> | You might want to consider hybrid RF modules.  I'm not sure about the
> | US, but the UK has parts of 418 MHz, 433 MHz, and 458 MHz allocated
> | for low power devices.  You can get approved modules (by the DTI in
> | the UK) which do not require a license.
> |
> | Some of these quote a 100m range, whicle others quote 1000m.  The bit
> | rates vary between 2 Kbps to 10Kbps.
>
> Do these devices handle analoge signals ? If you have specs or an adress where
 i
>  could
> get more info on these devices i would be very pleased.

Here is some info:

Note, 433MHz is designated for automotive applications.

Farnell see http://www.farnell.co.uk/ for outlets and
ordering/catalogues etc:

Products by RF Solutions

AM TX module (ultra miniture)
Supply 3-12V
Current 25mA (when TX)
Freq 418MHz
Range 100m (max)
Temp -10 to +40 C
License DTI approved
Can be driven from TTL/CMOS source
Price 15.24 UKP (ex VAT @ 17.5%)

AM RX modules
Supply 5V
Current 2.5mA
Freq 418 or 433MHz (different modules)
RF sens -105dBm
Temp -25 to +85 C
CMOS/TTL compatible O/P
Data rate 2Kbps
Price 15.24 UKP (ex VAT @ 17.5%)

FM TX modules

Supply 6-9V
Current 6mA@6V, 14mA@12V
Power (ERP) 10dBm@6V, 8dBm@9V, 6dBm@12V
Freq 418 or 433MHz (different modules)
Range 200m
Temp -10 to +55 C
License DTI approved
Analogue and digital inputs
Data rate 10Kbps
Price 14.50 UKP (ex VAT @17.5%)

FM RX modules (to match with above)

Supply 4.5-9V
Current 14mA
Freq 418MHz or 433MHz (different modules)
Range 200m
Temp -10 to +55 C
Analogue and digital outputs
Data rate 10Kbps
Price 29.95 UKP (ex VAT@17.5%)

FM Transceiver module

Supply 5V
Current 12mA
Power (ERP) -6dBm
Freq 418MHz or 433MHz (different modules)
Range 30m (in buildings) 120m (line of sight)
Temp -20 to +55 C
License DTI approved
Price 58.00 UKP (ex VAT@17.5%)

AM or FM key fobs are available.

Receivers which can learn upto 16 unique codes are available for use
with key fob systems for multi purpose control applications.

RS see http://www.rs-components.com/rs/ for catalogues, ordering and
service points etc:

Data sheets are available basically free of charge.

FM TX

Freq 458.650MHz
Freq response 100Hz to 3KHz
Baud 1200 to 2400 (RS232 inc start + stop bits) upto 4800 (data)
Temp -10 to +60 C
Power 10mW
Freq stabilty < +/- 2.5KHz
Spurious emissions 70dB at O/P
Modulation FM narrow band
Data input for CMOS/TTL
Supply 5.5-10V
Current 18mA (25mA max)
Weight 9.8g
Antenna L/4 whip
Range 1000m
License DTI approved
Price 90.00 UKP (ex VAT@17.5%)

FM RX (to match with above)

Freq 458.650MHz
Freq response 100Hz to 3KHz
Baud 1200 to 2400 (RS232 inc start + stop bits) upto 4800 (data)
Temp -10 to +60 C
Type double superhetrodyne
Sensitivity 0.2mV (typical) 0.3mV (max) (for 12dB SINAD)
Selectivity +/- 5KHz at -6dB point
Demodulation FM narrow band
Distortion < 5% at 1KHz
S/N ratio 50dB overall
Data output open collector (digital)
Other O/P's RSSI (field strength), AF (analogue O/P)
Supply 4.5-14V
Current 10mA (typical) 15mA(max)
Size and weight 50x30x7 19.3g
Range 1000m
Price 126.00 UKP (ex VAT@17.5%)

Ask for data sheet # 229-7358.

Hope this is useful.

Cheers, Ian.