Search found 453 matches

by G4EML
Thu Aug 11, 2022 9:23 am
Forum: TYT MD-9600 / Retevis RT-90
Topic: UHF Frequency problem.
Replies: 5
Views: 145

Re: UHF Frequency problem.

I just noticed that you said you used the TYT tuning in the original CPS to adjust the frequencies. That may be where the difference is occuring. The factory never changes the reference oscillators tuning values. They are always set to the same value for both bands in all radios. (From memory I thin...
by G4EML
Thu Aug 11, 2022 8:58 am
Forum: TYT MD-9600 / Retevis RT-90
Topic: UHF Frequency problem.
Replies: 5
Views: 145

Re: UHF Frequency problem.

The MD9600 has separate reference oscillators for UHF and VHF. The frequency of each is controlled by the sum of several signals. The bias point of the modulator, the bias point of the CTCSS encoder and a bias voltage from a potentiometer. We have made efforts to get the frequency calibration as clo...
by G4EML
Sun Jul 24, 2022 10:58 pm
Forum: General discussions
Topic: How do I roll back to the original firmware?
Replies: 14
Views: 2285

Re: How do I roll back to the original firmware?

They are unique to each radio. You would need to back them all up.
by G4EML
Sun Jul 24, 2022 7:12 pm
Forum: New members post here first
Topic: N5KRG new user
Replies: 3
Views: 185

Re: N5KRG new user

The manufacturers firmware does not enumerate as a com port. What you are seeing is correct.
You won't see a com port until you install the openGD77 firmware.

Colin G4EML.
by G4EML
Wed Jul 20, 2022 11:32 pm
Forum: TYT MD-9600 / Retevis RT-90
Topic: Calibration
Replies: 8
Views: 507

Re: Calibration

Many of the early MD9600s have problems with VHF DMR when running at less than full power. Unfortunately it is a design fault and not easily rectified. The only solution is to always run VHF at full power. Later models had significantly modified PA stages and power control circuitry to fix the probl...
by G4EML
Wed Jul 20, 2022 11:24 am
Forum: Development updates
Topic: New GD77 and MD9600 Beta firmware June 19th 2022
Replies: 50
Views: 7991

Re: New GD77 and MD9600 Beta firmware June 19th 2022

Linkford... Thanks for the explanation. From what you describe there certainly appears to be something wrong. The fact that you hear distorted audio tends to indicate it is not simply a timeslot detection issue. Switching timeslots with the star key will reset the decoding which is probably why it c...
by G4EML
Tue Jul 19, 2022 8:26 pm
Forum: TYT MD-9600 / Retevis RT-90
Topic: Calibration
Replies: 8
Views: 507

Re: Calibration

There is very little in the calibration that should ever require adjusting. The feature is really only used during manufacturing. Hence there is not a lot of urgency to provide this feature. It will probably happen eventually, but not soon. The only adjustment that may need to be made as the radio a...
by G4EML
Mon Jul 18, 2022 4:55 pm
Forum: Development updates
Topic: New GD77 and MD9600 Beta firmware June 19th 2022
Replies: 50
Views: 7991

Re: New GD77 and MD9600 Beta firmware June 19th 2022

The local RF environment has a big effect as well. Here I can only hear a few DMR repeaters and none of them are busy. It’s very rare to hear both timeslots in use at the same time. So trying to reproduce reports such as yours is difficult.

Colin.
by G4EML
Mon Jul 18, 2022 9:49 am
Forum: Development updates
Topic: New GD77 and MD9600 Beta firmware June 19th 2022
Replies: 50
Views: 7991

Re: New GD77 and MD9600 Beta firmware June 19th 2022

From your description it sounds like the timeslot detection is occasionally failing. It does not seem to be a common occurrence and so the cause might be difficult to find. It may depend upon the number of a DMR channels being scanned, the amount of activity on the scanned channels, the order of the...
by G4EML
Fri Jul 15, 2022 1:41 pm
Forum: General discussions
Topic: Feature request(s)
Replies: 18
Views: 1169

Re: Feature request(s)

Every country has different rules but in general the use of any transmitter requires that the equipment is approved. This applies even to the so called ‘Licence Free’ allocations. They are more correctly called ‘Licence Exempt’. The authorities grant an exemption to requiring a licence, but this is ...