K1TTT Technical Reference

This page has lots of notes from various sources, don’t ask me about messages or notes from others:



Pictures of K1TTT SO2R 12/2002: Operating Desk, Side arm with rotors and antenna switches.


Original Question:


I hate to reinvent the wheel, don't have a lot of time to homebrew or put together kits, and don't know much about operating so2r besides what I have seen from a few guest operators.  But I am ready to buy the stuff needed to make a better so2r setup option on my m/m station.  I am looking to buy as much as possible, preferably including cables already made up.


The equipment would be:

2x ft-1000mp

heil proset headset

ct or na logging software

dvp board for voice keying

aea morsemachine or other external keyer(s)

each band has its own coax coming in to the table


What I am looking for are suggestions for 2 or 3 things:

1. a headset/keyer/mic/dvp switch with cables

2. a 6 antenna to 2 radio antenna switch with band decoder for each radio and control cables. 3. a 6 band 2 radio bandpass filter switch for between the radios and amps, or possibly two separate switched bandpass filters with cables and decoder. 


Could one decoder run both the antenna switch and bandpass filter switch?


What is available off the shelf to do this?


What are the pro's and con's of different models that are available, if there are choices?


Is it better to run 1 computer or 2??  Why??


Web sites:



I have left out replies that said things like: ‘go to this website for everything’, or ‘I know xxx uses this stuff’, or ‘switch to writelog and use their unique stuff’, or ‘trlog is better’, or ‘I have a great homebrew setup’, or ‘these look good on the web site, but I have never used them’.  I am also leaving out the ones that went on about how to setup filters and stubs, as I stated I am presently set up for m/m operation so I know about filtering, what I am looking for is how to switch everything the best way for so2r.


Filtered replies:


Hi Dave,


I have the Top Ten DX Doubler SO2R controller, the Top Ten Band Decoders, and a WX0B Six-Pak and it is a VY FB arrangement.  A TTD decoder (with the source-driver option) can drive both the Six-Pak and a I.C.E. multi-band bandpass filter.  The key is, some devices switch to ground (the filter) and others switch to +12v (the Six-Pak).  For the SO2R controller, there is also

the WX0B SO2R Master.   The DXD is less expensive and I prefer the layout

and physical packaging, but both are great units.


With one computer, you can control everything from WriteLog, CT, or NA (and I suspect TR, although I've never tried it).  One computer consumes less real estate, requires only one human interface, and is less trouble.  I can't say enough good things about this arrangement.  All I need is another amp, another bandpass filter, and time to use it all (and a lot of practice to get the most out of it!), and I'll be in tip-top shape.


VY 73 de Glenn K3PP



ICE 419 easy, WX0B sells one that is probably better, and more rugged, but I think you have to build the transistor interface box to use with decoder. I have a WX0B box on the RUN station and a 419 on the Mult station... Not sure performance is noticably different, but I think lab sez the WX0B?? whatever they are called filters are a little better.


> Could one decoder run both the antenna switch and bandpass filter

> switch?


YES  I use diodes to keep things in order but one decoder per station is all you need.




> What is available off the shelf to do this?


TTD can sell you the decoders, and switches.

WX0B sells his 6pack which is one package for the switching for both rigs.


I think TTD stuff is a little cheaper for the works, but both will do the job nicely.


I bought the TTD DXdoubler,   the WX0B SO2R box and the W5XD

keyer/controller.  If you ever go writelog exclusively, that box will do the job, but for NA/CT  you want the WX0B or TTD box.  I am presently using the DXDoubler box, I think Dave can provide all the cables you would want.


WX0B box has a neat feature where you can easily monitor when you send with the keyer rather than the computer.. the DXDoubler is a little more easily customizable, especially when the computer is not running and you want to switch between rigs etc.


It comes down to features you like, both products are very nice.  I went from my homebuilt box to commercial stuff for neatness.




> What are the pro's and con's of different models that are available,

> if there are choices?


> Is it better to run 1 computer or 2??  Why??


SO2R, best with 1 computer , you can take advantages of all the software nice stuff.  TRlog is very slick, I think NA is still ahead of CT.  Writelog is good, if you ever give up DOS.


If you use PACKET, 2 computers are still pretty nice..easier to grab spots on 2nd radio...but for pure SO2R, or hybred with a little packet 1 computer for the 2 radios and main logging.  You can /should network another computer to keep a spare log on line ready to go.


73 Chas K3WW



> What I am looking for are suggestions for 2 or 3 things:

> 1. a headset/keyer/mic/dvp switch with cables


Either the Top Ten or Array Solutions SO2R boxes will work

nicely for you.


