RF Technology R220 User manual

Eclipse Series
RF Technology
[email protected]
November 2001
R220 Receiver
Operation and Maintenance Manual
This manual is produced by RF Technology Pty Ltd.,
10/8 Leighton Place, Hornsby, 2077, Australia, and is
Copyright ©2001, RF Technology
Part No. PCB 30/9132

Page 2 RF Technology R220
CONTENTS CONTENTS
Contents
1 Operating Instructions 5
1.1 Front Panel Controls and Indicators 5
1.1.1 Mon. Volume 5
1.1.2 Mon. Sq. 5
1.1.3 N. SQ 5
1.1.4 C. SQ 6
1.1.5 Line 6
1.1.6 PWR LED 6
1.1.7 SQ LED 6
1.1.8 Alarm LED 7
2 Receiver Internal Jumper Options 7
2.1 JP1: 240Hz Notch Filter 7
2.2 JP2: Audio Response 8
2.3 JP3: Audio Filter In/Out 8
2.4 JP4: 600ΩLine dc Loop COS 8
2.5 JP6: COS Polarity 8
2.6 JP7/8/9: dc Loop COS Configuration 8
2.7 JP7, JP8, JP9: Direct Output COS 9
2.8 JP11 EPROM Type 9
3 Receiver I/O Connections 11
3.1 25 Pin Connector 11
4 Channel and Tone Frequency Programming 12
5 Circuit Description 12
5.1 RF Section 12
5.2 IF Section 12
5.3 VCO Section 13
5.4 PLL Section 13
5.5 Audio Signal Processing 14
5.6 Noise Filter, Amplifier and Detector 14
5.7 Subtone Filter and CTCSS 14
5.8 External Squelch 15
5.9 Microprocessor Controller 15
5.10 Carrier Operated Switch 15
5.11 Voltage Regulator 16
6 Alignment Procedure 16
6.1 Standard Input Signal 16
6.2 RF Alignment 16
6.3 IF Alignment 17
6.4 Line Level Adjustment 18
6.5 Reference Oscillator Calibration 18

RF Technology R220 Page 3
CONTENTS CONTENTS
7 Specifications 18
7.1 General Description 18
7.1.1 Channel Capacity 18
7.1.2 CTCSS 18
7.1.3 Channel Programming 18
7.1.4 Channel Selection 19
7.1.5 Microprocessor 19
7.2 Physical Configuration 19
7.3 Front Panel Controls, Indicators and Test Points 19
7.3.1 Controls 19
7.3.2 Indicators 19
7.3.3 Test Points 20
7.4 Electrical Specifications 20
7.4.1 Power Requirements 20
7.4.2 Frequency Range and Channel Spacing 20
7.4.3 Frequency Synthesizer Step Size 20
7.4.4 Frequency Stability 20
7.4.5 Nominal Antenna Impedance 20
7.4.6 IF Frequencies 21
7.4.7 Sensitivity 21
7.4.8 Selectivity 21
7.4.9 Spurious and Image Rejection 21
7.4.10 Intermodulation 21
7.4.11 Modulation Acceptance BW 21
7.4.12 Noise Squelch 21
7.4.13 Carrier Level Squelch 22
7.4.14 Receiver Frequency Spread 22
7.4.15 Receiver Conducted Spurious Emissions 22
7.4.16 Audio Frequency Response 22
7.4.17 Audio Output Level 22
7.4.18 Audio Distortion 22
7.4.19 Channel Select Input/Output 22
7.4.20 Carrier Operated Switch Output 23
7.4.21 CTCSS 23
7.4.22 External Squelch Input 25
7.5 Connectors 25
7.5.1 Antenna Connector 25
7.5.2 Power and I/O Connector 25
7.5.3 Test Connector 25

