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K3 - qsk keying loop

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Barry N1EU

K3 - qsk keying loop

I'm surprised to notice no provision for tx enable/inhibit signals
(qsk keying loop) on the K3. I'd appreciate hearing comments on why
this wasn't part of the design and what the timing safeguards are in
the existing "key out" signal to prevent hot switching on make/break.

Thanks & 73,
Barry N1EU
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Don Wilhelm-4

Re: K3 - qsk keying loop

Barry,

Something was added to provide a "TX inhibit until PTT" function. That
discussion was late in the Field Test cycle. I was involved on the
sidelines of the discussion even though I was not a field tester.

The bottom line is that it is "in there", but I have not combed the
latest documents to determine where it is. Look through all the menu
items related to keying.

73,
Don W3FPR

Barry N1EU wrote:
> I'm surprised to notice no provision for tx enable/inhibit signals
> (qsk keying loop) on the K3. I'd appreciate hearing comments on why
> this wasn't part of the design and what the timing safeguards are in
> the existing "key out" signal to prevent hot switching on make/break.
>
>
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Barry N1EU

Re: K3 - qsk keying loop

Thanks Don. Although TX Inhibit is described in the latest C1 version
of the manual, I missed it because no mention is made of using it for
qsk amp control. It would have been nice to make +5V available on the
AUX I/O connector for the pullup wiring. Also, I'm not sure why the
manual text refers to the "ACC" labeled connector as "AUX I/O" -
shouldn't this be consistent?

I believe there's an omission in the manual - TX INH is not listed in
the CONFIG menu section and I believe it should be.

73,
Barry N1EU

On 11/28/07, Don Wilhelm <[hidden email]> wrote:

> Barry,
>
> Something was added to provide a "TX inhibit until PTT" function. That
> discussion was late in the Field Test cycle. I was involved on the
> sidelines of the discussion even though I was not a field tester.
>
> The bottom line is that it is "in there", but I have not combed the
> latest documents to determine where it is. Look through all the menu
> items related to keying.
>
> 73,
> Don W3FPR
>
> Barry N1EU wrote:
> > I'm surprised to notice no provision for tx enable/inhibit signals
> > (qsk keying loop) on the K3. I'd appreciate hearing comments on why
> > this wasn't part of the design and what the timing safeguards are in
> > the existing "key out" signal to prevent hot switching on make/break.
> >
> >
>

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Don Wilhelm-4

Re: K3 - qsk keying loop

Barry,

For amplifier keying, the K3 has an adjustable T-R delay that is very
much longer than that provided by the K2. It may be easier to use that
than fooling around with the external TX inhibit function.
The TX inhibit is more useful to folks who operate VHF/UHF with a
sequencer to switch a chain of preamps and antenna mounted gear between
TX and RX - it can also used to steer the keyer input to one of 2
transceivers in SO2R setups.

73,
Don W3FPR

Barry N1EU wrote:

> Thanks Don. Although TX Inhibit is described in the latest C1 version
> of the manual, I missed it because no mention is made of using it for
> qsk amp control. It would have been nice to make +5V available on the
> AUX I/O connector for the pullup wiring. Also, I'm not sure why the
> manual text refers to the "ACC" labeled connector as "AUX I/O" -
> shouldn't this be consistent?
>
> I believe there's an omission in the manual - TX INH is not listed in
> the CONFIG menu section and I believe it should be.
>
>

Allan Taylor

Re: K3 - qsk keying loop

Don and K3 fans,

I have a few comments on interfacing Elecraft transceivers with QSK amps.

When the K2 was first announced publicly (Oct 1999, Pacificon QRP forum)
Wayne and Eric invited those attending to give input and comments
regarding desired features. As I have been a Tentec fan for many years and own
two Tentec QSK amps, I requested of Wayne that a QSK keying loop be
provided in the K2 design. As you know, my request was not implemented.
This fall, again at Pacificon, I asked Eric I asked if there would be a QSK
keying loop provided, this time in the K3. His response was in the negative.

Don, in the email below, says that the time delay in the K3 will accommodate
a QSK amp. That is only partially true. The problem is in setting it
up. I could,
of course, put in a LONG delay but then QSK is gone. If I crank the delay down,
at some point I am relying on the RF sensing circuitry in my QSK amps to hold
the relays closed until RF is really gone from the input. That may work but I
would really prefer the sure-fire solution of a keying loop. This allows a QSK
amp to be set up optimally by just plugging in and does not require a scope
and a bunch of fuss. The QSK of my Tentec transceivers coupled with
either the Titan or Hercules II QSK amps is plenty fast for me as I
never go above 50 wpm anyway.

For what it is worth, the Yaesu transceivers and their Quadra QSK amp use a
keying loop. It works great also. We used it in SS this year and had a ball.

I am sure that the K3 will key perfectly with the yet-to-be-available Elecraft
amps, but it would be nice if interfacing with existing QSK amps could be
done in the obvious way.

BTW: I am purchasing a used K2/100 (updated, of course #755) from a
K3 buyer and am on the 3rd run for a K3.

73 Allan K7GT

southern Oregon

On 11/28/07, Don Wilhelm <[hidden email]> wrote:

> Barry,
>
> For amplifier keying, the K3 has an adjustable T-R delay that is very
> much longer than that provided by the K2. It may be easier to use that
> than fooling around with the external TX inhibit function.
> The TX inhibit is more useful to folks who operate VHF/UHF with a
> sequencer to switch a chain of preamps and antenna mounted gear between
> TX and RX - it can also used to steer the keyer input to one of 2
> transceivers in SO2R setups.
>
> 73,
> Don W3FPR
>
> Barry N1EU wrote:
> > Thanks Don. Although TX Inhibit is described in the latest C1 version
> > of the manual, I missed it because no mention is made of using it for
> > qsk amp control. It would have been nice to make +5V available on the
> > AUX I/O connector for the pullup wiring. Also, I'm not sure why the
> > manual text refers to the "ACC" labeled connector as "AUX I/O" -
> > shouldn't this be consistent?
> >
> > I believe there's an omission in the manual - TX INH is not listed in
> > the CONFIG menu section and I believe it should be.
> >
> >
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>

Brendan Minish

Re: K3 - qsk keying loop

Folks,

For what it's worth, My QSK amp is an Acom 1000, With the K2 and now
with the K3 I have never ever had it hot key or clip Dits.
With My old Icom pro2 I had hot keying issues until I started using the
solid state keying output (it's faster than the relay driven output)

None of my Icoms ever had a QSK keying loop as far as I am aware either,
perhaps it's a Ten-Tec thing

With the K3 I simply plugged it in and got on air. Full QSK with the
Acom 1000 in line is every bit as wonderful as the K3's full QSK
barefoot.
The K3 also has a PTT line, which with the footswich in my setup works
perfectly for overriding QSK when required

I would have thought that with any amp design, no matter how fast or
slow, each amp will have it's time constant.For slower 'qsk' Amps Surely
it's simply a matter of measuring this time constant and applying it as
the time delay?

If you absolutely have to have a QSK keying loop the presence of the
separate PTT line makes it possible to engineer a simple external
solution

Perhaps it's just me but I don't see any issues here, just the nicest
radio I have ever used.

73
Brendan EI6IZ

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Eric Swartz - WA6HHQ

Re: K3 - qsk keying loop

Administrator

In reply to this post by Barry N1EU

Hi Barry,

We will definitely have TX inhibit as an input on the K3 AUX I/O
connector. Its not turned on yet, but should be shortly as we add this
feature to the firmware. It certainly helps for some set ups when using
the rign in a SO2R arrangement etc.

73, Eric

Barry N1EU wrote: