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Re: [Amps] TX Inhibit on MK-V

To: amps@contesting.com
Subject: Re: [Amps] TX Inhibit on MK-V
From: Paul Gerhardt <phgerhardt@gmail.com>
Date: Wed, 24 Feb 2010 11:06:16 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Jim thanks for your write up on the Tx Inhibit.



I made a cable using the Acom link below but and the QSK worked fine with my
Alpha 78 but the TX Inhibit did not 'come on' when I plugged the din in.  I
had the rig delay set on 20 which seemed to be more than enough.

A lister from the 'MP' list also said that the TX Inhibit does not work!
RE: [FT-1000MP] Re: QSK interface


"At least on the Mark-V, the transmit inhibit does not work even though
the manual say it does. Others have tried and found the same condition.

Alternative:
Check the closing time for the Alpha because they are fast. My 91B is
ready in 2ms (high speed vacuum relays with high voltage close and low
voltage hold). The Mark-V doesn't put RF out until 7-8ms after PTT
output is initiated leaving 5-6ms head room.

The folks at Alpha can tell you the closing time if you can't measure it
yourself.

To measure it I used a dual trace 100MHz digital storage scope looking
at the Mark-V's TX-GND jack and the Alpha's output relay.

73,

Bob - W6OPO"

##  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] !!
-- 
Paul Gerhardt
K3PG
http://pgerhardt.blogspot.com
QRP ARCI 6674
FP 274
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