[Elecraft] [KPA500] Rear power switch thread

Thu Dec 1 13:27:51 EST 2011

Dave,

thanks for taking the time trying to explain it. I know what actually 
happens and why one should first power of the radio before cutting the 
lines. Nevertheless Elecraft is not the only one using encoders but still 
they are the only ones with a requirement for that procedure. This has 
nothing to do with being an SDR.

Lets stay at one defined example, the VFO. Everybody is using an encoder 
here, whatever brand it is. Still when I cut power off my Icom (and all 
other rigs I know of) it always comes back to the last used frequency & 
mode. If I just cut power from my K3 it never comes back to the same 
frequency! It usually is one in the same band but not the last used one.

So how do others do it? I imagine they simply write the current frequency 
into memory after probably a few milliseconds of no VFO move. Elecraft could 
do the same (actually they are doing it when powering down the rig).

So my question is simple: Why don't they do it? What are the reasons behind? 
Not enough time while working down the operations code? A limitation of the 
PICs used as the central brain (the other brands use bigger/faster 
processors)?

Don't get me wrong, I really like my K3 & KPA500 and have no problems at all 
with how they work. Nevertheless I am curios to know the reasons. Might be 
'cause I'm into (only a little) programming myself and want to understand 
other guys logics and learn something, too. ;-))

73, Olli - DH8BQA
http://www.dh8bqa.de

----- Original Message ----- 
From: "David Herring" <dave at ah6td.com>
To: "Oliver Dröse" <droese at necg.de>
Cc: <elecraft at mailman.qth.net>
Sent: Thursday, December 01, 2011 12:07 AM
Subject: Re: [Elecraft] [KPA500] Rear power switch thread

Olli,

This is a bit of an oversimplification, but I think it will convey the point 
good enough to address your very valid question without getting into what 
could otherwise be a very long answer.

On most other rigs on the planet, the settings are dictated by the position 
of the knobs and switches.  Pull the plug on them and whatever computing 
faculties are present in the rig will simply reboot their software and 
continue on as normal the next time power is applied.

The K3 is more software defined than that.  The settings are NOT necessarily 
dictated by the position of the knobs and switches.  The settings are 
defined by what's been stored in memory, which is a result of the last 
change in knob and switch position, not necessarily where the knob or switch 
is now.

When you power down the K3 using the front panel power button, this sends an 
instruction to the computer to save all this information in an orderly and 
proper manner for next time, and then power off.

When you pull the plug, the computer in the K3 doesn't get the opportunity 
to save this stuff out in an orderly fashion.  99% of the time it's no 
problem.  But pull the plug while the computer happens to be doing a routine 
save of this information, so that not all gets saved or saved properly (as 
an example), and you could wind up with a collection of settings that are 
inconsistent or self-contradicting.  At that point, when you power on next 
time the computer hasn't got a hope of figuring out what to do.  Your rig 
has just become hosed.  You'll need to reset everything back to a generic 
state and start over.

I don't have first hand knowledge of other SDR rigs, but I imagine Elecraft 
is not the only one with this "feature."  (I don't call it a problem because 
it isn't...it's exactly how the architecture is designed to work)

I hope that helps.

Dave
AH6TD

On Nov 30, 2011, at 12:35 PM, Oliver Dröse wrote:

> Hi Ron,
>
> the arguments are told over and over again ("it is like a computer, etc.")
> for the K3 and KPA500. Still I do not see WHY it is possible with every
> other transceiver and PA on earth to simply shut down power (disconnecting
> from mains) without first switching it off and without any possible
> problems? They use the same "computer technique" inside ...
>
> Just curious. ;-))
>
> 73, Olli - DH8BQA
>
>
>
> ----- Original Message ----- 
> From: "Ron D'Eau Claire" <ron at cobi.biz>
> To: <elecraft at mailman.qth.net>
> Sent: Wednesday, November 30, 2011 4:42 PM
> Subject: Re: [Elecraft] [KPA500] Rear power switch thread
>
>
>> Just to be clear - the Elecraft equipment should be turned off using the
>> front panel switch *before* it is disconnected from the mains supply so
>> the
>> logic system can do a proper shut-down. You can get away with "pulling 
>> the
>> plug" much of the time, but sooner or later you'll catch the logic in the
>> process do doing something critical - writing data to memory, etc. - and
>> will end up with scrambled data. That can be corrected by reloading the
>> firmware, but it's a hassle easily avoided by powering down with the 
>> front
>> panel switch first.
>>
>> Ron AC7AC
>>
>>
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