G2 External coupler

[dondb1]

I have a G2 non screen and cannot get the external coupler to stabilize on PSA. Everything else seems to be working fine.....including the internal coupler with PSA turned on. With the help of KI1N I was able to load all the up to dated Linux programs and still a no go with the PSA external coupler. I have a 7000 black face and the external coupler works fine....so I know the coupler and hook up is good as all i did was replace the G2 in the 7000 spot. Any ideas from anyone with G2 experience would be appreciated.

[w-u-2-o]

Are you running piHPSDR or Thetis as the SDR client software?

[dondb1]

Hi Scott
I'm running Thetis

[w-u-2-o]

What is your setpk value in Linearity > Advanced?

[dondb1]

0.6121

[dondb1]

That's using the internal coupler. And when I use the internal coupler with no amp 100 watts it is unstable. Seems to be unstable via drive power. I was on the radio with Chas K2BU and he had a different SetPk then mine. I will not change it until I hear back from you.
Thanks Scott W1ADB

[w-u-2-o]

I believe that is the correct value for the G2. You can double check that by using the "default" button in the linearity window.

More information would be helpful. What do you mean by "unstable"? When it is unstable what do you see for GetPk? What amp power level are you running? What external coupler are you using? What is the S-ATT driving to when transmitting?

[dondb1]

Hi Scott
What do you mean by "unstable"?
The S-ATT jumps all over the place from 0 to 31.

When it is unstable what do you see for GetPk?
It constantly goes from o to 0.0612 back and forth between those 2 numbers

What amp power level are you running?
Using a Lux amp 10 on the drive giving about 1kw.

What external coupler are you using?
Xtronic with -10db attenuator

What is the S-ATT driving to when transmitting?
Jumping between 0-31 and all numbers in-between

when i throw the 7000 back in same spot, everything works fine.

[w-u-2-o]

Assuming you are using all of the same cables, that does suggest a problem with the G2.

One diagnostic step you might try is to disable auto-attenuate and set the S-ATT manually (during TX) and see if that stabilizes things. If it does, then it's probably not a hardware problem. If it doesn't you might look for a loose connection inside the G2.

[dondb1]

Did the test with as you suggested and here are the results:

Automatic att off and set to 15 manually......internal coupler is stable from 1 to 75 watts of drive after 75 the internal coupler becomes unstable. Automatic att turned on I get the same results. I did check to make sure the PA Settings were correct.

Running the internal coupler with 10 watts drive 1kw out it is stable

Running external coupler with 10 watts drive 1kw out it is not stable or any combination with external coupler the att is not stable.

Everything else is working fine. I'm using the VAC1 through a focusrite with no under or over flows. No sequence errors.

looking through the forum i see no one else having this problem i believe?

Thanks for the help Scott.....if your down my way on the NH seacoast your welcome to stop in and have a crack at it:)

[dondb1]

I sent the radio to Doug and he found an issue with the step attenuator. Everything is working great with no issues at all! Thank you for the help Scott and also thanks to Doug for the quick fix and return of the radio. From NH to AK and back for the fix and return in 9 days!!!!!

Don 73

[w-u-2-o]

Great news!