Lectrosonics IFBR1a User manual

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Guide
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This guide is intended to assist with
initial setup and operation of your
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IFB Receiver
IFBR1A
06 july10
U.S. Patent 7,225,135

LECTROSONICS, INC.2
Battery Installation
The battery you use in the R1a receiver should be a 9 Volt alkaline or lithium,
available almost everywhere. An alkaline battery will provide up to 8 hours
of operation and a lithium battery will provide up to 20 hours of operation.
Carbon zinc batteries, even if marked “heavy duty” will only provide about 2
hours of operation. Rechargeable batteries will only operate the receiver for
an hour or less. Make sure your batteries are marked “alkaline” or “lithium.”
Short battery life is almost always caused by weak batteries or batteries of the
wrong type.
A green LED corresponds to a fresh battery. The LED will change to yellow
for low battery warning then to red to indicate the need for a fresh battery.
To replace the battery, open the bottom battery door cover with your thumb,
rotate the door until it is perpendicular with the case and allow the battery to
fall out of the compartment into your hand. It is difficult to install the battery
backwards. Observe the large and small holes in the battery contact pad
before inserting a new battery. Insert the contact end of the battery first, mak-
ing sure the contacts are aligned with the holes in the contact pad, and then
swing the door closed. You will feel it snap into place when it is fully closed.

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Control Knob
Headphone Jack
1.6M 100K
Frequency Select
Switches
012
3
4
5
6
7
8
9
A
B
C
D
EF012
3
4
5
6
7
8
9
A
B
C
D
EF
Status Indicator

LECTROSONICS, INC.4
Headphone Jack
On the front panel is a 3.5mm mini phone jack to accommodate a standard
mono or stereo type 3.5 mm plug. The jack is also the receiver antenna input
with the earphone cord acting as the antenna.
Mono Plug/Stereo Plug
Although the IFBR1a is mono only, a Mono or Stereo plug can be used with
the IFBR1a headphone jack directly. When a Mono plug is inserted, a special
circuit senses the “ring” to “sleeve” short and automatically switches off the
ring to prevent excess battery drain. To reset, switch power OFF then back
ON.
Audio Level
Headphones and ear pieces vary widely in sensitivity and impedance making
it impossible to design a receiver with a fixed output power level that is correct
for all situations. High impedance phones (600 to 2000) Ohms will have an
inherently lower power level due to their high impedance and likewise low
impedance phones may be extremely loud. CAUTION! Always set the Audio
Level knob to minimum (counter-clockwise) when plugging phones into the
jack, then adjust the knob for a comfortable audio level.
Frequency Adjust
Two rotary switches adjust the center frequency of the carrier. The 1.6M is a
coarse adjustment and the 100K is the fine adjustment. Each transmitter is
factory aligned at the center of its operating range. The receiver and transmit-
ter switches must be set to the same number/letter combination for proper
operation.
To gain access to these switches, slide the access door sideways with a
fingernail.
Features
The frequency agile IFB R1a FM Receiver is designed to operate with the
Lectrosonics IFBT1/T4 Transmitter and features 256 frequencies of operation
within each frequency block. Each block covers 25.6 MHz. Any one of nine
different frequency blocks are factory available from 537.6 MHz to 793.5 MHz.
The unique design in this receiver provides simple one knob and one LED
operation for audio level, switching frequencies (channels), and easy on-the-
fly programming. The receiver frequency can be set by manually using the
two rotary HEX switches on the side of the unit or by using the automatic scan
and store function, or both.
When powered ON, the receiver will default to the frequency set by the
switches. A nonvolatile memory can store up to five additional frequencies
accessible by pressing the knob. The memory remains during power OFF
and even with the battery removed.
Controls and Functions

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Control Knob
The single front panel control knob performs multiple functions;
1. Rotate for Power ON/OFF
2. Rotate for Audio Level
3. Push quick, Channel Switching. (Also see page 9
for special knob setup.)
4. Push and rotate for Scan and
Channel programming,
Refer to the OPERATING INSTRUCTIONS for full details on how to use the
single knob control for channel selection, scanning, and programming of the
five memory locations.
LED Indicator
The three color LED indicator on the front panel provides multiple functions.
CHANNEL NUMBER - The LED will blink OFF a number of times corre-
sponding to the Channel Number when the unit is switched ON and also
when a new frequency is added to an open channel. For example, for chan-
nel 3 the LED would blink OFF three times. After blinking the channel number
the LED will return to a steady ON indicating normal operation.
BATTERY STATUS – During normal operation, when the LED is GREEN, the
battery is good. When the LED is YELLOW the battery is getting low. When
the LED is RED, the battery is nearly depleted and should be replaced.
PROGRAMMING FUNCTIONS - In the programming mode, the LED will
blink at a fast rate to indicate scanning for an active frequency. It also flashes
briefly to indicate a frequency has been programmed into a channel.

