Experimental changes to code optimisation

kt4lh
Posts: 67
Joined: Sun Jan 12, 2020 4:27 am

Re: Experimental changes to code optimisation

Post by kt4lh » Sun Jan 19, 2020 12:12 am

F6GVE wrote:
Sat Jan 18, 2020 11:08 pm
The only problem I have for a long time is this sort of desync/dropout/bug that I have when receiving DMR. It is pretty rare with one GD77 but relatively frequent with the second one (it is the same with calibration ON or OFF).
Also when scanning, if the scanner stops on a DMR RX, most of time there is a sort of hesitation (dont know how to describe) before I can clearly ear. I suspect that these two observations are linked.
I tried to adjust the "reference oscillator tuning" with no success. In fact I can almot supress the dropout (it lasts about 2 to 3 seconds every time it happens) if I set to be really off frequency. But in this case the DMR sensitivity is bad of course.
I could suspect some I Q calibration issue? But I had no way to be sure nor to do anything.
Curious, if you're using pistar have you messed with calibration, just to see what your particular radio likes for RX and TX? I have a GD77 and MD380 and they're both a little different, but plenty of overlap so no problems. But if you haven't, read this page and see what offset your radio likes for both receive and transmit and do it for both, maybe one of them is way off from the other.

http://www.k9npx.com/2019/02/hotspot-of ... n.html?m=1

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m1dyp
Posts: 335
Joined: Sat Nov 16, 2019 8:03 am
Location: Hertfordshire, U.K.

Re: Experimental changes to code optimisation

Post by m1dyp » Sun Jan 19, 2020 12:19 am

that's handy thank you
73 de Ken :D

F6GVE
Posts: 43
Joined: Sat Nov 16, 2019 8:52 am

Re: Experimental changes to code optimisation

Post by F6GVE » Sun Jan 19, 2020 12:57 am

kt4lh wrote:
Sun Jan 19, 2020 12:12 am
F6GVE wrote:
Sat Jan 18, 2020 11:08 pm
The only problem I have for a long time is this sort of desync/dropout/bug that I have when receiving DMR. It is pretty rare with one GD77 but relatively frequent with the second one (it is the same with calibration ON or OFF).
Also when scanning, if the scanner stops on a DMR RX, most of time there is a sort of hesitation (dont know how to describe) before I can clearly ear. I suspect that these two observations are linked.
I tried to adjust the "reference oscillator tuning" with no success. In fact I can almot supress the dropout (it lasts about 2 to 3 seconds every time it happens) if I set to be really off frequency. But in this case the DMR sensitivity is bad of course.
I could suspect some I Q calibration issue? But I had no way to be sure nor to do anything.
Curious, if you're using pistar have you messed with calibration, just to see what your particular radio likes for RX and TX? I have a GD77 and MD380 and they're both a little different, but plenty of overlap so no problems. But if you haven't, read this page and see what offset your radio likes for both receive and transmit and do it for both, maybe one of them is way off from the other.

http://www.k9npx.com/2019/02/hotspot-of ... n.html?m=1
I would not like to spoil this topic with my personnal issue unrelated with this topic...
But to make short I have 3 GD77 (one stayed with the official firmware), 4 hotspots with Pistar and everything is adjusted as best as possible. BER is stable around 0,2% no matter which combination TX/hotspot I use.
I have no trouble at all when TX. But my two OpenGD77 have this sort of long dropouts when receiving DMR (the short dropouts disappeared with these last versions of the OPENGD77 firmware, as everybody said here).
I bought my GD77 in China at the very beginning, may be something could have been improved since?
I can add that I have not any dropout issue with the stock firmware. It seems to me (not 100% sure, I would have to check) that this issue appeared when Roger started to filter the two slots. I had not any trouble with the very first version of the hotspot firmware, only Tier 1.

