[Amps] Keying Kenwood TL922 with Yaesu FT1000D (both old

[Jim Thomson]

Date: Fri, 18 Oct 2013 23:14:20 +0200
From: "Behiels JeanPierre" <on4aef at telenet.be>
To: <amps at contesting.com>
Subject: [Amps] Keying Kenwood TL922 with Yaesu FT1000D (both old
guys)

Hi guys;

Anyone could me put in the right way for next coming contest.
Witch connection plug I best use on the back of the FT1000D for keying this old TL922.
I saw that the Tl922 keying system has been modified so it could be keyed by means of a low power transistor.
The keynig system of the FT1000D could not be damage by this setup !
I useual do not handle with amplifiers in my ham carreer so poor expirience around hi..  

Kindly regards and thanks to all I look forward 

Jean ON4AEF.

##  This is what I use to key these amps that have greater than 100 vdc on the key line.
http://www.opto22.com/site/pr_details.aspx?cid=4&item=ODC15A

##  I use em on hb  3CX-3000A7 and 3CX-6000A7 amplifiers that have sped up vac relays...and have 135 vdc on the key line.
On the hb amps, we use 1 gigavac GH1  vac relay for the input, a 2nd   gigavac GH1 vac relay for the bias,
...and 2  gigavac G2 vac relays in parallel for the output.   4  x vac relays in  total being keyed by the same opto isolator. 

##  I also use one on the inputs of my modified drake L4B amps.   The L4B uses +27 vdc on the ley line.
I changed the oem half wave rectifier to a FWDoubler.   Now its +67 vdc on the key line.   

##  The  ODC-15A  is superb.  It has 4 kv isolation between the input and the output.   100 microseconds to operate,
and 750 microseconds to release.   It also has a 1 second surge rating of 5A .   Anything from 9-16 volts  will
operate it.   It only draws  10-15 ma. 

##  what you DON’T  want to to is use a vac relay to key the TL-922.  As the vac relay will add an additional unwanted delay. 
##  In normal operation,   I use the solid state key line in the yaesu FT-1000D....which uses a switch transistor, 
to key the external opto isolator.   That pin comes out on the band data jack I believe.   Its only rated for very low
current + voltage..but will easily key the opto isolator.  

##  OK, the original  yaesu key line, RCA jack on back of yaseu... that puts out a  solid ground..is done via an internal spst
mechanical relay..that can be switched off  if required. The mech relay will handle more current + vdc.. BUT it adds an UNwanted
15 msec delay.....and that’s  in addition  of the TL-922  TR relay operate time. 

##  OK, heres  how to prevent hot switching the slow TL-922 TR relay when used in conjunction with an  FT-1000D. 
The yaesu RCA  key line is  now used to activate the  yaesu TX inhibit pin.......also on the band data jack I believe.  

##   So the TL-922 is actually keyed via the yaesu switch transistor direct output.... on the band data jack. That
switch transistor will switch in microseconds..blazing fast.   Meanwhile, until the TX inhibit lead gets a solid ground..
via the  yaesu RCA key line.... which takes aprx 15 msecs.... you will get ZERO watts  from the FT-1000D !! 
That’s good, cuz that gives the TL-922  a  15 msec headstart.    IE: TL-922 is keyed NOW.   15 msecs later
the TX inhibit lead gets grounded.   The TL-922 uses a slow clunky  TR  relay.... so you don’t want to be applying RF
to the amp till the TL-922 relay has finished operating. 

##  In normal operation, this works superb.    Now if you want to swap out the slow mech relay to a  fast Vac relay
at a later date, go for it.   Rich Measures and others have written about modifying the TL-922 to QSK. 

##  The above mod I cooked up years ago was a quick fix for keying amps with slow relays..without hot switching them. 

##  I also own a pair of yaesu  FT-1000MP  mk-Vs.    The MK-V has a menu driven 0-30 msec adjustable delay, for CW
only... to allow for slow mech relays in older amps to get a head start.  Essentially the same deal.  Amp is keyed NOW,
but NO RF from the MK-V  for 0-30 msecs.    No hot switching on CW.   For SSB though, I  that 0-30 msec menu option
wont work of course.  For SSB,  I use the same scheme as the FT-1000D.  Amp keyed NOW.... but  TX inhibit lead on the
MK-V is delayed  by  several  mescs  via the spst mech keying relay inside the MK-V.  = no hotswitching on SSB either,when used
with slower mech TR relays.

##  BTW... on a similar note, we also found that the large gigavac G2 and G2-ham relays, although rated for 15 msecs operate,
and 9 msecs RLS   will operate  a lot faster  when  sped up with the usual  overvoltage  + cap across the drop resistor. 
This is called a RC hotshot speed up circuit.    With aprx 140 vdc  + a .5uf cap across the drop resistor, the operate AND RLS
speed of the G2-G2ham vac relay is down to 2.5 msecs.  So they will operate QSK just fine. 

later........ Jim   VE7RF