Page 4 RF Technology R220
CONTENTS CONTENTS
BPartsList

RF Technology R220 Page 5
1 OPERATING INSTRUCTIONS
WARNING
Changes or modifications not expressly approved
by RF Technology could void your authority to
operate this equipment. Specifications may vary
from those given in this document in accordance
with requirements of local authorities. RF
Technology equipment is subject to continual
improvement and RF Technology reserves the right
to change performance and specification without
further notice.
1 Operating Instructions
1.1 Front Panel Controls and Indicators
1.1.1 Mon. Volume
The Mon. Volume control is used to adjust the volume of the internal loudspeaker
and any external speaker connected to the test socket. It does not effect the level of
the 600Ωline or direct audio output.
1.1.2 Mon. SQ.
The Mon. SQ. switch allows all squelch functions controlling the monitor output to
be disabled. When the switch is in the Mon. SQ. position the audio at the monitor
speaker is controlled by the noise detector. The CTCSS, carrier and external squelch
functions are disabled. This can be useful when you are trying to trace the source of
on-channel interference or when setting the noise squelch threshold. the audio from
the 600Ωline and direct outputs is not effected by the switch position.
1.1.3 N.SQ
The N.SQ trimpot is used to set the noise squelch sensitivity. Use the following
procedure to set the noise squelch to maximum sensitivity.
1. Set the toggle switch to the Mon. Sq. position and set the Mon. Volume control
to 9 o’clock.

Page 6 RF Technology R220
1.1 Front Panel Controls and Indicators 1.1 OPERATING INSTRUCTIONS
2. Turn the N. SQ. adjustment counter clockwise until the squelch opens and
noise is heard from the speaker. Adjust the VOLUME to a comfortable
listening level.
3. In the absence of any on channel signal, turn the N.SQ. screw clockwise until
the noise in the speaker is muted. Then turn the screw two additional turns in
the clockwise direction.
1.1.4 C.SQ
The C.SQ trimpot is used to set the carrier squelch sensitivity. Carrier squelch is
useful at higher signal levels than those at which noise squelch and can be used
typically from 1-200µV input.
It is provided mainly for use in fixed link applications where a high minimum signal
to noise ratio is required or where very fast squelch operation is required for data
transmission. The carrier squelch will open and close in less than 2 mSec.
In most base station applications carrier squelch is disabled by turning the adjustment
counter clockwise until the screw clicks.
The carrier squelch may be set to a predetermined level with the Techelp/Service
Monitor 2000 software or by using the following procedure:
1. First turn the adjustment fully counter-clockwise. Then set the noise
squelch as above.
2. Connect a source of an on channel signal with the desired threshold level to
the receiver's RF input.
3. Turn the screw clockwise until the SQ LED goes OFF. Then turn the screw
back until the LED just comes ON.
1.1.5 LINE
The LINE trimpot is used to set the line and direct audio output level. It is normally
set to give 0dBm (775mV) to line with a standard input signal equal to 60% of
maximum deviation at 1 KHz. The level can be measured between test socket pins 6
and 1 and set as desired.
1.1.6 PWR LED
The PWR LED shows that the dc supply is connected to the receiver.
1.1.7 SQ LED
The SQ LED comes on when the audio to the line and direct outputs is un-squelched.

RF Technology R220 Page 7
2 RECEIVER INTERNAL JUMPER OPTIONS
The LED and squelch function are controlled by noise, carrier and tone squelch
circuits.
1.1.8 ALARM LED
The ALARM LED can indicate the detection of several different fault conditions by
the self test circuits. The alarm indicator shows the highest priority fault present.
Receivers using software issue 5 and higher use the cadence of the LED flash
sequence to indicate the alarm condition. Refer to table 1.
LED Flash Cadence Fault Condition
5 flashes, pause Synthesizer unlocked
4 flashes, pause Tuning voltage outside limits
3 flashes, pause Signal level below preset threshold (fixed link)
1 flash, pause dc supply voltage low or high
LED ON continuously External squelch is active
Table 1: Interpretations of LED flash cadence
Receivers using software issue 4 and lower use the LED flash rate to indicate the
alarm condition. Refer to table 2.
Indication Fault condition
Flashing, 8 per second Synthesizer unlocked
Flashing, 4 per second Tuning voltage outside 2-7 Vdc
Flashing, 2 per second Signal level below preset threshold (fixed links)
Continuous dc supply voltage low or high
Table 2: Interpretations of LED flash speed, for early models.
2 Receiver Internal Jumper Options
In the following subsections an asterisk (*) signifies the standard (Ex-Factory)
configuration of a jumper.
2.1 JP1: 240 Hz Notch Filter
JP1 allows the 240Hz notch filter in the normal audio path to be bypassed.
Condition Position
Notch Filter In 1-2 *
Notch Filter Out 2-3

