Which MMDVM Board?

MMDVM_HS Hat hardware
G0KDT
Posts: 22
Joined: Sat Feb 29, 2020 12:22 pm

Which MMDVM Board?

Post by G0KDT » Thu Mar 05, 2020 4:20 pm

Sorry if I am being daft, but I would appreciate so guidance from those of you more knowlegable in this area. Newly back to amateur radio after about 30 years digital modes and hotspots seem a confusing game.

Most boards seem to be stated as MMDVM boards, some it seems don't have rf (I could be wrong) a lot seem to have 70cms. I've not seen one on 2m.

Next most self assembly item seem to pair up with a Raspberry Pi zero w or bigger.

So my questions are;

1. Are they pretty much the same device? as I can't see specific manufacturers except commercial pre built.

2. Is the digital mode they support dependent upon the Pi-Star firmware installed in the Raspberry Pi or is there a specific MMDVM hardware dependance for D-star, DMR and YSF?

Here's hoping that somebody can help clarify these points.
Thank you.
Phil.

KE7FNS
Posts: 1097
Joined: Wed Apr 17, 2019 11:11 pm

Re: Which MMDVM Board?

Post by KE7FNS » Thu Mar 05, 2020 7:35 pm

Welcome back.
G0KDT wrote:
Thu Mar 05, 2020 4:20 pm
Most boards seem to be stated as MMDVM boards, some it seems don't have rf (I could be wrong) a lot seem to have 70cms. I've not seen one on 2m.
The boards without RF are meant for repeater use, or they need an external radio. The boards meant for hotspot use support VHF, UHF, or even both UHF/VHF you just have to dig into the documentation and specs.

Here is one that I know supports both VHF and UHF, I have used it. The board was designed by S56AL
http://lea.hamradio.si/~s57nan/ham_radi ... vm_hs.html

The board I have does have a tiny design flaw, where 5 volts is not supplied to the Nextion port, but that might of been fixed on newer releases of the board.

G0KDT wrote:
Thu Mar 05, 2020 4:20 pm
Next most self assembly item seem to pair up with a Raspberry Pi zero w or bigger.
The overall majority are designed to be run on one of the Raspberry Pi variants with a 40 pin GPIO.

G0KDT wrote:
Thu Mar 05, 2020 4:20 pm
1. Are they pretty much the same device? as I can't see specific manufacturers except commercial pre built.
I'm not clear on what exactly you are asking. Are you wanting to know about the MMDVM device, or the RPi device?

G0KDT wrote:
Thu Mar 05, 2020 4:20 pm
2. Is the digital mode they support dependent upon the Pi-Star firmware installed in the Raspberry Pi or is there a specific MMDVM hardware dependance for D-star, DMR and YSF?
No, it is simply an option in the software configuration.

MMDVMHost (the software that does all the behind the scenes work) supports D-Star, DMR, P25 Phase 1, NXDN, System Fusion, and POCSAG paging on the MMDVM.

Technically I wouldn't call pi-star firmware, as it is just the raspbian operating system with a few specialized pieces of software preloaded to make things easy to setup.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

G0KDT
Posts: 22
Joined: Sat Feb 29, 2020 12:22 pm

Re: Which MMDVM Board?

Post by G0KDT » Fri Mar 06, 2020 11:55 am

Hi Jason,

Thank you for the kind reply. Sorry if I wasn't clear in how I set out my questions.

Most of the single antenna MMDVM boards I have found look the same or 'generic' and are listed via Ebay from China. I can't say that I have found Amateur Radio dealers that helpful or knowledgeable. Certainly there are no dealers local to me that I can go to and discuss options so using the internet seems the only way.

The link to the S55AL hotspot was interesting and different to the ones I have looked at that fit over a Pi Zero. As far as I could make out that was a build from scratch item as I could not see any selling information showing. The following link shows the items I've seen most of and as I say they all tend to look the same and I doubt there will be any documentation. Some show differing digital modes, for example the following don't list YSF operation. https://www.ebay.co.uk/itm/2Pieces-MMDV ... Swn~JeFXwI
KE7FNS Said - I'm not clear on what exactly you are asking. Are you wanting to know about the MMDVM device, or the RPi device?
In answer to that question, the reason given above is why I asked if there is some form of firmware or hardware embedded on the MMDVM boards to support the different digital formats which Pi-Star which runs on the Raspberry Pi uses to handle the different digital formats.

Or is your statement
KE7FNS Said -MMDVMHost (the software that does all the behind the scenes work) supports D-Star, DMR, P25 Phase 1, NXDN, System Fusion, and POCSAG paging on the MMDVM.
actually saying that there is firmware on the MMDVM board that the Raspberry Pi Star software uses.