LECTROSONICS, INC.6
Receiver Normal Operation
1. Set the Frequency of the receiver to match the frequency of the trans-
mitter by using the two HEX rotary switches located on the side of the
receiver under the sliding door. The 1.6M switch is for “coarse” adjust-
ment (1.6 MHz per click) and the 100k switch is for “fine” adjustment (0.1
MHz per click).
2. Plug an earphone or headset into the 3.5mm jack. Be sure the unit has a
good battery.
3. Rotate the knob clockwise to switch the power ON (Do NOT hold the
knob in while switching power ON). The LED will illuminate. Rotate the
knob to set the desired audio level.
4. If channel frequencies have been stored in the memory, change channels
by pressing the knob briefly and release. The LED will blink the next
channel number (frequency) and the receiver will resume operation on
that channel. If no channel frequencies have been stored when press-
ing the knob to change channels, the LED will flash from green to red to
yellow to green, indicating no stored channels and the unit will resume
operation on the channel set by the switches.
5. Whenever the power is switched ON, the unit defaults to the frequency
set by the switches.
Add a New Frequency to The Next Open Channel
Before operating a receiver, one or more IFBT1/T4 transmitters must be
placed in XMIT mode, with each transmitter set to the desired frequency and
connected to a proper antenna, audio source, and power source. The trans-
mitter frequency block must be the same as the receiver frequency block as
marked on each unit.
1. Position the receiver at a location within 20 to 100 feet of the transmitter
or transmitters.
2. With the power ON, depress the knob until the LED starts rapidly blink-
ing, then release the knob.
3. The unit goes into program mode and does a scan/search. Previously
programmed frequencies will be automatically skipped. When the unit
stops on a new frequency audio from the transmitter will be heard in the
earphone and the LED will stop blinking rapidly and will change to a slow
blink mode.
The unit is now waiting for an operator decision. You must now decide to
either SKIP or STORE the frequency (step 4 or 5 below.) Switching the
power to OFF without storing will delete the frequency.
4. To SKIP the frequency, depress the knob briefly and the scan/search will
resume.
5. To STORE the frequency into a channel memory, depress the knob and
hold it until the LED blinks the new channel number, then release the
knob. The frequency is now stored in an open channel.
6. The unit will continue scan/search for other frequencies. To store more
frequencies repeat steps 4 and 5 above. Up to 5 frequencies can be
stored in memory channels.

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7. When all desired frequencies are stored switch the power to OFF for a
few moments, then switch back to ON. The unit will default to the chan-
nel number set by the switches and resume normal operating mode.
8. The first scan is made at low sensitivity and searches for only high level
transmitter signals to avoid intermods. If the receiver does not stop on
any frequency in the first scan, that means an IFB transmitter was not
detected. In this condition the LED will change from a fast blink to a slow
blink indicating the end of the scan. The complete scan should take 15
to 40 seconds.
9. A second scan at high sensitivity is initiated by depressing the knob
briefly at the end of the first scan to search for low level transmitter
signals. When the scan stops and the transmitter audio is heard, either
SKIP or STORE the frequency (step 4 or 5 above).
10. If the receiver still does not stop on any frequency, check that the trans-
mitter is ON. Also, if a frequency is not received or received but dis-
torted, some other signal may be interfering on that frequency. Change
the transmitter to another frequency and try again.
11. Switching the POWER to OFF during any mode simply terminates that
mode and returns the unit to normal operating mode when the power is
switched back to ON.
Note: If knob does not change frequencies or begin scanning when
pressed, check to see if its function has been changed.
Erase All 5 Channel Memories
1. With power OFF, depress the knob and turn the unit ON. Continue to
hold the knob down until the LED starts rapidly blinking. The memory is
now erased and the unit will go into scan/search mode.
2. Continue from step 3 above - Add New Frequency.
Multiple Transmitter Setup
When using this IFB receiver in a search mode, with two or more transmitters
running at the same time, the receiver may stop on a false signal under the
following conditions:
• Two transmitters are on and transmitting.
• The distance from the transmitters to the IFB receiver is less than 5 feet.
The false hits are caused by intermodulation or mixing in the front end of
the IFB receiver. At a 5 to 10 foot distance, the two carriers are so strong at
the receiver, that even this well designed front end will mix the carriers and
produce phantom frequencies. The IFB receiver then halts its scan and stops
on these false frequencies. All receivers will exhibit this type problem at some
transmitter power level and range. You notice false signals more with a scan-
ning mode receiver since it will find them all.
Prevention is simple. Do one of the following:
• Do the scan with only one transmitter on at a time. (Time consuming)
• Increase the receiver to transmitter distance to at least 10 feet. (Pre-
ferred)