SBS FM30 Installation, Operator And Service Manual

Eddystone Broadcast Limited, Broadcast House, Lauriston Park, Pitchill, Evesham. WR11 8SN

Telephone [phone] Fax [phone]

Email [e-mail]

www.eddystone-broadcast.com

FM30

FM EXCITER/TRANSMITTER

& Transposer

Installation, Operator and Service Manual

FM30 Series Technical Manual Page 2

CONTENTS

1 Introduction
2 Safety, Electrical hazard
3 Safety, Toxic hazard
4 Unpacking
5 Controls and Connectors
6 Installation
7 Block diagram
8 Specifications
9 Contacting Eddystone Broadcast Limited
10 Technical Section Contents
11 Declaration of conformity

No part of this manual may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying, recording or information storage and retrieval systems, for any purpose
other than the purchaser's personal use, without the express written permission of Eddystone Broadcast Ltd.

Information in this document is subject to change without notice and does not represent a commitment
on the part of Eddystone Broadcast Ltd. Eddystone Broadcast Ltd shall not be liable for any direct, indirect,
consequential or incidental damages as a result of the use or misuse of this equipment,
handbook or any related materials.

FM30 Series Technical Manual Page 3

1 Introduction

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The FM30 is a top specification broadcast FM exciter that is also ideally suited as a
low power stand alone transmitter. Featuring wideband design techniques,
frequency adjustment is easily achieved by internally set direct reading dial switches

- no further tuning is required. Both the international 87.5-108MHz and Japanese
76-90MHz frequency bands are catered for.

The FM30 uses the renowned sbs ultra linear modulator to give superb sound
reproduction with freedom from overshoots and artifacts. It will operate into any
load without damage thanks to its VSWR cut back circuit that protects the power
amplifier stage from adverse operating conditions.

The FM30 front panel metering shows forward and reflected power together with
internal voltages and the modulation level. Additionally a monitor point for RF
output is provided. Quick-view status monitoring using dual colour LEDs indicate
that PLL lock, forward power and reflected power are within a preset tolerance when
green. The rear panel includes a remote control/monitoring socket that allows
carrier muting and status signalling to an external system.

Very conservatively rated components and a switch mode DC-DC converter are
used to ensure extremely high reliability and to give good efficiency. The FM30 is in
service with broadcasters worldwide and has been giving many years of trouble-free
service.

The FM30 is available with an unbalanced multiplex/composite input (FM30), mono
balanced with limiter (FM30/M) and balanced stereo with built in stereo
limiter/encoder (FM30/S). The FM30/RBRX includes a high quality single channel
receiver module based on the sbs RX400. The FM30/RBRX is a fully self contained
transposer, ideal for relay stations. A digital input version (AES/EBU) with stereo
encoder is also available.

Additionally the FM30 is available with an input mixer for mixing
balanced/unbalanced multiplex/composite with three SCA and a balanced mono
input with 0, 50 and 75uS pre-emphasis.

All versions of the FM30, apart from the multiplex/composite input type have a
switchable multiplex/composite loop for the addition of RDS or any other SCA
system.

The FM30 can be used with the sbs ACU3, ACU4 or E2075 changeover unit where
a fully backed up (redundant) system is required.

FM30 Series Technical Manual Page 4

2 Safety, Electrical hazard

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Important Notice

This unit contains high voltages which could be fatal. YOU MUST ALWAYS
ISOLATE THE UNIT FROM THE MAINS SUPPLY BY COMPLETELY
DISCONNECTING IT BEFORE ATTEMPTING TO OPEN THE CASE.

THIS EQUIPMENT MUST BE EARTHED.
Do not expose this equipment to rain or any other source of water.
In common with all mains operated equipment, only suitably trained competent

personnel should attempt to adjust, modify or repair this equipment or operate it with
the cover removed. In case of any query please contact your local agent or sbs.

Any unauthorised adjustment, modification or repair of this equipment may
invalidate any warranty and/or safety approvals that apply.

Please read all of this manual and familiarise yourself with the controls before
attempting to use this equipment.

To ensure safety, it is the responsibility of the user to install and operate this
equipment in a manner that is within the manufacturers specifications.

FM30 Series Technical Manual Page 5

3 Safety, Toxic hazard

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This equipment includes devices which contain Beryllium Oxide which is a highly
toxic substance. Inhalation or ingestion of even tiny particles could be injurious to
health or even FATAL!

Extreme care must be exercised when replacing and discarding components which
may contain Beryllium Oxide. If any such device is physically damaged you should
seek expert advice, e.g. by contacting the device's manufacturers.