Page 8 RF Technology R220
2.2 JP2: Audio Response 2 RECEIVER INTERNAL JUMPER OPTIONS
2.2 JP2: Audio Response
Condition Position
750 uSec. de-emphasis 1-2 *
Flat response 2-3
2.3 JP3: Audio Filter In/Out
JP3 bypasses the 300Hz high-pass filter and 240Hz notch filter if necessary.
Condition Position
Hi-pass, Notch In 2-3 *
Flat response 1-2
2.4 JP4: 600Ω
ΩΩ
ΩLine dc Loop COS
JP4 allows the dc return path through the output audio transformer to be broken, to
permit dc signaling via the audio pair or wires.
Condition Position
dc Loop Configured by JP7, JP8, JP9 1-2 *
dc Loop Not used 2-3
2.5 JP6: COS Polarity
Condition Position
Active on Signal 2-3 *
Active on No Signal 1-2
2.6 JP7, JP8, JP9: dc Loop COS Configuration (JP4 1-2)
These settings are relevant when the Carrier Operated Switch (COS) signal is to be
used across the same wires as the audio. Refer to setting of JP4, in section 2.4. They
control the levels and connection into the audio balanced line circuitry.
Condition JP7 JP8 JP9
Source +12 Vdc Loop 2-3 ON 1-2 *
Free Switch Output 1-2 ON 2-3

RF Technology R220 Page 9
2 RECEIVER INTERNAL JUMPER OPTIONS 2.7 JP7/8/9 Direct Output COS
2.7 JP7, JP8, JP9: Direct Output COS (JP4 2-3)
In this arrangement, the COS signal is taken via the separate COS+ and COS-
outputs, either with free (floating) output or with +12Vdc pull-up.
Condition JP7 JP8 JP9
+12 Vdc Direct
Output 2-3 OFF OFF
Free Switch Output 1-2 OFF OFF
2.8 JP11 EPROM Type
Condition Position
27C256 2-3 *
27C64 1-2
* = Standard Ex-Factory Configuration

Page 10 RF Technology R220
2 RECEIVER INTERNAL JUMPER OPTIONS
RX PCB TX PCB
The Receiver and Transmitter modules plug into the back plane DB25/F
connectors
Miniature spade connectors (2.1 x 0.6 x 7mm) are captive/ soldered at the labelled
points.
To configure: Solder wire connections between appropriate points.
Receiver
DB25/F RX PCB DESCRIPTION TX PCB Transmitter DB25/F
1, 14 +12V +12V DC SUPPLY +12V 1, 14
2 TXD TX Data TXD 2
15 RXD RX Data RXD 15
3 COR+ Carrier Operate Sw+ PressToTalk input PTT 3
16 COR- Carrier Operate Sw- Tx/Rx output T/R 16
4 TONE Subtone output Hi Z audio input+ AUD+ 4
17 AUDIO Audio output Hi Z audio input- AUD- 17
5 AGND Audio Ground Ext tone input+ TONE+ 5
18 DISC Discriminator output Ext tone input- TONE- 18
6 LINE+ Line output+ Line input+ LINE+ 6
20 LINE- Line output- Line input- LINE- 20
8 EXT SQ Ext Squelch input Auto Level Control ALC 8
13, 25 GND Ground, 0V GND 13, 25
21 BCD 1 Channel select 1’s digit BCD 1 21
9 BCD 2 Channel select 1’s digit BCD 2 9
22 BCD 4 Channel select 1’s digit BCD 4 22
10 BCD 8 Channel select 1’s digit BCD 8 10
23 BCD 10 Channel select 10’s digit BCD 10 23
11 BCD 20 Channel select 10’s digit BCD 20 11
24 BCD 40 Channel select 10’s digit BCD 40 24
12 BCD 80 Channel select 10’s digit BCD 80 12