Thank you very much for your kind reply
Phil

KE7FNS
Posts: 1097
Joined: Wed Apr 17, 2019 11:11 pm

Re: Which MMDVM Board?

Post by KE7FNS » Fri Mar 06, 2020 8:49 pm

G0KDT wrote:
Fri Mar 06, 2020 11:55 am
Most of the single antenna MMDVM boards I have found look the same or 'generic' and are listed via Ebay from China.
Correct, many look the same because the different companies that created the PCB all used the same open source files and documentation. They can however differ greatly once the components are populated on them. Some of the companies have used different components in order to save a few pennies here and there. They essentially sacrificed quality to increases their profits.
G0KDT wrote:
Fri Mar 06, 2020 11:55 am
The following link shows the items I've seen most of and as I say they all tend to look the same and I doubt there will be any documentation.
Yes, that is what is known as a "Jumbospot". It is silk screened onto the PCB under the left side of the OLED. It appears it is a fork with some modifications of this design https://github.com/HS8JCV/MMDVM_HS_Hat

G0KDT wrote:
Fri Mar 06, 2020 11:55 am
In answer to that question, the reason given above is why I asked if there is some form of firmware or hardware embedded on the MMDVM boards to support the different digital formats which Pi-Star which runs on the Raspberry Pi uses to handle the different digital formats.
Yes there is. This might get confusing pretty quickly.

The RPi has firmware that is stored on the SD card, it is only used during the boot process for some of the chips on the RPi. The RPi also has software stored on the SD card. That includes the linux operating system and a suite of software to communicate with the MMDVM.

The MMDVM has a STM32 microprocessor that has specialized firmware loaded onto the memory on the chip.
https://github.com/juribeparada/MMDVM_HS
G0KDT wrote:
Fri Mar 06, 2020 11:55 am
Or is your statement actually saying that there is firmware on the MMDVM board that the Raspberry Pi Star software uses.
Actually it is both. There is software running on the RPi (MMDVMHost), and there is firmware on the MMDVM that are constantly communicating with each other over a standard RS232 serial port.

https://github.com/g4klx/MMDVMHost

The reason why we need both is because the MMDVM does not have the standalone capability to connect to a network, so we use the RPi to handle the network side of things.

The reason a RPi was chosen was simply the cost and simplicity, when in reality any "computer" that could run MMDVMHost would work.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

G0KDT
Posts: 22
Joined: Sat Feb 29, 2020 12:22 pm

Re: Which MMDVM Board?

Post by G0KDT » Sat Mar 07, 2020 12:30 am

Hi Jason
Many thanks for your comprehensive reply. I think the key message I get from your response is that the MMDVM board has it own dedicated firmware and, if I am correct, it is that that facilitates the specific digital mode encoding\decoding that the hotspot can provide.

The Pi-star software on the Raspberry pi provides a control panel to configure internet data sources be they YSF,DMR or D-star that will be passed via the MMDVM board.

The question then is if the MMDVM firmware supports the digital mode in use and requested by the pi-star config. The boards I gave a link to don't list YSF so it is possible that they don't support that digital mode and 'may' require a firmware update, if indeed they are compatible with any updated firmware. And as you say, some makers change the components then I suspect this is a rats nest of potential problems as although they 'look the same they aren't'.

I have a D-star transceiver and the chap I am working on things with has Yaesu (C4FM/Wires-x) so we have a potential problem that the boards won't handle YSF and that is before we even think about trying to find a 'bridge' between the two modes.

The MMDVM firmware site link you gave, looks to be the source code to compile the firmware and a whole order of magnitude more complexity again if we had to compile it then only to find it isn't compatible with the MMDVM boards we have and that assumes we find out how to install the updated firmware onto the MMDVM board.

To me this is starting to sound like we are headed into a black hole and me especially, as I am the computer head in our little project. Maybe I have to concede defeat to my friend and forget digital as a wasted side of our transceivers. We only have one digital repeater on hand in our area that we can access for C4FM on 70cms that is heavily used making a personal hotspot essential for D-star if I am to use anything and highly desirable for my friend with Yaesu kit not to 'hog' the repeater he can access.

Please excuse me when I say I feel deflated and lost. It is so easy to spend ages hunting the internet to find so much data that is misleading that then perpetuates further lost time.

We'll see what turns up maybe they will operate YSF and it'll be ok or maybe they drop in the bin and we try to forget it as a bad experience.

Thank you so very much for your help.
Phil

KE7FNS
Posts: 1097
Joined: Wed Apr 17, 2019 11:11 pm

Re: Which MMDVM Board?

