[AMPS] Ten Tec Corsair QSK and the 87A

[Richard W. Ehrhorn]

Hello Jim...

ALPHA 87A's (and also 89's and 91B's) T/R response time typically is 1-2 
msec. Using any popular Japanese transceiver that I'm familiar with 
(FT-1000D,  TS-950SD & SDX, TS-850, IC-761 & 765, IC -781, etc... it's fine 
for full QSK to simply patch the transceiver's T/R output (grounded on 
xmit) to the ALPHA's RELAY jack. In general, provided that the xcvr gives a 
T/R closure at least 2-3 ms before actual rf output begins, no problem.

There are some older xcvrs - I may be mistaken but the Drake 7-line comes 
to mind, where the T/R relay closure actually LAGS the initial rf output at 
key-down. This would result in "hot-switching" the amp's T/R, which is 
verboten (with any amp) for any of several reasons - and QSK-capable ALPHAs 
(including all three current models) are electronically interlocked to 
prevent it. If rf drive is already present when the T/R line closes, the 
amp's T/R just stays in "receive," meaning that exciter power is bypassed 
directly to the antenna.

In this fairly rare situation, you can connect any of the current ALPHAs 
just as you describe for Ten-Tec linears: plug your key/keyer into the 
amp's "Relay" jack and patch the amp's KEY OUT to the transceiver KEY jack. 
Response time in this configuration remains on the order of 1-4 ms.

I'd try hooking it up as described first above: key to xcvr, xcvr T/R to 
amp RELAY. If you find the amp T/R line "hanging up" in receive when you 
close the key, which I doubt you will, you can try the alternate 
connection. It's quite unlikely that you could damage anything.

Hope this info clarifies things for you. Good luck & good DX!

-----Original Message-----
From:	Jim Reid [SMTP:jreid@aloha.net]
Sent:	Saturday, August 22, 1998 4:05 PM
To:	amps@contesting.com
Subject:	[AMPS] Ten Tec Corsair QSK and the 87A


Hi All,

My new-to-me Corsair II is going to be my CW rig;
I bought it because of the PTO's (lack of phase
locked loops,  synthesizer,  etc) and the legendary
Ten Tec QSK feature.

However, my linear is the 87A.  The Corsair provides
a key input socket and a key out socket.  I have learned
that,  with a complete Tec Tec station,  the CW key or
keyer,  is connector to a key input terminal on the
Ten Tec linear,  and a phono type jumper cable goes
from a key out terminal on the linear to the key in
socket on the Corsair,  or whatever Ten Tec
rig is being used.

Now my question.  The Alpha manual has a bit to say that the
87A has QSK capability,  but no where can I find how it is
to be used.  I believe that ETO actually does the same as
Ten Tec,  as there is a Relay Input terminal on the back of
the 87A,  and on the block diagram within the manual,
this is also called a Key In terminal!  There is also a Key
Out terminal on the back of the Alpha,  but this is said to
be for use with "exciters having poor T/R sequencing";
and not a word about use in QSK keying back to the
exciter!!  Then goes on to say to contact ETO customer
service for specific advice.

The block diagram within the 87A manual seems to show this
"relay" operation to be all microprocessor controlled,  no actual
mechanical relay is shown here.  But,  within what is called
a Simplified Schematic, and actual mechanical relay, DPDT,
at both input and output of the Alpha is shown with the microprocessor
seemingly controlling/driving the relay coil.

Don't know if this is real;  and if so,  is it truly fast QSK at QRS?
Ten Tec claims the Corsair response in 30 msec;  a 30  wpm
dit is 40 msec long,  so the Corsair is clearly QSK capable,
unsure about the 87A now.

I am not going to do any hook up between the 87A and the
Corsair until I know what I am doing,  hi.  So for now,  will
not bother with QSK,  but would sure like to know exactly
what to do to effect same.

BTW,  I asked  these questions on the Ten Tec reflector,  got only
one answer,  which told me how to do it with a Ten Tec
linear,  some help.

73,  Jim, KH7M
On the Garden Island of Kauai


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