EN300220-3 - Radiometrix Ltd - Datasheet.Directory

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 1

Features

• Conforms to EN 300 220-3 and EN 301 489-3 (10mW version only)

• Standard frequency 151.300MHz

• Other frequencies from 120MHz to 180MHz

• Available separately as BiM1T transmitter and BiM1R receiver

• TX1H is a BiM1T in TX1 pin-out

• Data rates up to 10kbps for standard module

• Usable range over 10km

• Fully screened

• Feature-rich interface (RSSI, analogue and digital baseband

• Low power requirements

The BiM1 is a half duplex radio transceiver module for use in long range bi-directional data transf er

applications at ranges up to 10kilometres. The module operates on the UK licence exempt frequency of

173.225/173.250MHz with 10mW RF output and Australian frequency of 151.300MHz with 100mW RF

output. The small footprint of 23 x 33mm and low profile of 10mm together with low power

requirements of <80mA (for 100mW) at 3.8V enables convenient PCB installation. BiM1 is also

available as separate BiM1T transmitter and BiM1R receiver which can be used as dual-in-line

equivalents of TX1 transmitter and RX1 receiver respectively.

Applications

• EPOS equipment, barcode scanners

• Data loggers

• Industrial telemetry and telecommand

• In-building environmental monitoring and control

• High-end security and fire alarms

• DGPS systems

• Vehicle data up/download

Technical Summary

• Size: 33 x 23 x 10mm

• Operating frequency: 151.300MHz

• Supply range: 100mW Transmitter 3.8V - 15V, Receiver: 3.0V-15V

• Supply range: 10mW Transmitter 3.0V - 15V, Receiver: 3.0V-15V

• Current consumption: 80mA transmit @ 100mW, 8mA receive

• Data bit rate: 10kbps max. (standard module)

• RSSI output with >60dBm range

• 10kbps, -120dBm sensitivity (for 12 dB SINAD)

The BiM1 transceiver modules offer a

100mW RF output VHF data link in

adiometrix transceiver standar

in-out and footpri nt. This makes the

iM1 ideally suited to those low

ower applications where existing

wideband transceivers provide

insuffic ient range.

Radiometrix

Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP , England

Issue 3, 14 September 2007 BiM1, TX1H

NEW

Tel: +4 4 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233

VHF Narrow Band F M transceiver

VHF Narrow Band F M transceiverVHF Narrow Band F M transceiver

VHF Narrow Band F M transceiver

Figure 1: BiM1-151. 300-1

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 2

BiM1 transceiver contains BiM1T transmitter circuit and BiM1R receiver circuit with their

RF output and input connected to a common RF pin via an internal RF switch.

TX1H transmitter circuit is the BiM1T transmitter circuit in the TX1 pin-out with slightly

enlarged dimension to accommodate extra Power Amplifier circuit to produce 100mW RF

output.

Figure 3: TX1H block diagram

Figure 2: BiM1-151.300-1

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 3

Functional description

The transmit section of the BiM1 consists of a frequency modulated Voltage Controlled Crystal

Oscillator (VCXO) feeding a frequency doubler with two stage amplifier and RF filter. Final Power

Amplifier stag e i s f actory p re -se t to ap pr op riate band po we r lev el. O peratio n is co n trolle d by a Tx Se le ct

line, the transmitte r achie ving full RF ou tput typ ically w ithin 5ms o f thi s line bein g pulle d low . The RF

output is filtered to ensure compliance with the appropriate radio regulations and fed via a fast Tx/Rx

changeover switch to the 5 0Ω antenna pin.

The receive section is a double conversion FM superhet with IF at 21.4MHz and 455kHz fed by a Low

Noise Amplifier (LNA) on the RF front-end. The receiver is controlled by RX Select line and will power

up typically <2ms. Quadrature detector output is available as Audio Frequency (AF) output and

transmitted digital data is regenerated from AF using adaptive data slicer. A Received Signal Strength

Indicator (RSSI) output with some 60dB of range is provided.