Post by KE7FNS » Sat Mar 07, 2020 1:49 am

G0KDT wrote:
Sat Mar 07, 2020 12:30 am
Many thanks for your comprehensive reply. I think the key message I get from your response is that the MMDVM board has it own dedicated firmware and, if I am correct, it is that that facilitates the specific digital mode encoding\decoding that the hotspot can provide.

The Pi-star software on the Raspberry pi provides a control panel to configure internet data sources be they YSF,DMR or D-star that will be passed via the MMDVM board.
Well, technically both MMDVMHost and the MMDVM have to have the ability in the software/firmware to be able to communicate for a specific digital mode.

For example, in DMR there are specific DMR packets that MMDVMHost sends to the MMDVM and vice versa, for YSF they are completely different packets, but similar in design.

But the RPi does more than just provides a control panel, it is the computer that bridges your MMDVM with a server, so you can communicate to other hotspots/repeaters over the network.
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
The question then is if the MMDVM firmware supports the digital mode in use and requested by the pi-star config. The boards I gave a link to don't list YSF so it is possible that they don't support that digital mode and 'may' require a firmware update, if indeed they are compatible with any updated firmware. And as you say, some makers change the components then I suspect this is a rats nest of potential problems as although they 'look the same they aren't'.
I'm pretty sure in your example the seller is simply uninformed about the specific capabilities of their product they are selling. I gathered that theory based on looking at the sort of stuff they recently sold and it's a hodgepodge of random things.
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
I have a D-star transceiver and the chap I am working on things with has Yaesu (C4FM/Wires-x) so we have a potential problem that the boards won't handle YSF and that is before we even think about trying to find a 'bridge' between the two modes.
If you are worried about that specific board, then don't buy it. There are plenty of other board designs out there to choose from. I don't want to say that YSF will work on that board because I am not 100% sure and have not tested that specific board for that ability. And at the same time, I don't see why it wouldn't (since it should be encoded/decoded on the STM32)... shrug.
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
The MMDVM firmware site link you gave, looks to be the source code to compile the firmware and a whole order of magnitude more complexity again if we had to compile it then only to find it isn't compatible with the MMDVM boards we have and that assumes we find out how to install the updated firmware onto the MMDVM board.
Yes, it is the source code used in many MMDVM hats. The good news is there are precompiled versions of the firmware for many of the popular designs out there, so you don't need to recompile unless you want to. That is one of the great things about pi-star is that is has included scripts to help someone download and update their firmware on their modem. It is as simple as running "sudo pistar-mmdvmhshatflash hs_hat" and following the prompts. I have seen users report issues with being able to successfully update the firmware on Jumbospots specifically, and from the design there doesn't appear to be a jumper to force the STM32 into bootloader mode to begin the update process. I myself would steer clear of Jumbospot boards just for that reason.
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
To me this is starting to sound like we are headed into a black hole and me especially, as I am the computer head in our little project. Maybe I have to concede defeat to my friend and forget digital as a wasted side of our transceivers. We only have one digital repeater on hand in our area that we can access for C4FM on 70cms that is heavily used making a personal hotspot essential for D-star if I am to use anything and highly desirable for my friend with Yaesu kit not to 'hog' the repeater he can access.
Try not to think like that. There is plenty of information on this, and I know you have the capability.

Check out Toshens (KE0FHS) plethora of information. He probably explains it way better than I have. I know when I was first starting out I stumbled into his site early on and it really helped me grasp the concepts and terminology.
https://amateurradionotes.com/pi-star.htm
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
Please excuse me when I say I feel deflated and lost. It is so easy to spend ages hunting the internet to find so much data that is misleading that then perpetuates further lost time.
That is completely understandable to see it that way, but there is no rush, take your time and ask as many questions as you would like, I'm sure someone is willing to add their own advice and experiences.
G0KDT wrote:
Sat Mar 07, 2020 12:30 am
We'll see what turns up maybe they will operate YSF and it'll be ok or maybe they drop in the bin and we try to forget it as a bad experience.
Like I said earlier, if you are worried about that board not supporting YSF, then simply don't buy it. There are tons of other ones out there to choose from that do specify YSF/C4FM capability.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

G0KDT
Posts: 22
Joined: Sat Feb 29, 2020 12:22 pm

Re: Which MMDVM Board?

Post by G0KDT » Sat Mar 07, 2020 4:38 pm

Hi Jason,

Thank you again for your support, technical and moral.