> 2. a 6 antenna to 2 radio antenna switch with band decoder

> for each radio and control cables.


Array Solutions Six Pack with RF Applications IBS or Top Ten

Automatic Band Decoder


> 3. a 6 band 2 radio bandpass filter switch for between the radios and

> amps, or possibly two separate switched bandpass filters with cables

> and decoder.


Array Solutions "RD-6" system (two "Six Packs" and one set of

W3NQN filters) or two sets of Array Solutions FM-6 (filer master)

switching matrix and W3NQN filters.


> Could one decoder run both the antenna switch and bandpass filter

> switch?


Yes ... all of the equipment (six pack, FM-6, etc.) switches from

12 volts.  You can use series isolating diodes to parallel drive

to the Six Packs and/or FM-6. 


> What is available off the shelf to do this?


See above ...


> What are the pro's and con's of different models that are available,

> if there are choices?


If you stick with the Array Solutions/RF Applications products

Jay will generate a preconfigured package for you.


> Is it better to run 1 computer or 2??  Why??


Your choice.  Single computer is probably easier in that you're

not switching from computer to computer.  However, two computers

(with properly designed software, e.g.. Writelog) will automatically

keep a backup log in case one machine were to crash.


73 & Good luck,


   ... Joe, K4IK






You can get everything you need from TopTen or Array Solutions. I use the TopTen Yaesu band decoders, A/B switches and 1-of-6 switches. They've all worked perfectly and I've been very pleased with them. I've used the Array Solutions SixPack at KR1G and that's a well-engineered and well-built solution, too. Ted has TopTen band decoders, so I haven't seen the ones from Array solutions. Price-wise, it looks like the band decoders and antenna switching setup will cost you $700 from Array Solutions and $860 from TopTen. However, I'm not familiar with the band decoders that come bundled with the Array Solutions $700 package. The website has specs for a separate advanced band decoder, but I don't think that's the one that comes with the package. The biggest difference I can see is that the SixPack connects the A/B switching internally, while the TopTen solution requires a dozen short coax cables and a bunch of external relay control wires. On the other hand, the separate relay boxes used for the TopTen setup could be more convenient for certain shack setups (in my case, I had to mount them in an outdoor utility cabinet that was too small for the SixPack.)


I use a single decoder to run the antenna switches, Dunestar filter switches and bandpass stub filter switches. The TopTen decoders have enough current capacity for that. Don't know about the Array Solutions decoders, but I imagine they can handle it, too. I use a pair of TopTen 1-of-6 switches for selecting multiple bandpass stub filter combinations. Ironically, I got the design information from your website! However, I've had to use this setup because the stubs are in the shack and all the other switching gear is at one of the towers (i.e., two coax lines, one for each radio, come into the shack; therefore, bandpass stub combinations have to be switched in depending on the band selected for each radio.) Since you have separate coax coming into the shack for each band, I would recommend bandpass stubs on each line and/or discreet high-power filters (WX0B has a complete line.) W4AN likes to put two 1/4-wave stubs a 1/4-wave apart on each line. Perhaps you already have effective filtering for your M/M? If it works for that, it should be adequate for SO2R. I would certainly test it before buying additional filters to go between the rigs and amps. I use a pair of Dunestar filters, but they only get rid of some residual phase noise on certain band combinations for which the stubs aren't effective. A pair of Dunestar filters will set you back $500. KR1G has a beautiful pair of switched bandpass filters from Array Solutions, which are much heavier-duty and which I've heard are more effective (I believe K5ZD recommends them over the Dunestars, but that's a rumor.) Those filters will set you back $1,000. Like I said, I would test post-amp filtering before going down this road. It's easy to add more filters later.


Both companies also offer an SO2R switch box. I made my own, so I'm not familiar with either. I'm sure they're both adequate. The Array Solutions box is more expensive (see next paragraph before you decide.)


I recommend using NA instead of CT. The SO2R switching is *much* better. I used it for a couple of years and was pleased. Except for SO2R switching, the user interface is so similar to CT that you won't have any trouble learning it. However, I've moved on to Writelog. If you can run Windows on your logging computer, I think Writelog is the best choice for SO2R (and for any other operating class.) The learning curve is steeper, but it's well worth it. If you run assisted, Writelog supports Telnet internet access (I don't think CT or NA can do that.) If you go with Writelog, be sure to buy the Writelog SO2R switch box. It has a special keyer and switching circuits optimized for Writelog.


