Radios

[Caradhras]

I just thought I would ask a brief idea from your greater experiences of these things.

I am running a T2K group but have little actual military experience (just some basic Territorial Army). My players always are asking questions that I have to wing-it with at times but this one is a bit of a niggle for me.

Radios - hand held, portable things like walkie-talkies. With their small unit actions they use these a lot - the FO to the mortar, the recon guy etc. But what range do these things realistically have (2-3 k) Next is the backpack style radio, presumably a considerable range compared to the others

Power sources for these also (the battery thread prompted this thread!) - I assumed that rechargable batteries would be available but how would it really be

Thanks for reading

[Twilight2000v3MM]

I can only give you input from a civilian poitn of view.

Our police radios (800 mhtz), now digital, have great reception and range IF you have a repeater closeby. If it's radio to radio (no repeater), even in a flat city, at BEST you may get 8-10 blocks with bad reception. I can only imagine that with big structures, hills, ect, this range would be cut in half easy. We used a specific channel for SWAT ops which is radio to radio and the range is no that great - like I said at best 8 blocks.

FYI - Battery life is probably good for 12 hours with "average" usage (I would say 70% standby and 30% transmitting and receiving). New batteries life woudl be longer and older batteries less.

[Marc]

Bon dia!

I will give my opinion without entering much in technical details, trying only to give some useful information at the level of game play. Take in to account that my direct experience about the matter is from 8 years ago...
About the walkie-talkies, you need to know that, in general terms, their range of available frequencies and their limited power output can provide a maximum distance of communication of about the range of sight in open terrain (between 4.5 and 5Km). This distance can be drastically shortened in an urban area and (in general terms) in any terrain with important obstacles cutting the line you can trace between the two communicators. Perhaps the effective range could be reduced to 1 to 2 Km. In that conditions, a good way to simplify the things would be: If there's an interrupted line of sight between us, we can communicate easily. If not, it's not an automatic task and you would need a roll to determine success.


I've got much more experience about backpack radios. I will suppose that you're talking about a VHF radios, the typical at platoon level. Their lower frequency and greater in power output usually makes them less vulnerable to the physical obstacles than the walkie-talkies. You could consider about 8 Km of effective range with the normal whip antenna and 4Km with the metallic-flexible antenna. Sorry, I do not know the correct English term for this type. Again, you can reduce the distance if there's a lot of obstacles, but, even in the worst conditions, you could consider that at 4km with the whip antenna and 2km with the flexible antenna, all communications attempts would be nearly an automatic success. Finally, this type of radio usually could be used with a 12m mast antenna (in a separate bag, of about 20Kg in weight) that can extend the maximum distance at about 30Km in optimum conditions. The task to deploy the mast usually implies two persons and can take about 5 to 10minutes depending of the training level of the operators. Again, a high position will help.

I hope it will be useful.

[pmulcahy11b]

Here's an interesting T2K idea -- major units that become disrupted due a breakdown in the radio nets of frequency-hopping radios. I don't know if it's classified anymore (it was when I was in), so I won't say how the frequency "hopsets" are distributed, but if the hopsets for FH radios aren't synchronized, you won't be able to talk to each other any more -- and you won't even know it's happening until you notice the rest of the formerly-chatty net has become silent. That can really disrupt unit cohesion. Are they on a different hopset Have they been wiped out Was there a hopset error at higher HQ that screwed up the works (easily fixed, but not if higher HQ has been destroyed) If you need help, are you going to get it

Eventually, everyone will be talking in the clear as hopsets and scrambling modules can no longer be synched except between small units, but in between during the Twilight War, there will be a lot of confusion.

[Twilight2000v3MM]

Makes for great plot devices Paul!! :-)

[Tegyrius]

Here's an interesting T2K idea -- major units that become disrupted due a breakdown in the radio nets of frequency-hopping radios. I don't know if it's classified anymore (it was when I was in), so I won't say how the frequency "hopsets" are distributed, but if the hopsets for FH radios aren't synchronized, you won't be able to talk to each other any more -- and you won't even know it's happening until you notice the rest of the formerly-chatty net has become silent. That can really disrupt unit cohesion. Are they on a different hopset Have they been wiped out Was there a hopset error at higher HQ that screwed up the works (easily fixed, but not if higher HQ has been destroyed) If you need help, are you going to get it

If you can say, Paul, could physical damage (or EMP, per the other current thread) compromise that synchronization without totally breaking the radio

- C.

[pmulcahy11b]

If you can say, Paul, could physical damage (or EMP, per the other current thread) compromise that synchronization without totally breaking the radio

- C.

Well...let's just say they are EMP-hardened, but EMP is still very much an unpredictable element in small electronics. EMP can literally push just a few a few atoms around in an electronic device and do something unpredictable.