RF Technology R220 Page 11
3 RECEIVER I/O CONNECTIONS 3.1 25 Pin Connector
3 Receiver I/O Connections
3.1 25 Pin Connector
The D-shell 25 pin connector is the main interface to the receiver. The pin
connections are described in table 3.
Function Signal Pins Specification
dc Power +12
Vdc
-12
Vdc
1, 14
13, 25 +11.4 to 16 Vdc
Channel Select 1
2
4
8
10
20
40
80
21
9
22
10
23
11
24
12
BCD Coded
0 = Open Circuit
or 0 Vdc
1 = +25 to +16 Vdc
RS232 Data In
Out 15 2Test and Programming use 9600, 8 data 2 stop bits
600ΩLine In
Out 20 6Transformer Isolated Balanced 0dBm Output
150Ω/ Hybrid 7
19
Discriminator 18 AC coupled, unsquelched
Direct Audio Output 17 Direct AC Coupled Audio
Audio Ground 5 Direct Audio Ground
Sub-Audible Audio
Out 4 Unsquelched, 1-250 Hz
Carrier Operated Sw
Carrier Operated Sw + -3 16 Opto-coupled Transistor Switch (10mA)
External Squelch Input 8 <1 Vdc to Squelch
>2 Vdc or open ckt to
unsquelch
Table 3: Pin connections and explanations for the main, 25-pin,
D-shell Connector

Page 12 RF Technology R220
4 FREQUENCY PROGRAMMING
4 Frequency Programming
Channel and tone frequency programming is most easily accomplished with RF
Technology TecHelp/Service Monitor 2000 software. This software can be run on
an IBM compatible/Windows PC and provides a number of additional useful
facilities.
TecHelp/Service Monitor 2000 allows setting of the adaptive noise squelch
threshold, provides a simple means of calibrating the signal strength output and
minimum signal alarm.
TecHelp/Service Monitor 2000 can be supplied by your dealer, distributor or by
contacting RF Technology direct.
5 Circuit Description
The following descriptions should be read as an aid to understanding the block and
schematic diagrams at the rear of this manual.
5.1 RF Section
A two pole voltage tuned filter (D13, D14, L35-39) is used to limit the RF band
width prior to the RF amplifier transistor Q1. The tuning voltage is supplied by the
frequency synthesizer through voltage follower U28D. The circuit values are chosen
so that the centre frequency tracks the VCO frequency.
RF amplifier transistor Q1 is followed by a second two pole voltage tuned filter
(D15, D16, L28-32) which provides additional image and spurious frequency
rejection. The filter output is connected to the RF input port of the mixer MX1.
MX1 is a high level double balanced diode ring mixer with excellent intermodulation
performance. It has a conversation loss of approximately 6 dB. The gain between
the receiver input and the mixer input is approximately 10 dB so that the total gain
between the antenna input and the IF input 3-4dB.
Monolithic amplifiers MA1, MA2 and transistor Q5 amplify the VCO output to the
necessary LO level for MX1 approximately +13dBm.
The network C8, C9 L1-3 and R6 passes the IF frequency of 45 MHz and terminates
the RF and LO components.
5.2 IF Section
The first IF amplifier uses two parallel connected JFET transistors Q2 and Q3 to
obtain 8-10 dB gain. The two transistors provide improved dynamic range and input
matching over a single transistor.

