I quite aware that open line is generally considered lost less feed line.
What threw me was the use of a 1:1 balun instead of a 4:1.
That's the head scratcher.
Mike wb8vge
Sent from my iPhone
On Jul 11, 2013, at 9:32 PM, k6jek <k6jek@comcast.net> wrote:
> Mike,
>
> You're matching the antenna system, the antenna and the feed line. You just
> can't separate the two. When the antenna impedance at a particular frequency
> is different from the feed line characteristic impedance, the impedance on
> the line is different every place on the line. You're matching whatever it
> happens to be at the shack end of the feed line.
>
> Losses are the reason to put the balun near the station instead of near the
> antenna. Open wire line has much lower losses than coax under conditions of
> very high SWR. That's the reason we put up with the stuff which is a royal
> pain in the arse, just so we can have a ridiculous SWR and not care about it.
> And very high SWR is exactly what we have at almost all frequencies when
> using a doublet as a multi-band antenna. The only reason we can get away
> with such a thing is the low loss of open wire line. So you want to run that
> stuff as far as you can before switching to coax. As long as you can is
> ideally right into a balanced tuner, no balun at all.
>
> Jon
>
>
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