Re: [K2] Safely running 100% key-down modes (K1FFX)

[Bob-19]

Hi Bruce,

I haven't tried JT-65 but I've been running PSK-31 on my K2 with the KPA100
power set at 50% (i.e., 50 watts) or less without any problems. Although my
transmissions are not longer than several minutes each, I understand that at
the power level, you could have much longer transmissions without problems.

Take care,

Bob W1SRB

PS- hope to see you at NEFFA this year
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Message: 1
Date: Thu, 26 Dec 2013 09:06:23 -0800 (PST)
From: K1FFX <[hidden email] <mailto:[hidden email]> >
To: [hidden email] <mailto:[hidden email]>
Subject: [Elecraft] [K2] Safely running 100% key-down modes
Message-ID: <[hidden email]
<mailto:[hidden email]> >
Content-Type: text/plain; charset=us-ascii

I starting to use my K2/100 in two 100% key-down modes, JT-65 and PSK-31.
What
should I be keeping in mind in protecting the output stage for the K2 and
for the KPA100?

For JT-65, since it is a QRP mode, I'm running at about 5 watts, and
transmissions are
limited to about 45 seconds.  So, I'm hoping that K2's output transistors
will not be stressed
in this mode.

But, how about PSK-31?  I'd like to run about 20 watts and each transmission
could easily
be 3 or so minutes.  I don't know at what output power the base K2 runs when
the KPA100
kicks in (i.e., at above 10 watts).  I assume that normally the KPA100 will
be loafing at 20
watts, but I'm not sure the impact of 100% key down on its output stage.

I'd appreciate any guidance in keeping the K2/100 "safe" in these modes.

Thanks -

Bruce K1FFX




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[k6dgw]

FWIW:  I used to run RTTY on my K2/100 [AFSK into mic jack and from
headphone jack].  I put a little square of sticky-back velcro on top of
the heat sink over the part that got the warmest and used it to stick a
12VDC muffin fan down, blowing down into the heat sink.  I found I could
run RTTY at 100W and the heat sink stayed cool to the touch.  The fan
was almost silent, totally silent with headphones on, and the only
anomaly was on 15 if the beam was pointed across the shack [toward
VK/ZL].  Then, when I was transmitting, the fan would slow way down. :-)

I use the K3 now, usually driving the KPA500 to 500W, and I sold the
KPA100 and KAT100 ... my K2 is my field rig.

I really don't think anyone need worry about Elecraft gear needing to be
derated very much.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 12/27/2013 1:21 PM, Bob wrote:
> Hi Bruce,
>
> I haven't tried JT-65 but I've been running PSK-31 on my K2 with the KPA100
> power set at 50% (i.e., 50 watts) or less without any problems. Although my
> transmissions are not longer than several minutes each, I understand that at
> the power level, you could have much longer transmissions without problems.


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