Digital radios

[insurin]

Recently staff where I work replaced their old analogue 2 way radios for some digital ones. Now I believe going to digital means that the transmissions can by encrypted if the user wishes to but they are all not necessarily encrypted by default. How can I find out if they are encrypted. I have access to the devices and I want to ensure that there is no sensitive data being leaked via the radios as I am sure it was when they were on analogue.

cheers

 

[troymail]

True - you can't assume encryption is enabled part or full time.

Ask the admins of the system?

Some radios have indicators that will tell you the transmission is secure - but I don't think that is universal.

Other than that, attempting to monitor the system with another radio (scanner) may be the only way...

 

[bob550]

It would help if we knew the make/model and frequency range of the digital radios. Encryption is not necessarily a feature built in to all digital two-way radios.

 

[insurin]

thanks chaps

There is no admin but I am IT so taking a vested interest in terms of security.

The models are Motorola SL4000. I will get hold of one and see if I cam make anything out that indicates it is encrypted or not.

cheers

 

[bob550]

To monitor this radio on a scanner, you'd need one that is capable of decoding DMR. By what I read about the SL4000e series, encryption is an option.

 

[tdeater]

If it has a display on it, look for a key icon on the screen along the top. It may be a clue.

Programming wise, it's hard to say without knowing if they are on some sort of system and what it is. At my office, we are on a connect plus system. We had setup encryption on one of our channels (or so we thought). I was messing around with a software decoder and SDR receiver and noticed I could listen to everything our crew was saying. The system operator had no idea how. Discovered a check mark that was not checked in a part of the software that was wrong. Now, this is just a weird thing with Connect Plus, because it works trough an option card. On our radios, a key with a / trough it meant encryption setup but not enabled, without the / meant enabled, and our clear to talk tone was different. This was using the enhanced encryption.

I have run encryption on simplex radio to radio digital channels as well, so it's going to be hard to say without some more info.

 

[insurin]

tdeater:

I feel for you thinking everything was in order only to find out it wasn't but glad you noticed it. I will take a look next week at the keys. Would it be any help to take in my SDR dongle and scan the frequency during a transmission or do the SDR dongles not do digital? If they do and it's not encrypted, should i be expecting to hear the transmission via SDR#?

Great info by the way from all replies

 

[jwt873]

thanks chaps

There is no admin but I am IT so taking a vested interest in terms of security.

Who programmed the radios? Get in touch with them. They would know for sure how the radios are set up.. (Frequency, encoding etc)..

 

[K4EET]

Pages 69 and 70 of this User Guide describe how to use/check for the Privacy feature.

https://www.motorolasolutions.com/c...50/_documents/_staticfiles/sl1k_userguide.pdf

73 (best wishes), Dave K4EET

 

[insurin]

excellent stuff chaps. It was an external company that came in to install the system. They have just been back in to install a repeater on the roof due to poor signal in some areas but unfortunately I missed them. Looking at the radio, there is key icon on the home screen with a red x on it which from the manual means 'Privacy Feature Disabled' That for me means that they are not encrypted and someone with a digital scanner could eavesdrop onto the transmissions. Would an RTLSDR dongle be able to hear the encrypted transmissions ?

I have followed pages 69,70 but I don't seem to have the 'Privacy' setting so it must be disabled. I will speak t the company about it.

 

[bob550]

Encrypted radio transmissions cannot be monitored by any scanner or SDR.

 

[insurin]

Encrypted radio transmissions cannot be monitored by any scanner or SDR.

sorry, I was meant to say "Would an RTLSDR dongle be able to hear the digital transmissions?" I get that they cannot hear/decipher encrypted stuff. I think because all my posts have to be verified first because I am new, I don't get to check them after I post. I have a habit of only seeing typos/errors etc once the post has gone live. Tdeater has already confirmed you can listen in on digital transmissions with an SDR dongle so I will try mine tomorrow.

 

[bob550]

sorry, I was meant to say "Would an RTLSDR dongle be able to hear the digital transmissions?"

You're forgiven! Using an SDR as opposed to a scanner is like making your own multi-course dinner vs. eating at a restaurant. There can be multiple pieces of software and configuration steps required to monitor digital signals. At least in my experience, it's not for the technically faint-of-heart.

 

[slicerwizard]

"Would an RTLSDR dongle be able to hear the digital transmissions?" I get that they cannot hear/decipher encrypted stuff.

Yes, absolutely. A dongle setup will also tell you what type of encryption (basic vs enhanced) is in use.

 

[insurin]

ok chaps

I have 2 Motorola sl4000's in front of me. I have my SDR dongle plugged in. When I broadcast from one Moto to the other I can see the the graph going mad on SDR#. I can see lots of peaks so I am clicking on the peaks to see if I can hear my transmissions through the PC via SDR# but nothing yet. The Motos say 438-470 on then so I am moving up and down and looking for signals while using PTT. They seem to effect a wide range of frequency but that may be because I am sat right next to the antenna. My goal here was to find the peak on SDR# while transmitting and the see if I can hear myself via SDR# but so far no luck.

cheers

 

[K4EET]

<snip> They seem to effect a wide range of frequency but that may be because I am sat right next to the antenna. <snip>

That is what it sounds like is happening. Fundamental overload of the SDR.

Why not just look at the output frequency of the repeater you all use? Can your SDR even receive digital transmissions to begin with? Alternately, can you take one portable and turn off the encryption per the User Guide and the other leave it on encryption. Go to the other side of the room and see if the "clear" portable can hear your transmission. Will that work for you?

Cheers! Dave K4EET

 

[insurin]

I am using the RTLSDR usb dongle and as mentioned in previous threads, I should be able to hear digital transmissions. Our radios are not encrypted. I just want to be able to listen to the transmissions between radios as a proof of concept. I can then present a case for encrypting them.

 

[popnokick]

I think you are missing a key component that will enable you to hear (demodulate) the SL4000's DMR digitally modulated voice transmissions. The RTL-SDR will receive the raw digital carrier from the radio, but not (by itself) perform the demodulation of the MOTOTRBO (DMR) transmission. As tdeater wrote in an earlier post in this thread -
"I was messing around with a software decoder and SDR receiver..."
Key words in the phrase above are SOFTWARE DECODER and SDR receiver. To be able to demodulate and hear the spoken voice transmissions you're going to need additional software that will be used with the SDR.... such as DSDPlus.

 

[insurin]

I think you are missing a key component that will enable you to hear (demodulate) the SL4000's DMR digitally modulated voice transmissions. The RTL-SDR will receive the raw digital carrier from the radio, but not (by itself) perform the demodulation of the MOTOTRBO (DMR) transmission. As tdeater wrote in an earlier post in this thread -
"I was messing around with a software decoder and SDR receiver..."
Key words in the phrase above are SOFTWARE DECODER and SDR receiver. To be able to demodulate and hear the spoken voice transmissions you're going to need additional software that will be used with the SDR.... such as DSDPlus.

Got you. I shall try again with the decoder. cheers