[Elecraft] Auto Bandpass Filter (sorry sent too soon)

[Dave Hachadorian]

I have a pair of Dunestar 600 boxes that I've used for years, 
including 100 watt rtty contests. I've never once had a problem.

My buddy W7WW across town has a pair of ICE boxes, and he has had 
a few problems. He has blown capacitors on 10 and 15 meters. We 
replaced the caps with heavier duty units, with multiple 
capacitors in parallel. He has also had problems with dropout of 
receive signals through the ICE. That unit has 12 sets of relay 
contacts in series with the signal path. On any given band, two 
of the contacts are energized closed, and ten are in the normally 
open position. It's the normally open ones that cause receive 
signal dropouts. The solution is to "whack the box," which gets 
old pretty fast.

For a band decoder, here is a cost effective solution:
http://www.unifiedmicro.com/decoder.html

K3's older than sn 2362 will need to have the "External Data 
Pull-up Mod" installed to work with this band decoder.


Dave Hachadorian, K6LL
Big Bear Lake, CA


--------------------------------------------------
From: "Brett Howard" <brett at livecomputers.com>
Sent: Monday, July 05, 2010 3:15 AM
To: "elecraft" <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Auto Bandpass Filter (sorry sent too 
soon)

> Ok so I'm looking for an auto band pass filter to use with the 
> K3...
> Would be slick if the filter could be interfaced directly to 
> the K3 but
> I'm planning on needing a band decoder/smart switch for 
> different
> widgets later in life that I've been planning on starting so 
> this may be
> the opportunity for that project to need to start.
>
> Anyway I've been trying to find all my options and some 
> pros/cons of the
> different solutions from people who have experience with them. 
> These
> are the units I've found...  Please let me know if you have 
> experience
> with these such as ease of interfacing, build quality, power 
> handling,
> longevity, loss, out of band attenuation and what not.
>
> Array Solutions FilterMAX II:
> http://www.arraysolutions.com/Hamation/bandpassfilters.htm#top%20of%20page
>
> Array Solutions Filter Master (FM-6):
> http://www.arraysolutions.com/Products/wx0bbpf6.htm
>
> I.C.E. 419B
> http://www.iceradioproducts.com/filtersrf.html#3
>
> DuneStar Model 600:
> http://www.dunestar.com/model600.htm
>
> Well crud I ended up sending too soon (hit ctrl+enter on 
> accident)
>
> Anyway I've considered the FilterMAX II as it seems to be the 
> best built
> with a nice modular filter replacement scheme but its the most
> expensive.  I wish that they were a bit more informative in the 
> manual
> and explained what the pinouts were and how the thing 
> determined what
> band to be on.  The switches mentioned don't really make a 
> whole lot of
> sense as there are more positions mentioned than one can hold 
> as far as
> filters...  Confusing to say the least but I'm sure once I had 
> one in
> hand I could figure it out.
>
> Then there is the filter master 6 which is a slick little idea 
> in that
> its just a coax switch essentially and then one can use 
> individual
> filters from Dunestar, ICE, or Array Solutions (I'm sure there 
> are
> others that I'm forgetting and I'd like to know about)...  I 
> have the
> same gripe about not explaining the pin outs here but I'd bet 
> it has the
> same configuration as the FilterMAX II
>
> Then there is the I.C.E. 419B which seems like its awfully 
> small in
> comparison to some of the other units.  I begin to wonder about 
> its
> power handling but I have a friend who has their individual 
> filters and
> seems quite happy with them.  I don't think he uses them very 
> often
> though so I don't know about longevity really or about power 
> handling
> all that much.  I do mostly CW but would also like to be able 
> to use
> this system during a RTTY contest at 100W.
>
> Finally the Dunestar model looks like its ok however power 
> ratings seem
> a bit scary.  All they state is that the filters are intended 
> for use
> wiht transceivers and then state that this is not to imply a 
> 100% duty
> cycle.  What the heck does that mean?
>
> Anyway input is greatly appreciated.
>
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