An attempt has been made to write this procedure for
those without a shop full of test equipment.You don't need to build a
test set.Many thanks to Brian Clarke VK2GCE who helped me test this procedures
and helped with the technical details.
General: The transceiver contains a receiver and transmitter module. The transmitter module is marked "Sender" and is located on the top of the unit. The unit shares a single crystal for transmitting and receiving and the I.F. (Intermediate Frequency) is 10.7 Mc's which runs continuously in transmit and receive. The radio is a nice well constructed unit both electrically and mechanically. The unit can be aligned in the range of 38 to 47 Mc* * * or 47 to 58 Mc. It's perfect for short range commo such as conveys,going to get pizza and hamfests.
* * *Hertizes, Megahertizes, Kiloherzskies are not recognized on this site. Wat are we gonna do next call a Motorcycle a Motorhertz ?
Crystals: The helmet receiver a PRR-9 has the same frequency scheme as the FSE 38/58 and the crystal works well in the 38/58. The formula for the crystal is Operating Frequency minus 10.7 Mcs. Calculating an Operational frequency of 51.0 Mcs the crystal frequency is 51.0 minus 10.7 which equals 40.3 Mcs.
minus 10.7 = 40.3
The power for the radio can be supplied via 24 VDC or 6 VDC. The 24 volt
input is via a standard 3 pin connector on the front. The 24 volt voltage
regulator provides 6 volts to the radio and the input is protected by a
"series" diode on the ground side of the 24 volt external connector to prevent
you from blowing up the circuit when you feed the 24 volts backwards. It's
very hard to read the external power connector pin labels so when attaching
24 volts be sure and confirm pins.
The radio contains a battery case for a 6 volt battery and you can put in 4 double A cells in series to power the radio several users have used a Radio Shack battery holder, the part number is 270-383. The schematic for the radio calls for 5.5 to 6.5 volts for the battery and for external power it lists 20 to 32 volts.
|The plus side of your 6 volt pack goes to a extended terminal
at bottom of the case, it sticks out from the case and has a existing Red
wire which feeds the radio's 6 volt circuits, Red is positive , the minus
side of the battery goes to the chassis installed a reverse protection diode
with the cathode or banded end on the red wire tie point and the anode or
unbanded end going to ground.
Click to enlarge
Warning: If you accident hook up your 6 volt battery pack backwards and it is not protected by a reverse polarity or series diode (which you must install)you may damage your transceiver.
The twist cap will no longer fit on the case so put it aside in a safe place or just chuck it. When you store the radio, you might want to remove the batteries or unplug and cover the battery case terminals for safety.
For my bench testing I simple tacked on a red plus wire to the battery case at the bottom and a black minus wire to the chassis of the radio. The 6 volt and 24 volt lines are protected by small 2 amp fuses located next to the battery case.They are vertically mounted fuses and are marked 125v.
|Alignment/Testing: Equipment: As a minimum you will need a receiver capable
of receiving the oscillator(oszillaator) crystal frequency and the transmitter
frequency, a 47 ohm resistor and a diode. A multi-meter in the 1 or 2.5
volt range as well as a 100 milliamp range. A small signal generator or
transmitter PRC.-10, PRC-25 etc. will be needed to generate a signal on
frequency to receive align the receiver. You will need to fashion a home
made tuning tool and may need a "snoop loop" as described below. Your power
supply needs to be 6 volts and be capable of 100 mills or one tenth of an
Overview: We will align the unit oscillator first using a single point on the "test" connector on the radio, . You will also observe the current draw while aligning the remaining stages of the transmitter. Now is you are lazy and don't want to hook up a current meter and observe the current draw then be prepared for trouble.
Alignment of the "front end stages" of the receiver will be done by listening to a signal generator or a nearby transmitter and only involves tuning two coils as the rest of the receiver does not need alignment
Procedure: The radio has 7 alignment tuning cores that are easily accessible. Five of the tuning adjustments are on the "sender" and two are on the "Empfanger". They are labeled 1 through 7 and I will refer to them as L1, L2 etc. The radio has two rotary switches that are located near the tuning cores. These switches are turned by a flat blade screwdriver and have two positions marked A and B. Position A is for 38 to 47 Mcs and Position B is for 47 to 58 Mcs.