RF Technology R220 Page 13
5 CIRCUIT DESCRIPTION 5.2 IF Section
A two pole 45 MHz crystal filter XF1 is used between the first and second IF
amplifiers. The second IF amplifier Q4 provides additional gain of 6-10dB. A two
pole crystal filter is used between Q4 and the 2nd oscillator mixer. These two crystal
filters provide some adjacent channel rejection and all of the second IF image
frequency rejection.
U1 is a monolithic oscillator and mixer IC. It converts the 45 MHz IF signal down to
455 KHz. The second oscillator frequency or 45.455 MHz is controlled by crystal
Y1. The 455 KHz output of the second mixer is fed through a ceramic filter CF1 to
the second IF amplifier transistor Q27. Q27 provides an additional 15 dB gain ahead
of the limiter and discriminator IC U3.
The limiter/discriminator IC U3 further amplifies the signal and passes it through
CF2. CF2 does not contribute to the adjacent channel rejection but is used to reduce
the wide band noise input to the limiter section of U3.
The limiter section of U3 drives the quadrature detector discriminator. C31 and IF
tuned circuit L10 comprise the discriminator phase shift network.
U3 also has a received signal strength indicator output (RSSI). The RSSI voltage
connects to the test socket for alignment use. The RSSI voltage is also used by the
microprocessor for the adaptive noise squelch, carrier squelch and low signal alarm
functions.
Dual op-amp U2 is used to amplify and buffer the discriminator audio and RSSI
outputs.
5.3 VCO Section
The Voltage Controlled Oscillator uses a junction FET Q6 which oscillates at the
required mixer injection frequency. Varactor diode D4 is used by the PLL circuit to
keep the oscillator on the desired frequency. Transistor Q7 is used as a filter to
reduce the noise on the oscillator supply voltage.
5.4 PLL Section
The synthesizer frequency reference is supplied by a temperature compensated
crystal oscillator (XO1). The frequency stability of the oscillator is better than 1
ppm.
The 12 MHz output of Q25 or XO1 is amplified by Q8 to drive the reference input
of the PLL synthesizer IC U4. This IC is a single chip synthesizer which includes a
1.1 GHz pre-scaler, programmable divider, reference divider and phase/frequency
detector. The frequency data is entered a serial data link from the microprocessor.
The phase detector output signals of U4 are used to control two switched current
sources. The output of the positive and negative sources' Q10 and Q16, produce the
tuning voltage which is smoothed by the loop filter components to bias the VCO
varactor diode D4.

Page 14 RF Technology R220
5.5 Audio Signal Processing 5 CIRCUIT DESCRIPTION
5.5 Audio Signal Processing
A 4 KHz low pass filter (U27b) is used to remove high frequency noise from the
signal. A 300 Hz high pass filter (U26a,b) then removes the sub-audible tones. A 240
Hz notch filter (U26c,d) is used to improve the rejection of tones above 200 Hz. The
high pass and notch filters can be bypassed by internal jumpers JP1 and JP3.
The audio frequency response can be set for either 750 uS de-emphasis or a flat
characteristic by JP2. JP2 selects the feedback network of amplifier U27c.
After de-emphasis and filtering, the audio signal is applied to the inputs of two
analog switches (U17a,b). These switches are controlled by the micro-controller and
squelch or mute the audio to the line and monitor output circuits. The monitor output
can be set for noise squelch only operation by S1.
The audio from U17a is adjusted by the volume control before connecting to the
monitor output amplifier U5. U5 drives the internal speaker and can also supply 3-5
watts to an external loudspeaker.
The audio from U17b is adjusted by RV3 before connecting to the line output IC
(U22a,b). U22 is a dual amplifier connected in a bridge configuration to drive the
600Ωline output transformer T1.
5.6 Noise Filter, Amplifier and Detector
The unfiltered audio from the discriminator is fed to trimpot RV4 which is used to
set the noise squelch threshold. From RV4 the audio goes to the noise filter (U27a).
This is a 10 KHz high pass filter and is used to eliminate voice frequency
components.
The noise signal is then amplified by U27d and fed to the noise detector. The noise
detector consists of D6, Q17 and U26c. D6 and Q17 are a charge pump detector and
pull the input to U26c low as the noise increases. U26c has positive feedback and
acts like a schmitt trigger. The output of U26c goes high when noise is detected. It
connects to the micro-controller and to analog switch U17d. U17d varies the gain of
the noise amplifier to provide approximately 2dB hysteressis.
5.7 Sub-Tone Filter and CTCSS
The discriminator audio is fed through cascaded low pass filters U28a and U28b to
filter out the voice frequency components. The filtered sub-tone audio is supplied to
the CTCSS hybrid and the rear panel system connector. The filtered output can be
used for re-transmission of CTCSS or DCS.
The CTCSS decoder module is a micro-controller base hybrid module. Under control
of the main microprocessor U15 it can decode all 38 EIA tones and 12 additional
commonly used tones. The decode bandwidth is set to 1% but may be changed to 2%
by a jumper on the printed circuit board.

