last updated 24 Jul 2007

People will buy PMR446, I would imagine, for specific reasons - probably in pairs at least. CB however, caught on because people bought into the craze with the aim of talking to strangers, installing a base station or mobile and finding plenty of other such stations within range. PMR446 will be used by groups of people who will be mostly unaware of other users or uninterested in making contact with them. I think there is scope for PMR446 to become a CB for the new millenium - all we need is ...

A general calling channel - this would give PMR446 a sociable aspect. The range isn't as great as with a CB base station, so the possibilities are more limited. If you do make the effort to drive to a hilltop or similar vantage point, the chances of getting a reply will still be remote! However, for special events that draw large crowds, like airshows, a calling channel would work, although you'd probably be more interested in whatever else is going on! Surely it's worth a try to establish a calling channel convention, to see if it catches on? Now, what channel would be best? With CB there's 14/19, with ham it's usually a 20, with marine VHF it's 16 for calling. These are out of our range of 1 to 8. There is an old code for friendly best wishes : "88s" and there happens to be a CTCSS tone of 88.5Hz - so I propose all the eights :
channel 8 tone 88Hz - I believe that this is tone number 8 on many sets too. How about it?

A calling channel would allow operation like an amateur band too. When the hams get a new band they rush to be the first to make contact with other countries - there are list kept of the first UK to France contacts, UK to Belgium, etc. Even G to GM - England to Scotland. Why shouldn't we do the same thing with PMR446? (channels 1 and 2 were not available in France until 2002 - which was more reason to use 8/88!).

LATER UPDATE it's nice to see that 8/8 has now caught on. One very slight snag, is that there are two particular models that include 8/8 straight from the box, which could be unfortunate (the Motorola Handie Pro - see http://www.superiorsignals.co.uk/pmr446.htm - and it's also the Kenwood TK3101 ch2) as some business users may be affected by DXing, but it's still a case of first come first served, they can always change channels. On the plus side, people with these radios who WANT to call on 8/8 have it easy! (A bonus for radios that are difficult to re-programme, perhaps needing a PC connection and hard-to-find lead)

8/8 is working well, and good DX contacts are being made. There is a Spanish initiative (at http://www.radionoticias.com/clubpmr/alaescucha.htm ) to use Ch 1 but it seems a little late in the day to propose an alternative. Besides, ch 1 seems to be the most popular channel for kids messing about - many radios default to ch 1.

LATER UPDATE - with regard to "Why use CTCSS?" - I suggested 8/88 with CTCSS because at the time it seemed that nearly all 446s would have CTCSS (and MOST do, in reality) and not all can be set to tone '0' (CTCSS OFF) - so SOME tone would have to be used. It wasn't purposely to needlessly 'use up' one of the tones on channel 8, or to filter out any other groups of users, but rather it was to help SIGNAL your general CQ intentions to other DXers. There's nothing to stop you calling with it, and listening without, so you hear ANY replies. Best of both worlds!

ANOTHER UPDATE - I have discovered that Heinrich Rudolf Hertz first satisfactorily demonstrated the existence of electromagnetic radiation by building an apparatus to produce and detect **UHF** radio waves - in 1888! 8/88 can, in a way, be a nice tribute to that pioneering work. 

GOOD SUGGESTION

Date: Wed, 29 Sep 1999
Mail: simon@32010.org.uk

If, as suggested, the calling channel was ch 8 / 88.5 Hz CTCSS,
wouldn't it be a good idea for 'radio hobbyists' to use 88.5 Hz
as the main tone on the other channels to make it easier to
contact people with a similar interest, leaving the other tones
free for people who want to use PMR446 for business (& other
purposes)?
If tone 8 becomes more heavily used by people who are trying to
get long distances or just using it like CB then any business
users of that tone would probably move.
Then if you were scanning round and heard something which sounded
a bit CB or amateur radio-ish then you would be able to select
88.5 Hz and try calling them. 




"MEG" replies :

Good idea.
The other day I was thinking about "reserving"
(i.e. trying to establish a convention) the
first few tones for such CB/ham-style use,
with higher tones meaning "leave us alone".

Then you'd know in advance to not butt in on
people who simply don't want interruptions.

But as you say, the one tone is all we really
need to "hog" for our purposes!

My original idea was that I could use a tone
that didn't bother me with ALL the general
calling but still signified "join in if you like".
But in that case I might as well use 88.5Hz on
another channel - it would be best to avoid
ch8 unless I was calling anyway.

