Re: K3 Keying Up For A Split Second When Power Button, IsPushed (Tom W8JI)

[k6xt]

It is not normal behavior for my K3. The red tx light comes on for a
split second but there is no amp keying or RF output.
73 Art

--
73 Art
Allison, Colorado
"Whether you believe you can do a thing or
not, you are right."  --Henry Ford.

Message: 51
Date: Thu, 1 Apr 2010 07:50:22 -0400
From: "Tom W8JI" <[hidden email]>
Subject: Re: [Elecraft] K3 Keying Up For A Split Second When Power
        Button IsPushed
To: "-.-.  --.-N3TU -.-.  --.-" <[hidden email]>,
        <[hidden email]>
Message-ID: <B545DB30C1794028B301FBF152F950A0@radioroom>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
        reply-type=original

<<<Is it normal for the K3 to key up right away for a split
second when turned
on. I have a Drake L4B with a soft key behind the radio. If
by accident the
amp is out of the  stand-by mode and you turn on the K3, it
will key the amp
for a split second. Is this normal? Don't get me wrong, I
try to put it in
standby but every now and then I'll forget. >>>

That's normal behavior for the K3.

I don't like it either, but a properly designed step-start
should still be OK with just the quiescent current of the PA
tubes so long as RF is not applied. The only problem would
come in when the step-start and the radio both have issues.
If the step-start isn't planned well, and blows a fuse or a
resistor when starting under quiescent current loads, then
the radio doing closing the relay line at power-on  becomes
a problem.

As a suggestion you could easily build a time-delay start up
for the amp, which it should have if simply closing the
relay control line at amplifier power-on causes damage.
You'd have to add a small relay and wire it in series with
the relay control jack.

My amplifiers start just fine at quiescent loads, so I don't
worry (although what you observe annoys me too and I can see
where it could cause step-start damage in some systems).

73, Tom

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[W8JI]

<<
It is not normal behavior for my K3. The red tx light comes
on for a
split second but there is no amp keying or RF output.
73 Art>>

Art,

Mine has always closed the amplifier relay control line upon
power up during the period after the power switch is pushed
"on" and the display illuminates. The K3's red TX light is
**not** on during that time. it does it any mode, and any
VOX or PTT setting.

Make sure yours doesn't do the same thing.

I think this would mainly be a problem if someone power the
amp and radio up at the same time, or powers the amp
slightly before the radio is turned on. While my amps are
immune to step-start damage, some systems can be damaged if
the relay line is pulled low during the amplifier's power-up
step-start sequence. This damage is a step-start design
shortfall aggravated by an unusual power up behavior.

It's more annoying to me, since it can't damage the amps I
have, but it does make me look carefully at meters to be
sure it isn't transmitting. Especially if I am reloading
firmware and I have the amplifiers and antenna transfer
systems all running. :-)

73 Tom

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[Ignacy]

I have this behavior when K3 is attached by a serial cable and RTS or CTS are set for keying. Must have something to do with COM port initialization. Nothing wrong with K3.
Ignacy

[Ken Kopp-3]

Perhaps related ....

I don't see the short output of RF that's being described.
(S/N 56 w/latest firmware).

I -do- note seven evenly-spaced +/- one second full power
key-ups as my computer boots up when I forget to unplug
the USB cable from the radio ... or initiate MODE/TEST.  

I have no contest or control software running that would
initiate these seven key-ups, so I assume this is the utility
polling the radio as it is launched during the computer's
boot-up.

I do have a Tokyo Hi-Power PA, but it's seldom on and
wouldn't be turned on -before- the K3 is turned on.

73! Ken Kopp - K0PP
       [hidden email]
       http://tinyurl.com/7lm3m5




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[W8JI]

<<I don't see the short output of RF that's being described.
(S/N 56 w/latest firmware).>>

That's probably because no one ever said there was an RF
pulse.      :-)

It just pulls the TX line that runs out to the amplifier
low. That's only a problem when the amp has a step start
that cannot handle the quiescent current of the amp in the
TX mode during start. RF would be a disaster with almost any
amp, the TX line enable is just a worry with some amps and
the real worry is only with a poorly implemented step start.


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[Vic K2VCO]

Ken,

This sounds like your K3 is configured for DTR keying. Go to the CONFIG menu and look for
the PTT-KEY parameter. If it is set for DTR keying, then when the computer boots, its BIOS
raises the DTR line a few times which keys the radio.

Unless you are normally keying your radio this way, you should set the menu parameter to
OFF OFF.

I find it easier to turn it off between contests than to remember to go into test mode or
unplug the cable every time I boot the computer.

On 4/1/2010 11:35 AM, Ken Kopp wrote:

> Perhaps related ....
>
> I don't see the short output of RF that's being described.
> (S/N 56 w/latest firmware).
>
> I -do- note seven evenly-spaced +/- one second full power
> key-ups as my computer boots up when I forget to unplug
> the USB cable from the radio ... or initiate MODE/TEST.
>
> I have no contest or control software running that would
> initiate these seven key-ups, so I assume this is the utility
> polling the radio as it is launched during the computer's
> boot-up.
>
> I do have a Tokyo Hi-Power PA, but it's seldom on and
> wouldn't be turned on -before- the K3 is turned on.
>
> 73! Ken Kopp - K0PP
>         [hidden email]
>         http://tinyurl.com/7lm3m5

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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