[Elecraft] T32MI K3 rig problem

[Rich - K1HTV]

Hi Bob,
OK on seeing the problem of the K3 shutting down when the transmitter is keyed
on 40 Meters. If there is a 40 Meter 'sensitivity-to-RF' problem with the K3,
then there is a reason for it. It may take a super sleuth to discover the cause.
It may be a component resonance problem within the radio such as a combination
of a trace length and a bypass cap causing a parallel resonant circuit at 40M.
Who knows.

If the problem is being triggered by 40 Meter RF and the internal fix can not be
found, then the user should be able to take some actions to reduce the problem.
Stray RF can be reduced with a good RF ground at the radio, using a resonant
antenna with low standing waves, adding coax chokes or installing ferrites on
antenna coax feedline. Your mileage may vary :-). 

73,
Rich - K1HTV

= = =   

-----Original Message-----
From: Bob Naumann [mailto:W5OV at W5OV.COM] 
Sent: Monday, March 29, 2010 21:21 PM
To: 'Rich - K1HTV'
Subject: RE: [Elecraft] T32MI K3 rig problem

I've seen this problem many times in the past - that's why I ask. I don't know
the connection, but 40m seems to do this a lot.

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Rich - K1HTV
Sent: Monday, March 29, 2010 8:06 PM
To: 'Bob Naumann'
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] T32MI K3 rig problem

They don't, but if it is triggered by RF, the proposed suggestion is simple one
and worth trying with available parts.  

Rich - K1HTV

-----Original Message-----
From: Bob Naumann [mailto:W5OV at W5OV.COM]
Sent: Monday, March 29, 2010 21:00 PM
To: 'Rich - K1HTV'; iz1crr at tin.it
Cc: elecraft at mailman.qth.net
Subject: RE: [Elecraft] T32MI K3 rig problem

How do they know it's the radio and not the power supply shutting off?

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Rich - K1HTV
Sent: Monday, March 29, 2010 7:46 PM
To: iz1crr at tin.it
Cc: elecraft at mailman.qth.net
Subject: [Elecraft] T32MI K3 rig problem

IZ1CRR

Maury,
   Regarding the 40M problem with Derek's K3, it may be related to stray 40M RF
getting into the radio when it is keyed. If this is the cause, an easy fix may
be to create an imaginary ground on it by connecting a 1/4 wave long (around
10.56 Meters or 34.6  feet) wire to the ground screw on the back of the K3.
The
high impedance end of the 1/4 wave wire is transformed to a low impedance at the
radio. This should reduce any stray RF around the radio. It is a simple thing to
try and may fix the problem. 

I would be interested to hear if it fixes the 40 Meter problem.

I had no difficulty in working T32MI on CW & SSB with 100 Watts and a wire
antenna from my QTH in Virginia,  my IOTA number 964. They are a great
operators!

73,
Rich - K1HTV
Retired from VOA 

= = = 
>From a post of the K3 Reflector from Roland, DC1RS

2010-03-28 08:30

This morning local time (Saturday 21:00 gmt) we started our journey to Caroline
island. Estimate 5 days sailing. Almost 9,000 Qs in our logs from the 3 days on
Malvern. Derek's beloved Elecraft K3 has a problem! On 40m only, the instant the
rig is keyed, even at min power, it switches off as if the supply plug is
disconnected. After an indeterminate delay power is restored and the rig can be
used on other bands. Any ideas, please contact Maury, IZ1CRR (iz1crr @ tin.it).
73 Derek

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