User interface

0 Volt

Vcc

RX select

TX select

TXD

RXD

RSSI

0 Volt

RF GND

Antenna

RF GND

0 Volt

No pin

33 mm

30.48 mm

23 mm

10 mm

side view (through can)

top view (without can)

side view (with can)

recommended PCB hole size: 1.2 mm

module footprint size: 25 x 32 mm

pin pitch: 2.54 mm

pins 4, 5, 6, 7 & 8 are not fitted

Figur e 4: BiM1 pin-o ut and dimension

7 holes of 0.7 mm dia.

pin spacing 2.54 mm

123 456

5mm

43mm

14.5mm

15.24 mm

pin spacing:

2.54 mm

1 = RF gnd

2 = RF out

3 = RF gnd

4 = En

5 = Vcc

6 = 0V

7 = TXD

TX1H

Figure 5: TX1H pin -out and dimension

Weight: 11g (BiM1), 5g (TX1H)

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 4

BiM1 Pin TX1H pin Name Function

1, 3, 9, 10, 18 1, 3, 6 0V Ground

17 5 VCC 3.8 – 15V DC power supply

RX Pull low to enable Receiver

EN Pull low to enable Transmitter

Pull high to enable Transmitter

14 7 TXD

DC coupled input for 3V CMOS logic. R

= 100kΩ

13 - AF 500mV

pk-pk

audio. DC coupled, approx 0.8V bias

12 - RXD Received Data output from the internal data slicer. Output will have

a rail to rail output swing (i.e. 0 -Vcc depending on the supply

voltage). Suitable for Biphase codes

11 - RSSI DC level between 0.5V and 2V. 60dB dynamic range

NOTES:

1. RX and TX have internal (10kΩ approx.) pull-up to Vcc

2. EN pin should not be left floating

3. For Vcc greater than 9V, transmit duty cycle must be limited to 25% or less

4. Avoid RX and TX both low: undefined module operation (but damage will not result)

5. A 10mW UK version is available on 173.225MHz. (3-16V operation, 10mA TX)

6. Pin out is as BiM2. On RF connector end only pins 1, 2, 3, 9 are present.

Absolute maximum rating s

Exceeding the values given below may cause permanent damage to the module.

Operating temperature -10°C to +60°C

Storage temperature -30°C to +70°C

RF in (pin 1) ±50V @ <10MHz, +13dBm @ >10MHz

All other pins -0.3V to +16.0V

Performance specifications:

(Vcc = 3.8V / temperature = 20

C unless stated)

