GD-88, the new Radioddity DMR radio

VK3KYY
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Re: GD-88, the new Radioddity DMR radio

Post by VK3KYY » Wed Jul 20, 2022 6:24 am

W5RAH wrote:
Wed Jul 20, 2022 6:03 am
It looks to be along the same lines as the Kydera DM880UV. Their DB-25G mobile is also derived for the similar Kydera product. I have one of the DB-25G radios and it seems to work fine as long as you use the third party CPS.
Radioddity don't make their own radio hardware.

The radios branded as Radioddity, as just re-badged radios from other companies.

The GD-77 is actually a TYT MD-760.

The only differnce is that sometimes Radioddity pay for firmware customisations, and in the case of the GD-77 they commissioned a new CPS. i.e If you look at the TYT CPS e.g. for the MD380 or MD9600 it looks similar but is actually a complete re-write in C# whereas the TYT CPS's are written in C++ (using Microsoft Foundation Classes)

Although this looks a nice radio, I think they are missing a trick by it being DMR only. From what I've heard the new Connect Systems radios support, or will support D-STAR and other modes as well as DMR, albeit I think there is an additional free for each extra mode that is supported, becuase of the licensing costs.

Really, all these radios need to be switching to being SDR so they can be true multi mode e.g. including AM for Air Band and also SSB etc

But looking at the frequency range it looks identical to all the other radios which use the AT1846S FM only, TRx chip.

My guess is its got 2 x AT1846S TRx chips hence why it can do true dual standby.

Or if its like the new DM-1801 it may use 2 complete radio RF + CPU modules

ve7mdt
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Re: GD-88, the new Radioddity DMR radio

Post by ve7mdt » Fri Jul 29, 2022 9:55 pm

VK3KYY wrote:
Wed Jul 20, 2022 2:16 am
ve7mdt wrote:
Wed Jul 20, 2022 2:09 am
I went to the Radioddity website and also used Google Search and could not find the GD-88 model from Radioddity's website.
https://www.radioddity.com/products/rad ... 51e2&_ss=r
Thanks!

Biggest feature diff compared to the Anytone HT models:
1. Same Frequency Repeat. (Only top model Hytera HT has this function, no other DMR radios I know of has this, and the Hytera only works w/ other Hytera radios in this mode.)

2. Cross band repeat including D to A, A to D, and A to A mode. The only other radio that has this is the Anytone D578, but it's a mobile (and it can even do D to D). Definitely unique for an HT.

Just b/c of these 2 functions, I am very likely to get one, as long as reviews said no major bugs and these functions do work properly.

Other things seem to point that it is from Anytone, but I am curious why Anytone hasn't announced a similar model (previously, they did announce models well ahead of shipment.)

kt4lh
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Re: GD-88, the new Radioddity DMR radio

Post by kt4lh » Sat Jul 30, 2022 2:49 pm

ve7mdt wrote:
Fri Jul 29, 2022 9:55 pm
2. Cross band repeat including D to A, A to D, and A to A mode. The only other radio that has this is the Anytone D578, but it's a mobile (and it can even do D to D). Definitely unique for an HT.
Cross band repeat is uncommon, but not unique, on this HT. However it is the only HT I've seen so far that does so and is DMR.

I've said for a few years that I'll only replace the 878 with a DMR radio that's dual receive, I really miss that feature (not missing a call when the radio is busy with the other VFO).

I am not going to jump in feet first on this one though, I'll let it bake a bit, see what Anytone does if they actually have one, do you have information that this is actually an Anytone radio? Or is it a TYT that a few people are OEM'ing?

ve7mdt
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Re: GD-88, the new Radioddity DMR radio

Post by ve7mdt » Mon Aug 08, 2022 7:21 am

kt4lh wrote:
Sat Jul 30, 2022 2:49 pm
ve7mdt wrote:
Fri Jul 29, 2022 9:55 pm
2. Cross band repeat including D to A, A to D, and A to A mode. The only other radio that has this is the Anytone D578, but it's a mobile (and it can even do D to D). Definitely unique for an HT.
Cross band repeat is uncommon, but not unique, on this HT. However it is the only HT I've seen so far that does so and is DMR.

I've said for a few years that I'll only replace the 878 with a DMR radio that's dual receive, I really miss that feature (not missing a call when the radio is busy with the other VFO).

I am not going to jump in feet first on this one though, I'll let it bake a bit, see what Anytone does if they actually have one, do you have information that this is actually an Anytone radio? Or is it a TYT that a few people are OEM'ing?
Of course I meant cross band repeat that works with DMR mode at least on one side. My first dual band radio was the Standard C550 (Asian version of the C558A, which I also acquired lately as a spare as the old one was getting bad) and it has cross band repeat. I bought it in 1993. It was not that uncommon back then, as a matter of fact, almost all dual band HT models during that era all could do cross band repeat. My other models that I have owned and still owned today, have these: Alinco DJ-580T (owned 2 i diff time frames), Icom IC-24AT (had been having problems), Yaesu FT-51R. I have also owned Yaesu FT-470, iirc, also has that feature.

ve2ugo
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Re: GD-88, the new Radioddity DMR radio

Post by ve2ugo » Thu Aug 11, 2022 6:44 am

W5RAH wrote:
Wed Jul 20, 2022 6:03 am
It looks to be along the same lines as the Kydera DM880UV. Their DB-25G mobile is also derived for the similar Kydera product. I have one of the DB-25G radios and it seems to work fine as long as you use the third party CPS.
Exactly, the Kydera is a true dual band. It can receive DMR or FM at the same time on each side and has independent digital volume control.
They even make an LTE/WiFi version of the same model.
But the DB-25G is not a true dual-band.

