Hi Eric --
We have an AM station about 2 miles from the W1KM site. It's small
but runs 5 kW during the day on 1420... enough to mess up antenna
analyzers hooked to the low band verticals... and enough to trash receivers.
Fortunately at night it drops to a 1 kW directional pattern and we
don't see it. But we've been thinking about a filter anyhow so that we
can chase DX near sunset/sunrise on 160m. I would be curious to learn
more about the BCI filter you are using.
73,
-- Eric
on 05 May 28 21:21 Eric Rosenberg said the following:
> I've been following the thread on BCI to the Orion with both interest
> and amusement.
>
> I live in Washington, DC proper, 5.5 miles from a 50kw AM station
> operating at 1500 kHz (signal measured a -10 dBm with a lab-grade
> spectrum analyzer on my inverted-L), and another relatively high power
> AMer at 1260 kHz.
>
> From my roof I can see (and have photos of) all of Washington's TV
> (NTSC and HD) and FM broadcast towers, not to mention the plethora of
> US and foreign government, commercial and other point-to-point
> transmitters and repeaters that operate into the microwave bands and
> seemingly beyond.
>
> Regardless of the number and size of cavity filters, weak signal and
> amateur satellite operations are difficult (I used to operate on AO-13
> and to a lesser degree the pacsats) or impossible.
>
> And the intermod/overload on 160 is pretty amazing, regardless of the
> radio I've used... be it Kenwood, Icom, Yaesu or Ten Tec.
>
> For the past 5 years, I had an Omni-6+. For the past year, an Orion.
>
> The solution? Well designed and built BCI filters. I spent as lot of
> time researching what was available in the amateur radio
> world. Neither the ICE filter (402X), W3NQN, Top 10 Devices or anyone
> else's worked for me. In the end, I did find one, not (yet)
> commercially available filter that worked so well for me that I had my
> best score ever in the CQ 160 contest! If and when it becomes
> available, I'll post information here on the reflector.
>
> A great resource for locating the broadcast (AM, FM and TV) stations in
> your neighborhood is AMSTNS and TVFMSTNS by Bob Carpenter,
> W3OTC. Bob's software was invaluable to me in identifying the local
> broadcasters to better understand who and where and to what degree the
> offending stations might be. An overview of the software is available
> at http://users.erols.com/rcarpen/INFO0227.html while the latest
> versions of the software are available at
> http://home.earthlink.net/~lvehorn/ For best results follow the
> various links!
>
> The bottom lines is that if you're close to a broadcaster and suffer
> from intermod and overload problems, don't blame it on the
> radio! External filters are the only solution.
>
> GL!
>
> Eric W3DQ
> Washington, DC
>
>
>
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