TYT Radios don't Receive after v0131 update

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TYT Radios don't Receive after v0131 update

Post by AE2A » Thu Nov 30, 2017 8:28 pm

After a few of us in the area upgraded the firmware to 0131, we began to notice that some radios
(TYT and other Chinese derivatives) do not receive correctly. The Radios do detect the signal but quickly go silent even though the openSPOT is still transmitting. There may be some minor changes to the modulation of the talk group that is affecting these radios. Reverting back to v 0127 seems to cure the issues, so it is my belief that some of the modem code in v0131 has been changed for the worst.
I run my openSPOT at the minimum power so as not to overload these radios when in close proximity.
Mitch Baum - AE2A

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Re: TYT Radios don't Receive after v0131 update

Post by Tyrbiter » Thu Nov 30, 2017 9:48 pm

What is the modem modulation mode set to?
Brian

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Re: TYT Radios don't Receive after v0131 update

Post by AE2A » Fri Dec 01, 2017 3:05 pm

After a few of us in the area upgraded the firmware to 0131, we began to notice that some radios
(TYT and other Chinese derivatives) do not receive correctly. The Radios do detect the signal but quickly go silent even though the openSPOT is still transmitting. There may be some minor changes to the modulation of the talk group that is affecting these radios. Reverting back to v 0127 seems to cure the issues, so it is my belief that some of the modem code in v0131 has been changed for the worst.
I run my openSPOT at the minimum power so as not to overload these radios when in close proximity.
Mitch Baum - AE2A

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Re: TYT Radios don't Receive after v0131 update

Post by AE2A » Fri Dec 01, 2017 3:06 pm

Modem Profile "d".

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Re: TYT Radios don't Receive after v0131 update

Post by HA2NON » Fri Dec 01, 2017 4:14 pm

Yes, some users have this issue, which we still can't reproduce. We tested with several radios even with the new and old vocoders, and all of them work for us perfectly. We still trying to get a radio which does not work well with openSPOT.
Norbert "Nonoo" Varga, HA2NON
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Re: TYT Radios don't Receive after v0131 update

Post by AE2A » Mon Dec 04, 2017 1:44 pm

Norbert,

This may be an issue of frequency stability or accuracy that the TYT radios cannot tolerate well.
I program all of my TYT MD-380/390/2017's for MIDDLE reference frequency. I tried all three settings with no differences. This issue does NOT happen with Hytera radios. I would recommend checking the RF purity
with test equipment to see if the set frequency is exact and the modulation vector constellation is within tolerance. This is definitely related to firmware changes as the issue is not present in earlier versions.
I have reverted back to srf-osp-1.1-0108 which is RF stable and does not have this issue.

Thanks for looking into this! Mitch - AE2A

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Re: TYT Radios don't Receive after v0131 update

Post by w2sdr » Tue Dec 05, 2017 6:04 pm

My Anytone has the issue with 0131. Set modem to 4FSK and no issues. Seems like the raised cosign is the issue here

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Re: TYT Radios don't Receive after v0131 update

Post by AE2A » Wed Dec 06, 2017 8:29 pm

I did the same thing on my radio - I set it to 4FSK instead of the raised cosine 4FSK and it seems to work, but I also reverted back to v0127 also. In doing my homework I found out that the raised cosine filters (on transmit) would be the right choice if there is no problem with the formulas as this would improve the ideal filter shape to close to perfect rectangle. The TYT radios might be sensitive to the narrower occupied spectrum and subsequently fail to decode accurately. With little technical data on each of the options, we are left to guess rather than make technical decisions.
There is also the issue of the BrandMeister servers going up and down randomly and the lack of a status page to check on the health of the network. I have done testing on the DMR Plus network which seems to be much more stable.
Mitch - AE2A

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Re: TYT Radios don't Receive after v0131 update

Post by n9pna » Mon Dec 18, 2017 9:23 am

I have this issue too with an MD-380. I upgraded from 0123 to 0131 and I could not decode the transmission from the openspot. I went back to v 0123 and I could decode audio. Both had 4FSK set. I am trying v 0131 again and with 4FSK I can't decode transmissions, but I can with 4FSK RC set. With 4FSK RC, the MD-380 sometimes decodes poorly and stutters.

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Re: TYT Radios don't Receive after v0131 update

Post by G0UJA » Mon Dec 18, 2017 2:50 pm

I'm having the exact same issue as you guys since v0131 and with an MD-380 and I think I have found a 'fix' in my instance.

I usually have openSPOT power set to minimum possible to avoid possibility of overload as HH is within 6 feet of openSPOT but I have found setting to -10dBm 0.1mw seems to cure the problem?

Try it and let me know if I am just lucky.

Perhaps the modem is not stable enough at the very lowest setting?

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