I would also like the return of real dual bands with 2 physical volume controls, each with its own Squelch.
ve7mdt wrote:
Mon Aug 08, 2022 7:21 am
Of course I meant cross band repeat that works with DMR mode at least on one side. My first dual band radio was the Standard C550 (Asian version of the C558A, which I also acquired lately as a spare as the old one was getting bad) and it has cross band repeat. I bought it in 1993. It was not that uncommon back then, as a matter of fact, almost all dual band HT models during that era all could do cross band repeat. My other models that I have owned and still owned today, have these: Alinco DJ-580T (owned 2 i diff time frames), Icom IC-24AT (had been having problems), Yaesu FT-51R. I have also owned Yaesu FT-470, iirc, also has that feature.

The Standard C558A was really a good radio for its time.

Cross-band repeat was also interesting in the 1990s. And you could often just plug in a simple 12v power cord to operate and charge the radio. No need for Battery Eliminator and another charger...

It would be interesting if the GD-77 could serve as an interface to connect to the Raspberry Pi for communicate digitally via the Internet on various networks. It couldn't do it in RF given the architecture but could do it otherwise.
A bit like the Node-Ventures and the interface they created that will connect to the Raspberry with a speaker and microphone that will allow you to talk on various digital modes via the internet. We replace the module and take the GD-77.
The tools are already there with among others MMDVM_Bridge and Analog_Bridge from DVswitch.
It would just be necessary for the GD-77 to be able to talk to the computer and the radio could surely do even more without having to make heavy physical modifications.
An idea like that in order to make it evolve even more since it is itself limited, it will then need external tools to do even more in a radical way.

73!
Last edited by ve2ugo on Thu Aug 18, 2022 5:46 am, edited 1 time in total.

VK3KYY
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Re: GD-88, the new Radioddity DMR radio

Post by VK3KYY » Thu Aug 11, 2022 7:35 am

ve2ugo wrote:
Thu Aug 11, 2022 6:44 am
....

It would just be necessary for the GD-77 to be able to talk to the computer and the radio could surely do even more without having to make heavy physical modifications.

There are no analogue audio paths to the CPU in the GD-77, so it would not be possible to do what you discussed without significantly modifying the hardware.

ve2ugo
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Re: GD-88, the new Radioddity DMR radio

Post by ve2ugo » Thu Aug 11, 2022 8:21 am

Would it be possible to do then like a Node-Ventures but with just the DMR function in RX/TX but allowing multimode via the raspberry pi. It could thus in HotSpot mode have access to AllStar, Echolink, YSF, D-Star, NXDN and P25. The only thing is that the input and output will absolutely have to be DMR.

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Re: GD-88, the new Radioddity DMR radio

Post by VK3KYY » Thu Aug 11, 2022 11:28 am

ve2ugo wrote:
Thu Aug 11, 2022 8:21 am
Would it be possible to do then like a Node-Ventures but with just the DMR function in RX/TX but allowing multimode via the raspberry pi. It could thus in HotSpot mode have access to AllStar, Echolink, YSF, D-Star, NXDN and P25. The only thing is that the input and output will absolutely have to be DMR.
The radio won't support any other digital modes than DMR because its call controlled via a dedicated DMR only chip.

FM is onl via direct paths from the mic to the RF chip and from the RF chip to the speaker

For DMR Tx the DMR chip directly modulates the master reference oscillator, all the RF chip does is produce what it thinks is a silent carrier, because its mic input is turned off.
For DMR Rx, the audio from the RF chip is routed directly into the DMR chip which does the complete decode into the high level DMR data, i.e the Source and Destination ID's and the audio byes etc.

There is no low level access to the decoded 4FSK inside the DMR chip and no way to tell it to modulate a 4FSK bitstream.

ve2ugo
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Re: GD-88, the new Radioddity DMR radio

Post by ve2ugo » Thu Aug 11, 2022 11:51 am

In HotSpot mode, the gd77 receives a dmr signal which sends it to the raspberry pi which is processed via a software suite, including mmdvm. This one does the routing or transcoding according to the command sent at the Pi-star for example. If I dial TG 71083 I communicate in YSF but i'm in dmr. The radio sends and receives in dmr only but transcoded in the desired mode via the raspberry pi. The flux will always remain dmr for the gd77.
By adding some modules, it is possible to add options like dstar, allstar and echolink. The mmdvm and other tools will do the dmr to ysf, dmr to p25, dmr to d-star but passing via internet and not rf.
The mmdvm and dvswitch will simply hook up and transcode the dmr stream to the desired mode.

It will not be possible to use any other radio with the hotspot than a dmr radio. It's clear. But transcoding the dmr in another mode via Internet surely...

The processing has nothing to do with the radio's internal chip. Everything could be done externally and sent in dmr to the radio. It would be a way to cheat to gain access to other modes and networks.

ve7mdt
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Re: GD-88, the new Radioddity DMR radio

Post by ve7mdt » Wed Aug 17, 2022 9:48 am

these last posts are very long and verbose, and the proposals have been repeated again and again. Moreover, what's being asked above is about development on both the radio side but also the "hotspot" side, which has never been the focus of this development and this forum. I suggest my fellow Canadian ham to seek that level of commitment from the hotspot platform people instead.

And I thought this thread is about the new Radioddity GD-88? Please don't hijack the thread, thanks!

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