[Elecraft] Possible bad KREF or K144XV Ref Lock or ???

[Harry Yingst via Elecraft]

Thank you for the insight.

Last night I pulled the K3 back over to the workbench and probed the
lines coming to and from the ref lock board with a oscilloscope.
What I discovered is that the rear of the jack had pushed back out of the socket.
Once I corrected that everything worked fine.


On a side note: I have a nice Down east Microwave Transverter I built last fall. 
Since I wanted to reduce the clutter so I went with the internal transverter.




________________________________
 From: Vic Goncharsky <us5we at yahoo.com>
To: Harry_Yingst <hlyingst at yahoo.com> 
Cc: elecraft at mailman.qth.net 
Sent: Sunday, May 4, 2014 5:28 AM
Subject: Re: [Elecraft] Possible bad KREF or K144XV Ref Lock or ???
 

Hi Harry,
Hope the info that follows will be useful.
I have made some research of how to make the internal K144XV Elecraft transverter be useful in contests. 
Originally it was almost useless due to many parasitics all across the band even from S9 signals.
The stronger – the worse and there were a lot of them even here in KN29AU. 
So in July, last year, during IARU R1 3-rd subregional VHF contest, the band was full of clones. HI HI.

Comparying the schematics of both internal and external Elecraft 144 transverters shows three major differences that could have caused the different dynamic performance of the internal one.
Firstly - the usage of three diode switching components in the Front-End chain up to the ADEX mixer.
Secondly - usage of MMIC instead of BFR96 in the LO amplifier stage.
Thirdly - the K144XV PHASE LOCK BOARD

Here are some findings and possible solutions.
1.Remove (do NOT install) the K144XV PHASE LOCK BOARD!
In this case transverter is using just its own Xtal generator and spirious signals caused, possibly, by leakage from the synthesizer are gone. 
2. Bypass the input diode T/R input switch by using separate receiving path. Remove the shorting block from pin1-2 of the P3 connector and connect separate coax to pin2 – RF, pin3 – ground.
This requires adding some front-end filtering and RF relays in PA, LNA or wherever you like.
(I would have prefer to get rid of all diode switching in RX RF path but have no idea of RF relays small enough to fit into K144XV box).
I have tested this setup in September during IARU R1 VHF championship and compared to July's event it looked like day and night.

-- 
73, Victor Goncharsky US5WE/K1WE (UW5W in VHF contests, EO90WF in 2014)
UARL Technical Committee
DXCC card checker (160 meters).

--------------------------------------------
On Sat, 5/3/14, Harry_Yingst via Elecraft <elecraft at mailman.qth.net> wrote:

Subject: [Elecraft] Possible bad KREF or K144XV Ref Lock or ???
To: elecraft at mailman.qth.net
Date: Saturday, May 3, 2014, 8:57 PM

I have a recent K3 (2 months old)
that has the KX144XV Two meter module
and the KXV144 Ref Lock. Today I installed the KBPF3 and
some filters.

After installation I attempted to calibrate the TX Gain and
it kept failing
on 60 meters.

Through testing what I found is that if I connect the KSYN3
directly to the
KREF3 and
not through the K144XV Ref Lock it will calibrate and
appears to function
correctly.

I am let to believe that either the KREF board is not
putting out
enough signal or the KXV144 Ref Lock is loading the line to
much.

Has anyone else seen this issue?


Thank you





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