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SmartSDR V3 TX Delay for Sequencing Transverters - SSB vs CW

KM0T Member ✭✭
edited May 2019 in SmartSDR for Windows

Hi all, Working with new SmartSDR 3, just upgraded. 

Using the new bit cable USB interface to an 8 channel USB relay board with FTDI control.  That works good.  Using the "PTT On" mode on three relays via the USB Bit menu to sequence mast mounted pre-amps/relays, power amplifier and also the transverter itself.  These USB controlled board relays will connect that radio equipment to "ground" in order to activate it in a sequenced manner based on the time delays I set.

So in the bit cable setup menu- three relays set to PTT ON.  First one is zero delay, second is 75 ms, third is 150 ms.  Then on the third relay, the TX delay is set to 500 ms.  (note these are not the real delays, they are set longer to demonstrate the issue)

The 4th relay is just set to TX slice - band of the transverter, to know I'm on the correct band for testing.

On SSB mode, all is good (and AM, FM, DIGI, etc).  The relays sequence as they should and TX RF is delayed by 500 ms after the third relay switches, then backwards out of the sequence, the RF is "UN-applied" so to speak, then after delay the relays switch back.

The problem is on CW... the RF does not seem to be delayed.  The TX indicator switches immediately upon hard PTT.  This is a problem if my elbow is on the paddle by mistake when hitting the PTT button at the same time, the preamp on the mast does not have time to get turned off and switch out of line - kaboom....

For me this is a VHF-UHF issue, we don't really do QSK (at least I don't) up there with transverters when we have to switch preamps, transverters, amps, all sequenced.  Hard PTT is the norm on CW or break-in CW with some drop out delay set to keep it from dropping out between letters based on the sending speed.

I hope the video is adequate, just a quick recording with my phone, but you can see the TX indicator on SSDR in the lower right corner switching on and off, in conjunction with the 8 channel relay board doing its work.

Also, if this all can be confirmed that under CW the TX delay is being implemented, this I feel is by far the best way to do my transverter control, staying away from TX1, TX2 and TX3 where you might need to share with HF stuff, etc.  This one 8 channel relay board can easily do 2 transverters for both with independently programmable 3 step sequencing.  If less steps are needed (say your not running mast preamps) you could probably do 3 or 4 transverters from one board for sure.  Just add another board to control the IF relay or use another USB BCD cable if needed, its all very slick.

One note, I bought two of these SainSmart USB 8 channel boards, only one works half way, it has some issues.  The other one I'm using works perfectly, just a heads up.  I have ordered some of the Denkovi version of the boards, I will see how they work when I get them...

Looking for input, or am I totally missing something here, please enlighten me!

73 - Mike - KM0T


  • Ed.G
    Ed.G FlexRadio Employee ✭✭
    edited April 2019

    The delays in your configuration will be taken into account when generating the RF for the CW elements. The PTT indicator works slightly different in CW - the indicator will turn red immediately but the RF won't be sent until the delays expire. 
  • KM0T
    KM0T Member ✭✭
    edited May 2019
    Ed, very good on the explanation.  So behind the scenes this is not a problem, but the visual indicators don't follow on CW like they do in SSB, this leaves the operator always wondering.

    As an example, in normal antenna mode, the front panel hardware power switch turns green to red on TX when RF goes out.  In transverter mode it goes green to red to orange, orange based on TX delay set.  But again it only does this in SSB.  When on CW and in transverter mode, it never goes orange..it just goes to red immediately with no delay...where red indicates RF out of main antenna connectors...not wanted when your in transverter mode.

    So the hardware power switch issue somewhat mimics the issue with the TX indicator on the software screen.. TX indicator delays to red on SSB, but does not delay on CW.

    If we are looking for feature request..software update..etc.....Here is what I feel is needed to make the system consistent and have the proper feedback to the operator:

    • TX indicator on SmartSDR goes red after set TX delays are expired for all modes.  (does not work in CW)
    • Hardware Power Switch color changes (indicating RF) after TX delays are expired for all modes.  (does not work in CW)
    • Power Switch turns Orange while sending CW in transverter mode.  (Works in SSB, stays red in CW)
    • TX indicator on SmartSDR screen to turn Orange when in transverter mode for any mode in lieu of red.  This will mimic the color change on the power switch.  Also has a good visual indicator to the operator looking at the SmartSDR screen that you are utilizing the transverter port.
    Thanks for your time.  73 - de KM0T

  • Ed.G
    Ed.G FlexRadio Employee ✭✭
    edited May 2019
    Thank you for your feedback! I agree that it is confusing and not consistent with operation in SSB. I've entered your comments into issue #7442 to discuss with the team and for tracking. 
  • KM0T
    KM0T Member ✭✭
    edited May 2019
    Thank you Ed!

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