Mihail,
Some of the best filters I have seen so far for M/S or M/2 are the
Dunestar 600's. These can also be run via band-decoder. If you are
planning on going for M/M, you won't want switchable bandpass filters on
each station, luckily Dunestar has you covered there as well, with their
model 300's. These are single band filters, and are very hard to notch out.
As said in a previous message, ICE also has single band filters as well as a
combination system. I have never used these, so I cannot comment on them.
The run and multiplier antennas here are only about an acre apart, and
we have never had any real trouble with RF, especially after using Dunestar.
Mike DeChristopher KB1FWN
> ----- Original Message -----
> From: "Mihail Mateescu" <yo3ctk@alltrom.ro>
> To: <CQ-Contest@contesting.com>
> Sent: Wednesday, June 09, 2004 9:03 AM
> Subject: [CQ-Contest] Bandpass filters for M/S or M/M environment
>
>
> > Hello,
> >
> > We are in the process of upgrading the YR7M site from SO capable to
> M/S.
> > That means, among other, a second workplace equipped with
> transceiver and
> > linear amplifier. We expect to need bandpass filters at each
> workplace.
> >
> > We have identified three manufacturers for such filters (homebrew is
> > excluded since we have barely enough free time to set-up antennas):
> >
> > ICE via WX0B: model 419A, $228
> > W3NQN via WX0B: set of 6 filters, $525 plus FM-6 switch, $165
> > Dunestar model 600, $339
> > All models are 200W capable.
>
> I use two Dunestar 600's, which I purchased used, and they have worked
> well for me for about five years. My antennas are only 6 - 10 feet
> apart and I run 1500W. You need to build your own little manual or
> automatic control box for these units. The Dunestar units can be wired
> for either +12vdc or ground switching.
>
> My friend W7WW has a pair of ICE filters, and they also work well for
> him, with his closely spaced antennas and 1500 watts. He has had a few
> problems with his though. On initial delivery, one of his boxes had a
> problem with the received signal intermittently dropping out. That
> unit was replaced by the manufacturer. He has also blown a few
> capacitors in the ICE units, even with 100 watts of drive. The caps
> actually change value, rather than blow, but the swr goes sky high.
> The manufacturer has provided replacements, but we get them a lot
> faster from a commercial source (Mouser). It is fairly easy to change
> the caps. He now has two low-drive amplifiers, which has solved that
> problem for him, at least in the high-power contests. The ICE units
> come with a manual DC switch that picks up the internal relays. The
> ICE units use +12vdc switching. There is no provision for ground-type
> switching.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>
>
>
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