Baby monitors transmit in the 48-50 MHz range. Common baby monitor channels:

• 49.300
• 49.830
• 49.845
• 49.862.50
• 49.845

The range of the PMR446, just like any VHF or UHF radio, is dependent on many factors like environment (in city range is far less than in open field), your height above surrounding obstructions and to a very much lesser extent weather conditions. The antenna type and location, transmit power and receive sensitivity also affect range. However with PMR446 most of these variables are fixed at manufacturing to comply with the PMR446 specifications.
Range may be many kilometres e.g from hilltop to hilltop, or only a few hundred meters if for example a hilltop or large metal construction is in the transmission path i.e. between radios.
The best known long distance record is 535.8 km (333 mi) from the town of Blyth in United Kingdom to the city of Almere in The Netherlands.

Due to the considerable uptake of the service, PMR446 radio sets can now be bought from as little as €30 Euro a pair. The Odtr requires that radios have a maximum of 500mw (1/2 watt) ERP (Effective Radiated Power) to an internal antenna. This limites range to, realistically 1/2 to 1 mile around town and up to 2 miles in open country. In line of sight conditions and at altitude ranges of over a hundred miles have been obtained.

CTSS (continuous tone squelch system) is incorporated in most radio sets as a means to prevent interference with only 8 channels available - the radio ignores all incoming signals except those that are also transmitting this sub-audible tone.

There are eight 12.5 kHz simplex frequencies which can be used anywhere in Ireland. The frequencies have been harmonised (but not necessarily authorised) for use across Europe. The channels centre frequencies are as follows:

1. 446.00625
2. 446.01875
3. 446.03125
4. 446.04375
5. 446.05625
6. 446.06875
7. 446.08125
8. 446.09375

The frequencies are shared and users may, under local heavy use conditions, experience interference and problems with sharing channels. These may be reduced by changing frequency and/or CTCSS tone and/or DCS code. PMR 446 is not suitable for safety of life use or for users who need to have access to frequencies at particular locations and times.

Before speaking you should check that a frequency is free by either listening or using the channel busy indicator. When you speak you should identify yourself and the person you are calling. The radios allow communication in only one direction at a time so you will find it helpful to identify when you have finished speaking. It is expected that the frequencies will become particularly busy in cities or where large numbers of people gather such as large sporting events. All users will benefit if messages are kept short.

The following is a non-exhaustive list of license exemptions.

Exemptions

Radio Type	Description	Exemption Order	ComReg Document	Other Information
Short Range Devices (SRD)	The vast majority of licence exempt equipment falls under this category. SRDs include various low power devices such as inductive applications, alarms, model control, walkie talkies, wireless microphones and audio systems, radio LANS, Road Transport and Traffic Telematics (RTTT), Radio Frequency Identification systems (RFID) etc. Operation of Wideband Data Transmission Systems (including WAS/RLANs) in the 5.8 GHz band is also subject to the Registration of operational base stations with ComReg.	S.I. 405 of 2002 S.I. 160 of 2006	02/71R1 06/47R 03/42	ERO Recommendation: ERC/REC/70-03
Citizen’s Band	AM citizens’ band (CB) and PR 27 radio equipment. Operational modes are AM (1W erp), FM (4W erp) and SSB (4W pep). CB is from 29.96-27.41MHz where 40 100kHz channels are available.	S.I. 436 of 1998	06/47R	ETSI  Standards: ETS 300 433, ETS 300 135
Satellite	Certain Land Mobile Earth Stations including Inmarsat, Eutelsat, Italsat, Arcanet and Thuraya Stations.	S.I. 398 of 2001	00/68 06/47R	ETSI  Standards: TBR 026, TBR 044, TBR 027, EN 301 681
	Certain Fixed Satellite Receiving Earth Stations including VSAT and SNG receivers.	S.I. 273 of 2000	00/68 06/47R	ETSI  Standards: TBR 28, TBR 30, TBR 43
	Mobile Earth Stations for Satellite Personal Communications Systems <1GHz (S-PCS<1GHz)	S.I. 173 of 2000	06/47R	ERO Decision: Annex 2 of ERC/DEC/(99)06
	Satellite Earth Stations for Satellite Personal Communications Systems <1GHz (Global Mobile Personal Communications Service, GMPCS) Exemption of Low Power Aircraft Stations	S.I. 214 of 1998 S.I. 007 of 2004	00/68 06/47R	ERO Decision: ERC/DEC/(97)03
	Low Power Satellite user Terminals	S.I. 505 of 2003	06/47R	ERODecision: ERC/DEC/(00) 03 ERC/DEC/(00) 04 ERC/DEC/(00) 05  ETSI  Standards: EN 301-459 TBR 28
	Onboard Aircraft Satellite Terminals	S.I. 007 of 2004	06/47R	ETSI Standards: EN 301-473; EN 302-186
	Mobile Satellite User Terminals	S.I. 128 of 2005	06/47R	ERODecision: ECC/DEC/(02) 11  ETSI  Standards: EN 301-444 EN 301-681
PMR 446	Short range business radios operating in the 446MHz band	S.I. 93 of 1998	06/47R
Mobile Phones	IMT-2000 (3G), GSM 900 and GSM 1800 MHz mobile phones	S.I. 158 of 2003	06/47R
	GSM mobile phones operating in the 900MHz band	S.I. 409 of 1997	06/47R
	GSM mobile phones operating in the 1800MHz band	S.I. 107 of 1999	06/47R	ETSI  Standards: TBR 31, TBR 32
Cordless Telephones	Analogue cordless phones operating at 31.025 - 31.325MHz (fixed part) and 31.925 - 40.225MHz (portable part) DECT cordless phones operating between 1800 -1810MHz CT2-CAI digital cordless radio communications system operating in the band 864.1 - 868.1MHz and complies with ETS 300 131	S.I. 410 of 1997	06/47R
Broadcasting	Certain wired broadcast relay stations Sound broadcasting receivers	S.I. 200 of 1976 S.I. 211 of 1972	06/47R
Radio Receivers	General Radio Receivers (excluding Television Sets)	S.I. 197 of 2005 S.I. 292 of 2005	06/47R

