Topband: BCB Filter (related to Antenna Analyzer question)

n4is n4is at bellsouth.net
Sat Oct 17 11:41:15 PDT 2009


Rick

> Telepost makes a Digital Vector Wattmeter, model LP-100A, that also

>>I need to know the complex impedance of the antenna, not the
impedance at the transmitter.  


We have few available options. I am using the LP-100 for several years and I
love it. To know the impedance at the antenna there are several programs to
help with. I used "TLine", it is easy to find it in the internet and it is
free. Them I connect 2 know loads at the end of the cable, and adjust the
cable parameters, like speed, length, and other so the line impedance
reading with the LP-100 and load into TL, shows the impedance I connected.
After that calibration IO connected the feed to my TX antenna and read the
input impedance at the LP100, feed it into TLine and get the real impedance
ant the antenna feed point.

That way I was able to get close to the real impedance and I was able to
calculate a better matching circuit to feed my 160m 1/4 wave UNIPOLE. It
worked just fine. 

I agree, it is not practical but it works.

Regards
JCarlos
N4IS
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