I'm pretty sure that there is a lot of evidence, both empirical and
theoretical, that says pattern is important when you're trying to
actually aim at something or when you're concerned about interaction
among adjacent antennas ... not to mention the implications for RFI and
noise rejection that a well behaved feedline offers. But the silliest
part of your argument is the bit about not worrying about "a couple of
db", since the effects can be considerably greater ... and if a few db
and a predictable pattern wasn't worth pursuing there wouldn't be much
point in using anything other than a simple vertical in the first place.
Dave AB7E
On 11/26/2014 10:48 AM, Wilson wrote:
I have asked my resident experts (U know who u r.) and added my own unschooled
opinion.
For the three band range (20-10) it’s really trivial.
Going on down to 30 and 40 is only slightly more tricky.
The ARRL Antenna Book deals with this quite concisely and gives winding data for the
“best” chokes for each situation.
Looking a little deeper, they say that if the coax goes down the mast, so it
doesn’t pick up and reradiate a lot of energy (which compromises the pattern),
the balun isn’t really needed. So maybe someone will swing some patterns
with and without the choke, for us?
My own take is that after hearing a lot of talk, much of it BS, and being exposed to a lot of
colorful ads, we have developed a “need” that far overshadows reality.
And if the coax choke works, why on earth would one want to spend $50-$100,
which will buy a LOT of beer, on $10 worth of stuff crammed into a little box
AND four more connectors to get wet?
I think there’s a real possibility that the losses in the fancy balun, not to
mention poor ones, may be more of a problem than the pattern distortion caused by not
having one.
EZNEC is absolutely astonishing and a wonderful thing, but you can’t let it
wind you up over a couple of dB when you are dealing with propagation ranging over 60
dB!
Isn’t it amazing that the $18,000 Hilberling had to go back to the factory?
Of course this is a simpleminded argument, so it should be easy to show why
it’s incorrect, right?
Wilson
W4BOH
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