General pin min. typ. max. units notes

DC supply

Supply voltage (100mW BiM1T) 17 3.8 - 15 V

Supply voltage (10mW BiM1T, BiM1R) 17 3.0 - 16 V

TX Supply current (100mW) 17 80 mA

TX Supply current (10mW) 17 25 mA

RX Supply current 17 8 mA

Antenna pin impedance 2 50 Ω

RF centre frequency (100mW) 151.300 MHz

RF centre frequency (10mW) 173.225 MHz

Channel spacing 25 kHz

Number of channels 1

Transmitter

RF power output (100mW) 2 +19 +20 +21 dBm 1

RF power output (100mW) 2 +9 +10 +11 dBm 1

Spurious emissions (100mW) 2 -40 dBm

Spurious emissions (10mW) 2 EN 300 220-3 dBm 2

Adjacent channel TX power (100mW) -37 dBm

Adjacent channel TX power (10mW) TBD 2

Frequency accuracy -2.5 0 +2.5 kHz 3

FM deviation (peak) ±2.5 ±3.0 ±3.5 kHz 4

Baseband

Modulation bandwidth @ -3dB 0 5 kHz

TXD input level (logic low) 14 0 V 5

TXD input level (logic high) 14 3.0 V 5

Dynamic timing

TX select to full RF 5 ms

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 5

General pin min. typ. max. units notes

Receiver

RF/IF

RF sensitivity @ 12dB SINAD 2, 13 -120 dBm

RF sensitivity @ 1ppm BER 2, 12 -115 dBm

RSSI threshold 2, 11 -127 dBm

RSSI range 2, 11 60 dB

IF bandwidth kHz

Blocking 2 85 dB

Image rejection 2 60 dB

Adjacent channel rejection 2 70 dB 2

Spurious response reject ion 2 65 dB

LO leakage, conducted -70 dBm 3

LO leakage, radiated -60 dBm 3

Baseband

Baseband ban dw idth @ -3d B 13 5 kHz

AF level 13 400 mV

P-P

DC offset on AF out 13 0.8 V

Distortion on recovered AF 12 TBD %

Load capacitance, AF / RXD 12,13 TBD pF

Dynamic timing

Power up with signal present

Power up to valid RSSI 16, 11 TBD ms

Power up to stable AF output 16, 13 2

Power up to stable RXD output 16, 12 10 ms

Signal applied wit h supply on

Signal to valid AF 2, 11 TBD ms

Signal to stable data 2, 12 TBD ms

Time between data transitions 12 0.1 ms 8

Mark : space ratio 12 20 50 80 % 8

Notes:

1. Measured into 50Ω resistive load.

2. Exceeds EN/EMC requirements at all frequencies.

3. Total over full supply and temperature range.

4. With 0V – 3.0V modulation input.

5. To achieve specified FM deviation.

6. See applications information for further details.

7. For received signal with ±3kHz FM deviation .

8. For 50:50 mark to space ratio (i.e. squarewave).

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 6

Applications information

Power sup ply requirements

The BiM1 have built-in regulators which deliver a constant 3.5V to the transmitter (100mW) and 2.8V

to the receiver circuitry when the external supply voltage is 3.8V or greater. This ensures constant

performance up to the maximum permitted rail, and removes the need for external supply decoupling

except in cases where the supply rail is extremely poor (ripple/noise content >0.1V

p-p

TX modulation requi rements

The module is factory-set to produce the specified FM deviation with a TXD input to pin 14 of 3V

amplitude, i.e. 0V “low”, 3V “high

If the data input level is greater than 3V, a resistor must be added in series with the TXD input to limit

the modulating input voltage to a maximum of 3V on pin 7. TXD input resistance is 100kΩ to ground,

giving typical required resistor values as follows:

Vcc Series resistor

≤3V

3.3V

10 kΩ

68kΩ

220kΩ

Reducing the output power of the BiM1

If the BiM1 is to be used for applications for which the regulatory Effective Radiated Power (ERP) limit

is lower than 100mW its output power can be reduced to comply with relevant regulatory requirements.

This is done by inserting a 10dB attenuator network between the module and the antenna or feed, as

follows:

68R

100R

To antenna

100R

68R

ground foil/

vias to ground plane

50 ohm microstrip lines

to antenna from TX1

schemati c diagram physical arrangement

Resistors are SMD (0603/0805)

Antenna

RF Ground

Figure 6: 10 dB attenuato r for BiM1 transceiver, BiM1T trans mitter

Keep all tracking around the attenuator network as short as possible, parti cularly ground paths, and

use matched 50Ω microstrip lines for input and out put connections (track width of 2.5mm if using

1.6mm thick FR4 PCB).

However, this 10dB attenuator will also reduce the sensitivity of the BiM1 transceiver by 10dB.

RF output can also be factory set from +5dBm (3mW) to +20dBm (100mW) depending on minimum

order quantity.

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 7

RX Received Signal Strength Indicator (RSSI)

The BiM1 wide range RSSI which measures the strength of an incoming signal over a range of 60dB or

more. This allows assessment of link quality and available margin and is useful when performing range

tests.

The output on pin 11 of the module has a standing DC bias of up to 0.5V with no signal, rising to 2.4V

at maximum indication. ∆V

min-max

is typically 1V and is largely independent of standing bias variations.

Output impedance is 56kΩ. Pin 11 can drive a 100µA meter directly, for simple monitoring.