I run one computer, as do many other SO2R ops. But some like the two-computer setup better (I believe KQ2M falls into that category.) I prefer not having to move my hands from one keyboard to the other and don't want an extra monitor cluttering up the operating position. I believe I'm correct in saying that you can't do keyer/mic/audio/ptt switching from the keyboard with a two-computer setup -- you'll need a manual switch to share one set of headphones/mic/keyer. The SO2R switch boxes are all designed to work from a single computer, driven by keyboard commands. Also, a single computer setup automatically deals with cutting off transmission on the CQ radio when transmitting on the S&P radio (if you use NA or Writelog.) Of course, that's important only if you operate by the rules: one transmitted signal at a time ;-). Two computers may be best for CT.


Hope this helps.


73, Dick WC1M



I'm also an SO2R beginner. I took it up mainly so I could write upbeat, encouraging columns about the experience for the NCCC newsletter. So if you get responses from the Great Ones, listen to them more carefully. FWIW, here's what I got and am pretty happy with (in order of your questions):


1. Top Ten Devices DX Doubler - well thought out, simple to use. Just plug in the rigs, the

    paddel, an (optional) external keyer, the computer, the phones and the mic.

    Includes an optional cable for the 1000MP which is OK although the connectors

    and stiff cables stick out awkwardly from the radio. Good review of this box in NCJ

    recently by N0AX I believe.


    Note that if you want to put an external DVK between the mic and the DXD you will

    need to make up a cable with a male mic connector. Rare. I'm doing it this way but some of

    the logging programs allegedly do well with sound cards in the computer and that would

    be a simpler hook-up.


2. WX0B Array Solutions Six Pack two radio antenna switch does exactly what you want.


3. I got a pair of Dunestar 600 BPFs. One is driven by a Top Ten  Band Decoder for the 1000MP. (You will need one decoder for each MP). My second radio is a 930 so I have to use a manual switch for its filter. I got the decoder with two sets of outputs so I can, in theory, drive the MP half of the Six Pack automatically. Haven't hooked that up yet but I'm confident it can be made to work. You have to  build up a little diode matrix if any one feedline serves more than one band. If you have multiple antennas for some bands, you may prefer not to automate antenna switching.


You absolutely, positively want to use a single computer to drive this stuff for SO2R. Don't even think about two. Programs like trlog understand you are SO2R and do a lot of the headstanding for you. The DX Doubler has a cable to the (single) computer that eliminates lots of custom cabling in and out of your computer's parallel port. You don't want to worry about two keyboards and don't have to with this setup. OTOH, if you want to do M/S you will have to have two computers and network them. I've seen this done but never set it up myself.


The main alternative to all this stuff seems to be the Array Solutions SO2R Master. I found several excellent contesters using each box. SO2R Master has most of the connections on a box with no controls so it can be out of the way behind the rigs. But the switch box takes up desk space. But it has nice switches. The DX Doubler fits nicely under my rigs which sit on a shelf supported by 2x4's. If you keep your rigs at table level, this may be a problem. I chose DX Doubler because I understood the switch labels and N6RO recommended it. But K5RC recommended SO2R Master. Study the ergonomics and pick one.


If you have a second-radio antenna that is far away from the primary radio, consider skipping the BPFs. Mine are quite unnecessary when I have Rig 1 on the tribander and Rig 2 on the vertical 300' away. OTOH, when Rig 2 is on the 40m rotary dipole on the same boom as the tribander, the BPFs are the only thing that keeps the 20m receiver from turning to toast.


I have one RFI problem with this setup - the TTD band decoder gets funny when I transmit on 10m so I have to switch in the 10m filter manually. Even with the DXD you end up with quite a rat's nest of cables so I advise you to be more careful with cable construction, grounding and connections.


It has been much more fun integrating all this stuff than actually operating SO2R. That's hard!  ;-)




Rick N6XI


Either the Top Ten DX Doubler or the WX0B SO2R Master will

handle your rig, paddle, headphone, and keyer switching. 

I use the Top Ten unit, and can recommend it.


You can switch both bandpass filters and antenna relays

with a single band decoder (per radio.)  Since you are

not using tribanders, you will not have to "group" antennas

and bandpass filters separately.  Should be straightforward.

I had to use blocking diodes on the signal lines to the

band pass filters in order to prevent stray currents from confusing the band decoder.


I am using the Top Ten band decoders and relay swithes.  I have chosen (so far) to not add

 the automatic A/B station selection. In other words, I still do the A/B selection manually.

The Top Ten approach to SO2R antenna selection is more modular, allowing you

the choice of automatic or manual A/B selection of antennas.

If you want instant A/B selection, you may find the WX0B Six Pack does it more simply for your six-coax setup.


