Fw: Interfacing K3 to TenTec QSK

[Richard Ferch]

I used exactly that setup with my K3 and a Titan (425) during a guest
operation as VE2OJ in the CW Sweepstakes (Winkeyer to key in on the Titan,
key out from the Titan to the K3). After the contest I had one report from a
local amateur of "choppy" CW, which I interpreted as possibly an indication
of some shortening of the CW elements. It didn't seem to be bad enough to
hinder copy, as I did not have an unexpected rate of repeat requests, and
there were no comments on the keying during the contest.

If I were using that amplifier again in QSK mode I would try to set aside
some extra time before the contest to look at the CW on a scope to see
whether any keying compensation was called for.

73,
Rich VE3KI


----- Original Message -----
From: "Tim Heasman" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, November 20, 2008 8:59 PM
Subject: Re: [Elecraft] Interfacing K3 to TenTec QSK
Amplifiers/AutomaticAntenna Tuner

> Hi All,
>
> Connect a keyer to key in on the Titan and use key out from the Titan to
> key the K2.  There will be no timing problems doing it that way.
>
> 73
>
> Tim
>
> gm4lmh
>

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[Vic K2VCO]

Richard Ferch wrote:

> I used exactly that setup with my K3 and a Titan (425) during a guest
> operation as VE2OJ in the CW Sweepstakes (Winkeyer to key in on the Titan,
> key out from the Titan to the K3). After the contest I had one report from a
> local amateur of "choppy" CW, which I interpreted as possibly an indication
> of some shortening of the CW elements. It didn't seem to be bad enough to
> hinder copy, as I did not have an unexpected rate of repeat requests, and
> there were no comments on the keying during the contest.
>
> If I were using that amplifier again in QSK mode I would try to set aside
> some extra time before the contest to look at the CW on a scope to see
> whether any keying compensation was called for.

In my opinion, the shortening was caused by feeding the key line through
the Titan. But you don't need to do this. The Titan has a fast enough
t/r switching time and the K3 a long enough delay between key-down and
RF output to allow you to connect the K3 key-out directly to the Titan
key-in line.

At the very worst, you might have to increase the K3's TX DLY time a bit
from minimum -- but I don't think so (the Titan uses vacuum relays
spec'd at 6-8 ms. pull-in time and the minimum delay of the K3 is 8 ms).

I am using the K3 with a similar vacuum relay in my amplifier and there
is no hot-switching detectable with the K3 set to minimum delay.

The key-in/out loop protects the amplifier relay against hot-switching
if the exciter does not provide a built-in delay. Both the K2 and the K3
do have such a delay (the  K2's is a bit longer than the K3 and not
adjustable).
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[Tom Hammond-2]

Hi Rich:

Similarly, I (originally) tried keying my rig (at that time, a TS-930S) via
the KEY input of my Alpha 76PA which had been retrofitted with the QSK from
an Alpha 78.

I experienced the same report(s) and was actually able to see the choppiness
and 'crud' on my CW waveform when allowing the amplifier's QSK to key the
exciter.

The problem was NOT that of the QSK having been retrofitted to the non-QSK
amp but that of the original design of the keying scheme. Tried a real
Alpha 78 (OEM QSK installed) and had the same problem.

Moved the Key to the exciter and allowed it to key the AMP's T-R line and
NEVER again had a problem. The TS-930S also had a built-in slight delay in
generated RF following T-R line closure.

I now key my K3 and allow it to key the QSK amp, again, with no complaints
from ANYONE, and the keying is as clean as a pin.

Cheers,

Tom Hammond   N0SS

At 15:53 11/20/2008, Richard Ferch wrote:

>I used exactly that setup with my K3 and a Titan (425) during a guest
>operation as VE2OJ in the CW Sweepstakes (Winkeyer to key in on the Titan,
>key out from the Titan to the K3). After the contest I had one report from a
>local amateur of "choppy" CW, which I interpreted as possibly an indication
>of some shortening of the CW elements. It didn't seem to be bad enough to
>hinder copy, as I did not have an unexpected rate of repeat requests, and
>there were no comments on the keying during the contest.
>
>If I were using that amplifier again in QSK mode I would try to set aside
>some extra time before the contest to look at the CW on a scope to see
>whether any keying compensation was called for.
>
>73,
>Rich VE3KI
>
>
>----- Original Message -----
>From: "Tim Heasman" <[hidden email]>
>To: <[hidden email]>
>Sent: Thursday, November 20, 2008 8:59 PM
>Subject: Re: [Elecraft] Interfacing K3 to TenTec QSK
>Amplifiers/AutomaticAntenna Tuner
>
>
> > Hi All,
> >
> > Connect a keyer to key in on the Titan and use key out from the Titan to
> > key the K2.  There will be no timing problems doing it that way.
> >
> > 73
> >
> > Tim
> >
> > gm4lmh
> >
>
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