Typical RSSI characteristic is as shown below:

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.8

2.2

2.4

-140

-135

-130

-125

-120

-115

-110

-105

-100

-95

-90

-85

-80

-75

-70

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

RF L e ve l (d Bm )

RSSI (V)

Figure 7: RSSI level with respect to rec eived RF level at BiM1 antenna pin

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 8

Packet data

In general, data to be sent via a radio link is formed into a serial "packet" of the form :-

Preamble - Control - Address - Data - CRC

Where: Preamble: This is mandatory for the adaptive data slicer in the receiver in the BiM1 to

stabilise. The BiM1 will be stable after 10ms. Additional preamble time may be

desired for decoder bit synchronisation, firmware carrier detection or receiver

wake up.

Control: The minimum requirement is a single bit or unique bit pattern to

indicate the start of message (frame sync.). Additionally, decoder

information is often placed here such as: packet count, byte count, flow

control bits (e.g. ACK, repeat count), repeater control, scrambler

information etc.

Address: This information is used for identification purpos es and would at least

contain a 16/24 bit source address, additionally - destination address,

site / system code , unit number and repeater address's may be placed

here.

Data: User data , generally limited to 256 bytes or less (very long packets

should be avoided to minimise repeat overheads on CRC failure and

channel hogging).

CRC: 16/24 Bit CRC or Checksum of control-address-data fields used by the

decoder to verify the integrity of the packet.

The exact makeup of the packet depends upon the system requirements and may involve some complex

air-traffic density statistics to optimise through-put in large networked systems.

Networks

BiM1’s may be used in many different configurations from simple pair's to multi-node random access

networks. The BiM1 is a single frequency device thus in a multi node system the signalling protocol

must use Time Division Multiple Access (TDMA). In a TDMA network only one transmitter may be on

at a time, ‘clash’ occurs when two or more transmitters are on at the same time and will often cause

data loss at the receivers. TDMA networks may be configured in several ways - Synchronous (time

slots), Polling (master-slave) or Random access (async packet switching e.g. X25). Networked BiM1's

allow several techniques for range / reliability enhancement:

Store and forward Repeaters: If the operating protocol of the network is designed to

allow data path control then data may be routed via

intermediate nodes. The inclusion of a repeating

function in the network protocol either via dedicated

repeater/router nodes or simply utilising existing

nodes allows limitless network expansion.

Spatial Diversity: In buildings multi-path signals create null spots in the

coverage pattern as a result of signal cancellation. In

master-slave networks it is cost effective to provide 2

BiM1's with separate antenna at the master station.

The null spot patterns will be different for the two

BiM1's . This technique ‘fills in’ the null spots, i.e. a

handshake failure on the first BiM1 due to a signal null

is likely to succeed on the 2nd BiM1.

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 9

"RS232" Se rial data

It is possible to transmit "RS232" serial data directly at 600 to 9600bps baud between a pair of BiM1

transceivers in half duplex mode. The data must be "packetised" with no gaps between bytes. i.e. The

data must be preceded by >1 0ms of preamble (55h or AAh) to allow the data slicer i n the BiM1 to settle,

followed by one 00h and one FFh bytes to allow the receive UART to lock, followed by a unique start of

message byte, (01h), then the data bytes and finally terminated by a CRC or check sum. The receiver

data slicer provides the best bit error rate performance on codes with a 50 :50 mark:space average over a

5ms period, a string of FFh or 00h is a very asymmetric code and will give poor error rates where

reception is marginal. Only 50:50 codes may be used at data rates above 1kbps.

We recommend 3 methods of improving mark:space ratio of serial codes, all 3 coding methods are

suitable for transmission at 10kbps:-

• Method 1 - Bit coding

Bit rate , Max 10kbps , Min 250bps

Redundancy (per bit) 100% (Bi-phase)

Each bit to be sent is divided in half, the first half is the bit to be sent and the second

half, it's compliment. Thus each bit has a guaranteed transition in the centre and a

mark:space of 50:50 . This is Bi-phase or Manchester coding and gives good results,

however the 100% redundancy will give a true throughput of 5kbps.

