On Thu, 2009-05-21 at 03:35 -0700, Jeff wrote:
> I have a palstar tuner and as a tuner think it is great. BUT !!! mine the
> model AT1KP has a really crappy balun. The balun fried at 600 watts and is
> grossly under sized. To make matters worse the used a 4:1 balun i this model.
> I contacted Paul about the fried balun and got a silly reply that the tuner
> will only match 200 ohm loads on the balanced lugs. "what" Here is the
> email replies from Paul.
> t is 200 ohms in balanced mode only as the balun
> is a 4:1 current balun
> You also said that you were in balanced
> mode
> The other specs are for the coax mode
> Regards Paul
> AND
> The Z that the balun is looking into must be out of
> the range of the
> 200 ohms that is the output Z of the balun
> itself
> This is an antenna problem not a balun
> issue
> R Paul
>
> Again love the tuner Just needs some serious improvement's in the balun area.
> Jeff N3JBH
>
That's the fundamental problem with tuning trough a balun. If the load Z
is high the voltage goes high and saturates the core which leads to much
loss and heating. If the load Z is very low, the wire can overheat, and
in that case the impedance ratio is exactly backwards.
I quit liking tuning through a balun one day about 1961 when I tuned up
an antenna through a balun and the tuning didn't change when I unhooked
the antenna. I had tuned up the balun, not the antenna feed. That can be
another way to fry the balun.
I prefer a link coupled tuner that needs no balun for balanced feeds.
They have been working reliably since the 1930s. I've used them on the
same center fed wires from 160 meters through 2m very effectively. One
of those was 325 feet long.
73, Jerry, K0CQ
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