FlexRadio/4o3a TunerGenius XL – SO2R or 3-port version?

Last weekend Mike WB6DJI posted a very good question about the FlexRadio/4o3a TGXL TunerGenius and choosing between the two initial versions:

SO2R versus 1inx3out TGXL version debate

Placed my preference back in Sept 2020 for the1inx3out TGXL version with FRS

Never operated SO2R but have a 6600M and PGXL ( acquired over 3 years ago )

My Bands are 40 meter dipole with a 20meter thru 6meters using a HexBeam
Use my radio remote with a Palstar HF Auto for now

Thought 3 Bands Remotely would be good if I want to use 3 different antennas like with I do with the Palstar HF Auto

Been on the fence in trying to decide if SO2R is

Do not use 2 Bands at same time with My HF

I chase some DX but not in 24hr DX contests

What are your thoughts Steve



Mike WB6DJI followed this up with an email, as he too like myself is trying to figure out which version would work best for our particular station setup.

So everyone is on the same page the SO2R version (Single Operator 2 Radios) is optimized to rapidly alternate between essentially two parallel RF paths. The paths are distinct and cannot cross. I’ve read a 20ms path-flip number, once each path is stored in memory.  When the radio is a multi-SCU (Spectral Capture Unit) FlexRadio (6700/6600) the single physical radio is well suited to take the place of both radios in the SO2R equation.

The 3-port version is optimized for a single RF path and basically has a 3-port antenna switch integrated into the tuner.  There needs to be a separate feed line from the three possible antennas, one to each designated port.  I’ve not picked out a specific switch time, but the same 5ms for solutions stored in memory would seem likely.

In either version the tuner cannot flip-between-paths (SO2R version) or switch antennas (3-port version) while transmitting.

For those who have a tuner included in their PowerGenius XL early purchase, they have been asked by survey whether they would like the SO2R or the 3-Port version when their order is fully completed.

In my case I have been using a Palstar AT-AUTO (the earlier version) for some tuning needs.  Mike WB6DJI reports he is using the newer Palstar HF-AUTO tuner.

A sharp truthful fact is while many hams aspire to contest and further aspire to run SO2R, only some achieve contesting prowess and even fewer run effective SO2R.

Some additional FlexRadio/4o3a ecosystem considerations (accurate in Nov 2020, as some of these thought may change as the ecosystem evolves):

  • Flex-6700 and Flex-6600/6600M radios have two SCUs and RF paths, optimized for the SO2R concept
  • The 4o3a AntennaGenius 2×8 switch is conceptualized to meet the SO2R station idea
  • Other than some rudimentary amp toggling and metering with the PowerGenius XL Amp within SmartSDR, the 4o3a control and utility software is separate from SmartSDR
  • None of the separate 4o3a software is set up to coexist on a SmartLink negotiated connection
  • TunerGenius XL SO2R presumes two outputs that would have to be matrixed together to use the same antennas (To Be Confirmed) and two RF input paths
  • TunerGenius XL 3-port presumes three outputs that would have to be matrixed together to use the same antennas (To Be Confirmed) and one RF input path
  • TunerGenius XL SO2R and TunerGenius XL 3-port are designed to be colocated with your PGXL Amp and/or FlexRadio Flex-6000
  • Future TunerGenius XL configurations have been hinted at by 4o3a, but only detail so far is a version intended to located at your antenna end of the feed line is expected to follow in time
  • Like your Flex-6000 radio, PGXL amp and AG 2×8 (or other AG versions) the TunerGenius XL expects an ethernet connection
  • TunerGenius XL tuning solutions memories are mapped by input + band + output combination

Some thoughts on picking between the SO2R version and the 3-port version of the TunerGenius XL:

  • Is SO2R important or a future interest for you? – if yes then the SO2R is likely the way to go.
  • Is your station configured with a remote switch between antennas? – either choice may work for you
  • Is your configuration dependent on an antenna switch in your tuner? – the 3-port might be ideal for you
  • Do you have a dual-path ready radio? – the SO2R version might be a good choice if you want to use both paths
  • Are you a regular ham, where one path is all you really need? – either version will work the same for you if you have only one path
  • Do you have a lot of antenna options on the same bands? – if you have two choices the SO2R might have some advantages, if you have more either would have to retune for new choices.

While I am a casual contester and not skilled enough to run SO2R for any length of time, I selected the SO2R version in my survey response.  I based that on operating with a Flex-6700 which supports the dual-path idea and use of a remote 4o3a 2×8 AG switch which also fits that concept.



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2 thoughts on “FlexRadio/4o3a TunerGenius XL – SO2R or 3-port version?

  1. Mike Aust says:


    Added Comment and Point to consider

    To run to A/D’s Waterfall Displays Remotely for SO2R over Internet via Cellular is Prohibitive in
    Demand of Data and the reason I use the Flex Solution is for Remote Usage of my HF Station

    The idea of a Matrix Switch within the ATU and being controlled with a Remote Unit
    like the FRS Maestro drove me toward the1in3out version of the TGXL tuner


  2. Mike Aust says:


    Having it all workable with within SmartSDR for me without the need of the additional 2in8out Matrix Switch was the my other consideration toward the 1in3out TGXL version rather than the
    SO2R version for me

    Best regards


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