[EIDXA] K3 Intermod

Thu Apr 19 18:42:06 EDT 2012

For what it is worth I quote form an e-mail I got from Wayne Burdick 
on this topic.

"Eric knows Glenn. According to Eric, this is the exact opposite of 
the report from the DXpedition team leader.  I'm sure Eric will 
contact Glenn himself and try to figure out what he's talking about.""

It's a mystery as to what is going on.

David K0LUM

At 10:38 AM -0500 4/19/12, Nelson Moyer wrote:
>Thanks for your thoughtful and informative contribution, Rick. Yes, I had
>the dreaded PWR ERR fault on my K3 toward the end of  HK0NA. It turned out
>to be burned pins on the PA cable from too many RTTY calls on too many bands
>; )
>
>
>
>Nelson, KU0A
>
>
>
>-----Original Message-----
>From: reheinri at rockwellcollins.com [mailto:reheinri at rockwellcollins.com]
>Sent: Thursday, April 19, 2012 9:15 AM
>To: Nelson Moyer
>Cc: eidxa at qth.net; eidxa-bounces at mailman.qth.net
>Subject: Re: [EIDXA] K3 Intermod
>
>
>
>
>Nelson,
>
>I hesitate to enter this discussion/debate for many different reasons,
>but...
>
>I have some experience with mixing K3s and other radios at PJ2T.  So what I
>am about to offer is direct experience/observations from someone who has
>worked to put together a station infrastructure for Multi/Multi competition.
>
>
>1)  The K3 has a very capable receiver.  It is quiet and for that reason is
>regarded as one of the most "fatigue free" radios.  The fact that it has a
>second receiver with the same design for split, diversity, etc. makes it
>unique and contributes to its status as highly capable.
>
>2)  The K3 has an outstanding synthesizer with very low phase noise.  This
>helps with a variety of mixing products that make multi-transceiver
>operation possible.
>
>3)  For normal, typical ham station installations it is likely one of the
>best, most cost effective solutions.  It has high praise by many for its
>overall performance.
>
>Now having said that, I will offer its challenges.  It seems to have spurs
>and unusual antenna "re-radiation" characteristics that are dependent on how
>it is assembled.  I have had the opportunity to sit three different K3s side
>by side, different releases of software and hardware variants, and assembled
>by different people.  Each had different spurs and birdies and showed up in
>other receivers on other bands.  Now at PJ2T we go through an extensive
>planning and pre-operational exercise to select specific frequencies for
>each band to minimize interference.  We have stub decoupling/filters.  We
>have cascaded bandpass filters, and as you note we have an extensive copper
>strap interface that is common for the four main operating positions.  We
>have to jump through pretty difficult hoops when we add a 5th station for a
>specific contest.  But the key is that we pick our frequency of operation
>based on extensive pre-contest testing.  We listen for not only harmonic
>relationships but also specific radio induced noise and strange signals that
>appear to be radio dependent.
>
>We can mix FT-1000MPs, FT-1000 MkVs, FT-2000s, Omni-V, TS-930s, and IC-765s
>and each of these radios have different noise/emission "signatures" and we
>adjust accordingly.  The same thing happens when we bring the K3 on line.
>The only difference is that once we characterize an FT-1000MP we can
>substitute another FT-1000MP and get the same signature.  The same goes for
>most of the other compliment of radios.  but the K3 is a bit of an enigma in
>that there is no consistent noise/emission "signature".
>
>I would bet that unless you stress an installation like a DX-pedition in a
>hostile environment, you would never know about these issues.  Now take the
>hostile Malpelo Island environment and it becomes very challenging.
>Poor/impossible common grounding between the A and B stations, heat,
>humidity, etc. - most transceivers would not do well.  Look at TS-930S which
>was a good radio during their heyday.  Great when operated on stable 60Hz.
>Take one to field day on a generator where the line frequency varied between
>50-60Hz and the radio heated to the point where you could cook on it until
>the power dropped back.  Some of the Ten Tec radios would shut down in high
>humidity conditions.
>
>So let's make this more personal on my part.  I struggle with the decision
>to move to a K3 for a few well documented reasons.  First I am a contester
>and that has its own challenges.  I love the receiver in the K3.  I love the
>completely separate second receiver - it has more versatility for split
>receive including diversity reception.  But I think what challenges me more
>than anything is that I have seen the hood up on more than one K3 during a
>contest.  That is one thing if you have a backup, but if you don't then you
>lose while you make on line repairs or you throw in the towel.  The event
>that has me more challenged than anything with the K3 is the connector
>robustness.  We have had two power amplifier DC power connections fail
>during the high humidity operation at PJ2T - and I believe you have
>experienced a similar challenge.  I can better deal with a component failure
>than I can connectors.  I know broken is broken, but having built radios for
>my livelihood, I know connector choice is one of the critical design issues.
>And I am challenged by tin plated connectors.  They fail.  So that is what
>is causing me the most consternation.
>
>The fact that the radios did not fail on Malpelo speaks volumes for me and
>my decision.  I have used the new ICOMs like the IC7700 and personally I do
>not like them.  I have used the FT-2000 and believe there are better
>receivers out there.  But the bottom line is that everyone has their
>favorite for whatever reason.  You pay your money and you make your choice
>
>So for Glenn and the Malpelo Team, they have their experience that will
>guide their decision making in the future.  For them and their style of
>operation the K3 may not fit their need.  For others it might.  You made
>your decision based on your research and preferences.  I will make my choice
>based on my criteria.  We may wind up with the same radio or not.
>
>Rick
>
>
>
>
>
>
>"Nelson Moyer" <ku0a at mchsi.com>
>Sent by: eidxa-bounces at mailman.qth.net
>
>04/19/2012 08:04 AM
>
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>To
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><eidxa at qth.net>
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>cc
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>[EIDXA] K3 Intermod
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>Glenn's indictment of the K3 receiver got me thinking about why HK0NA
>experienced intermod and other K3 DX'peditions haven't reported that
>problem. Could it be that that inadequate station grounding on the rock
>could have been the culprit? I'm sure that the seawater ground at Ducie was
>much more effective than anything they could have achieved at Malpelo,
>considering that its solid rock. The only conductive material would have
>been the guano and algae on the surface.
>
>
>
>I know we all have our favorite radios, and I think Glenn likes ICOM, but to
>issue a very public blanket indictment of the K3 based upon HK0NA experience
>only seems a bit harsh to me. If ground issues were the problem, perhaps a
>qualifier is in order before Glenn gives his talk at Dayton or wherever.
>
>
>
>Nelson, KU0A
>
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