RF Technology R220 Page 15
5 CIRCUIT DESCRIPTION 5.8 External Squelch
5.8 External Squelch
The audio output can be muted through pin 8 of the receiver system connector P1.
When pin 8 is pulled to less than 1 volt above ground, the micro-controller U15 will
mute the audio output.
This facility can be used to mute the audio during transmission, as is required in
single frequency systems, by simply connecting pin 8 of the receiver to the
transmitter T/R relay driver output (pin 16 on Eclipse transmitters).
5.9 Microprocessor Controller
The microprocessor controller circuit uses an advanced eight bit processor and
several support chips. The processor U15 includes EE memory for channel
frequencies, tones, and other information. It also has an asynchronous serial port and
an analog to digital converter.
The program is stored in U12, a CMOS EPROM. U13 is an address latch for the low
order address bits. U11 is used to read the channel select lines onto the data bus. U7
is an address decoder for U11 and U12. U14 is a supervisory chip which keeps the
processor reset unless the +5 Volt supply is within operating limits. U16 translates
the asynchronous serial port data to standard RS232 levels.
The analog to digital converter is used to measure the received signal strength, tuning
voltage, dc supply voltage and the carrier squelch setting.
5.10 Carrier Operated Switch
The carrier operated switch is an opto-coupled (ISO1) output. Internal jumpers
(JP4,7,8,9) can be connected to provide loop source, loop switch, free switch and
various other configurations.
The COScan be set to be active (switch closed) on carrier or active in the absence of
carrier.
The generic term ``Carrier Operated Switch'' may be misleading in this case. SINCE,
if a sub-audible tone has been programmed for the channel in use, the COS is
controlled by carrier and tone detection.

Page 16 RF Technology R220
5.11 Voltage Regulator 5 CIRCUIT DESCRIPTION
5.11 Voltage Regulator
The dc input voltage is regulated down to 9.4 Vdc by a discrete regulator circuit. The
series pass transistor Q20 is driven by error amplifiers Q21 and Q22. Q23 is used to
start up the regulator and once the circuit turns on, it plays no further part in the
operation.
This circuit is short circuit and overload protected. It provides much better line
isolation and lower dropout voltage than can be obtained with current integrated
circuit regulators.
6 Alignment Procedure
The following procedures may be used to align the receiver for optimum
performance. Normally only RF alignment will be required when changing
frequencies. IF alignment should only be necessary after repairs on that part of the
circuit.
Reference oscillator or TCXO calibration may be required periodically due to crystal
aging. The aging should be less than 1 ppm/year.
6.1 Standard Input Signal
RF Signal Generator
50Ωoutput impedance
Frequency range 215 - 240 MHz
FM modulation at 1KHz
1.5KHz peak for 12.5KHz channel spacing
6.2 RF Alignment
Alignment Frequency
215 - 240 MHz range 221.000 MHz

RF Technology R220 Page 17
6 ALIGNMENT PROCEDURE 6.3 IF Alignment
Step Input Measure Adjust
1 Select alignment
frequency channel dc Volts on test socket pin 9 to pin 1 L34 to read 4.00Vdc
2 Signal generator on
centre frequency
channel to J1.
Modulation off.
dc Volts on test socket
pin 7 to pin 1 Generator level to read 1 - 2 Vdc
3 Signal generator on
centre frequency
channel to J1.
Modulation off.
dc Volts on test socket
pin 7 to pin 1 L29, 31, 36, 38 for maximum reading.
Reduce generator
output to keep below
2 Vdc
6.3 IF Alignment
Step Input Measure Adjust
1 Signal generator on
center frequency
channel to J1.
Modulation OFF
dc Volts in test socket
pin 7 to pin 1 Generator level to read 1 - 2 Vdc
2 Signal generator on
center frequency
channel to J1.
Modulation OFF
dc Volts in test socket
pin 7 to pin 1 L5, L6, L7, L8 for maximum reading.
Reduce generator
output to keep below
2 Vdc
3 Set generator level to
10
µ
VFrequency U3 pin 9 L9 to read 455 KHz
+/- 10Hz
4 Set generator level to
1 millivolt.
Modulation ON.
Audio level test socket
pin 6 to pin 1 Line level (RV3) to obtain approx. 1
Vrms
5 Set generator level to
1 millivolt.
Modulation ON.
Audio level test socket
pin 6 to pin 1 L10 for maximum
6 Set generator level to
1 millivolt.
Modulation ON.
Audio level P1 pin 18
to pin 5 RV1 for .5 Vrms
7 Set generator level to
approx. 25
µ
VSINAD on test socket
pin 6 to pin 1 Reduce generator level to obtain 12 Db
SINAD. Carefully
adjust L5, L6, L7, L8
to obtain the best
SINAD. Reduce
generator output to
maintain 12 dB
SINAD

