General Information; Scope Of Manual; Radio Description; General - E.F. Johnson Company 5100 Series Service Manual

1.1 SCOPE OF MANUAL

This service manual contains operation, program-
ming, alignment, and service information for the
EFJohnson 5100 series portable radio.
The 51SL and Ascend (Multi-Net) models are
similar in appearance and covered by separate manuals
as follows:
51SL Portable Serv Man - P.N. 001-5200-0010CD
Ascend Portable Serv Man - P.N. 001-5584-0010CD
The distinguishing characteristics of the 5100,
51SL, and Ascend models are as follows:
5100 Series Portable
•
Part No. 242-51xx-xxx (see Section 1.4)
•
EFJohnson logo under display
•
Black front bezel with black keypad keys
51SL Series Portable
•
Part No. 242-52xx-xxx (see Section 1.4)
•
"51SL" label under display
•
Grey front panel bezel with white keypad buttons
Ascend Series Portable
•
Part No. 242-558x-xxx (see Section 1.4)
•
"ASCEND" label under display
•
Black front panel bezel with black keypad buttons

1.2 RADIO DESCRIPTION

1.2.1 GENERAL

The 5100-series portable transceivers have
multiple system programming capability to allow
operation in various types of radio systems as
described in the information which follows.
Models are available for operation in the
following frequency ranges. Repeater talk-around,
which allows transmitting on the receive frequency, is
also available with all bands.
SECTION 1 GENERAL INFORMATION
VHF: 136-174 MHz
UHF Low: 380-450 MHz (Federal Users Only)
UHF Mid: 403-470 MHz
UHF High: 450-512 MHz
700/800 MHz: 762-806 and 806-870 MHz
800 MHz: 806-870 MHz (see next section)
Power output is user switchable for low and high
levels as follows:
VHF - 1 and 5 watts
UHF - 1 and 4 watts
700 MHz - 1 and 2.5 watts
800 MHz - 1 and 3 watts

1.2.2 NEW 700/800 MHZ BAND INFORMATION

As described in Section 1.13, 5100 models are
starting to ship with a new design RF board. The 800
MHz models with this new board operate on both the
700 and 800 MHz bands. Earlier models can operate in
only the 800 MHz band. Other bands remain the same
with this new board.
With the 700/800 MHz models, channels can be
programmed anywhere in the 700 and 800 MHz
bands. For example, Channel 1 can be programed for
768.000 MHz, Channel 2 for 810.000 MHz, and so on.
The only restriction is that the FCC does not permit
receiving in one band and transmitting in the other
band on the same channel and vice versa.

1.2.3 ANALOG/DIGITAL OPERATION

The 5100-series transceiver uses a digital signal
processor (DSP) to provide IF and audio filtering and
modulation functions. This allows operation on the
various types of channels (see following), backward
compatibility with existing equipment, and the ability
to operate on various types of radio systems.
Narrow Band Analog - FM modulation is used with a
maximum deviation of 2.5 kHz. This mode is usually
used in systems with a channel spacing of 12.5 or
15 kHz.
Wideband Analog - FM modulation is used with a
maximum deviation of 5 kHz. This mode is usually
1-1

GENERAL INFORMATION