Motorola L305 Manuel de service télécharger pdf

Modifications to the Motorola UHF Micor mobile transceiver

for use with high speed FSK Data Modems

receiver and the transmitter. Since one

oscillator serves both the receiver and

transmitter, the transmit frequency will

“track” the receive frequency as it changes

with temperature.

The transmitter incorporates a circulator in the

antenna output network to protect the PA

transistors from high SWR. The presence of a

circulator insures that the UHF Micor will be

a “good neighbor” when installed at a site that

is shared by other services.

Before proceeding any further, take a few

minutes to become familiar with the radio

that you plan to convert. Refer to the

illustrations in the Motorola Service Manual

for the location of major components.

_______________________________________________________

Now that you know the physical layout of the

radio, let’s cover some of the technical aspects.

What is the transmit power output ?

The answer to this question can be found by

looking at the model number. The chart below

translates these numbers into useful

information.

While the model number may contain a

combination of 11 or more numbers and

letters, the first 5 of these are the ones of

interest. The rest describe various options such

as “ PL “.

Model Transmit current

T34RTA 25W 10.5 A @ 13.6 V

T44RTA 45W 15.9 A @ 13.6 V

T54RTA 75W 25.0 A @ 13.4 V

T74RTA 100W 35.5 A @ 13.4 V

As you can see, the 75 and 100 watt radios

draw a lot of current on transmit. If you have

one of these radios and you don’t need that

It is assumed that those attempting this conversion

will have the test equipment, service manuals, and

expertise necessary to tune and service this radio.

THIS IS DEFINITELY NOT THE RADIO

FOR BEGINNERS.

Please review the conversion instructions before

you begin. In several areas, there are two sets of

instructions, one set is for use with a TAPR/

G3RUH modem, the other is for use with a TPRS

Texnet modem. You might want to mark the steps

that apply to your modem. This could prevent some

confusion and possible mistakes during the

conversion process.

The UHF Micor mobile radio is a fine high

power UHF radio. This unit is a true “cadillac”

radio that incorporates many advanced

features.

The transmitter employs a hetrodyne exciter.

Receiver oscillator injection is mixed with the

signal from an offset oscillator to generate the

transmit frequency. The offset oscillator is

varactor modulated for true FM.

The receive channel element output is

multiplied by 24 and serves as the main

frequency determining element for both the

1 2 3 4 5 6 ... 11 12

Schematic in Appendix ?? 7

Résumé du contenu

Page 1

3Modifications to the Motorola UHF Micor mobile transceiverfor use with high speed FSK Data Modemsreceiver and the transmitter. Since oneoscillator se

Page 2

125. Meter position 3. Tune L105 CCW for a peakon M3. Tune L104 for a peak on M3. Re-peakboth coils.6. Meter position 3. Detune L101 until meter 3drop

Page 3

13Adjust L305 [L405] for a peak reading.Adjust L306 [L406] for a minimum reading.Adjust L307 [L407] for a peak reading.Adjust L302 through L307 [L402

Page 4

Page 5

4much RF or your power supply can’t handlethe load, don’t worry. There is a power adjustcontrol that will allow you to lower the power.For the record,

Page 6

5PL Encoder and decoder removal.If you do not have an encoder or decoder, skip tostep 3. If you have one board but not the other,follow step 1 or 2 an

Page 7 - Schematic in Appendix ??

64. Remove the exciter board. This board isheld in place by 7 screws. You will alsoneed to remove 2 (or 3 WS) phono plugconnections. One is the excite

Page 8

7If you are using a TAPR/G3RUH Modem, skipsteps 3 ,4, 10 and 11.3. Refer to Appendix A for the data inverterschematic. Build the data inverter on asma

Page 9

8Pin 16 of P904 is connected to ground andthe foil that connects to this pin is a goodplace for the shield connection. It may benecessary to use a scr

Page 10

9Data Connections.Data connections to the outside world arebrought out on unused pins on the power plugP901. These connections are as follows:Pin Fun

Page 11

108. TX Data In. (TPRS Modem) Connect ashielded cable to P901-31 center, P901- 32shield. Route this cable from the powerplug to a hole in the side of

Page 12

118. Connect the center conductor of the TXdata cable to the free end of R319 (15K).This completes the standard excitermodifications. Re-install the e

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Motorola L305 Manuel de service

Naviguer en ligne ou télécharger Manuel de service pour Téléphones Motorola L305. Motorola L305 Service manual Manuel d'utilisatio

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