Let's hope this catches on!


(If you have a 446 site, please promote 8/88 with this, or another banner) 

8/88 settings on various models

8 and 8
38 tone radios - standard for most

8 and A02 (!) - Alinco DJ-SR1

8 and 9
   Having 69.3Hz as an extra tone
   shifts the sequence along by one.
39 tone radios
47 tone radios
   Eurowave
   Maycom MH-446
38 tone non-standard
   Team TeCom 446

8 and 5
32 tone MPT1306 radios
   UK Maycom MH-446



Default channel settings
"from the box" for 8/88 :

Kenwood TK3101/361   ch 2
Motorola Handie Pro  ch 8

Amateurs - how about calling with a mention of PMR446...
"CQ 2, CQ 2 metres, this is G9ABC/M at Local High Point, also listening on PMR446 channel 8..." or even "listening on all 8 PMR446 channels". It might be a good idea to add
"I will be here for another half an hour..." or "standing by until 3 o'clock..." as this will give others a chance to go and fetch some suitable equipment and run to the hills too. An example call by non-amateurs on PMR446 might be
"Hello anybody, this is 26EG123 at Local Hilltop standing by for any possible contacts, 26EG123 listening on channel 8 with both tone 8 and no tone..." When calling or answering a call it would help to specify which tone frequency you are using, for the benefit of those listening without CTCSS, to help them select the right tone to respond. Listening with no tone will enable anyone with any 446 radio to get through (if in range of course). If you answer someone it's best to say which tone you're using, to help them respond.

Please DON'T INTERRUPT other users without good reason. They are more than likely to think you're very odd, possibly dangerous or threatening. Most people will be buying these radios for "private" comm.s and they won't be expecting other people to break into their conversations. You would probably get "Who is this?" or "Get off my channel!" etc. Let's not upset people and give ourselves a bad name. Those of us hoping to find in PMR446 a replacement of sorts for CB, must bear in mind what other users are expecting from the service. An FRS mailing list posting from "QRM2000" suggests the following guidelines for various situations :

  • Someone is lost and needs directions. Okay to offer assitance. You might want to say that you were just checking if the channel was in use, and from what you heard you thought you may be able to help. They may not take kindly to the idea that you have been listening to their every words for the last half an hour.
  • YOU are lost and need help. Okay to ask.
  • People riding along in cars nearby, chatting about where they are going and what they are gonna do. Iffy. Remember the party and the line/queue at the movies (would you simply butt in?). Use your good judgement.
  • Children talking with adults. May be OK to call in - discretion required.
  • Children talking with children. Probably best to keep your mouth shut and avoid giving the appearance of a predator.
  • You are on top of a tall building or mountain and want to see how far you can talk. Okay to make some general calls. Identify what you are doing and where you are, in order to generate immediate interest (use the calling channel : 8 with tone 88.5Hz).
  • When you are in a conversation with two or more stations of your own group, you can "invite" others by saying, "We're going to pause a few seconds to see if there is anyone who wants the channel to make a call, to ask directions, or who wishes to join our conversation. Anyone else, please go ahead now." (use tone 88.5Hz perhaps, too)
Always start by apologising for breaking in, and follow this up with a clear explanation of why you have. Remember that the other stations may be using Tone-Coded Squelch to avoid other operators. Don't be offended if folks don't respond to your advances. If they ignore you, leave them be!

Handy hint - try to avoid distortion when talking into any two-way radio, by not talking too close any hand microphone or to the mic hole on the walkie-talkie. Use another radio with the volume set to avoid feedback, and see what you sound like at various distances. Distorted speech on FM sounds really horrible!

To get the best out of handheld radios, be aware that the signal strength from one radio to another can vary wildly from one spot to another at any given location. This is due to reflections adding together or cancelling each other out. If either station is mobile there's nothing much you can do, but how many times have you heard someone breaking up into a repeater because they're moving the radio about as they talk? Radio users need to be taught to hold the radio upright to their mouth, and to be aware of nearby obstructions and stand clear. Extra height is usually an advantage. When you're listening to a signal, move about a bit to get the best reception you can. This can be done without embarrasment, moving naturally and slowly stopping when you've found a good spot. Keep the radio in the same place to talk back, and the other party will reap the benefit of your better position. Any path a radio signal makes works the same in both directions. If both parties use this technique it can make all the difference between being able to communicate or not.