K3: very low power out with sub rx turned on

[Ed K1EP]

Here is a strange problem that seemed to be intermittent last night
and now has disappeared.

Last night in the 160 contest, when I turned on the subrx, I lost
transmit power.  (It had been fine up until then.)  I was operating
at 100W with (or without) the ATU into an okay ~1.5:1 load.  When I
pressed the SUB (or did it from software), the SWR would go up to
~6:1 as read on an external meter and power out would be about 3
watts.   Yes, an external meter said that the power out was about 3
watts and the SWR was now high.  To me that indicated I wasn't
transmitting on 160M anymore, although the K3 display still read
1.8xxMHz.  Either I was suffering from lack of sleep or something was
strange.  I only have one antenna, there is no switching.  I was on
ANT 1 (or else the meter wouldn't work).  After going back and forth
from the sub rx on and off, I power cycled the radio, still no
change.  I just decided to not use the sub rx to get on with the
contest.  A little later I tried it again and could not reproduce
it.  It probably had something to do with the frequency I was on
(high up in the band) or the lack of sleep.   Any clues?

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[Guy, K2AV]

Often when confronted with wild behavior, which goes away when the K3 is
cycled, one has a problem with RF in the shack, poor grounds, etc.  All one
needs to create strange behavior is to scramble ONE bit in K3 internal
software somewhere.

The remedy will be the usual things, often discussed, grounds, misc
conductors, rat's nest of wires, antenna's too close to the shack, etc, etc,
etc, ad nauseum.

What the power cycle does is to reload and reinitialize volatile memory in
the various K3 subsystems from the FIRMWARE memory, thus getting rid of
botched bits causing all the wildness.

YMMV as logging programs, etc can also do very strange things, when THEIR
volatile memory gets messed up and starts sending command sequences to the
K3 that make no sense. Then there's all the physical problems with cable
connectors.

One problem I was SURE was in the K3, went away when I cold powered down my
 PC, removed a USB/Serial cable at BOTH ends, rebooted and then inserted the
cable alone to reinitialize it's driver software, and then plugged it into
the K3.

It turned out to be a Windows 7 64 bit thing.

It's counter-intuitive for some reason, but always start by looking in the
K3 ENVIRONMENT.  That's where most of the trouble is.

73, Guy.

On Sun, Jan 30, 2011 at 10:37 AM, Ed K1EP <[hidden email]> wrote:

> Here is a strange problem that seemed to be intermittent last night
> and now has disappeared.
>
> Last night in the 160 contest, when I turned on the subrx, I lost
> transmit power.  (It had been fine up until then.)  I was operating
> at 100W with (or without) the ATU into an okay ~1.5:1 load.  When I
> pressed the SUB (or did it from software), the SWR would go up to
> ~6:1 as read on an external meter and power out would be about 3
> watts.   Yes, an external meter said that the power out was about 3
> watts and the SWR was now high.  To me that indicated I wasn't
> transmitting on 160M anymore, although the K3 display still read
> 1.8xxMHz.  Either I was suffering from lack of sleep or something was
> strange.  I only have one antenna, there is no switching.  I was on
> ANT 1 (or else the meter wouldn't work).  After going back and forth
> from the sub rx on and off, I power cycled the radio, still no
> change.  I just decided to not use the sub rx to get on with the
> contest.  A little later I tried it again and could not reproduce
> it.  It probably had something to do with the frequency I was on
> (high up in the band) or the lack of sleep.   Any clues?
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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