The interior of a SINGCARS radio, though, doesn't look the inside of like a PRC-77 -- The old PRC has a lot of gizmos and components that look like they have no rhyme or reason to my un-commo-MOS. The inside of a SINGCARS is smaller and looks basically like layered circuit boards -- even a grunt like me can fix one with the right parts.

So yeah, you could probably break the hop module without ruining the radio -- but there are features to prevent it from transmitting if the hop module itself is compromised.

[chico20854]

Years back, somebody developed a set of pretty workable radio range rules - take a look at http://www.reocities.com/david_km/table.htm

[Caradhras]

Thanks for the informed replies people.

I know the basic rules give some set numbers of ranges but obviously there is going to be more to it as you have shown. I will take more account of terrain (and weather maybe too) especially urban or players using hills to aid range/reception int he future.

Battery life will by an issue also, if rechargables are not available. Sounds like a VHF backpack radio with a good antennae is a must for a T2K party/group.

Another question - if anyone is bored - my players also try to 'listen in' to other units who thay may know are operating in the area. I know the rules have a mention of built in encryption radios too but guess these are not foolproof (do they counteract each other). My basic way of dealing with this is to have a hidden roll/chance of the enemy radio being in use at the time and of how useful the info may be and make the player roll a difficult electronics and relevant language skill. Any other ideas/input welcome.

[Nowhere Man 1966]

I'd say a backpack radio is a must but if you are resourceful, even a handheld radio hooked up to a good antenna will do wonders. I've gotten out to 25 miles using a good antenna on my handie-talkie running 1 watt and 50 when I kick it up to 2.5 watts or higher, depending on the voltage I feed it. I get 2.5 with 7.2 volts, 4 with 9 volts and 5 with 12 volts. I did talk to Canada across from the shore at Lake Erie with 1 watt and a rubber duckie antenna, my signal went close to 80 miles but the weatherm ust have been good that day and radio crosses over water much easier.

Well, if you are hard pressed, a handie-talkie hooked up to a good base or vehicle antenna will work wonders along with a good power supply.

In radio terms, a $100 radio with a good/great antenna will out perform a $1000 radio with a poor antenna.

Chuck M.

[Caradhras]

Your help here was appreciated, I have a follow-up query tho now

My players want to listen in on enemy radio traffic (and maybe my npc's want to do the same to them), I have no experience with this equipment and dont want to rely on movies etc.

Questions are :-

How easy is it to use a backpack radio with good antenae to intercept radio traffic within it's range Use a normal 'electronics' roll Or is it harder than it sounds

Other than moving frequencies or using an unusual language (2 of my group use Welsh ), is there other ways to stop interception/understanding of a radio message - at least at T2k group level (I appreciate that encryption can be used at higher level but guess not in the field).

Any other input greatly welcomed.

[pmulcahy11b]

Other than moving frequencies or using an unusual language (2 of my group use Welsh ), is there other ways to stop interception/understanding of a radio message - at least at T2k group level (I appreciate that encryption can be used at higher level but guess not in the field).

Any other input greatly welcomed.

Oh yes, there are field encryption modules. I don't know what they're using these days, but we used the VINSON module (an encryption module) along with FH radios. You should have heard how pissed off the North Korean intel guys were when we started doing that (you could hear their broadcasts in the TOC) -- they were absolutely livid when our broadcasts went for all intents and purposes silent.

[headquarters]

An-PRC 77 and that hand held doohiky

The an prc 77 and 1077 used rechargables when i was in ,one plugged in and a spare in the batteri compartment .Reloading had to be done by a cord in the NM-135 / M113 variant we used.

It gave app 5 km range in good conditions but could do better if lucky .

Foliage ,terrain,buildings ,weather would easily cut range in 2 or 4 .

The An-Prc whats its name handheld 2,5 km radio was strictly LOS in many cases.Sometimes it would do better if lucky ,but I recall talking with the guys who used them a lot and they said to make sure of contact you would have to be abl eto see the other guy !

Old version this .

Couldnt say about more modern stuff.The AN pRC 77 we had in our IFVs using long whip antennas and vehicle powersource I guess could do 20 km or more if lucky .

All American made stuff.

Tried Motorola handsets later got a good 2 km out of them if not to much obstacles ,but this dropped with above mentioned conditions .Used a civvie VHF radio in our APC too ,got a good 20-30 km out of it -more if lucky .

Sometimes radios sound crystal and sometimes like mush even if the weather is the same and the radio location too.

Go figure.

[TiggerCCW UK]

We use motorolas in the bar building here, similar to ones I've used in the hills when supervising hill walks. On the hills we were able to use them, line of sight, for anything out to 8 - 10 km. Here in a building with similar radios we often have difficulty talking between the bar on the first floor and the basement - just too much interference from the floors, walls and electrics in the building.

[kalos72]

Whats the longest ranged radio we might expect to find in a military unit

I am trying to figure out how to stay in touch for a patrol unit over 100km away.