Re: Broadcast interference on the Argosy - high dipole.
I have a similar situation with an Omni D and my high 80/40 dipole. It
doesnt happen with the Omni 6. Bottom line, there is a nearby AM
broadcast station on 1010Khz 5KW daytime, 500w night that puts a 100mv+
signal to my radios. The worst thing is to try and use my MFJ antenna
analyzer, which is useless.
Imagine it has to do with front end mixing/overload susceptibility of
the particular radio design. The solution: spend $38 and purchase an
ICE broadcast filter. They make 4 models, (2 high power 300w and 2 low
power not intended for transmit) with a 1.8Mhz cutoff and the other is
3.5Mhz cutoff. I now have high power units in line right after the
transmitters and of the lower power/receive units on my beverages. I
believe the rejection is 25-40 db in the 160m band and it gets better as
you fo up in frequency. Now I can use my antenna analyzers again and
the Omni D is happy on the dipole.
As to why only on the dipole, I imagine the other antennas you have are
higher Q in their respective bands and you will find they dont pass as
much of the broadcast RF back down the pipe!
--
Thomas M. Delker - K1KY CFO#395 - Smyrna / Gallatin / Short Mtn. TN
C.A.T.S. (W4CAT) - 147.30 (114.8) / 145.23 / 223.98 / 444.45 & 444.65
Stones River A.R.C. (K4FUN) - http://www.Voy.net/~rfi/stones.html
Tennessee Contest Group (K4TCG) - http://geo1.tdec.state.tn.us/tcg.html
Fistfighters United Nashville (NT4L) 146.955 (114.8)
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|