[Elecraft] K3 and Sequencer

[Tom Hammond]

Fellas:

Not being a VHF guy, please help me understand the need for a sequencer...

The K3 already issues a T-R relay output closure some tome before RF is
generated at it's output. This allows external devices 'down stream' of
the K3 itself to actuate their T-R relays so they will be in-line by the
time RF hits them.  I'm using this pre-keying to ensure that my QSK HF
amp (which uses both reed and vacuum relays for internal T-R switching)
is in-line, to prevent 'hot keying' of its T-R relays.

I think the K3's present pre-keying is about 20 mS, but I may be off
there.

Does VHF operation require a significantly longer set of pre-keying
signals? And if so, how many are required to sequentially key the down-
stream devices?

And, is it the concern that one of the down-stream devices might be so
slow that it doesn't get switched in time, so there must be a sequencer
present to ensure that EVERY device HAS actually been switched before
the K3 would be allowed to generate RF?  I guess QSK is NOT of any
concern when operating on these bands... right?

73,

Tom Hammond   N0SS


At 07:02 09/23/2007, Evert Bakker (PA2KW) wrote:
>Hello Ron,
>
>Yes I am.
>I raised this issue several month ago during the announcement of the K3.
>I did suggest the "Ten-Tec solution" which works fantastic.
>Before RF gets out (either from the main antenna or transverter RF-out), the
>TX-Request initiated by the PTT/VOX/Key from the K3 (which should be
>available on one of it's acc connectors) has to confirmed (TX-Enable) by the
>sequencer. Together with the KXV3 board, it would be a fantastic solution to
>use this radio for serious VHF/UHF operation.
>Either Eric or Wayne (forgot who answered me) put this topic on the
>wish-list and promised me to contact me (and others) if and when they decide
>to add this option.
>
>I'm most willing to develop a sequencer-board and make it available when the
>K3 will have this option integrated.
>
>I do have a homebrew sequencer and audio-interface for using FSK441 and JT65
>on 144 Mc together with my homebrew transverter but a "quick and dirty" one.
>
>Let's keep in touch.
>
>73's, Evert PA2KW
>
>
>_____________________________________________________________________
>I think many of us would use the K3 not only on HF but also for VHF
>because of the excellent phase noise characteristics and dynamic
>range.
>
>As such a sequencer build into the K3 would be ideal to switch the PA
>and antenna relays.
>
>Would it be possible to make an option board for this.
>This would be a minor task for the CPU, but would be so neat!
>
>I want one, any one else intrested ?
>
>73 Ron VK4KDD.
>____________________________________________________________________
>
>
>
>
>
>_______________________________________________
>Elecraft mailing list
>Post to: Elecraft at mailman.qth.net
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com
>
>_______________________________________________
>Elecraft mailing list
>Post to: Elecraft at mailman.qth.net
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com