Click to enlarge
These switches are used to switch small values of "ganged" capacitance in and out of the receiver and transmitter circuits to provide proper tuning in the selected range. The tuning shaft or stub positions in relation to frequency of operation are generally at the bottom or all the way in the core of the coil for the bottom end of each range A and B range. As you go higher in frequency the core tuning stubs will extend out of the core and become more visible. We will "preposition the tuning stubs later in step 3(three). Power up the radio using 6 volts and attach a milliamp meter in series with the plus lead of your power supply. The function switch on the front of the radio selects between the 6 volt positions on the left and the 24 volt position on the right. "Aus" is off. M.r. positions are for squelched operation, o.R is for open, unsquelched operation. Make sure your volume is clock wise.Unsquelched or squelched in the receive mode the radio draws 20 milliamps If it doesn't then something is wrong.
| Try and get the unit to work with the original crystal
that was installed. Once it is working PRACTICE the alignment on that channel
to get a feel for the radio and this basic procedure if you don't want to
follow this tip and follow your old CB(* * * )practices then be my guest.
Now if you can't get the unit to transmit or receive and actual signal but
the receiver current is still around 20 mills, repeat 20 mills and you hear
noise on the receiver --then press on.
* * * See Glossary elsewhere
1. Determine that the receiver is working by un-squelching, you should be able to hear noise.You do not need a crystal to do this, just simple unsquelch and monitor the current draw of 20 mills. Make sure that your power supply is supplying 6 volts!
3. Alignment on 51.0 Mcs requires that you preposition the coils by tuning them down (clock wise)into the radio. When pre-positoning the coils don't get carried away and get the coils too far into the radio, they will be hard to get started out CCW(counter clock wise) again. The threads of the tuning stubs should be well down into the radio with just the flat portion of the stubs sticking out a turn or so.
4. Turn both rotary switches to the "B" position for alignment on 51.0 Mcs. Note: You do not have to transmit to tune oscillator coil L1 in the following step number 5 as it is the master oscillator and is used for both transmit and receive, you can tune it while in the receive mode.
5. Locate the small test connector which is next to the bottom of the battery case and has many little mystery holes in it. Looking at the connector there is a "notch" on the side, the oscillator test pin is located immediately to the left (port side) of the notch. Hook up a voltmeter (preferably analog), select a low voltage scale of 1 or 2.5 volts and monitor from that pin to ground.It is best to use an analog meter instead of a digital for peaking. If you can't get your test probe in the test socket points then try using one of my favorite tools a safety pin
During our alignment we peaked Coil L1 and monitored the test pin voltage and listened on a receiver to the crystal fundamental of 40.3 Mcs(that 40.300 on ur scanner). If you have trouble hearing the crystal oscillator with your "monitor"then fashion a "snoop loop" out of a short length of coax. Put on a connector for the "monitor receiver" and at the end of the 2 or 3 foot coax section and put a two inch piece of insulated wire from the center conductor of the coax to the shield and fashion a small loop. Use this to couple the " monitor receiver" to the area of the FSE 38 coil L1 and crystal. Snoop around for the best signal near L1 and the crystal. As the stage is tuned the crystal will take off and start oscillating then you should have plenty of signal. While tuning coil L1 look at the test meter and peak to maximum voltage around .4 or approximate half a volt. Just tune for peak don't worry abut the exact voltage. Coil L1 does effect the transmit and receive frequency slightly but peaking is close enough for government work.
|6. Confirm that you are indeed listening to the crystal frequency by pulling the crystal out of the socket and the signal disappears, then put the crystal back in its socket.Sometimes stages like to sort of take off and oscillate on their own. NOTE: Prior to transmitting hook up a dummy load to the FSE 38/58's antenna BNC connector by construction one out of a small 47 ohm resistor.
WARNING:Don't tune up the transmitter without a load, you can damage
the final transistor stage.
Note :Eventually our goal is to draw about 100 mills when transmitting in the 50 mw position of the radio. You can monitor your progress and the output of your transmitter by watching for the goal of a 100 mills.
Note: You can not tune L6 and L7 by transmitting, at least I could not
do it. It is a band pass circuit that is shared by both the receiver and
the transmitter. So we tuned 6 and 7 by tuning the receiver for maximum
signal.You can still leave the dummy load on the receiver for tuning the
|Note:Modifications to the output power circuit were not made. Why screw up a perfectly good unit and increase battery drain etc.