Another variation of this code is to encode a ‘1’ as a long bit with one transition and ‘0’

as a short bit with two transition or vice versa. Each encoded bit starts with a

guaranteed transition to reverse the voltage level even if stream of 00h/FFh is encoded.

This is called Differential Manchester Encoding. This encoding method is easier to

decode as the decoder has to sample encoded bit several times and if the sample value is

more than 75% of a long bit period, then it is decoded as ‘1’ and if there was transition

then it is decoded as ‘0’ or vice versa.

• Method 2 - FEC coding

Bit rate , Max 10kbps, Min 2.4kbps

Redundancy (per byte) 100%

Each byte is sent twice; true then it's logical compliment. e.g. even byt es are true and

odd bytes are inverted. This preserves a 50:50 balance.

A refinement of this simple balancing method is to increase the stagger between the

true and the inverted data streams and add parity to each byte. Thus the decoder may

determine the integrity of each even byte received and on a parity failure select the

subsequent inverted odd byte. T he greater the stagger the higher the immunity to

isolated burst errors.

Digitised analogue data

Linear operation of BiM 1 transceivers will allow direct transfer of analogue data, however in many

applications the distortion and low frequency roll off are too high (e.g. bio-medical data such as ECG).

The use of delta modulation is an excellent solution for analogue data in the range 1Hz up to 4kHz with

less than 1% distortion. A number of propitiatory IC's

such as Motorola's MC3517/8 provide CVSD Delta mod/demod on a single chip.

Where the signal bandwidth extends down to DC , such as strain gauges, level sensing, load cells etc.

then Voltage to Frequency / Frequency to Voltage chips (such as Nat Semi LM331) provide a simple

means of digitising.

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 10

Expected range

Predicting the range obtainable in any given situation is notoriously difficult since there are many

factors involved. The main ones to consider are as follows:

• Type and location of antennas in use

• Type of terrain and degree of obstruction of the link path

• Sources of interference affecting the receiver

• “Dead” spots caused by signal reflections from nearby conductive objects

• Data rate and degree of filtering employed

The following are typical examples – but range tests should always be performed before assuming that

a particular range can be achieved in a given situation:

Data rate Tx antenna Rx antenna Environment Range

1.2kbps half-wave half-wave rural/open 10-15km

10kbps half-wave half-wave rural/open 3-4km

10kbps helical half-wave urban/obstructed 500m-1km

10kbps helical helical in-building 100-200m

Note: The figure for 1.2kbps assumes that the receiver bandwidth has been suitably reduced by

utilising an outboard sallen-key active audio filter and data slicer or similar arrangement.

The BiM1 TXD input is normally driven directly by logic levels but will also accept analogue drive (e.g.

2-tone signalling). In this case it is recommended that TXD (pin 14) be DC-biased to 1.2V approx. with

the modulation ac-coupled and limited to a maximum of 2V

p-p

to minimise distortion over the link. The

varactor modulator in the BiM1 intr oduces some 2

harmonic distortion which may be reduced if

necessary by predistortion of the analogue waveform. At the other end of the link the BiM1 RX D output

is used to drive an external decoder directly.

Although the modulation bandwidth of the BiM1 extends down to DC it is not advisable to use data

containing a DC component. This is because frequency errors and drifts between the transm itter and

receiver occur in normal operation, resulting in DC offset errors on the BiM1 audio output.

The BiM1 in standard form incorporates a low pass filter with a 5kHz nominal bandwidth. This is

suitable for transmission of data at raw bit rates up to 10kbps.

In applications such as long range fixed links where data speed is not of prime concern, a considerable

increase in range can be obtained by using the slowest possible data rate together with filtering to

reduce the receiver bandwidth t o the minimum necessary.

Antennas

The choice and positioning of transmitter and receiver antennas is of the utmost importance and is the

single most significant factor in determining system range. The following notes are intended to assist

the user in choosing the most effective antenna type for any given application.

