Also, for digital modes, I run my equipment at half power, max. So, for
a 100W XCVR, I run it at 50W.
This serves two purposes. One, it's easier on the PA, and two, it
leaves a 3dB 'overhead' for the digital mode, and less likelihood of
distortion getting into your TX signal. This has been SOP for many
years for digital modes.
A difference of 1/2 S-unit on the receiving end will generally be
unnoticed, and your equipment will thank you, as well as any receiving
nodes that may not be able to decode your signal if you are pushing your
equipment to its limits.
73,
-- Dave, N8SBE, Hamshack Hotline 590-0971, HamsOverIP 101018,
AmateurWire 1348
On 2024-08-28 07:24, G4GNX wrote:
My K3S did this a couple of months ago - 40m SSB - 100W. I restarted it
and it continued for nearly another month before switching off again.
It did it a couple of times more over a week or so, before finally
turning off and refusing to turn on again.
On investigation, I realised that I had “temporarily” connected the K3S
power cable to a distribution box, using PowerPoles - bad move. When
tracing the cable routing, I pressed against one of the PowerPoles and
the radio came back on again. I found it impossible to pull the
PowerPoles apart, which was due to the plastic covers being badly
distorted by heat. I eventually got round to pulling the PowerPoles
apart by force and unfortunately the + connector flew in the air and I
haven’t found it yet. 😀
However, the contact in the dis-box looks suspiciously like it’s gotten
hot and coupled with the other “evidence” I conclude that the contacts
deformed under heat caused by high current spikes (SSB).
Also, my IC-9700 (although connected to a different PSU - via
PowerPoles) did the same thing, but unlike the K3S, it just rebooted
itself.
I have completely rewired all of the high power cables in my shack
directly back to the PSU (Sharman Multicom - 60A) and I’ve had no more
problems.
In your case, you’re running 100W for longer periods and that is one
possible cause of a premature breakdown. You could save yourself a lot
of trouble, by examining all of the power connections, including the
PowerPoles on the K3 itself.
73,
Alan - G4GNX
South Coast UK
Elecraft K4D / KPA500 / KAT500 / IC-9700
On 28 Aug 2024, at 03:30, Glenn Thorne <kd0q.gl...@gmail.com> wrote:
Just tonight my K3 with KPA3 running 100 watts shuts down during
digital
transmissions. It appears that it happens after the PA temp is 47 C.
Maybe the first time it hits 48 C?
I checked the KPA3 FN1 - 4 settings and it appears that the fans work.
At what PA temps should the fans come on? Increased speed?
Any ideas where to start troubleshooting will be appreciated.
Glenn - KD0Q
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