Hello,
I have read that newer versions of the TYD MD-UV380 and the Retevis RT-3S have chipsets that are not compatable with OpenGD77 firmware. Is this true? How do I find one of these radios on EBay or Amazon which is compatable with OpenGD77?
Thanks,
Dave W4EIP
Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
I ordered a Retevis RT-3S with GPS direct from Retevis at the beginning of 2025 and it works brilliantly with the OpenGD firmware. Alas, just within the last week it seems to have blown its finals and won't transmit at more than a few milliwatts (see my new members post). All the firmware functions still work however.
de KC1VXD
de KC1VXD
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
Does it drop power even on the lower power settings ?KC1VXD wrote: ↑Thu Jul 17, 2025 12:17 amI ordered a Retevis RT-3S with GPS direct from Retevis at the beginning of 2025 and it works brilliantly with the OpenGD firmware. Alas, just within the last week it seems to have blown its finals and won't transmit at more than a few milliwatts (see my new members post). All the firmware functions still work however.
de KC1VXD
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
W4EIP wrote: ↑Wed Jul 16, 2025 11:59 pmHello,
I have read that newer versions of the TYD MD-UV380 and the Retevis RT-3S have chipsets that are not compatable with OpenGD77 firmware. Is this true? How do I find one of these radios on EBay or Amazon which is compatable with OpenGD77?
Thanks,
Dave W4EIP
This month, I uploaded OpenGD77 to two newly purchased RT3s (aliexpress). Both had "plus" stickers under the battery. Both OpenGD77 works without any problems.
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
Yes, it does. I was running it at 4W because at 5W it showed spurious emissions that were not present at lower power. All was well for multiple months of intermittent use. Now, if I have had it off for a while and turn it on and test it immediately it will output 4W initially but after a few seconds it drops to the milliwatt range and stays that way; I don't know if there is a component overheating, some sort of protection circuitry, or what. Starting at 1W doesn't prevent the power drop from happening. I haven't tried at ultra-low outputs but maybe I should. It still produces a transmission that is usable at quite short range even when the output is only 1mW, though! So I can maybe still set it up as a hotspot...SA0BUX wrote: ↑Thu Jul 17, 2025 5:23 amDoes it drop power even on the lower power settings ?KC1VXD wrote: ↑Thu Jul 17, 2025 12:17 amI ordered a Retevis RT-3S with GPS direct from Retevis at the beginning of 2025 and it works brilliantly with the OpenGD firmware. Alas, just within the last week it seems to have blown its finals and won't transmit at more than a few milliwatts (see my new members post). All the firmware functions still work however.
de KC1VXD
One thing I did discover, after the fact, is that the rubber duckie antenna that comes with it has an SWR of like 14 at VHF frequencies (I had initially tested the power output with a TinySA and an in-line attenuator but now have a SWR meter/power meter). So I do wonder if that could have been the reason it stopped working. At some point when I have time I'm going to take the radio apart and see if I can figure anything out that's fixable, but it's doubtful I will be able to fix it.
I like the platform well enough that I will definitely be buying another radio. The GPS, for me, is a game changer when travelling (and it's good enough that I'm considering getting the mobile TYT 9600 although it seems like the implementation for that radio is not as good as for the handhelds.
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
It's not possible to test a "rubber duckie" in a good way on a VNA or antenna analyzer/swr meter in a proper way.KC1VXD wrote: ↑Thu Jul 17, 2025 8:19 pmYes, it does. I was running it at 4W because at 5W it showed spurious emissions that were not present at lower power. All was well for multiple months of intermittent use. Now, if I have had it off for a while and turn it on and test it immediately it will output 4W initially but after a few seconds it drops to the milliwatt range and stays that way; I don't know if there is a component overheating, some sort of protection circuitry, or what. Starting at 1W doesn't prevent the power drop from happening. I haven't tried at ultra-low outputs but maybe I should. It still produces a transmission that is usable at quite short range even when the output is only 1mW, though! So I can maybe still set it up as a hotspot...SA0BUX wrote: ↑Thu Jul 17, 2025 5:23 amDoes it drop power even on the lower power settings ?KC1VXD wrote: ↑Thu Jul 17, 2025 12:17 amI ordered a Retevis RT-3S with GPS direct from Retevis at the beginning of 2025 and it works brilliantly with the OpenGD firmware. Alas, just within the last week it seems to have blown its finals and won't transmit at more than a few milliwatts (see my new members post). All the firmware functions still work however.
de KC1VXD
One thing I did discover, after the fact, is that the rubber duckie antenna that comes with it has an SWR of like 14 at VHF frequencies (I had initially tested the power output with a TinySA and an in-line attenuator but now have a SWR meter/power meter). So I do wonder if that could have been the reason it stopped working. At some point when I have time I'm going to take the radio apart and see if I can figure anything out that's fixable, but it's doubtful I will be able to fix it.
I like the platform well enough that I will definitely be buying another radio. The GPS, for me, is a game changer when travelling (and it's good enough that I'm considering getting the mobile TYT 9600 although it seems like the implementation for that radio is not as good as for the handhelds.
You need to create an earth plane that is similar to the radio including a person who is holding the radio.
But it's not a perfect match when using the radio normally either, the swr is probably around 3:1 or so on most frequencies.
I have also tested some duckies on my TinySA but I at least noticed some resonance points where the swr was low.
Re: Is OpenGD&77 Compatable with newer RT-3S or MD-UV380
That's a good point. It is the only HT antenna I have that doesn't have at least a 3:1 or better in its intended range, however, which is what made me think there might be a problem there.SA0BUX wrote: ↑Thu Jul 17, 2025 9:41 pm
It's not possible to test a "rubber duckie" in a good way on a VNA or antenna analyzer/swr meter in a proper way.
You need to create an earth plane that is similar to the radio including a person who is holding the radio.
But it's not a perfect match when using the radio normally either, the swr is probably around 3:1 or so on most frequencies.
I have also tested some duckies on my TinySA but I at least noticed some resonance points where the swr was low.