Integral antenn as

These are relatively inefficient compared to the larger externally-mounted types and hence tend to be

effective only over limited ranges. They do however result in physically compact equipment and for this

reason are often preferred for portable applications. Particular care is required with this type of

antenna to achieve optimum results and the following should be taken into account:

1. Nearby conducting objects such as a PCB or battery can cause detuning or screening of the antenna

which severely reduces efficiency. Ideally the antenna should stick out from the top of the product

and be entirely in the clear, however this is often not desirable for practi cal/ergonomic reasons and

a compromise may need to be reached. If an internal antenna must be used try to keep it away from

other metal components and pay particular attention to the “hot” end (i.e. the far end) as this is

generally the most susceptible to detuning. The space around the antenna is as important as the

antenna itself.

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 11

2. Microprocessors and microcontroll ers tend to radiate signi ficant amounts of radio frequency hash

which can cause desensitisation of the receiver if its antenna is in close proximity. The problem

becomes worse as logic speeds increase, because fast logic edges generate harmonics across the VHF

range which are then radiated effectively by the PCB t racking. In ext reme cases system range may

be reduced by a factor of 5 or more. To minimise any adverse effects situate antenna and module as

far as possible from any such circuitry and keep PCB track lengths to the minimum possible. A

ground plane can be highly effecti ve in cutting radiated interference and its use is strongly

recommended.

A simple test for interference is to monitor the receiver RSSI output voltage, which should be the same

regardless of whether the microcontroller or other logic circuitry is running or in reset.

The following types of integral antenna are in common use:

Quarter-w ave whip. This consists simply of a pi ece of wire or rod connected to the module at one end.

At 151MHz the total length should be 471mm from module pin to antenna tip including any

interconnecting wire or tracking. Because of the length of this antenna it is almost always external to

the product casing.

Helical. This is a more compact but slightly less effective antenna formed from a coil of wire. It is very

efficient for its size, but because of its high Q it suffers badly from detuning caused b y proximity to

nearby conductive objects and needs to be carefully trimmed for best performance in a given situation.

The size shown is about the maximum commonl y used at 151MHz and appropriate scaling of length,

diameter and number of turns can make individual designs much smaller.

Loop. A loop of PCB track having an inside area as large as possible (minimum about 5cm

), tuned and

matched with 2 capacitors. Loops are relatively inefficient but have good immunity to proximity

detuning, so may be preferred in shorter range appli cations where high component packing density is

necessary.

Integral antenna summary:

whip helical loop

Ultimate performance *** ** *

Ease of design set-up *** ** *

Size * *** **

Immunity to proximity effects ** * ***

Helical antenna

Loop antenna

RF GND

tune

match

capacitors may be variable or fixed

(values depend on loop dimensions)

track width = 1mm

min. area 500mm

Whip antenna

471mm @ 151MHz

wire, rod, PCB track

or a combination of these

length(mm) = 71250 / freq(MHz)

trim wire length or expand coil

for best results

35-40 turns wire spring

length 120mm, dia 10mm

Figure 8: integral antenna configurations

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 12

Extern al anten n as

These have several advantages if portability is not an issue, and are essential for long range links.

External antennas can be optimised for individual circumstances and may be mounted in relatively

good RF locations away from sources of interference, being connected to the equipment by coax feeder.

Helical. Of similar dimensions and performance to the integral type mentioned above, commercially-

available helic al antennas normally have the coil element protected b y a plastic moulding or sleeve and

incorporate a coax connector at one end (usually a straight or right-angle BNC type). These are compact

and simple to use as they come pre-tuned for a given application, but are relatively inefficient and are

best suite d to sh or te r ranges.

Quarter-w ave whip. Again similar to the integral type, the element usually consists of a stainless

steel rod or a wire conta ined within a semi-flexible moulded plas tic jacket. Various mounting options

are available, from a simple BNC connector to wall brackets, through-panel fixings and magnetic

mounts for temporary attachment to steel surfaces.

A significant improvement in performance is obtainable if the whip is used in conjunction with a metal

ground plane. For best results this should extend all round th e base of the whip out to a radius of

300mm or more (under these conditions performance approaches t h at of a half-wave dipole) but even

relatively small metal areas will produce a worthwhile improvement over the whip alone. The ground

plane s hould be electrically connected to the coax outer at the base of the whip. Magnetic mounts are

slightly different in that they rely on capacitance between the mount and the meta l surface to a chieve

the same result.