kt4lh
Posts: 67
Joined: Sun Jan 12, 2020 4:27 am

Re: Experimental changes to code optimisation

Post by kt4lh » Sun Jan 19, 2020 2:29 am

F6GVE wrote:
Sun Jan 19, 2020 12:57 am
I would not like to spoil this topic with my personnal issue unrelated with this topic...
But to make short I have 3 GD77 (one stayed with the official firmware), 4 hotspots with Pistar and everything is adjusted as best as possible. BER is stable around 0,2% no matter which combination TX/hotspot I use.
I have no trouble at all when TX. But my two OpenGD77 have this sort of long dropouts when receiving DMR (the short dropouts disappeared with these last versions of the OPENGD77 firmware, as everybody said here).
I bought my GD77 in China at the very beginning, may be something could have been improved since?
I can add that I have not any dropout issue with the stock firmware. It seems to me (not 100% sure, I would have to check) that this issue appeared when Roger started to filter the two slots. I had not any trouble with the very first version of the hotspot firmware, only Tier 1.
You can verify RX and TX frequency stability with the calibration tool, that's what I'm suggesting. TX is spot on, but maybe your RX frequency is way off? It's worth a shot, just to see, if you have not tested both. IE: RX of course you listen to a tone transmitted by pistar, move it up and down to find the spots where it fails, then find the offset. If you have very low BER, no point in doing the test where you transmit on the HT and watch the calibration program for feedback.

I got my GD77 in July of 2018 but I don't know when they very first came out.

F6GVE
Posts: 43
Joined: Sat Nov 16, 2019 8:52 am

Re: Experimental changes to code optimisation

Post by F6GVE » Sun Jan 19, 2020 11:16 am

kt4lh wrote:
Sun Jan 19, 2020 2:29 am
F6GVE wrote:
Sun Jan 19, 2020 12:57 am
I would not like to spoil this topic with my personnal issue unrelated with this topic...
But to make short I have 3 GD77 (one stayed with the official firmware), 4 hotspots with Pistar and everything is adjusted as best as possible. BER is stable around 0,2% no matter which combination TX/hotspot I use.
I have no trouble at all when TX. But my two OpenGD77 have this sort of long dropouts when receiving DMR (the short dropouts disappeared with these last versions of the OPENGD77 firmware, as everybody said here).
I bought my GD77 in China at the very beginning, may be something could have been improved since?
I can add that I have not any dropout issue with the stock firmware. It seems to me (not 100% sure, I would have to check) that this issue appeared when Roger started to filter the two slots. I had not any trouble with the very first version of the hotspot firmware, only Tier 1.
You can verify RX and TX frequency stability with the calibration tool, that's what I'm suggesting. TX is spot on, but maybe your RX frequency is way off? It's worth a shot, just to see, if you have not tested both. IE: RX of course you listen to a tone transmitted by pistar, move it up and down to find the spots where it fails, then find the offset. If you have very low BER, no point in doing the test where you transmit on the HT and watch the calibration program for feedback.

I got my GD77 in July of 2018 but I don't know when they very first came out.
You are right I will investigate deeper in this way. I already did it in the past, but it is time to check it again, intensively. I forgot that pistar have this useful mmdvmcal tool...
Thanks a lot
73
Luc

F6GVE
Posts: 43
Joined: Sat Nov 16, 2019 8:52 am

Re: Experimental changes to code optimisation

Post by F6GVE » Sun Jan 19, 2020 2:16 pm

nohope. TXOffset was OK on pistar. But when I adjust the parameters of the DMR generator, in order to determine the low and high extrem UHF frequencies where I can decode the DMR signal, I may have some bad noise (dont have that with the stock firmware) and the high limit is difficult to say as there is a sort of pulse of the tone covering about 1 kHz width.
My two "OPENGD77" GD77 do the same.
Finally my TXOffset seems good. I am afraid that I have to live with that. My GD77's were bought in 2017,november during the black friday

Thanks for trying helping me
73
Luc

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