Single Operator Two Radio

SO2R…all the con­testers are doing it.

I have want­ed to try it for a num­ber of years now. Final­ly, after sev­er­al tri­als around the sta­tion engi­neer­ing I used it to great suc­cess in the 2011 Wpx RTTY contest.

My set­up: Icom IC-7600 as pri­ma­ry rig, Yae­su FT-857D as sec­ondary. I.C.E 419B band­pass fil­ters con­nect­ed to each. All my anten­nas con­nect­ed to the IC-7600, a 90-foot Invert­ed L con­nect­ed to the 857D. Yan­kee Clip­per Con­test Club SO2R+ con­troller box between them, con­nect­ed to my main sta­tion com­put­er run­ning N1MM and MMTTY for RTTY.

Aside from some slight har­mon­ic QRM from each radio the set­up worked beyond expec­ta­tion. I esti­mate that I added bet­ter than 150 Qs on the sec­ond radio. I found it very con­ve­nient for using searching/​pouncing using both radios. I am a lit­tle sta­tion and not like­ly to hold a fre­quen­cy except on 40/​80M evenings when I am strong state­side. Being able to scan two bands was very use­ful. There were times when I was run­ning on 40M and was able to use the sec­ond radio look­ing for addi­tion­al sta­tions on anoth­er band.

RTTY oper­a­tion was a great first intro­duc­tion to SO2R. I have tried it sub­se­quent­ly with CW and found it to be very con­fus­ing. More prac­tice is need­ed there (and like­ly try­ing dif­fer­ent modes of head­phone mix­ing). I played a lit­tle in the ARRL DX CW con­test and found NO head­phone mix­ing was OK. This is prob­a­bly not optimum.

Things need­ed from this point forward:

  • Coax­i­al stubs to pass/​reject pri­ma­ry and har­mon­ic fre­quen­cies. I could hear myself on my har­mon­ics, some­time loud­ly and with block­ing of the RX rig. Noth­ing dam­ag­ing of the radio but annoy­ing to say the least. I think I should be able to get anoth­er 40dB of rejec­tion with coax­i­al stubs for var­i­ous bands (and a way to switch them)
  • Bet­ter anten­na switch­ing. I have a 6×2 switch but cur­rent­ly using just 1 sec­tion. Need to fix that! I want to use any anten­na on any radio…
  • Band choice automa­tion. I need to be able to have my fil­ter­ing track my band-choice. I don’t have ded­i­cat­ed anten­nas for each band so no track­ing need­ed there. I picked up a KK1L dual-radio board for this very pur­pose. He has an Icom band-volt­age mod­ule com­ing soon!
  • Com­mon-mode fil­ter­ing. The more I read about com­mon-mode inter­fer­ence rejec­tion tech­niques (check the YCCC web­site) the more I am hear­ing hash/​trash that is com­mon-mode relat­ed. Need to start whit­tling away at this.

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