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Old November 15th 06, 11:03 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default matching 50 ohm line to 75 ohm antenna

On 15 Nov 2006 12:03:12 -0800, "N4aeq" wrote:

You have not stated which LP you are using.


Hi OM,

You never really answered this for Dave.

Im using a double boom LPA,


50 coax connected to the front with shield
to one boom and cc to the other.


Do you have any feedline decoupling/choking?

The back of the boom is shorted with a bar,


That should be a hairpin matching element.

it is a
monoband 50-54mhz
5 element. Swr nowhere near 2:1 (i wish) and i have checked the line
so its ok so maybe
i should have ask how do you adjust the impeadance on a double boom lpa?


The point of a Log Periodic is you are not expected to tune it. The
tune is built into the design as long as it is up high enough (and
probably even if it isn't).

If you SWR is so wildly off, you have a wild problem (feedline is
undecoupled is my guess).

73's
Richard Clark, KB7QHC