[TowerTalk] Was: Getting antennas into the shack. Now: SO2R antennaswitching

[Pete Smith]

I would recommend a look at <http://www.qth.com/topten/apnote1.htm> which 
explains how this works.  Their A/B selectors have one excellent feature 
which is unique so far as I know, a hardware lockout to prevent 
inadvertently "stealing" an antenna from a radio that is already using 
it.  Once one radio has commanded the A/B switch for a particular antenna 
to either A or B, applying a control voltage to the other terminal will not 
cause it to switch until the first radio releases it.

I am using W9XT's very inexpensive (<$20) band decoder PC board 
<http://www.unifiedmicro.com/decoder.html> to control a Top Ten relay box, 
and both have been very satisfactory.

Finally,  the free N1MM Logger <www.n1mm.com> provides programmable control 
signals through a parallel port or ports, which can be used with W9XT band 
decoders (or any others) to control up to 10 antenna selections per 
transceiver.  For example, you can have high and low 40M antennas and 
select between them from the keyboard.  Very neat.


73, Pete N4ZR

At 09:58 PM 3/14/2005, Dick Green WC1M wrote:

>Top Ten makes good SO2R switches, too. I've been happy with them. Different
>approach -- separate A/B relays for each antenna and separate 1-of-6 relays
>for each radio. This might provide better isolation, and could be more cost
>effective if you don't have exactly 6 antennas.
>
>73, Dick WC1M
>
> > -----Original Message-----
> > From: Chuck Chandler [mailto:chchandler at adelphia.net]
> > Sent: Monday, March 14, 2005 7:48 PM
> > To: towertalk at contesting.com
> > Subject: [TowerTalk] Was: Getting antennas into the shack.
> > Now: SO2R antennaswitching
> >
> >
> > Thanks to all who replied!
> >
> > The consensus of the listmembers who live(d) in brick houses
> > is that removing one brick (hammer and chisel, masonry drill
> > w/big pipe-sized bit) or possibly more than one brick (for a
> > bigger hole) and PVC or galvanized pipe with a rain elbow
> > outside, stuffed with insulation is the best way to go.
> > Quick and easy to repair if/when we leave.
> >
> > My plan is to have several antennas - I use a Butternut HF9V
> > vertical now, which will be the last one down here and the
> > first one up at the new QTH. After that will come a wire
> > antenna (not sure what yet) and then the tower and beam.  I
> > may also experiment with a second vertical with elevated
> > radials later.  There will be a primary rig, a secondary rig
> > and several QRP rigs.
> >
> > My current idea is to use an Array Solutions six-pack to
> > allow any antenna to be selected for the primary or secondary
> > radios.  Any of the QRP rigs would have to get their antennas
> > off the secondary radio feed when the secondary was not in use.
> >
> > I started to diagram how to do this with manual switches to
> > save a buck or two but the page got so covered over with
> > crossed out, erased, scribbled shapes that I think I was
> > going to almost spend more on manual switches and coax
> > jumpers than the Six-Pack costs.  I managed to diagram
> > something that I think would give me the ability to have any
> > antenna on either rig but I'd hate to have to build it.
> >
> > Am I missing something?  I checked e-ham and found only two
> > makers of this sort of SO2R switching - WX0B and microham(?).
> >  Prices are about the same and reasonable for the product.
> >
> > What do others do for this sort of functionality?  I don't
> > want to use cheap switches with little isolation and that
> > drives up the price for a manual arrangement.  The most
> > reliable and simplest is to physically swap cables and that
> > has excellent isolation qualities plus automatic lockout
> > between the two rigs.  A bit slow and awkward, though...
> >
> > I'm leaing strongly towards the Six-Pack - added bonus of
> > keeping all cables entering the shack within the one-brick
> > width pipe size mentioned above.
> >
> > Bill, W5VX, got it right when he wrote "I never dreamed it
> > would take so much planning."
> >
> > 73,
> > =======================
> > Chuck Chandler
> > WS1L
> > chchandler at adelphia.net
> > =======================
> >
> >
> >
> >
> >
>_______________________________________________
>
>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>any questions and ask for Sherman, W2FLA.
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk at contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk