Can I convert a radioless node to Shari radio setup yet stay Private?

Hello all,

I have a radioless node running and it’s great. However, I’d like to add a SHARI radio hat to my Pi 3B so that I can use my handheld radios and base station radios to connect to the node. This seems very straightforward and simple. However, what security measures do you recommend I implement to keep the node less vulnerable from any malicious people. For example, if I use a handheld radio at low wattage, some neighbor may sniff out my transmission by using SDR software and decipher not only the frequency I use, but also the DTS/CTCSS squelch/reception code. At which point, easily hijack my Allstar radio node for malicious use.

Is there an additional security measure that is best implemented that I have overlooked? Maybe rely on a weaker antenna to the Shari hat is my only hope?

I look forward to any advice.


By private I’m guessing you mean private on the radio side.
You can never achieve privacy on the radio side. You can make it slightly difficult, but hardly.
Police your radio node. Pranksters are going to prank.
There is nothing you can encode with that is not detectable.
You can turn it off or turn off functions.

Why not wait till you have a issue and fix that issue would be my suggestion.

Thanks for the quick reply Mike!
Yes…The radio side.

I understand the “wait until it’s needed” suggestion but I leave the node running 24/7 so that I can IAXRPT into it. I’d hate to have it hijacked on the radio side while I am at work so there lies the problem.

However…You’re on to something there when you said turn on/off the radio. I suppose I can create a script to listen for specific DTMF codes, or a specific internal webpage visited, to enable or disable the radio functionality. As long as I run the script internally through the LAN (or VPN when remote), I should be golden.

Thanks for the suggestion. It was just the seed I needed to run with.

I’ll proceed in ordering the SHARI hat now. Once I get the script up, tested, cleaned, and commented, I’ll share it with the community.


Firstly, if your neighbors are using SDR to footprint your radio usage, they really ought to get their ham radio license. We could use more folks with a deep interest in the science!

Before I got my ham radio license, I bought a Baofeng radio. I did not key up. I was hoping it would help motivate me to study for the test. And boy did it! Hearing traffic – including neighbor’s nodes – was exactly the motivation I needed to study and get licensed.

Those points notwithstanding, there are valid reasons to limit radio’s coverage. Probably the easiest way, as you suggested, is to use a very small antenna, or possibly even none-at-all. If you’re worried about damaging the transmitter, you can use a 50-ohm resistor or “dummy load”.

Placement of the node would also be a factor. Do some testing. Take your HT outside and see how far you can still hear your node. It is certainly on par with the spirit of amateur radio, along with your consideration about safeguarding your node!

I don’t think you’ll have to worry about interference. And, if a nearby neighbor has done exactly as you hypothesize, now you have a foxhunt, and hams love a good foxhunt!

Good luck.

haha. Thank you Aaron for humoring me with the positive side of the situation.

Yes, this is all hypothetical. I just want to be vigilant and responsible with my equipment so that I am not ground zero of an annoyance to the Allstar community.

I agree, a foxhunt is also fun as long as the fox hasn’t caused too much destruction in his/her path.

I will certainly combine the solution of a limited antenna on the SHARI radio module as well as a locking down the radio portion of the Asterisk environment with activation/deactivation scripts.

I reached out to place my order for the SHARI and apparantly, there is a 4 week delay as they are clearly busy with orders. So nice to work with a successful private business.