[Amps] MK-V and opto isolator/ TX inhibit. /1000-D notes.

[Jim Thomson]

Date: Wed, 24 Feb 2010 17:32:18 +0800
From: Alek Petkovic <vk6apk at bigpond.com>
Subject: [Amps] More on the 30S1 and MP MKV

Hey Jim, with regard to what you wrote below a few days ago, I looked 
in the radio manual and the band data jack pinout as well as the 
linear connection guff  on page 13.

As I see it, you have the opto isolator connected to pin 1 (13.8V) 
and  pin 2 (TX Gnd) on the 8 pin Band Data Jack. This means that the 
linear control is taken out before the relay and its RCA TX Gnd jack.

I take it that this is what you have done.

###  YES.  That's  exactly how it works.   The TX grnd on pin 2 is NOW
... [ a few microseconds]. OK, now u have sunk the opto isolator.
Opto takes 100 microseconds to operate. After 100 microseconds,
sec of opto keys the amp. 

##  The yaesu SPST mech relay is NO longer used !  It's too slow
anyway, and has a 15 msec operate time.  You can shut it off, via
 the slide switch.  [ it has another use, see below !]

## The internal yaesu  switch transistor splits like a 'Y'... with one leg
going  in and out of that slide switch, then to RCA  TX  jack.   Other leg
of 'Y'  goes directly to PIN 8  on band data jack. 

##  presto, you just gave the relays in your amp an instant 15 msec
head start.   For cw, or qsk cw, I'd still  set the yaesu menu delay for
5-10 msecs... or XXX msecs.. something slightly longer than whatever
speed ur amps vac relays operate at. 

##  OK, this is all fine for sped up vac relays in ur amp, and even if slow
mech relays used in amp, the yaesu  MK-V  0-30 msec CW digital delay
solves all hot switch problems. Now, what about  VOX SSB.. and used with
slow vac relays [G2,RJ2-B/C etc ??   Even sped up, the G2/RJ2-B/C  is only
7-9 msecs, and typ 3PDT mech relays are 15 msec !   Here's the fix.
  http://www.qsl.net/n1eu/Yaesu/MPAcom.htm   shows the mk-v 
pin out.   I use the MK-V TX INHIBIT LEAD.   TX is inhibited when
+13 vdc [pin 1]   is placed via a 10 k /.25 w Resistor, onto TX inhibit lead,
[pin 8] .    You grnd pin 8 on TX, via the handy dandy  TX  grnd  from rear panel
RCA  TX JACK !!     Since that yaesu spst mech relay has a 15 msec op time, we
now use it to apply a solid grnd to TX inhibit lead [pin 8] !!  

## End result is, on VOX sideband,  that opto keys the amp NOW, slow relays
in amp operate in 4-15 msecs.  Meanwhile  NO  RF  out of xcvr, until AFTER 15
msec delay, since the TX inhibit lead, gets grnded..DEAD LAST.  OK now we have
this 15 msecs TX inhibit delay in the circuit.. all the time.  ON CW.. the yaesu MK-V
menu option [digital CW delay]  MUST be set  for at least 15 msecs.. other wise
you will truncate stuff.   This total effect is now smooth qsk CW , nothing truncated,
and   when on VOX  SSB, Ist 15 msecs gets truncated, meanwhile NO hotswitching,
and the amps slow relays  have up to 15 msec to operate.   An external 0-15 msec delay
can also be used, if < 15 msecs is desired on VOX ssb. 

## On the yaesu 1000/D,  as soon as u plug the din into the band data jack,  TX inhibit 
is enabled !!  [NO RF] .  Grnd from yaesu RCA TX jack can now be used to grnd the TX inhibit 
lead, [after 15 msecs] and now RF flows  from xcvr.   No 10 k and +13 vdc used on the 1000/D
inhibit setup.  Also, NO  0-30 msec CW digital delay feature  available on the 1000/D !! 
Opto still used.  With SLOW  t/r relays [6-15 msecs]  no hotswitching on ssb/cw... BUT  you 
WILL truncate the 1st 15 msecs.  IF fast t/r relays used [1.8  to 5 msec]... then don't use the
TX inhibit scheme. 


later... Jim  VE7RF   





My ODC-15s are in the mail form far away across the sea.

73 and thanks,
Alek. VK6APK.