Page 18 RF Technology R220
6.4 Line Level Adjustment 6 ALIGNMENT PROCEDURE
6.4 Line Level Adjustment
Step Input Measure Adjust
1 Signal generator on
centre frequency
channel to J1.
Modulation ON.
Level 1 millivolt
Audio level test socket
pin 6 to pin 1 RV3 for 390 mV rms
6.5 Reference Oscillator Calibration
Step Input Measure Adjust
1 None required Frequency junction of
R69 and R26 on the
top of the PCB. (LO
input to the mixer)
C181 or XO1 for L.O.
+/-100 Hz
L.O. = Fc+45 MHz
7 Specifications
7.1 General Description
The receiver is a high performance, frequency synthesized, narrow band FM unit
which can be used in conjunction with transmitter and power supply modules as a
base station or as a stand alone receiver. All necessary control and 600Ωline
interface circuitry is included.
7.1.1 Channel Capacity
Although most applications are single channel, it can be programmed for up to 100
channels numbered 0-99. This is to provide the capability of programming all
channels into all of the receivers used at a given site.
7.1.2 CTCSS
The CTCSS tone or no tone can also be programmed for each channel. So that each
channel number can represent unique RF and tone frequency combination.
7.1.3 Channel Programming
The channelling information is stored in a non-volatile memory chip and can be
programmed via the front panel test connector using a PC and RF Technology
supplied TecHelp/Service Monitor 2000 software.

RF Technology R220 Page 19
7 SPECIFICATIONS 7.1.4 Channel Selection
7.1.4 Channel Selection
Channel selection is by eight channel select lines. These are available through the
rear panel connector.
A BCD active high code applied to the lines selects the required channel. This can be
supplied by pre-wiring the rack connector so that each rack position is dedicated to a
fixed channel.
BCD switches inside the receiver can be used to pre-set any desired channel. These
eliminate the need to externally select the channel.
7.1.5 Microprocessor
A microprocessor is used to control the synthesizer and squelch functions and
facilitate the channel frequency programming. With the standard software it also can
provide fault monitoring and reporting.
7.2 Physical Configuration
The receiver is designed to fit in a 19 inch rack mounted frame. The installed height
is 4 RU (178 mm) and the depth 350 mm. The receiver is 63.5 mm or two Eclipse
modules wide.
7.3 Front Panel Controls, Indicators and Test Points
7.3.1 Controls
Mute defeat switch - toggle (Overrides CTCSS, noise and carrier squelch at the
monitor output)
Monitor Speaker Volume - Knob
Line Output Level - screwdriver adjust multiturn pot
Noise Squelch Setting - screwdriver adjust multiturn pot
Carrier Squelch Setting - screwdriver adjust multiturn pot
7.3.2 Indicators
Power ON - Green LED
Squelch Open - Yellow LED
Fault Indicator - Flashing Red LED

Page 20 RF Technology R220
7.3.3 Test Points 7 SPECIFICATIONS
7.3.3 Test Points
Line Output Level - 1 + Gnd
Receive Signal Strength - 1 + Gnd
Tuning Voltage - 1 + Gnd
Serial Data (RS232) - 2 + Gnd
7.4 Electrical Specifications
7.4.1 Power Requirements
Operating Voltage - 10.5 to 16 Vdc
Current Drain - 250mA Max.
Polarity - Negative Ground
7.4.2 Frequency Range and Channel Spacing
215 – 240 MHz 12.5KHz
7.4.3 Frequency Synthesizer Step Size
5.0 or 6.25 KHz
7.4.4 Frequency Stability
+/- 1 ppm, 0 to +60 C
7.4.5 Nominal Antenna Impedance
50Ω