# 2 Way Radios.



## AlexR (May 11, 2003)

Have you noticed the many different types of these new 2 way radios for sale?

With advertising like save on phone bills,easy to use etc?

I bought some,range specified as 5km conditions permitting.What conditions, is that then?Living in Holland?Bloody speedbumps affect these things









Biggest waste of money ever.They might be good for calling me when I am in the garden,instead of opening a window and shouting me









Can you hear me?No


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## chrisb (Feb 26, 2003)

Just remember....Line Of Sight


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## AlexR (May 11, 2003)

Pity they don't put that on the box,so you can see this before you buy them,and not be told a load of bull by a 17 year old Saturday shop girl


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## raketakat (Sep 24, 2003)

Two tin cans connected by string has always worked for me







.


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## Nalu (Nov 28, 2003)

These handhelds operate on FM which is LOS transmission as mentioned. Tell the 710 to go up the second floor









We used pairs of Motorola handhelds to good effect in Iraq. Convoys, especially at night, could get sporty and since my command vehicle was the only one with a radio, we had to rely on these commercial products in order to maintain comms in the event of separation, mechanical problems, etc.

Garmin make a Rino handheld with an 8Km range and built in GPS. I'm bringing a set on my next deployment.


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## Stan (Aug 7, 2003)

I used to use two bean cans but without the string.

Reception was bloody awful beyond our town. The drum's were much better.

Coat found and is girding my loins.


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## Mrcrowley (Apr 23, 2003)

oooooooohh........

8km range and GPS.........

Must resist.....gadget urge


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## FrankC (Nov 3, 2003)

What gets my goat about these things is that I flogged to pass a radio exam and a morse test so I could go on the air. Then they start giving licences out to CB er's with no exam and now anyone can buy a walkie talkie and use it willy nilly. I'm glad they are crap rigs, it serves 'em right.

I know, I'm a grummpy old man

Frank


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## AlexR (May 11, 2003)

Frank









You can't compare 5k range walkie talkies to radio Ham,or even CB,unless the set up is illegal,AM Sideband with a big linear amp and die pole







These are the people you should have a moan at.

These walkies don't use repeaters,so are not serious radio equipment,hence no exam.Whole different ball game IMO


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## FrankC (Nov 3, 2003)

Alex

What you say is true but like I said I'm a grumpy old man.

I look around and think ...........!!??*&*

Cheers


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## Roger (May 17, 2003)

> These handhelds operate on FM which is LOS transmission


As someone who spent my whole career in radio and telecomms, the above quote is both misleading and factually incorrect.

FM is just the type of signal modulation and has little or no effect on range. The frequency of the signal has the major bearing on range as do ionospheric conditions.

If the radios in question were the newish PMR sets operating at around (from memory) 446 mHz, they should have reasonable coverage in an urban environment. Frequencies in this part of the spectrum have a tendancy to " bounce around " and reflect well from buildings and such. It was no coincidence that frequencies around 452 mHz were chosen by the then Home Office for Police use for this very reason.

Frank, I can sympathise with your views, I did my exam and morse test in 1964 and have now all but gone QRT, I never agreed with this give-away licensing regime.

Roger G0IUW, 73 AR SK


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## pg tips (May 16, 2003)

when I started on the AA we had 2 way radio. We had to take a procedure test! Being ex mil I ran the tester round in circles









Mind you once out on the road it seemed to be a competition on who could stray from procedure the most!

Best one was

Control: Delta 89 what's your position? over

Patrol: Sat behind the steering wheel as bloody usual!









The control always used "Fanum * listening out" to end a transmission.

We always tried to get in after them and see how many times they'd try and close before getting pissed off.

. (* was a number asigned to each office and Fanum the AA's call sign)

We now have a GPRS system or something that works like mobile phones and is all data, no voice. If we want to talk we have to ring the office on the mobile.