All such devices must be disposed of in accordance with local regulations. In the
UK your local council will have a toxic waste disposal department who will be able to
advise you. Elsewhere you should contact the responsible authorities.

NEVER DISPOSE OF A DEVICE CONTAINING BERYLLIUM OXIDE WITH
GENERAL WASTE.

FM30 Series Technical Manual Page 6

4 Unpacking

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This package should contain:­1x FM30 Series broadcast exciter/transmitter

1x IEC Power lead
1x FM30 series manual

If any items are missing or damaged please inform your supplier immediately.
Initial Checks
Ensure that the FM30 has been set to the correct power/line voltage for your

country.

FM30 Series Technical Manual Page 7

5 Controls and Connectors

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Front Panel:

PLL LOCK Modulator functioning correctly (when green).
P.FWD Green when the RF output level is above a

predetermined level (see installation section).

P.REF Green while the reflected RF power is below a pre-

determined level (see installation section). Red when the
VSWR cut-back system is operating.

LIMIT Shows green when internal limiter option is limiting audio

input level.

SIGNAL (FM30/RBRX) Green while a signal is received. Red when signal is

absent or below the preset mute level.

O/P Monitor Monitor of RF output (approx. -40dBc). This point should

not be used for harmonic or power measurements

Meter and selector Selects and indicates important FM30 parameters.

FM30 Series Technical Manual Page 8

Rear Panel:

Audio/MPX input Unbalanced on BNC female connector or balanced on

female XLR connector with optional limiter/encoder or
/SCA version (pin 1 ground, pin 2 hot, pin 3 cold).

Multiplex/composite loop With switch in ON position, the output of the

limiter/stereo encoder (if fitted) can be routed via an
external system such as an RDS/SCA encoder. With the
switch in the OFF position, the multiplex/composite
output of the limiter/encoder is present on the unbuffered
output connector, but the input connector is
disconnected.

Monitor 25 way female D-type connector.

Pin 1 Forward power alarm.
Pin 2 Reverse power alarm.
Pin 3 PLL lock alarm.
Pin 4 Mute RF output (link to ground).
Pin 5 Receive signal alarm (FM30/RBRX)

Pin 25 Ground.
All outputs are open collector and low in their normal
state. The output transistors are BC184L's, which can
sink up to 100mA maximum with an absolute maximum
switched voltage of 30V.

RF Input (FM30/RBRX) N type female connector.
RF Out N type female connector.
DC IN 4 pin XLR male, pin 1 and 2 negative, 3 and 4 positive

for 24V to 30V DC power supply. This supply may be
connected at the same time as the mains input. The
TX400 will then use the DC supply as a backup if the
mains supply fails.

AC Mains Filtered IEC male connector with fuse in pull out drawer.

T3.15A fuse.

FM30 Series Technical Manual Page 9

6 Installation

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RF leads should be made from high quality low loss cable and connectors of the
correct impedance, using the manufacturers recommended termination techniques.
Since connectors are a source of un-reliability in any system, the number of
terminations in any RF lead should be kept to a minimum.

All other cables for audio and control signals should be high quality screened types.
For XLR connectors, the screen should be connected to the connector body.

Before normal operation of the FM30 can commence the following parameters will
require setting, assuming the equipment supplier has not done so:

6.1 Frequency

6.2 Output power

6.3 Forward power alarm

6.4 Modulator input level

6.5 VSWR Cut-back level

Please read through ALL of the following stages before attempting any adjustment.
When an automatic change over system is in use (such as the ACU3) this should be
disconnected/overridden such that the FM30 operates continuously during the set­up procedure.

6.1 FREQUENCY SETTING

Setting the frequency is a simple operation. Direct reading dials are located on the
PLL7 PCB. For example, to set a frequency of 107.30MHz, set the 10MHz dial to 0,
the 1MHz dial to 7, the 100kHz dial to 3 and the 12.5kHz dial to 0. For 98.35 set
10MHz dial to 9, the 1MHz dial to 8, the 100kHz dial to 3 and the 12.5kHz dial to 4
(4 x 12.5kHz = 50kHz).

Whilst the Phase Locked Loop is Locking up the modulator output is muted
(indicated by the front panel PLL LOCK LED). When the FM30 is either powered up
or the frequency changed, it will normally take about 5 seconds for the PLL to lock
up. However if the frequency is changed from a high one to one at the bottom of the
band, with the unit in operation, it can take up to 10 seconds for the PLL to lock up
properly.

6.2 OUTPUT POWER

A small trimmer tool or precision screwdriver will be required to adjust the output
power.

