K3 : ERR TXG on 50W TX Gain Calibration routine...

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

K3 : ERR TXG on 50W TX Gain Calibration routine...

VK7JB


        Group,

         I think I've discovered the cause:  I noticed the SWR seen by the
K3 at 52.00MHz is 1.2:1, whereas it's 10:1 on all other bands. This
was shown on the K3 SWR meter and confirmed with my antenna analyser
at the K3 antenna connector.  I did some detective work and
discovered that the length of the (short) jumper cables connecting the
K3, the sensor of my LP-100A and the dummy load was either having a
transformer effect or otherwise introducing stray reactance.  The
results was a less than perfect 50 ohm match on 52.000MHz.

         I changed the length of the jumper cables just a little (swapping
them out with  others of different length), and the SWR seen by the
K3 came down to 1.0:1 @ 50Mhz and the Tx Gain calibration routine then
ran perfectly. 

         I'm using LMR-240 ultraflex jumpers and individually, connected to
the dummy load, they check out OK.  It's something about the total
inter-connect length at 50Mhz.

        Thinking back, I suspect I've changed the in-shack jumper
arrangements since the last calibration.

         Thanks for everyone's help.

        73,

        John

        VK7JB


______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Reply | Threaded
Open this post in threaded view
|

Re: K3 : ERR TXG on 50W TX Gain Calibration routine...

Gary Gregory
*John,

Checked my emails later than normal for the day and so I see you have had
an issue like I had once except i discovered the jumper was indeed faulty.

Glad to see you got it sorted.

73
*
On 8 October 2012 08:31, <[hidden email]> wrote:

>
>
>         Group,
>
>          I think I've discovered the cause:  I noticed the SWR seen by the
> K3 at 52.00MHz is 1.2:1, whereas it's 10:1 on all other bands. This
> was shown on the K3 SWR meter and confirmed with my antenna analyser
> at the K3 antenna connector.  I did some detective work and
> discovered that the length of the (short) jumper cables connecting the
> K3, the sensor of my LP-100A and the dummy load was either having a
> transformer effect or otherwise introducing stray reactance.  The
> results was a less than perfect 50 ohm match on 52.000MHz.
>
>          I changed the length of the jumper cables just a little (swapping
> them out with  others of different length), and the SWR seen by the
> K3 came down to 1.0:1 @ 50Mhz and the Tx Gain calibration routine then
> ran perfectly.
>
>          I'm using LMR-240 ultraflex jumpers and individually, connected to
> the dummy load, they check out OK.  It's something about the total
> inter-connect length at 50Mhz.
>
>         Thinking back, I suspect I've changed the in-shack jumper
> arrangements since the last calibration.
>
>          Thanks for everyone's help.
>
>         73,
>
>         John
>
>         VK7JB
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html




--
*Gary*
*Start the day off slow, then taper off.........*
K3 #679
KPA500FT #18
KAT500FT 007
P3 #1629
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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