If you want bad radio comms my little 'un has a Barbie 2 way radio set with a supposed range of 300 meters! We have to use it within ear shot of each other to keep her happy, she thinks it's coming through the handset yet all we do is shout louder as she runs down the garden!


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## Roger (May 17, 2003)

PG,

Wasnt Fanum House their HQ at one time?


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## pg tips (May 16, 2003)

Certainly was Roger. There is still a Fanum House in basingstoke, the big tower block, but the HQ is now at Southwood. I think they are trying to sell the tower.

Fanum used to be their call sign for everything at one time, don't know where it comes from.


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## FrankC (Nov 3, 2003)

Roger

You'll remember UHF 625 line TV comming in then, the end of TVI as we know it !. What a joke.

Put a 3 ele yagi on a 60 ft tower and they'll come from miles around, not to wonder at such a sight but to complain of al sorts of imaginary interference problems, believe me I've had it all. Even complaints that I was a Russian spy Hi! and of course guy who could hear ever word I said even though I was speaking Russian

73's Frank G4HBI


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## Roger (May 17, 2003)

PG,

Yes thanks for that, I seem to remember sending my annual fees to that address


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## Nalu (Nov 28, 2003)

Roger said:


> > These handhelds operate on FM which is LOS transmission
> 
> 
> As someone who spent my whole career in radio and telecomms, the above quote is both misleading and factually incorrect.
> ...


I should have known there would be RIS's in amongst the WIS's









OK, I may have simplified the situation, but I stand by my point that these mobile handhelds are best used as LOS devices. They operate on FRS/GMRS bands (which in the US is 462 & 467MHz) and are limited to 5 watts - no license required at these staggering power levels. _Only_ FM (Frequency Modulation) transmission is allowed in this band. This can give you a range of 1-2 Km, or "much higher" for LOS transmission. Therefore, the best way to improve your handheld's range is to have clear terrain between units or to to get higher to eliminate obstructions. At 5 watts (typically much less: 0.5 watts for FRS for example), reflected signals are weak and these pocket-sized units aren't exactly kings of conquering multipath. And if you are inside a building, forget it.

Paul, I should point out that these are US units and may be illegal in the UK - they are in Canada (we weren't really concerned what the Iraqi Ministry of Information thought about our units







). This is because they transmit/receive _data _for their GPS function and data transmission is _verboten _in this frequency range (it's for non-commercial voice transmission only). Garmin received a special authorization from our Federal Communications Commission in order to put this feature in their units. Interestingly, the FCC recently added permission to allow 1 sec text messaging data bursts in FRS units, as long as it is no more frequent than every 30 sec. *WARNING **gadget alert* I expect to see handhelds with GPS and text messaging between units soon


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## Roger (May 17, 2003)

> but I stand by my point that these mobile handhelds are best used as LOS devices


Almost any radio signal (with a few exceptions such as VLF ) will work better on LOS paths. I am not aware of how there trancievers were advertised, but if they were intended for urban as well as LOS use, then the frquencies in the UHF spectrum at around 450 mHz would still be one of the best choices. As for power levels, 5 watts is far more than necessary for a couple of miles. I remember (as will Frank) when the second hand market was flooded with Pye Pocketphones for various police forces, we all bought them and re-aligned them for amateur use. Even with the feww hunder milliwatts of output power, we got outstanding ranges around town.

If the readios in question were fitted with the flexible rubber type antenna, then this could also be a cause of poor performance as they are often inefficient and are often not resonant at the frquency of interest.



> these pocket-sized units aren't exactly kings of conquering multipath. And if you are inside a building, forget it.


The phenomenen of " Capture Effect " with FM is one of the reasons it would be a good choice for this type of set and should mean that it will effectively lock-on to the strongest of the available signals so that multi-path should not be much of a problem.

I suspect that the main cause of disappointment with these sets is poor design and inefficient antennas rather than power output and frequency of operation. Given the same power and frequency a good commercial or amateur market set will usually outperform an Argos Binatone special.

BTW what actually is a RIS and a WIS? just curious.


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