A ground plane can also be simulated by using 3 or 4 quarter-wave radials equally spaced around the

base of the whip, connected at their inner ends to the outer of the coax feed. A better match to a 50Ω

coax feed can be achieved if the elements are angled downwards at approximately 30-40° to the

horizontal.

Fig.9: Quarter wave an tenna / ground plane c onfig uratio ns

Half-wave. There are two main variants of this antenna, both of which are very effective and are

recommended where long range and all-round coverage are required:

1. The half-wave dipole consists of two quarter-wave whips mounted in line vertically and fed in the

centre with coaxial cable. The bottom whip takes the place of the ground plane described previously.

A variant is available using a helical instead of a whip for the lower element, giving similar

performance with reduced overall length. This antenna is suitable for mounting on walls etc. but for

best results should be kept well clear of surrounding conductive objects and structures (ideally >1m

separation).

2. The end-fed half wave is the same length as the dipole but consists of a single rod or whip fed at the

bottom via a matching network. Mounting options are similar to those for the quarter-wave whip. A

ground plane is sometimes used but is not essential. T h e end-fed arrangement is often preferred

over the centre-fed dipole because it is easier to mount in the clear and above surrounding

obstructions.

Ω

coax feed

Metal ground plane

Ω

coax feed

30-40deg.

(3-4, equally sp a ced)

1/4-wave radial elements

1/4-wave

whip

(471m m long @ 15 1MHz)

1/4-wave whi p

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 13

Yagi. This antenna consists of two or more elements mounted parallel to each other on a central boom.

It is directional and exhibits gain but tends to be large and unwieldy – for these reasons the yagi is the

ideal choice for links over fixed paths where ma ximum range is desired.

Please note: Using a Yagi or other gain antenna with the BiM1 will exceed the maximum radiated

power permitted by UK type approval regulations. It can be used in the UK only in conjunction with the

BiM1R receiver.

For best range in UK fixed link applications use a half-wave antenna on BiM1T transmitter and a half-

wave or Yagi on BiM1R receiver, both mounted as high as possible and clear of obstructions.

Module mounting considerations

Good RF la yout practice should be observed. If the connection between module and antenna is more

than about 20mm long use 50Ω microstrip line or coax or a combination of both. It is desirable (but not

essential) to fill all unused PCB area around the module with ground plane.

Variants and ordering information

The BiM1 transceiver is manufactured in the following variants as standard:

For Australian general applications on 151.300MHz

TX1H-15 1.3 00-10 Trans mit te r

BiM1T-151.300-10 Transmitter

BiM1R-151.300-10 Receiver

BiM1-151.300-10 Transceiver

For UK alarm applications on 173.225MHz:

BiM1-173.225-10 Transmitter

BiM1-173.225-10 Receiver

BiM1-173.225-10 Transceiver

For UK general applications on 173.250MHz:

BiM1-173.250-10 Transmitter

BiM1-173.250-10 Receiver

BiM1-173.250-10 Transceiver

Other variants can be supplied to individual customer requirements at frequencies from 151.300MHz to 173.250MHz

and/or optimised for specific data speeds and formats. However these are subject to minimum order quantity (MOQ)

and long lead time. Please consult the Sales Department for further information.

Some of the non-standard frequencies readily available. i.e. no MOQ or long lead time, are as follows:

Part number: BiM1-xxx.xxx-10 (where xxx.xxx is the operating frequency)