The output power should ideally be set using an accurate power meter connected to
the RF output which in turn should be connected to an adequately rated dummy
load. If either of these items are not available then the front panel meter could be
used and/or it could be operated into the aerial or PA stage. In this latter case the
Output Power control (rear panel) should be set to minimum (counter clockwise)
before powering up the FM30.

FM30 Series Technical Manual Page 10

Connect the FM30 to the mains or DC supply and wait for the PLL to LOCK (the
front panel LED indicates lock when green). Using the rear panel power adjust
control (PWR. ADJ.) set the power to that required.

6.3 FORWARD POWER ALARM

This setting defines the point at which the front panel P. FWD. light changes to red
and also the point at which a forward power fault is indicated at the Control/Monitor
socket (for telemetry and/or operation of an automatic change over system). Adjust
the output power to the fault level required. This must always be less than the
normal output power level by enough to prevent spurious triggering, 1dB is an
appropriate margin (80% of the correct full power). Adjust the P FWD OK (RV4)
control on the FMTXDIS board such that the front panel P. FWD. light just turns red
from green. Finally set the output power back to the normal output level.

6.4 MODULATOR INPUT LEVEL

For FM30/M and FM30/S see the adjustment section of this manual covering LimX.

The FM30 is normally supplied with the modulator input level set so that an input
level of +8dBu over the range 5Hz to 100kHz (without pre-emphasis) gives a
deviation of 75kHz. If a different level is required then it will be necessary to reset
the ‘MOD LEVEL’ control (VR2) on the PLL7 modulator board. To set it properly a
deviation meter will be required. This should be connected to the front panel O/P
monitor socket. If a deviation meter is not available then the front panel meter
should be used, though this will not be as accurate. Apply a 400Hz sine wave at
the level required for maximum deviation (normally 75kHz). Adjust VR2 control to
give the required deviation. The front panel meter is calibrated at the factory at the
centre of the operating frequency band. There will be a very small calibration error
at either end of the band.

6.5 VSWR CUT-BACK LEVEL

This is the minimum RF output power that the FM30 will provide with a badly
matched load such as a defective aerial. It should never be set above 7.5W to
protect the power amplifier unit. As supplied it will be set to 4.5W. To set a different
value turn the FM30 output power down to minimum, connect a power meter to the
output and disconnect the dummy load or aerial. Remove jumper LK1 on the
FMTXDIS PCB. Turn the output power up until the desired reflected power cut-back
level is obtained. Replace LK1 and adjust the CUTBACK control (RV2) such that
the front panel P. REF LED just changes from RED to GREEN. Turn the output
power up to full and if necessary slightly adjust the CUTBACK control to reduce the
cut-back level to the value required. Finally reset the forward power to the required
level.

FM30 Series Technical Manual Page 12

8 Specifications

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8.1 Electrical specification

RF Interface ports Output type N, monitor BNC. All 50
Power output 0 - 30W typ.
Power output stability <±0.5dB1 <±1.0dB

2

Minimum return loss for full power output 8dB
Frequency range (International version) 87.5 to 108 MHz in 12.5kHz steps
Frequency range (Japanese version) 76 to 90 MHz in 12.5kHz steps
Frequency error <± 50Hz1 <± 100Hz

2

Frequency drift (3 month interval) <± 50Hz
Frequency adjustment continuously variable to <± 10Hz
Mute attenuation (PLL out of lock) >90dB
External mute control attenuation at full power >50dB
Deviation sensitivity stability

3

<± 1%
Spurious outputs (76 to 137Mhz @ fc>±0.5MHz) < -100dBc
Harmonic & spurious output (30MHz to 1GHz) < -70dBc
Synchronous AM (500Hz @ 40kHz dev.) <-50dB
AM Hum & Noise <-55dB
Input sensitivity for 75kHz dev (Factory setting)+8dBu or 3.5V p/p US/Canada (adj)
AF response (MPX Input) <±0.5dB (5Hz-100kHz)
MPX/CompositeTHD < 0.05% at 75kHz
Power supply 100/110/230VAC +10%/-20%

24 - 30V

DC

Power consumption < 80VA

8.2 Mechanical specification

Dimensions 3Ux260mm
Weight 6kg
Dimensions exclude rear panel connectors and front panel heatsink (40mm).

8.3 Environmental specification

Ambient temperature range (normal conditions) 0 to 50 Celsius
Ambient temperature range (extreme conditions) -20 to 60 Celsius
Humidity 90% non condensing

1

Under normal operating conditions

2

Under extreme operating conditions

3

Under all operating conditions