Tag Archives: ALLSTAR

Radio

ALLSTAR NODE

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#126 Creating An Allstar Node

Display prototype on an actual Bread Board 🙂

In my previous article I was focused on the RTCM and the VOTER PCB which are used with repeaters. however I found out you could make a node instead for personal use. So basically a node is a radio connected through a sound card to a raspberry pi acting as an Allstar server.

You setup and connect this to the internet and you have a home made personal gateway to the Allstar servers. now you can listen or chat with anyone on the Allstar network

With that being said I was very interested in making my own version but I wanted it to use LiPo battery power for portability and a solar panel as power intake. I wanted a complete stand alone unit that could be setup once and placed somewhere and almost forgotten just remembered for maintenance and check ups.

I also wanted clean audio which could be a whole article in itself but for this write up I’ll be brief.

Testing out different filters and super capacitors
Eventually settled on a case with very short wires

I got the initial setup working using a UHF only Analog radio connected to a CM108 sound card that is plugged into a raspberry pi 2w with an OTG adapter. (it’s very important to keep all the wires as short as possible to prevent them from becoming antennas!!)
This was connected to a 5V step up converter and charger in 1 module. Now the radio needs max around 4.2V so I had to add an additional stepdown converter to accommodate this.

CM108 FOB

Everyting worked well and the system was portable but there was a very annoying whine. with some filtering I was able to reduce this significantly and the setup was almost done.

One annoying issue was that when the 5vstep up converter switched from main to battery power there was a very brief short delay where power to the raspberry pi could be lost casing a brownout and reboot of the pi. The solution was to add super capacitors in parallel with the supply to keep the volts flowing during this dip in power.

Also using a linear voltage regulator with a high ripple rejection circuit helped reduce the audio whine and noise

Over all this was a fun success of a project I will be creating a permanent case for my DIY version and I will be creating my own custom Nodes with a professional PCB for sale in future!

COS wires location on the radio
RX, PTT and GND solder areas

Experimental, Radio

ALLSTAR VOTER

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#125 Creating a DIY VOTER

Unpopulated VOTER PCB from the factory

VOTER (Voice Observing Time Extension for Radio) 

For a while now I have been involved with some troubleshooting at my radio clubs repeater site closest to me.
we have had a few issues where our equipment gets damaged from lightning water and rats.

We’ve tried to mitigate these problems however the reality is that it more of a manage the symptoms situation rather than solve the problem situation.

With this in mind we have had some damaged RTCM devices, the RTCM (radio thin client module)
is connected to the internet and to the repeater. It has an IP address and forwards the voice data to other sites or nodes that have the Allstar system setup. It’s basically like a small VOIP system that can adjust squelch and do simulcasting but the repeater site can choose what settings to enable or disable.

In our case its just connecting the Voice data to the internet so that club members can chat with other repeater/node users over a greater distance through the internet.

E.G: talking to someone in Durban is not possible using VHF at the altitude where I am situated, due to the terrain, large mountains and a hefty over 100Km+ distance away VHF will have a really hard time. Also with all the solar whether these days… I would expect diminishing results.

But… with an RTCM connected to a repeater or a Node, I can now communicate over that distance using Analog VHF radio to the RTCM over the internet and then through the repeater or node on the other side in this case in Durban.

Checking and adding components to the PCB

So now the big issue I had was that RTCM devices will be just under 10K south African ZAR from America for 1 with shipping and all the tax applied it’s very expensive and I wish money was no object but the truth is our club is not super financially inclined due to many reasons a lot of them out of our control.

This prompted me to investigate on an alternative and I found a few but I chose the original 2011 VOTER PCB which allows us to do the same thing basically just on the prototype board.

Of course this rises some concerns like:

  • THT components used
  • Parts are all PDIP and most have to be substituted
  • No case provided
  • A larger size
Back of the PCB while I was populating it

But… in my case weighing up the pros and cons there’s no major issue using this VOTER version.

So I got a few professionally made, read the datasheets for all the IC’s and purchased the available parts.
I also substituted the parts no longer available and integrated them with some small modifications.
(I will create my own PCB based on this in the future for better availability and usability)

Overall It took me around 3 month just to read all the datasheet and to get familiar with they systems bootloader and firmware of the VOTER PCB not to mention learn about the Allstar system as I had not really been educated on it. Though it was worth it and the research paid off in the end.

I was able to learn fast and I can say that I was happy with this project and the VOTER boards turned out great!!

Front of PCB while I was populating it.