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Old September 9th 07, 07:30 PM posted to rec.radio.amateur.antenna
Tam/WB2TT Tam/WB2TT is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 125
Default Trouble with MFJ-269 and local AM broadcast station


"Bob D." wrote in message
m...
I bought an MFJ-269 antenna analyzer with some 160 meter antenna design in
mind. It works fine on my VHF and UHF antennas, but the local 1350 AM
station (which is just a half mile away) interferes when an HF antenna is
connected. The SWR reads 31 and the two analog meters dance to the
station's audio. I tried a home made 1350 KHz notch filter I've used with a
few receivers. The notch filter gets rid of the offending signal, but makes
the 160 and 80 meter readings bad (verified with a dummy load).

Any solutions out there? Is it possible to build a 1350 KHz filter that
won't throw off the impedance reading at 1800 KHz?

Luckily my Kenwood TS-570 is able to contend with the AM station.

--
Bob D. ND9B

MFJ sells a tunable band pass filter, which you would tune to 160 m. By the
way, a high pass filter won't work either. I built a 2 MHz high pass filter
to use on 75 m, but it affected all readings below about 5 MHz. My AM
stations aren't real close; so, the 269 works OK on 75 m during the middle
of the day.

Tam/WB2TT