I am in the position that the fellow radio amateur I am helping has already ordered the two kits whilst I was doing research, he was being kind and trying to say thank you for the help I have given him in not just this areas but others like FT8 and PC configuration etc. Like you I looked at the sellers 'other items' and thought that they may not know much about with these kits are.

So your
KE7FNS Said - Well, technically both MMDVMHost and the MMDVM have to have the ability in the software/firmware to be able to communicate for a specific digital mode.
I take as the MMDVMHost is an internet data streaming source, the format of that source is dependent upon whatever the user has configured the Raspberry Pi to access using the Pi-star software.
KE7FNS said - For example, in DMR there are specific DMR packets that MMDVMHost sends to the MMDVM and vice versa, for YSF they are completely different packets, but similar in design.
So the pi-star needs to connect to data sources that our radio primarily is capable of (D-star/YSF etc.) those sources can be connected repeaters or other user hotspots and possibly internet based 'bridge' locations or nodes that facilitate D-star to YSF and vice versa ( I could be wrong).

Anyway I am buoyed up by your kind help and will persevere and see how we go hoping that I don't need to try and change the MMDVM embedded firmware. Thank you though for the 'Sudo instruction' to do this, which I assume is done from the Raspberry Pi command Line console.

Don't knock your own clear and helpful support Jason. I will read the other links you have offered up but without your help I would be far less certain. By the way, this is the 5th time of trying to post a reply as the forum seems to bomb each time I try and post losing everything I typed so this doesn't carry all I had originally set out to say (probably just as well Hi).

Most importantly I hope that eventually it will work and we can use one of the hotspots to say direct thankyou.

Kind regards
Phil.

KE7FNS
Posts: 1097
Joined: Wed Apr 17, 2019 11:11 pm

Re: Which MMDVM Board?

Post by KE7FNS » Sat Mar 07, 2020 8:09 pm

G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
I am in the position that the fellow radio amateur I am helping has already ordered the two kits whilst I was doing research, he was being kind and trying to say thank you for the help I have given him in not just this areas but others like FT8 and PC configuration etc.
Ah ok. You could always pick up a cheap DMR handheld radio and use it with the hotspot, or your buddy can have one hotspot at his home and one in his car, while you get a different one.
G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
I take as the MMDVMHost is an internet data streaming source, the format of that source is dependent upon whatever the user has configured the Raspberry Pi to access using the Pi-star software.

So the pi-star needs to connect to data sources that our radio primarily is capable of (D-star/YSF etc.) those sources can be connected repeaters or other user hotspots and possibly internet based 'bridge' locations or nodes that facilitate D-star to YSF and vice versa ( I could be wrong).
Yeah, yeah, yeah, thats the ticket. Also we are streaming data both ways, from hotspot to the server, and server to the hotspot, depending on what you are doing on the radio.
G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
Anyway I am buoyed up by your kind help and will persevere and see how we go hoping that I don't need to try and change the MMDVM embedded firmware.
Honestly, that part is what I'm concerned about. I have seen posts (both here and on github) where people with that same board design can't seem to get it to accept a flash properly. Normally there are two pins on the GPIO of the RPi which are connected to and then toggled which put the STM32 into a bootloader mode so that it is ready to accept the flashing process. Other board designs have a jumper or solder pad that you can bridge to force the bootloader mode on board power up. Jumbospots seem to have left out that handy feature. It is still possible to get the bootloader mode enabled, but requires touching some pins on the STM32 chip manually, which are pretty tiny. I've never done it myself, but I'm fairly certain it could be done with a steady hand, and something like a needle. So if it comes to that then I'll do some testing and write up the instructions on how to do it.
G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
Thank you though for the 'Sudo instruction' to do this, which I assume is done from the Raspberry Pi command Line console.
I assume that is the correct command since I've never physically touched a Jumbospot board, but even if I'm incorrect, there are a number of different scripts for different boards and configurations so one of them should work.
G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
Don't knock your own clear and helpful support Jason.

I will read the other links you have offered up but without your help I would be far less certain.
Seriously, everything you've ever wanted to know about hotspots is clearly and written beautifully on Toshens website.

G0KDT wrote:
Sat Mar 07, 2020 4:38 pm
By the way, this is the 5th time of trying to post a reply as the forum seems to bomb each time I try and post losing everything I typed so this doesn't carry all I had originally set out to say (probably just as well Hi).

Most importantly I hope that eventually it will work and we can use one of the hotspots to say direct thankyou.
Uggh, that is so frustrating and annoying. That has happened to me so many times its pitiful. The one I get all the time is I spend so long typing up something and when I click submit it says I've been logged out. :evil:

On other phpBB forums I've been on they save your draft automatically, this one only seems to save it manually. It would be nice if the mods would turn that automatic save feature on.

