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Old January 2nd 06, 08:45 AM posted to rec.radio.amateur.antenna
David
 
Posts: n/a
Default Use of MJF-269 Analyzer help

Hi,

I am wanting to check the match efficiency or return loss
of a C-Tap matching network that matches 50 Ohms in to 4500 Ohm load
with 2.5pF in parallel. Match at single Freqency = 45 MHz.

Using a 134nH inductor with Q of approx. 85
My calculations result in Cap to ground = 864pF, Cap to inductor = 102pF

I tried the match on the front end of my IF circuit and it appears to
tune smoothly and peak ok at 45MHz.

I then wanted to measure the return loss to see how good the match is.
Using the MJF-269, I get a lousey reading of 0.9dB. (almost everything
reflected).

Either my calculations are way off base, or I am not using the MJF-269
correctly. I also get lousey SWR (16.5), match efficiency below 5%.

I purchased the analyzer ages ago and have only used it to measure Vp of
coax till now.

Any help appreciated.

Thanks