard voltage balun.  (The scramble wound and solenoid 
type seem to have much greater immunity from such mistakes.)

There is however growing and persistent use of  4 to 1 baluns in almost 
every ATU on the market that offers a "balanced feed".  If you use such 
a device you might want to have a clip lead available to compare using 
the ATU unbalanced output feeding the open wire on 160.  I have tried 
several ATU's that use this approach and did not like the heat generate 
in the cores while running normal power. Thus I ended up using the T or 
L match capabilities and avoiding the voltage baluns that they come 
with.  ( I did have a Johnson Viking KW Matchbox with the famous split 
stator breadslicers and no ferrite. In a moment of stupidity I sold it 
on e-Bay for $350.  (It did not have 160 meters but probably was the 
best designed amateur commercial ATU for open wire feedlines ever.)

In summary:  if you have any doubts about why you are using a balun on 
160 meters, you may be further ahead by  removing it and selling it at 
the next hamfest.

Regards,

Herb Schoenbohm, KV4FZ



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