I look forward to future conversations with you, both on here and on the radio. (but we'll have to find a DMR to YSF bridge, and I've never messed with that bridging stuff so we will have to learn it together, lol)

Good luck.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

G0KDT
Posts: 22
Joined: Sat Feb 29, 2020 12:22 pm

Re: Which MMDVM Board?

Post by G0KDT » Mon Mar 16, 2020 4:42 pm

Well Jason,

I can let you know that you were spot on. The boards arrived, they weren't as shown in the pictures so definitely clone boards without markings. The build quality wasn't that great either but they work and I have tested both boards on a single Pi Zero (can't buy them here at the moment for ready cash). The boards also cover YSF too so that's ok.

I have hooked one up and set it up with the IC-9700 and worked through a reflector, more by luck that design so have had a test report from N8XOL (Ron in Michigan) so I'm glad I got that far. The settings and navigating d-star are all a bit of a maze. Setting the [DR] screen from to the Hotspot and then the [To] to Linking to a Reflector REF001C , 030C or 067C all seems to work. Quite where I go from here is a bit of a mystery trying to get to grips with Reflectors vs Repeaters and then how to find a link between D-star and Wires-x which others around here predominantly use as there is a fusion repeater.

When we get another Pi zero I have to build the one for my friend here. With current situation we may have to hand over at a distance and me remote into his pc and setup as he is in a vulnerable group for this Covid-19 virus. With any luck we may have another Pi later this week but we aren't counting on it.

Thank you for your encouragement and help.
73's Phil.

KE7FNS
Posts: 1097
Joined: Wed Apr 17, 2019 11:11 pm

Re: Which MMDVM Board?

Post by KE7FNS » Mon Mar 16, 2020 7:55 pm

G0KDT wrote:
Mon Mar 16, 2020 4:42 pm
I can let you know that you were spot on. The boards arrived, they weren't as shown in the pictures so definitely clone boards without markings. The build quality wasn't that great either but they work and I have tested both boards on a single Pi Zero (can't buy them here at the moment for ready cash). The boards also cover YSF too so that's ok.
That is great to hear, glad it worked out perfectly as you wanted.
G0KDT wrote:
Mon Mar 16, 2020 4:42 pm
I have hooked one up and set it up with the IC-9700 and worked through a reflector, more by luck that design so have had a test report from N8XOL (Ron in Michigan) so I'm glad I got that far. The settings and navigating d-star are all a bit of a maze. Setting the [DR] screen from to the Hotspot and then the [To] to Linking to a Reflector REF001C , 030C or 067C all seems to work. Quite where I go from here is a bit of a mystery trying to get to grips with Reflectors vs Repeaters and then how to find a link between D-star and Wires-x which others around here predominantly use as there is a fusion repeater.
I don't have any familiarity with those modes, perhaps someone else reading this will chime in and offer some assistance. You could always ask in a new thread in some of the other sections of the forum, I'm sure someone will explain it.
G0KDT wrote:
Mon Mar 16, 2020 4:42 pm
When we get another Pi zero I have to build the one for my friend here. With current situation we may have to hand over at a distance and me remote into his pc and setup as he is in a vulnerable group for this Covid-19 virus. With any luck we may have another Pi later this week but we aren't counting on it.

Thank you for your encouragement and help.
You could use any of the other RPi variants with a 40 pin GPIO if you wanted to spend some extra money and get it completed sooner. The RPi 3B+'s are a massive increase in performance. I compared them once, and the time for a few of the services to start and complete during booting were huge. It is mostly due to CPU speed and single vs quad core processors.

Code: Select all

RPi Zero W
nextiondriver.service (6.454s)
mmdvmhost.service (5.695s)

RPi 3B+
nextiondriver.service (102ms)
mmdvmhost.service (724ms)
Also, what I would do for your buddy is configure a second SD card with all of his settings as if it was his hotspot, and enter his wireless settings as a second network. Then when you are ready to ship it, you can go in and delete your network (if you don't want him to have that information) and power it off. Then ship it to him and all he'll have to do is plug it in and he'll be ready to go.

You could also clear the wireless settings at the last step if your buddy doesn't want to share that info and you can still setup the hotspot with his settings. Then when he gets it he can create and copy a file to the SD card, and when it boots it should automatically configure the settings and connect to his network.
https://www.pistar.uk/wifi_builder.php

Good luck.
If someones previous actions are any indication of their future actions, then I predict the deletion and removal of access will happen at any moment. 7-11-2020.

"07/13/20 This Website Has Been Taken Down" ... again :lol:

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