Licensed Radio Network

[Briggs 2.0]

I would really love to be able to understand all this stuff a lot more. I am really trying to get my head around it but i really need it explained to me.

I will try, but this may just make it more confusing so if your head implodes, I take no responsibility.

There is a very wide spectrum of radio frequencies available and their usage is strictly governed in the UK by Offcom.

Bands of frequencies are allocated to different users, for example your FM radio dial goes from 76Mhz up to 108Mhz with good old Radio 4 on 92.5Mhz or thereabouts. Your standard FM radio only receives the signal, it does not transmit. You can understand why Offcom would soon be breathing down your neck if you were transmitting on 92.5Mhz and disrupting the Today program so Offcom allocate separate bands of frequencies for amateur radio users to receive and transmit, within strict guidelines.

FM radio occupies a relatively narrow band and there's a world of other radio 'stuff' going on right the way through the entire radio spectrum. Essentially the lower the frequency, the greater the distance the signal will travel, tune into 7Mhz (High Frequency) and you'll be picking up the darker edges of Europe, tune into 3Mhz and you could be receiving from much farther afield, it's all to do with how the radio waves bounce off the ionosphere.....we'll leave it there, we're drifting into tech-overload!

Go up above 108Mhz and you're into Very High frequency VHF and Ultra High Frequency. These signals do not reflect off the ionosphere as well as so their range is not so great. It's typically line of sight, unless (as Megatron said) you are transmitting with a lot of power. You can pick up some cheap-ish UHF/VHF handhelds which will cover a distance of not much more than 5 or 6 miles, with good line of sight. Buildings and hills will have a detrimental effect upon range.

Malthouse is proposing to use the 70Mhz band. I'm not sure exactly what he's got planned but he may have the right mix of range versus cost. I'm sure he will elaborate in good time.

It's perfectly okay for you to listen on any frequency. It's only if you transmit without a licence then you will fall foul of Offcom. Malthouse may just have the answer with his proposal.

[Malthouse]

Very well said Briggs

The thing to remember about frequencies is that the lower ones "bounce" and the higher ones "punch", hence why 400MHz is great for cave rescue but 80MHz is better for open ground. Maritime VHF lives in the middle of those two and is ideally suited to line of sight, i.e. as far as the horizon.

I have written an online course that talks about all of that, with UKP discount of course.

Also as Briggs nicely pointed out, the frequency I am talking about is very similar to broadcast radio frequencies (Radio 4 etc). So this straight away gives you an idea of the range that is possible with both power and height.

Day to day we won't have power and most of us won't have a handy hill to park on, but even so the 70-90MHz frequencies do offer a nice trade off of range versus cost. Obviously if we were all millionaires then there would be other options, but for minimum cost and optimum efficiency I think this is the right way to go. Any lower frequency is going to be subject to weather (that might be the cause of the shtf) and also be pricey kit. Any higher frequencies are easily blocked by rolling hills.

Enter any radio buffs that can come up with something better... Bear in mind it is no good looking at trunked systems, as they will fall over faster than a communication satellite in a solar flare.

[RockingDad]

As a noob in ham radio... what handheld kit would we need? Baofeng UV-5R?

Rockingdad

[Briggs 2.0]

As a noob in ham radio... what handheld kit would we need? Baofeng UV-5R?

Rockingdad

That Boefang won't cover the 70Mhz/4m band which Malthouse is proposing. Take a look at the Wouxun KGUVD6L, this does 4m and 2m.

[Malthouse]

From a point of view of access, it might be better to use a higher frequency? As there are lots of preppers with Boafeng and they are cheap enough for someone wanting to get involved. The cost of vehicle mounted radios is also much better for the higher frequencies. Hmmm

Does anyone have a like for like comparison of 70MHz versus 170MHz?

[Briggs 2.0]

I'm probably going to get stick from the traditional hams for posting this but if anyone is interested in listening in to what goes on in the wide and varied radio spectrum then perhaps an SDR dongle is an idea. Here is a pretty good write up.

http://www.essexham.co.uk/news/realtek- ... ounds.html

This only allows listening - not broadcasting but it will give you an idea of what HF/VHF and UHF radio is like. As with all things radio, the devil is in the antenna so don't expect much from the small antenna, the web site above explains how to upgrade the antenna and I'd say that's a must-do.

Anyway, this may be an idea if you're interested in the wonders of the radio world-wide-web and what you can pick up. From a prepping point of view being able to listen for information is a good thing.

Back to Malthouse's frequency dilema - The low cost handies are price attractive and work okay on VHF/UHF but the lack of range is the buggeration if we're considering a network.

[Malthouse]

The low cost handies are price attractive and work okay on VHF/UHF but the lack of range is the buggeration if we're considering a network.

I shall do some sums and see what the difference is likely to be....

[Hamradioop]

I'm probably going to get stick from the traditional hams for posting this but if anyone is interested in listening in to what goes on in the wide and varied radio spectrum then perhaps an SDR dongle is an idea. Here is a pretty good write up.

http://www.essexham.co.uk/news/realtek- ... ounds.html

This only allows listening - not broadcasting but it will give you an idea of what HF/VHF and UHF radio is like. As with all things radio, the devil is in the antenna so don't expect much from the small antenna, the web site above explains how to upgrade the antenna and I'd say that's a must-do.

Anyway, this may be an idea if you're interested in the wonders of the radio world-wide-web and what you can pick up. From a prepping point of view being able to listen for information is a good thing.

Back to Malthouse's frequency dilema - The low cost handies are price attractive and work okay on VHF/UHF but the lack of range is the buggeration if we're considering a network.

That is an excellent suggestion Briggs. My experience with 70Mhz is it is not good at the power levels likely to be available to most peeps. It was used to replace some 149mhz stuff when I worked and it was crap. The system needed a repeater in fact 2 on Salisbury plain. However on ssb with directional antennas you can get the Balkans in the right conditions and the Baltic.

[metatron]

I've got a modified Icom IC-E90 which works on 6m/4m/2m/70cm on 4m and 6m if you pair the radio with single-band helical antenna range is good, but at 5 Watts we are talking maybe 40 miles with a HT, 2m/70cm is less but you have lots of repeaters.

[Rincewind]

Running the risk of repeating some others ,I personally would be more than happy to pay into a "secure-ish" radio network ,to keep in touch with people on my local area and beyond,I already have a Uk and European cb radio with large mobile antennas ready to go ,so an added benefit of another handheld would be a godsend.