Frequency (MHz) Type approval Note Frequency (MHz) Type approval Note

138.125 - 1, 2, 3 157.420 Yes 1, 2

149.170 - 1, 2, 3 159.685 Yes 1, 2

151.275 - 1, 2, 3 159.6875 Yes 1, 2

151.300 Yes 1, 2 161.975 Yes 1, 2

151.775 Yes 1, 2 162.025 Yes 1, 2

152.175 Yes 1, 2 162.975 Yes 1, 2

152.500 Yes 1, 2 163.000 Yes 1, 2

152.575 Yes 1, 2 164.525 Yes 1, 2

152.650 Yes 1, 2 167.420 Yes 1, 2

152.850 Yes 1, 2 169.435 Yes 1, 2

153.8125 Yes 1, 2 169.41875 Yes 1, 2

153.9125 Yes 1, 2 172.420 Yes 1, 2

153.925 Yes 1, 2 173.075 Yes 1, 2

154.463 Yes 1, 2 173.175 Yes 1, 2

155.475 Yes 1, 2 173.200 Yes 1, 2

155.715 Yes 1, 2 173.960 Yes 1, 2, 3

Radiometrix Ltd., BiM1 transceiver, TX1H high power transmitter data sheet Page 14

155.725 Yes 1, 2 180.175 - 1, 2, 3

Note 1: Complies with the ETSI standards but NOT approved

2: For specialised application, NOT for general purpose

e.g: 121.500MHz is an international distress frequency

3: NOT a European Harmonised frequency. Consult local radio regulatory authority.

Type approval

The BiM1-173 module is meets European harmonised standard ETSI EN 300 220-3 for UK u se within

the following categories:

(a) General applications in the band 173.2-173.35MHz but excluding 173.225MHz.

(b) Industrial/commercial applications at the same frequencies as category (a).

(d) Medical/biological applications (including airborne use for the tracking of birds) in the band 173.7-

174.0MHz.

REQUIREMENTS FOR CONFORMANCE TO ETSI EN 300 220-3:

1. Transmitted ERP (effective radiated power) must not exceed the limit of 1mW (0dBm) for category

(a) or 10mW (+10dBm) for categories (b), (c) and (d). Equipment in category (a) must include a 10dB

attenuator between the RF output pin and the antenna or feed, as specified on page 6 of this leaflet.

2. Any type of antenna system may be employed provided that the applicable ERP limit is not exceeded

- i.e. transmitting antenna structures which exhibit ERP gain (such as yagis) are not permitted. See

pages 10-13 of this leaflet for details of suitable antennas.

3. The module must not be modified or used outside its specification limits.

4. The module may only be used to transmit digital or digitised data. Speech and/or music are not

permitted.

Breaching any of these conditions will inva lidate t y pe app r oval.

Radiometrix Ltd

Hartcran House

231 Kenton Lane

Harrow, Middlesex

HA3 8RP

ENGLAND

Tel: +44 (0) 20 8909 9595

Fax: +44 (0) 20 8909 2233

sales@radiometrix.com

www.radiometrix.com

This product data sheet is the original work and copyrighted property of Radiometrix Ltd. Reproduction in whole or in

part must give clear acknowledgement to the copyright owner.

Limitation of liability

The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the

right to make changes or improvements in the design, specification or manufacture of its subassembly products without

notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or circuit

described herein, nor for any infringements of patents or other rights of third parties which may result from the use of

its products. This data sheet neither states nor implies warranty of any kind, including fitness for any particular

application. These radio devices may be subject to radio interference and may not function as intended if interference is

present. We do NOT recommend their use for life critical applications.

The Intrastat commodity code for all our modules is: 8542 6000

R&TTE Directive

After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of the R&TTE

Directive. Equipment within the scope o f the R&TTE Dire ctive may demonstr ate compliance to the essential

requirements specified in Article 3 of the Directive, as appropriate to the particular equipment.

Further details are available on The Office of Communications (Ofcom) web site:

http://www.ofcom.org.uk/radiocomms/ifi/

Information Requests

Ofcom

Riverside House

2a Southwark Bridge Road

London SE1 9HA

Tel: +44 (0)845 456 3000 or 020 7981 3040

Fax: +44 (0)20 7783 4033

information.requests@ofcom.org.uk

European Radiocommunications Office (ERO)

Peblingehus

Nansensgade 19

DK 1366 Copenhagen

Tel. +45 33896300

Fax +45 33896330

ero@ero.dk