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Flex 6400 Contesting question

Wyatt Law
Wyatt Law Member
Quick simple question about the Flex 6400. I have a 40-6m hexbeam that I like to use for contesting, With the Flex 6400 can I call CQ on 20m and look around for multipliers at the same time using the hexbeam? I realize that it can only transmit at one time but is the second receiver locked out when transmitting? Would I be able to look for multipliers while calling CQ on the same antenna and band simultaneously?

Thanks for your time,


  • Rick Hadley - W0FG
    edited July 2019
    Short answer, no.  The 6400 has only one SCU, which makes simultaneous reception during transmit impossible.  Only the 6600/6700 series have dual SCUs.
  • Ha Gei
    Ha Gei Member ✭✭
    edited July 2019
    That ́s why we bought it, You can look for multi ́s but when you send, you hear nothing
  • Joe N3HEE
    Joe N3HEE Member ✭✭
    edited July 2019
    And the 6600/6700 support full duplex (FDX) which is required to hear something while transmitting. 

    However you can still find and work multipliers and such with the 6400 without FDX.  Use the needed mults and Q's window in N1MM and pounce on the spots as they populate and then go back to calling CQ.  I do this all the time with my 6600M.  It's called SO2V.  Single operator two VFO's. 
  • Wyatt Law
    Wyatt Law Member
    edited July 2019
    Thanks for the reply. If I used the 6600, could I call CQ on 20 and look for multiplayers on 20 simultaneous with the same antenna without blowing myself out ? Or would the second receiver be blown out from receiving the cq from the transmitter, or is there some filtering to prevent this? Thank you

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