I’m working as a media tech at a school. We have a load of walkie talkies and I’m doing my nut in trying to get them to talk to each other. There’s 2 kinds here. some nrc air (old) and mitex general (new). The nrcs talk to the nrcs and the mitex talk to the mitex. I assumed that walkie talkies were walkies talkies and the channels would be the same across all, but apparently not. From what I gather there’s UHF and VHF types and a decent chunk of spectrum for them to use.
So my questions are;
How can you tell if you have a VHF or UHF handset?
How can you find what frequencies each channel represents? The nrc ones say 400-470MHz under the battery but I can’t find what the mitex are.
The mitex FAQ mentions says 1-12 for general use (the airs are the original set and are on channel 2 if that matters) 13-15 all mitex types can use 16 is a scan channel. What’s a scan channel?
Any help would be muchos appreciado.
Ta
On further research an amazon page says the mitex is 403MHz and the box says its UHF. So I guess the nrc are UHF aswell as that falls within the nrc range and is probably around channel 2 anyway. The nrc air product page though says Wide/narrow bandwidth selective (25KHz/12.5KHz)which would suggest VHF and has confused me further so what’s the deal with that?
A LMRS technician has tools that can measure the frequency of the radio, a Frequency Counter, Service monitor etc…
When a public service - etc buys radios, it is with a certain specific frequency for which it is licensed.
Sometimes the license to use those frequencies are rented from the dealer that sold the radios to them, along with repeaters to make them talk further.
Either or - they all need to be on the same frequency.
Tell them to take them to a two way radio shop and have them evaluated…
Hi Stealth, based the two brands of radios you have, I gather you are in the UK. Based on the information I have on these radios, here are a few pointers that may help.
To answer the last question first, 25KHz/12KHz refers to wide/ narrow bandwidth, not frequency, so they are likely both UHF radios as the labels suggest.
I am not sure what frequency range in which the NRC Air operates, but assuming it is the same, the radios should be able to talk to each other, provided they are all programmed to the same frequency or frequencies. It seems both of these radios are pre-programmed to specific frequencies, so if those frequencies are different on each model, they won’t talk to each other.
I am not familiar with these two models so I don’t know if they can be re-programmed to your frequencies or not, but it seems all the channels are pre-programmed to specific frequencies by the manufacturer, so it is possible they may not be able to be changed.
Did you receive manuals with these radios? If not, my first suggestion would be to find one for each and find out what specific frequencies they are programmed to and if they can be changed.
Also, apparently these radios require a “Business Radio Light License”, to operate on those frequencies, so you may want to check with the regulatory agency in your country (OFCOM in the UK) for information on licensing.
If he’s not in the US, the FCC rules don’t apply to him.
Also, MURS certainly can be used by businesses in the US. That’s why it’s called Multi-Use Radio Service.
From the FCC website:
Licensing
The Multi-Use Radio Service (MURS) is licensed by rule. This means an individual license is not required to operate a MURS device. You can operate a MURS device regardless of your age and for personal or business use so long as you are not a representative of a foreign government.
I managed to find the manual for the mitex but not the nrc and it gives a couple clues.
First it has a bit about CTCSS and DCS which it says blocks transmissions without the right code. It says these codes are pre-programmed and pre-set but doesn’t say if it’s something that can be switched on or off. I’m not sure if thats a propriety thing or part of walkie talkie ISO.
Second clue is in the tech specs the frequency range says 136MHz-174Mhz and 400MHz - 470MHz. Im pretty sure the nrc said 400MHz-470MHz on the body. Again it doesn’t mention any way to switch between these two bands.
I’m assured the school has a registered license though.
136MHz-174Mhz are VHF frequencies. 400MHz - 470MHz are UHF frequencies. Having seen the spec sheet for the Mitex but not the manual, I believe the radio only uses one band or the other. Based on what you said earlier, you have the UHF model.
CTCSS and DCS codes are commonly known as “privacy codes”. They allow you to filter out chatter from other users or groups on the same frequency so you hear only those radios in your group that are using the same code.
This is another reason your Mitex and NRC Air radios may not talk to each other. If both radios are set to the same frequency, but one or the other (or both) are programmed with a different CTCSS or DCS code, one won’t hear the other. They need to be set to the same frequency and the same code to communicate.
CTCSS and DCS codes can be confusing if one is not familiar with how they work, so we dedicated an entire episode of The Two Way Radio Show Podcast to this topic.
This video offers a quick explanation. It discusses privacy codes on GMRS radios sold in the US but the general concept applies to CTCSS and DCS codes in general.
The short answer is that if the Mitex and NRC Air radios support the same band and frequency range but they won’t talk to each other, one or the other will need to be re-programmed to do so. You would need to find the specific frequency (and CTCSS/DCS code if programmed) one radio is programmed to and program it into the other radio to match.
Thanks for that, so from what a gather, privacy codes can be switched on and off and changed much like the channel. These radios don’t have a display of anykind and the only controls I have are channel and volume/power on the top. PTT obviously on the side then another button below that which I’m unsure the function of but just seems to make the thing burst into static?
I wonder if because these are probably the cheapest ones they could source that they are locked to a specific ctss code or whatever?
It’s possible, but it may be more likely they are pre-programmed to different frequencies. You would need to consult with the manufacturer of each radio.