TX power levels are not always correct on any releases after 2020.10.16

KI5GZK
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Joined: Sat Apr 11, 2020 6:27 pm

TX power levels are not always correct on any releases after 2020.10.16

Post by KI5GZK » Thu Oct 29, 2020 7:57 pm

The transmit power levels seem to be out of calibration at times on all development releases after the 2020.10.16 stable release which does work correctly.

I tested this with a power meter and dummy load attached.
My GD-77 has been previously calibrated with firmware prior to 2020.10.16.

Test setup:
Channel 1: 145Mhz, using saved power level 2w.
Channel 2: 147Mhz, using master power level.
Channel 3: 440Mhz, using master power level.
Channel 4: 445Mhz, using saved power level 2w.

Steps to reproduce issue:
Radio is powered on while tuned to VHF channel 2, master power is set to 1w, measured power level is 1w.
Radio is tuned to UHF channel 3, master power is still set to 1w, measured power level is 0.3w, not 1w as expected.
Radio is tuned to UHF channel 4, saved power is set to 2w, measured power level is 2w.
Radio is tuned back to UHF channel 3, master power is still set to 1w, measured power level is now 1w.
Radio is tuned back to VHF channel 2, master power is still set to 1w, measured power level is now 1.6w, not 1w as expected.
Radio is tuned to VHF channel 1, saved power level is set to 2w, measured power is 2w.
Radio is tuned back to VHF channel 2, master power is still set to 1w, measured power level is now 1w.
Radio is tuned to UHF channel 3 once more, master power is still set to 1w, measured power level is back 0.3w.

Switching from a VHF channel to a UHF channel seems to reliably trigger the issue.

When using stable release 2020.10.16 measured power levels are as expected. When using the newer development releases the measured power levels behave as shown above.

IU8OGE
Posts: 65
Joined: Tue Sep 29, 2020 3:35 pm

Re: TX power levels are not always correct on any releases after 2020.10.16

Post by IU8OGE » Thu Oct 29, 2020 8:44 pm

interesting
I can't test this loke you bur during normal use I am having tx problem like sometime the power was not set correctly as diplayed at 5w, so I suppose I am having this issue like you but mine is just a sensation

VK3KYY
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by VK3KYY » Thu Oct 29, 2020 9:11 pm

Is this still going wrong in the latest version?

I thought the problem was the calibration data was not being reloaded when bands where changed, but I just retested it and I can't replicate the problem

KI5GZK
Posts: 85
Joined: Sat Apr 11, 2020 6:27 pm

Re: TX power levels are not always correct on any releases after 2020.10.16

Post by KI5GZK » Thu Oct 29, 2020 9:38 pm

Yes, even with the latest development release 2020.10.29 the actual power levels are not always correct.
If I go back to 2020.10.16 the power levels are working correctly.
At least in my case anyway.

VK3KYY
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by VK3KYY » Thu Oct 29, 2020 9:52 pm

OK.

I see the problem.

If the band is changed, or even if the Channels are more than 5Mhz apart, then the calibration data will change, but because the Power level has not changed, then the new PA drive voltage is not calculated.

VK3KYY
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by VK3KYY » Thu Oct 29, 2020 9:56 pm

KI5GZK wrote:
Thu Oct 29, 2020 9:38 pm
Yes, even with the latest development release 2020.10.29 the actual power levels are not always correct.
If I go back to 2020.10.16 the power levels are working correctly.
At least in my case anyway.
I've made a bug fix release

https://github.com/rogerclarkmelbourne/ ... 2020.10.30

You can get it via the CPS etc

Can you try it and let me know whether it fixes the problem for you.

The calibration in my radio is a bit screwed up, so I"m having difficulty totally testing it

KI5GZK
Posts: 85
Joined: Sat Apr 11, 2020 6:27 pm

Re: TX power levels are not always correct on any releases after 2020.10.16

Post by KI5GZK » Thu Oct 29, 2020 10:26 pm

Well, it's still behaving the same except the power levels are a little less wrong now. :?

VK3KYY
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by VK3KYY » Thu Oct 29, 2020 11:18 pm

KI5GZK wrote:
Thu Oct 29, 2020 10:26 pm
Well, it's still behaving the same except the power levels are a little less wrong now. :?
:-(

OK

I'll look later. Go to do paid work now.

VK3KYY
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by VK3KYY » Fri Oct 30, 2020 2:43 am

OK.

I think I've fixed it now.

There was another "Band"setting which I had overlooked.

https://github.com/rogerclarkmelbourne/ ... 2020.10.30

KI5GZK
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Re: TX power levels are not always correct on any releases after 2020.10.16

Post by KI5GZK » Fri Oct 30, 2020 4:55 am

Well, I know you are tired of hearing from me, and I hate to be the bearer of bad news all the time, but there is still an issue with the power levels.

For example:
Channel1 is set to 400Mhz at 1 watt.
Channel2 is set to 475Mhz at 1 watt.
These frequencies are at the bottom and top of the range used for calibrating the UHF band as I'm sure you know.

When I key up on channel1 it measures 1 watt as expected.
When I key up on channel2 it measures 0.5 watts.
If I power cycle the radio while still on channel2 and then key up, it now measures 1 watt as it should.
If I key up on channel1 again it now measures 1.5 watts.

WTF :?
I'm convinced that my GD-77 hates me, and I'm beginning to think you might too!

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