All of the above will work fine with your MPs, and CT or NA.


I prefer one computer, but I use TR-Log.  If you use two computers, then you must have a lockout mechanism to prevent simultaneous transmission from both rigs.  TR handles this beautifully with one computer.


That is my experience, from a relative newcomer to SO2R operation.


A photo tour of my simple station is available at http://www.k4ro.net.


Good luck, and thanks for your useful and informative web site.


-Kirk  K4RO




KQ2M notes:

This thread is almost as old as SO2R itself and keeps coming up every year.


OK, here it is:


1) SO2R is an advantage over SO1R, but ONLY for those operators who gain more with the 2nd radio than they lose on the 1st radio.  REREAD THAT PLEASE!


Many people try SO2R, discover that it's tougher than they thought and really mess up with the first radio (as well as the 2nd radio), get flustered and really tired and frustrated, and LOSE SCORE compare to simply being SO1R.  Plus the discouragement they feel REDUCES their energy level and their score further.


IMO, computer logging was a quantum leap over paper logging, and in my case, I KNOW that computer software has helped increase my efficiency and score FAR MORE than adding a 2nd radio ever did!  Despite that, the contest sponsors didn't see fit to put create a new category for computer loggers - they were right NOT to do so.


Sure software costs less than a 2nd station, but you can borrow a 2nd radio and amp and it costs a lot less to build a wirebeam that it does for computer software!


2) This $5,000, - $10,000 for SO2R is TOTAL NONSENSE!  While I don't doubt that some have spent this and more, I started with a USED TS830, USED SB220 and a few wire antennas.


Total cost MAYBE was $1,200, and that was 15 years ago.  Today you could buy them for less.  Heck, someone would probably give you the TS830 for FREE! What does it cost to build a 20 M Inverted V out of spare wire and RG8X? $10?  The computer that I used was a really slow 286.  It would have cost more to throw it away than to use it!


Even as recently as 4 years ago, I was still using a TS940 and SB220 with a few wire antennas as my 2nd radio.  Good enough to beat quite a few Northeastern good ops with stacks and real SO2R capability and come in 3rd in ARRLDXCW SOABHP Unassisted and finish in the top-ten in ARRLDX and CQWW each year.  As many have said, SKILL COUNTS!


3) I still DO NOT use automatic ant/radio/amp switching.  I have some of the stuff I need but I never installed it.  I'm not sure that it will be durable enough and I don't have the time to install it.  IT IS NOT NECESSARY for competitive SO2R, but it sure makes it more fun and more efficient if you have it.


So spend (or don't spend) all the money you want, but understand that MONEY ALONE does not change the standings.  A great opr at a decent station will almost always beat a decent opr at a great station!


4)  Competitive SO2R is primarily about skill building, operating efficiency and challenging yourself.  Operating 2 radios (or more) is a skill that is developed.  While some may be born with more inherent talent than others (no different than athletes, musicians, or anything else), a real "pro" takes pride in it, works at it and seeks to find new things to do to aid the operation.  The more you push yourself, the better your skills get, and the more often you push yourself, the more consistent the improvement and the higher the baseline level of skill available for next time.


I haven't nearly maxed out my skill level yet.  If I gave it as much time as I do my career, I would probably be an order of magnitude better at it with that much LESS effort.  I can't wait to hear when someone has managed to "perfect" a really efficient SO3R.  I don't think it has happened yet, but I am sure it will and I will applaud it when it does!


5) I won't address all the other areas covered, but suffice it to say that life is unfair and contesting is unfair.  There will NEVER be a level playing field: there will never be equal propagation, or equal disposable income, or equal location, or equal time flexibility, or equal anything - that's just how it is. So, I try to focus on a few key things:


1) Having fun

2) Improving myself and my skills

3) Competing with myself, and

4) Talking with my friends


IMO, that's really all that should matter, and leads to maximum enjoyment.


I can NEVER win SS Phone from Connecticut, but I can still enjoy operating in it (one of my favorite contests) and I won't ask for the contest sponsor to create a new category to give me a better chance to win.


Someone can go to a big station in Nev or PR and make 30% more q's and score than me, SO WHAT?


If they can use 8 radios and increase that to 40% more q's than me , SO WHAT?  They should be congratulated for their extra effort!


I know, that's not how everyone feels.  That's simply my opinion.  I leave the judicious use of categories to the contest sponsors.


In the meantime, and as the debate rages on, please remember that what matters most is to get on, operate and try to have fun.




Bob KQ2M



VE1OP notes:

  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...





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


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...




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...




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



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...




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://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