My main interest then and now was shortwave as well as a smattering of airband and up. But I really liked the idea of a handheld unit.

Again, it was declared that a handheld wideband scanner couldn’t compete against a dedicated HF rig.

I’ve no doubt that that’s true.

But the impression given by a lot of articles I read was that I’d be lucky to hear anything other than European broadcast stations.

That, most certainly has proved not to be the case.

To sum up my set up;

An Icom IC-R20 & about 30 feet of thick electric cable, strung about 6.5 feet off the ground, North-South, on a semi permanent basis.

A few minutes ago I was listening to a Ham in New Hampshire - my first transatlantic copy. But before that I had been getting voice transmissions from Finland, Spain, Germany and beyond.

But the nerd in me was also interested in the various digital modes, and with this simple set up I’ve been able to pick up PSK31, RTTY, MFSK et al from around the world, in addition of course to Morse.

As I posted before, I was able to experiment with PSK31 & SSTV modes through a cheap PMR446 radio to my scanner.

Hearing Santa Maria or New York Atlantic ATC at night is the norm. Number stations originating in Cyprus and Israel are all copyable, especially so at night.

Hearing distant lightning claps for the first time on the radio was a wake up call to set up a proper ground. Strange signals that I couldn’t make sense of were later explained to me as Ionospheric Sounders - something I never even knew existed.

HF/Shortwave listening has proved what a magically atmospheric and interesting band it really is.

So what I’m trying to say is, sure a Wideband Handheld Scanner can’t be considered to be as sensitive as a good dedicated HF rig, but it can be good enough to let you experience the band.

In addition the doom laden warnings of overloading now appear to have been somewhat exaggerated, throwing RF gain a few notches does the job perfectly. Again I’m sure overloading can result in serious problems, but for me, with basic precautions - it hasn’t been an issue.

So if you’re on a budget, or don’t know what frequency range is going to grab your particular interest - based on my experience, by all means get a good handheld unit.

Now, that being said, don’t expect a miracle radio. I’m told that the R20 is rather deaf when it comes to the microwave region, and in my experience it’s pretty deaf on Long Wave too. But nothing’s ever going to be perfect.

To me the most impressive thing about this radio, is the fact that I can go from listening to Austrian Radio on shortwave, to listening to a SAR operation off the west coast, to listening to RTE 2 television, to listening to acars, PMR446 comms, etc etc.. as quickly as i can turn the dial.

In a while I plan on making a small high gain antenna to mount on a small motorised telescope bought from Lidl last year - to see if I can successfully pick up AMSAT comms - and I assure you that it will be the little R20 on the end of the cable.

One can do a lot on a budget if they’re resourceful

Anyway, that’s my 2 cents

Evol

AIS is a global system. It is mandatory on passenger ships and all larger boats from 1st of July 2003. During the years to follow, successively smaller and smaller ships will be required to carry an AIS transponder.

AIS uses two channels (VHF 161.975 and 162.025 MHz) that have been reserved worldwide for this purpose. The modulation type is GMSK (Gaussian Minimum Shift Keying) and the data speed is 9600 bps. It is not easy to distinguish the AIS transmissions from the background noise — they sound the same and the data bursts last only 30 ms. Perhaps the simplest way to tell if you receive anything is to look at your S-meter needle, or adjust the squelch so you can hear it go on and off.

In order to decode the data you will need a scanner tuned into either frequency and a copy of shipplotter.

	Shipplotter on an icom 1000
	shipplotter on an icom 1500
	Dublin Harbour

In order to plot the ships to google earth do the following:
- Run shipplotter.
- Open Google Earth.
- File/Open , select google_ships.kml

For further information visit the great tutorial by Ais Greece.

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