[Elecraft] Sequencer keying with K3/XV-144 without rigblaster?

[David Cutter]

When you changed from ac to dc did you add an anti-stiction part to the magnetic junction?  If not, that's why it takes so long to separate.  It' just a copper or brass shim to keep the parts at a slight distance.

David
G3UNA
  ----- Original Message ----- 
  From: ANDY COOK 
  To: elecraft at mailman.qth.net 
  Sent: Friday, January 16, 2009 4:28 PM
  Subject: Re: [Elecraft] Sequencer keying with K3/XV-144 without rigblaster?


        To make this all simpler I normally run the transverter as the LAST box to be sent to transmit (ensuring that RF switching is disabled!). So Rig->sequencer->Tx relay->PA bias->transverter. This may hot switch the transverter, but that's rarely a problem in reality with the low powers and enables the system to be built with all the normal VOX / Semi-break in facilities on the radio working normally. 

        Now just need to find out why some of the Amphenol N-type relays used for high power switching have got into a state that can take up to 0.5 second to release after volts have gone. Maybe they've got magnetised - they were originally 115V AC relays re-wound for 28V DC, but one has already bitten the dust from the consequent hot switching where the sequencer didn't figure on needing to take 1 second to changeover!

        73,

        Andy, G4PIQ
        -----------------------------------
        Brian Alsop wrote :
        I guess I'm missing the boat on this discussion.  

        I thought all high power VHF ops used an external sequencer board that 
        did the following type of thing.
        RX to xmit:
        1) Bypass the mast mounted preamp, wait a bit
        2) Put the amp in the tx mode, wait a bit
        3) Put the xvtr in the tx mode, wait a bit
        4) inhibit the RF output from the rig until 1-3 are complete.

        With a relay based system 1-3 could easily be 60ms or more.

        Going to receive does a similar thing --i.e. unkeying the various 
        components with delays..

        You're not going to get his set of multiple delays from the K3.

        There are external sequencer boards available as kits for about $20.  
        The K3 has an inhibit line for such use.

        And yes, the big guns do have difficulty in the bang-bang contest 
        mode.   You call them once and occasionally get the comment,  I'm not 
        getting your call, my sequencing hasn't completed.

        73 de Brian/K3KO 



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