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Does the 6300 have Pin Diode switching for QSK?

KD8K Member ✭✭
edited December 2017 in FLEX-6000 Signature Series

I am hearing what sounds to me like a reed relay during CW elements even though the QSK annunciator is active. The SmartSDR manual to me indicates all 6000's are pin diode switched for CW. Is this correct, does the 6300 use Pin diode switching for CW? If so, I would like to figure out what setting is causing it to use relay switching.

Thanks, John


  • K6OZY
    K6OZY Member ✭✭
    edited February 2017
    It is completely silent and instant like the 6500 and 6700.  I leave my delay between 0 and 10 depending on the band noise.   I use it with my Elecraft KPA500 and KAT500, and it works perfectly using DDUtil to control the amp drive and band chasing of the setup.   Love it!
  • Al_NN4ZZ
    Al_NN4ZZ Loganville GAMember ✭✭✭
    edited March 2017
    Are you using 2 antennas (tx on one and rx on the other)?  There is a relay switching if so.

    Regards, Al / NN4ZZ  
    al (at) nn4zz (dot) com

  • KD8K
    KD8K Member ✭✭
    edited December 2017

    No, just 1 Antenna. Its not loud and definitely not a deal breaker, but I do notice it. Its sounds similar to the Kenwood rigs I used to own.

    I did check the antenna settings. I also verified the delay setting an it is set to 0.



  • Steve N4LQ
    Steve N4LQ Member ✭✭
    edited September 2015
    Since we don't seem to have a schematic we can only guess. The sales reps don't seem to understand either. They claim "full duplex" cw when using a separate receive antenna and "pin diode switching" in single antenna CW mode. Written material is all over the map and as you can see, even owners disagree. My 6300 obviously uses a reed relay when in QSK, single antenna mode. It is very quiet but I can hear it. It's about like the older TenTec rigs. QSK speed is very fast. I can hear tones at up to 100 wpm dits! When using the receive antenna #2, the Frankenstein relays take over and you can hear the sucker next door! This is totally opposite of what Flex's sales reps are telling people. I did see a statement in some Flex manual which stated that the 6700 was the only one with QRQ CW. Whatever that means. There was no explanation. 100 WPM would seem like QRQ to me. As for pin diodes.....Who knows? Maybe it's got those plus a reed relay. We will never know until we see a schematic. I was told the same story about a TS-590s. I had to buy one to find out. Claims of "totally silent, silky smooth QSK" abounded. So I opened it up, located the relay, made a video and put it on YouTube. Check it out. 73 N4LQ
  • Gerald-K5SDR
    Gerald-K5SDR FlexRadio Employee ✭✭
    edited December 2017
    All FLEX-6000 Series models use exactly the same TR circuit.  The transmitted signal goes through a pin diode and the receiver is switched through a reed relay.  The reed relay will make a tiny "tink" sound that is barely audible. You really don't want to use pin diodes in the RX path for a number of reasons.  Reed relays add virtually no distortion or signal loss.

    You can hear between elements on any model with a single antenna up to approximately 35 WPM.  For QRQ, you would need to have a separate receive antenna.  With a separate receive antenna, you can hear between elements at QRQ speeds.  On the 6300, the separate RX antenna MUST be on XVTR.  On the 6500 it must be on RXA or XVTR.  On the 6700, it must be on RXA, RXB or XVTR.  You CANNOT use ANT1 or ANT2 as a separate receive only antenna for QSK. You will see the QSK indicator turn off in the GUI when you do so indicating that true QSK is not available.

    Use of a separate RX antenna eliminates the reed relay switching from the RX path.  We have QRQ operators in Eastern Europe who proved this out for us about a year ago.
  • Steve N4LQ
    Steve N4LQ Member ✭✭
    edited September 2015
    Wow. Yet another explanation for the 6300. I just tried connecting my RX antenna to the xvtr input then switched to xvtr on the slice flag. Yes I can still hear signals. No it is not QSK. The loud relays start clanking exactly the same as when the RX ant. is connected to ANT-2. Delay is at zero and the little QSK indicator is lit up saying QSK is active. Well it's not QSK by any means since the receiver goes silent between cw characters and the relays are very loud. Am I doing something wrong here Gerald?
  • KD8K
    KD8K Member ✭✭
    edited May 2015
    Thanks Gerald. I am primarily a CW Op and wanted to make sure everything was configured properly. I was also getting audio artifacts and this added to the apparent noise/chatter. I adjusted the volume settings as recommended by Steve in another post and the QSK is excellent now. Really enjoying the new 6300! Thanks!
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    Steve - "Yes I can still hear signals. No it is not QSK. "

    This is a software defect that will be fixed in the next release of SmartSDR.

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