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Re: [Amps] Vox ssb, time for RF to appear ?

To: amps@contesting.com
Subject: Re: [Amps] Vox ssb, time for RF to appear ?
From: Jim <jimw7ry@gmail.com>
Date: Tue, 30 Oct 2018 20:46:17 -0500
List-post: <mailto:amps@contesting.com>
Some various radio measurements here:

http://www.w0qe.com/amplifier_timing.html

Notice that the Ic706 and others actually unkey the relay (H-send line) before the tranciever stops sending RF.


73

Jim W7RY


On 10/28/2018 7:06 PM, Bob Wilson, N6TV wrote:
Using a scope on a Elecraft K3 with KSYN3A upgrade, K3 in SSB mode + VOX,
I measured a 30 ms delay between KEY OUT (amp relay) going to ground and
the first RF output from the transceiver.  That's significantly longer than
CW mode + VOX (about 6 ms TX delay with *CONFIG:TX DLY nor 008*, about 4.3
ms in CW QRQ mode, with or without QSK enabled).  There is a jitter in the
delay.  It varies +/- 1 ms (approx.).

I haven't done this measurement on any other radios.

73,
Bob, N6TV

On Sun, Oct 28, 2018 at 5:52 AM Jim Thomson <jim.thom@telus.net> wrote:

RE:  TR relay  timing, hot switching etc.   What is  typ time, between
talking into mic on SSB VOX,
and when  RF  1st starts to even appear  at the output of the  typ  xcvr
??   On my yaesu MK-V,  on CW
mode only,  I can vary the delay between internal keyer.... and   RF
appearing at the output of xcvr,
by anywhere from 0-30 msecs.... in 1 msec increments.  That adjustment
allows for precise  external
amp TR relays  to get a ..head start... depending on how fast the TR
relays are in the external amp. IE:
will allow  for vox  cw, when using slow open frame relays..... or sped
up, faster vac relays, or pin diodes
etc, when using qsk cw.

I see no adjustment for plane VOX  SSB.   Is this  a concern..esp with
slower TR relays in an external amp ?
I can add additional delay  via the...  TX inhibit lead, if required.
  But IF the xcvrs  natural delay is say  7 msecs,
inserting 7 msecs delay into the  TX INHIBIT lead  will buy me..nothing.
  Any added TX inhibit delay would have
to be longer than what is in the xcvr.   IE:  xcvr is say 7 msecs,
between  coughing into mic on vox ssb,  and TX inhibit
delay  set to say 15 msecs..or longer..to match the slow TR relays in an
external amp.

I dont see any  delay specs on typ xcvrs.... when used on vox  ssb.   And
I dont mean between  coughing into mic...
and  full pep output.  I mean between  coughing into mic....and  just a
few watts pep  appearing at output of xcvr.

Jim   VE7RF
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