[CQ-Contest] SO2R Questions/Responses

[Scott Nichols]

  Hi all...

This is a bit long and deals with getting setup for SO2R...

A week or so ago I posted a couple of open-ended questions here 
concerning my plans to convert my station to SO2R...Really, I needed 
some basic information to try and get my brain wrapped around all the 
hardware issues involved, including antenna switching, bandpass 
filtering and SO2R controllers...The responses were numerous and greatly 
helpful...Thanks to everyone who helped me out...Information is king, 
and I received a ton of it...

It appears that there are others who are trying to sort all this SO2R 
stuff out too, as I've received a dozen or so emails in the last couple 
days asking for a summary of what I found out...

So, I'll try to sort out and summarize what I've been told and what I've 
read...I'm no expert at this stuff , in fact I haven't converted to SO2R 
yet, but I now have enough information to make some decisions about what 
I need to do...Maybe this will help others wrestling with the same issues...

Here's what I found out:

For most SO2R setups you will need:
        -Banpass filters for each radio
        -A switching unit(s) for your antenna system
        -Band decoders for each radio
        -A SO2R controller
        -Patience...Operating SO2R effectively takes practice
        -$$$...It can get expensive, depending on what you do...


BANDPASS FILTERS

Unless your antennas are well physically seperated, you will likely need 
some bandpass filters to protect Radio B's receiver while transmitting 
on Radio A. This was the biggest issue that most had trouble resolving. 
You can buy single-band BPF's and multi-band BPF's. Dunestar Model 600 
Multi Band Remote Switched Bandpass Filters 
<http://www.dunestar.com/model600.htm> seemed to be the choice of 
most... $339 US each...

The I.C.E. Model 419A Combination Bandpass Filter was also 
popular...http://www.arraysolutions.com/Products/ice/filtersrf.html#3
These are $228 US each...

I did some testing in my own shack and found very little cross-band 
interstation interference with my MP and Mark V at 100/200 watts...There 
was heavy same-band interference...My beam and dipoles are all within 
100 feet of each other...My amp is busted right now so I didn't try high 
power...However, on the advice of those who know, and my better 
judgement, I'll be putting a BPF on each radio...Keep in mind that BPF's 
can eat 15% to 20% of your output power...Better than a blown 
receiver...I tend to be cautious with this stuff...

Lots of hams also use coaxial "stubs" for additional filtering protection...

ANTENNA SWITCHING

Lets just say that there are thousands of choices and possible 
combinations here...You will need some way to switch antennas between 
radios...This can go anywhere between fully manual to fully 
automatic...By far the most popular choice of switches is the "Six Pack" 
by Array Solutions...It seems to offer the best protection for your 
radios...It handles 6 antennas and two 
radios...http://www.arraysolutions.com/Products/sixpak.htm  Cost - $400 US.

Another popular choice is the Top Ten Devices Six Way Antenna Relay 
Box...this one has 6 antenna outputs but only one 
input...http://www.qth.com/topten/sixway.htm  Cost - $125 US

Antenna switching can be fully automatic if you employ band decoders 
(see below) to control the antenna switches...

You, of course, can get along very well with two manual coax switches, 
if you have enough antennas to assign to each radio...Again, the 
possibilities are endless...I've chosen the SixPack...

BAND DECODERS

You can control both the bandpass filters and antenna switches with a 
Band Decoder on each radio...These units sense what band the radios are 
on and switch the filters and antennas accordingly...Two brands 
mentioned to me were the Top Ten Devices Automatic Band Decoder (Seemed 
to be the favourite of most) http://www.qth.com/topten/sixway.htm and 
Array Solutions DBS-1 Band 
Decoder...http://www.arraysolutions.com/Products/banddecoders.htm#top%20of%20page

There are package deals offered by some as well...Array Solutions has 
several packages, including "#4" - a SixPack antenna switcher, two DBS-1 
band decoders, 2 ICE 419 filters and some cabling for $1,205 
US...http://www.arraysolutions.com/Products/pricelist.htm#SixPak - 
Scroll down until you see "Packages"...This would appear to give you a 
good, fully automatic system...

SO2R CONTROLLER

This unit handles all the audio, microphone, keyer, headphone etc 
switching between the two radios...

There are 3 well known off the shelf controllers available...Top Ten 
Devices "DX Doubler" http://www.qth.com/topten/index.htm , Array 
Solutions "SO2R Master" 
http://www.arraysolutions.com/Products/so2r.htm#top%20of%20page and the 
W5XD MK-1100 Multi Keyer http://www.writelog.com/SO2R/w5xd_multikeyer.htm

I'm still undecided about this as all 3 got high marks...One thing to 
keep in mind is that the W5XD Keyer is designed for use with Writelog 
but apparently works fine with other software...Some hams have built 
their own controllers, others don't use one...

 From my own personal perspective, the system that has caught my eye is 
the Package #4 (see above) from Array Solutions...It has most everything 
you need to get an automatic and safe setup...It comes highly 
recommended from people who use the gear...

Some other very useful and informative sites: 
http://www.arraysolutions.com/Products/so2rbasics.htm   
 http://home.columbus.rr.com/jmaass/Radio/K8ND_SO2R.htm (GREAT pix of 
SO2R setups at K8ND's site)   
 http://www.k1ttt.net/technote/tworadio.html (some excellent reading 
from users of various products at K1TTT's site)...

I basically spent a week searching the internet, reading emails, asking 
questions etc...I could spend two months and still not see everything 
that's available...There are numerous other products available, but the 
ones I mentioned above wewre BY FAR the most popular with the kind folks 
who took the time to tell me their stories...I know there are other 
issues, products, methods, scenarios...Every shack is different...My 
advice is to read everything you can get your hands on and ask questions...

That's what I found out, I hope it's accurate and hope it helps if you 
are thinking about going the SO2R route...See you later in the summer 
after my shack renovations are completed...

73, Scott VE1OP