Tuesday, January 17, 2017

Communicating between two DVMEGAs without access to the internet

So previously I installed the DVMEGA hardware onto a Raspberry Pi, and installed an image running MMDVMHost which makes the DVMEGA-Pi into a digital radio hotspot...specifically in my case a DMR hotspot.

It is very handy in my application...that is my house is apparently a faraday cage and no radio signals shall pass.

But what if you are out in the field with no access to the internet (no Brandmeister) and too far remote to reach a repeater...how can you use your DMR capabilities?

I dug through the internets for a while until I stumbled over some open source software developed apparently to run full size repeaters.

HBlink   https://github.com/n0mjs710/HBlink

So here is the scenario.  You have your mesh network setup, but the internet is not connected to your MESH.   You have two or more DVMEGAs deployed at different locations...and obviously you have DMR radios at those locations.  With an additional Raspberry Pi running the HBlink software somewhere on the MESH, and the DVMEGAs pointed toward it, now your DMR radios are doing their DMR thing within your MESH network.  (or another way of looking at it is a private DMR network)

This will be a quick walkthough of the software install and config...pretty straight forward, and I am not a Pi genius.

I started with the latest Raspbian Jessie with Pixel.  https://www.raspberrypi.org/downloads/raspbian/

For my purposes I used raspi-config to enable SSH and VNC...

Once all the reboots are done and software updated...

--:   sudo apt-get update
--:   sudo apt-get update

and install the python-dev tools for our Jessie version of Raspbian.   If you don't do this step the rest of the installs will not work.

--:  sudo apt-get install -t jessie python-dev

Then I opened the Pi's browser and downloaded the following software. (in all cases I downloaded the zip or tar.bz2 or tar.gz file)

Bitstring 3.1.5

Bitarray 0.8.1

Twisted 16.3.0  (download the Source)

service_identity 16.0.0  (download the Source)



Then using the File Manager in Raspbian I went to the downloads folder, right clicked on each file individually and selected "Extract Here"

I did the following steps within the terminal window.  These were all python scripts, and all installed the same way.

--:  cd Downloads

We will start with service_identity.

--:  cd service_identity-16.0.0
--:  sudo python setup.py install

after it finishes downloading and installing

--: cd ..

and so on and so forth through the rest of the downloads

--:  cd bitarray-0.8.1
--:  sudo python setup.py install
--: cd ..

--:  cd bitstring-3.1.5
--:  sudo python setup.py install
--: cd ..

--:  cd Twisted-16.3.0
--:  sudo python setup.py install
--: cd ..

--:  cd dmr_utils-master
--:  sudo python setup.py install
--: cd ..

--:  cd HBlink-master
--:  sudo python setup.py install

now stay in the HBlink-master directory...we need to edit the hblink.cfg file...there is none, but there is a sample to be edited.

--:  nano hblink-SAMPLE.cfg

scroll down until you see [MASTER-1] ...make it look like this.

IP:                                                             (I left this blank...seems to still work)
PORT: 54000
PASSPHRASE:                               (I use the same one I used for brandmeister...)

I also scrolled down to [REPEATER-1] and set ENABLED: False

now within nano save the file, but change the name to hblink.cfg

(for nano editing, the CTRL key and whatever option you want...so to save = CTRL-o   ; to quit = CTRL-x)

We are done installing and configuring.

To run, simply type (we are still in the HBlink-master directory)

--:  python hblink.py

You will see some messages like

-DEBUG - Logging system started.
-DEBUG - (MASTER-1) Master maintenance loop started
-DEBUG - MASTER instance created

if you see anything other than that especially with words like FAIL or ERROR...you probably have a problem...google is your friend.

After those start up messages you will simply see the 'DEBUG Master maintenance loop started'  message every few seconds...

Now on your DVMEGA, edit the MMDVM.ini file to have the DVMEGA use the HBlink machine as the server.

[DMR Network]
Address=xxx.xx.xx.xx        (your HBlink machine IP address goes here)
Port=54000                          (the HBlink port#...)
# Local=3350
Password=s3cr37w0rd      (make this password match the one you put in HBlink)

At this point start up MMDVMHost  (personally I just reboot the DVMEGA pi)

If you are watching the HBlink screen you will see the following message when the DVMEGA logs into it.

-INFO (MASTER-1) Repeater Logging in with Radio ID: xxxxx,
-INFO (MASTER-1) Sent Challenge Response to (your DMR ID) for login:
-INFO (MASTER-1) Client (your DMR ID) has completed the login exchange successfully
-INFO (MASTER-1) Client (your callsign and DMR ID) has sent repeater configuration

now when you kerchunk your DMR radio to the DVMEGA you will get the following message on HBlink

-DEBUG (MASTER-1) Received and answered RPTPING from client (your callsign and DMR ID)

after some inactivity you will get

-INFO (MASTER-1) Client (your callsign and DMR ID) has timed out

that RPTPING is all you need to see to know it is working...of course the DVMEGA machine should successfully login to the DMR server also.

Now from this point all you have to do is point the DVMEGAs to the HBlink server and it is all up and running.   I successfully tested this using two DVMEGAs set 5Mhz apart in freq, connected through different nodes of the MESH, the server and the DVMEGAs were on different nodes.