Rhys' website

Notes on radios

Disclaimer

Please be aware that information provided by this blog is subject to change. I recommend that you do not take any information held within as a definitive guide to the law or the relevant matter being discussed. You are advised to seek legal or professional advice where necessary rather than relying on the content supplied by me.

Due to the nature of the matters discussed on this blog, the information contained within it and any pages linked to from it are clearly subject to change, without warning. The law, regulations and other forms of legal governance are constantly changing and adapting to meet the needs of the modern world and it is impossible to comprehensively detail the nature of such within the confines of a blog in a concise, up-to-date manner.

Me

I’m still pretty new to radios! The page currently focuses on consumer facing voice options. I hope to cover cool things like LoRa and 5G soon and itt will likely be updated as I discover more :)

I can’t remember exactly how I discovered amatuer radio. However, I eventually found a club nearby to where I lived previously. Sadly, I didn’t stay too long there as I left after completing my foundation license exam. I’ve recently gotten back into it and am now trying to document my journey and understanding of it since whilst there are resources online, I feel it’s still difficult to get a grasp of.

DMR

DMR is the most standard digital radio option out there. It has quite a lot of functionality but at the same time complexity and cost. Main things to note:

There are multiple tiers of DMR (1 to 3). 1 for PMR, 2 for amatuer, and business, 3 is for big biz which features trunking.

Amatuer networks

DMR has the option of connecting to networks. Effectively a bunch of interconnected radios. The most popular being DMR-MARC and Brandmeister.

Whats the difference between a hotspot and a repeater

A hotspot is a gateway between different communication standards such as to go from DMR to D-Star. These are commonly done with Raspberry Pi’s and a low power radio.

A repeater is a high power radio which has an input frquency where you can transmit messages too. Then an output frequency where the input messages are sent to with a higher output power.

Do I need a DMR ID?

This is a unique number for the radio / operator that identifies you on a network.

When connecting to an amatuer network you’ll need to follow their rules. For the two mentioned above they required an ID provided by radioID.net. The website does look a bit outdated, but I can assure you it is the authoritive source of amatuer IDs.

Now, if you are using DMR not on one of these networks you can use any arbitrary ID you want, so whether your chatting with your amatuer friends or doing business.

When I’ve been researching this it made it seem like you needed to go through this website for all usecases, so please don’t make the same mistake and only do what you need.

Business radio

If you are wanting to have:

You will need a form of business licence. I’ll mention the two most relevant ones, but there are 5 of them.

For more information check out the Business Radio Technical Frequency Assignment Criteria.

Business Radio (Simple UK)

This license allows radios for chatter related to the business on this bandwidth. Where you can use this anywhere in the UK.

Valid for these frequencies (note: does not overlap with the simple site)

For a list of valid frequencies, refer to this licence template.

Business Radio (Simple Site)

For a list of valid frequencies, refer to this licence template.

FT8

This is a popular form of data radio. There is a limit of 13 characters per message, but it is fairly low power and uses HF. You can go a pretty far distance with this.

PMR446

Private Mobile Radio. This is what a common walkie-talkie uses. 12.5kHz channels with a power output of 500mW ERP. There are three communication standards that you can use:

(dPMR is separated by 6.25kHz instead of 12.5kHz)

Must be used on a mobile basis, you cannot use base stations or repeaters. Although you will read online about simplex repeaters (where a radio repeats what was heard on the same channel) being used.

The guidance on if this can be used with an internet gateway is very unclear i.e. create a bridge between a radio channel and Mumble. You have guides online showing how this is possible, yet legally in some Ofcom guidance it just contradicts itself if it is allowed.

Some other interesting constraints:

A disregard for the rules

One manufacturer appears to have ignored the regulation. The Midland GB1, I’ve got no idea how it is legal. Literally defined in ETSI definition of PMR446 4.2.1 it says:

The equipment shall not be any of the following:

  • Vehicle mounted device using an external power source.

It looks cool and everything, but what!

The hobbyist usecase

Whilst you can use these for anything, there is a small hobbyist side to it. You will want to Be tuning into channel 8 at 8pm on a Sunday, get yourself in a good high location such as a hill to maximise your range and therefore increasing the amount of potential contacts and have a chat!

Things to check out

What is a base station?

Good question. It’s vague. My understanding is that they are devices that a lot of clients connect too, rely on extermal antennas, can’t be moved easily.

Ofcom defines a base station in “Business Radio Technical Frequency Assignment Criteria” as:

A fixed location at which transceivers and antennas are installed to offer a service to the surrounding area.

Using that as a definition also, repeaters would be classified as a base station.

dPMR

Alternative to DMR made by the same group ETSI. The main differences is that it uses FDMA instead of TDMA, operates with half the bandwidth, and it costs more. It’s similar to NXDN.

The future

For the hobbyist-side, Software Defined Radio. Chatting with traditional radios has been made obsolete with IP based networks. There is going to be more and more digital things.

For business, I suppose a more scoped area of SDR. 3GPP based networks like 5G. Due to how software driven these networks are they are becoming more accessible to businesses to run themselves. I imagine we’ll be seeing private networks becoming more commonon to handle a wide range of usecases replacing analog and primitive digital radio.

Some radio manufacturers have began to notice that and have started to develop products called “network radios” or POC (Push To Talk Over Cellular 4G Radios) which have the form factor of a traditional walkie-talkie but utilise mobile phone networks, run a mobile OS such as Android, and do VoIP through apps such as Zello. Some manufacturers are combining the features of a traditional and a network radio into one device, really cool.

So overall, I’m really excited for what is to come :)

#hobby