[Elecraft] K144XV Strange Readings

Sat May 18 18:36:31 EDT 2013

Jim, it was a ground loop problem caused by the metal spacer. You'd have to
have a very early K144XV for it to be present. Here's how to tell if yours
needs modifying as described in the mod instructions:

This change was incorporated into the K144XV assembly process in September,
2010. All K144XV's shipped
after September are already modified. If you are unsure, remove the K3 top
cover and inspect the K144XV
module mounted on the left side panel. If there is a screw in the hole
directly above the Elecraft
name on the top label, the modification has not been done.

The K144XV module is directly under the K3 top cover mounted on the left
side panel (when the front of the K3 is toward you). The label says
"Elecraft K144XV 2M Module".  You probably don't need to completely remove
the top cover. Just lift it enough to see that label. Note that there should
be two empty holes in the top - that one and one closer to the side panel
(unless Elecraft has redesigned the cover to remove the superfluous holes).

Note that there SHOULD be a screw in a hole just to the right of the word
"STATUS" on the edge farthest from the side panel.

If yours has a screw in that location (instead of an empty hole), let me
know and I'll dig up a copy of the mod sheet for you. I can no longer find
it on the Elecraft web site. 

73 Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Miller
Sent: Saturday, May 18, 2013 1:59 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K144XV Strange Readings

Will someone please describe this "center spacer" so I can verify whether it
is in mine or not?  

Was it an active part of the circuitry?  If I have it in mine can I just
remove it without any other modifications?  Why does removing an inactive
part have any effect?

73, Jim KG0KP

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
Sent: Friday, May 17, 2013 10:20 PM
To: mteberle at mchsi.com; elecraft at mailman.qth.net
Subject: Re: [Elecraft] K144XV Strange Readings

Mike: First e-mail K3support at elecraft.com or call them (831-763-4211) for
further guidance. 

As Dave says the center spacer was removed very early on when some stability
issues arose. I have an early pre-production board, but it was stable with
and now without that spacer. This sounds like something new but may be
something that you can tackle yourself. 

73, Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Michael Eberle
Sent: Friday, May 17, 2013 7:57 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K144XV Strange Readings

Dave,

Yes that is exactly what it appears to be doing.  My frequency counter is
showing RF at 153.600 MHz regardless of what part of the band it is tuned
to.  I removed the K144XV Reference Lock Board and there was no change.  Is
there anything that can be done to correct this, or do I need to send it
back to Elecraft?  I just bought it 2 months ago so it shouldn't be an early
production run board.

Thanks,
Mike KI0HA

On 5/17/2013 6:50 PM, WW2R Elecraft wrote:
> Both my early edition K144XV were not unconditionally stable and were 
> swr intolerant
>
> I think you will find that the 3:1 swr is because it is oscillating 
> "out of band". Try listening on a scanner. I have experienced this on 
> my two k144xv and g4ddk had the same issue with his. One example 
> produced 162MHz, one 168MHz one around 158MHz. When you tune or speak 
> it
stabilizes and generates
> on 2m   My k144xv were fine if I operated at the bottom end of 2m where
the
> swr was 1.1:1 but my antenna swr rose to 1.6:1 at around 144.8MHz  and 
> above this point it showed the instability you mentioned
>
>
> Mine were replaced with the later production run k144xv (the one 
> without the centre spacer, but that could just be coincidence!) and 
> the issue has not arisen since
>
> Dave
>
> G4FRE

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html