I enjoy ham radio nets and try to reach out to the furthest ones I can pull off with my 2-meter radio and J-pole antenna (81.4 miles is the record to the K3NQT repeater as of this posting on 21 Apr 2020). I have used EchoLink to reach out to some West Coast nets in California and Washington (usually the Puget Sound Repeater Group nets) but I prefer using a radio over my cell phone. Also, building my own AllStar node would allow me the flexibility to control the link. Furthermore, I wanted to join in the East Coast Reflector which I could only break the squelch on the nearest repeater.
Credit goes to K3KDX for providing me with instructions as to how he set up his node which I based this built off of.
Here are the items I used to build the node:
- Alinco DR-135 MkIII (2 meter single band transceiver)
- Raspberry Pi (I used a RPi 4 4GB/RAM, but 3B+ is fine)
- RIM-Alinco (Interface from Pi’s USB to Radio’s DB-9)
- Dummy Load (Use one sized appropriately, this one is 50W)
- SMB-201 Cooling Stand (Reuse of this, you can use a cheaper fan)
- SD Card with HAMVOIP image installed
- Keyboard, Power, HDMI, Coax and other cables as needed
- Raspberry Pi Case with fan recommended
- Register with AllStarLink for a server and node
- A second radio that is the control point you wish to use
The first recommended step is to register with AllStar. They validate your license and it takes a bit of time for them to set up your node in the database. This only took a few hours in my case, but it’s better to do this ahead of time if you can. You need to register and set up a “server” under the “Portal” menu. The server is just the name and location. Next you have to create a “node” for that server, also under the “Portal” menu. AllStar will take the time to create a node number and password. You will need these in the setup of HAMVOIP.
Next load the HAMVOIP image onto the SD card. Choose a good quality card. I had a Samsung 32 GB card handy, so I used that. The HAMVOIP site has instructions on how to install the image on to the card (if you have not done this before). I already had win32diskimager on a Windows machine so I downloaded the Windows .exe (execute to decompress the image) and used the win32diskimager to write the image to the SD card.
Here is how the RIM-Alinco device arrived. It looks of excellent quality. Note that this is a mini-USB not the more common micro-USB. The RIM-Alinco comes with this cord so no worries about finding one if you don’t have it. Install this to the DB-9 connector on the radio. Note the lack of heat sink fins on the bottom side of the radio, we will come back to that later…
I had an unused SMB-201 cooling stand which fits the form-factor exactly. The only catch was the Alinco radio has the majority of the heat sink fins on the top, not the bottom. Originally I set this up facing the “proper” direction.
However, look at the above picture. There is a lack of heat sink fins on the bottom side (do not run the length of the radio). While the fan on the bottom still kept the radio at a reasonable temperature (low power), I decided to flip it over for proper cooling. Eventually I’ll make a stand that inverts the entire setup.
Remember, the radio is a node so the TX and RX duty cycles are reversed. That means the TX duty time is the time you are listening on your node channel on your other radio. That is a very heavy duty cycle especially for long nets. I am hoping the Alinco can handle this long term. This is why cooling is extremely important. Also, setting the power at the lowest setting necessary is also very important. Right now I use a dummy load because the radio is nearby. Low power on this radio is listed as <5 Watts. This is 50 Watt dummy load so I have no overheating issues or SWR problems. I measured around 4.5 Watts output at the radio on low power. Oh, and I recommend setting the radio to tone-coded squelch so you don’t rebroadcast other simplex users inadvertently. Set the radio to the simplex frequency you plan to contact your node with.
If not done already, connect everything together as appropriate and power the devices. Set up the RPi to display the HDMI on a monitor/TV and have a USB keyboard plugged in. When you boot the RPi, it will launch the installation program. It will ask for your assigned node number and password (from registering with AllStar). It will also ask you for a number of setting choices. The RIM-Alinco page provided a few seen here:
I noticed my TX was quiet, so I modified a few settings. Don’t worry you can always go back in and adjust things as needed. When you boot from now on you will see this screen allowing you to modify the settings as needed. I performed the system updates after I set up WiFi. There is also an echo function in the simpleusb-tune program which helped me set the audio levels.
AllStar has a list of commands you give the node over the radio (starting with a “*”). I prefer to use the command line (Asterisk CLI client). That way I’m not keying the radio all the time to issue commands via RF. This is not necessary but a preference on my part.
That’s all there is to it! It took me no more than an hour to set up. The hardest part was waiting for the parts to arrive.
I’ve also set up the node to relay weather information using the AutoSky SkyWarn module. Setup can be found here from HAMVOIP.
Next, I plan to dual-purpose the Alinco. Since it’s a well-performing 2-meter radio, I want to use this as a base-station as well when not in use on a node. I have programmed a momentary switch in Python which is connected to the RPi GPIO pins to shutdown and restart the AllStar node asterisk service. That way I can disable the node and use the radio as a normal 2-meter transceiver when I want without having to SSH to the RPi and turn off the node. Once I formalize this, I will publish the process and Python code.