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Syntor Transceiver with PIEXX SynControl Installed
The Motorola Syntor is an early 1980’s two-way radio designed and
manufactured to Motorola’s traditionally high standards. It was intended
to provide trouble free service in the public service, military, and commercial
fleets, a goal that it easily met. The Syntor was one of the first transceivers
to provide frequency synthesized ‘programmable’ operation. The frequency
determining control element was a factory, or service center, programmed
PROM chip that was specifically set up for a given customer. This was a
great advantage over the more common technique of using custom made crystals,
or channel elements, to set the transceivers frequencies. The Syntor design
was a winner with Motorola’s customers and many, many units were sold.
Two decades later, the state of the art in 2-way radio communications has
made great progress in the area of control electronics, specifically with
the use of microprocessors in their design. Current generations of transceivers
employ channel programming via computer / micro-controller software; custom
programmed PROM chips are just too inflexible and are no longer used for
this purpose. The Syntor, like some other great Motorola designs, has become
obsolete. These radios are showing up at Hamfests and online auctions in
large quantities at prices for pennies on the dollar. However, this obsolescence
is due to the lack of control sophistication not the Syntors excellent
RF design. In order to ‘revive’ this great transceiver we needed to come
up with an easy way to replace the aging control design with a more modern,
microprocessor based system. To this end, our SynControl System was born.
The PIEXX SynControl System evolved in two steps. Our original goal was to provide a system that would allow the replacement of the old bipolar PROM frequency controlling element with a computer downloadable uP based board. In the original design, a board was mounted inside the radio and connected to the PROM socket via a ribbon cable. The appropriate firmware was generated for the uP board to allow the selection of channel frequencies, and PL tones via a remote computer. Although this first generation design worked well, it became apparent that with a few more features we could really solve a big problem with the Syntor radios showing up in the surplus market, namely that there were a lot of radios showing up but hardly any control heads / cable sets. Our second generation SynControl design is a direct, plug in replacement for the original Interconnect Board. The new design takes over the functions of:
Because the SynControl Board replaces the original Interconnect Board,
the custom Motorola power / signal connector is no longer used. The function
of the old connector is replaced by a standard Molex style 9 pin connector
for power and speaker connection, and a 8 pin modular jack that carries
the signals for RS-232 communications, PTT, microphone and speaker audio.
The SynControl Board is a direct plug in replacement for the original equipment,
installation is very easy and involves very few hard wired interconnections.
Since the transceiver can now be completely controlled through the 8 conductor
RJ-45 cabling by way of an external PC, it is possible to remotely locate
the Syntor from the control operator. Instead of running a long antenna
cable to the radio, you can run a short antenna feed line to the radio
and run a longer, inexpensive, control cable to the operating position.
The Win9x software package, provided with the SynControl System, allows
all of the flexibility of a modern transceiver with the ease of use of
an on-screen virtual control panel, The operator can set radio frequencies,
offsets, PL tones, memory location (with names), scan channels, view the
signal level, set volume and squelch all from a remote PC.
The standard SynControl package includes:
An option LCD control / microphone board, available shortly, will
allow the radio to be operated without an external computer once the channels
have been set up.
The SynControl Upgrade System is intended to be installed in Motorola
Syntor Radios Not Syntor X Radios. We currently support VHF high band radios
and the conversion is for the use of these radios on the 2 meter amateur
radio bands. At the time of this writing, radios with VCOs in ranges 2
(HDL4036A), 3 (HDL4037A) and 4 (HDL4038A with jumper modification) are
supported. I have never had a range 1 (HDL4035A) radio to try our conversion
on, if we find one we will make the required firmware changes to support
the range 1 VCO radios. Needless to say, range 1 VCO radios seem to be
If available, a Signal generator and deviation meter will help with
Please read and understand all of the installation
instructions before starting the installation.
HDL4038 VCO jumpered for use in the 2 meter Amateur band.
Meter lead (orange wire) installed in Limiter / Detector pin of the receiver metering connector
Software Installation The SynControl Software is intended for operation under the Windows 95 or Windows 98 operating system. Install the software by placing the provided CD in your CDROM drive, press the Start Icon (usually in the lower left of your desktop), proceed up to and press the Run selection of the pop-up menu. In the open dialog box type:
Where D is the drive designator for your CDROM
drive After entering the command line press enter, and the system software
will be loaded.
If the SynTalk Dialog Box doesn’t appear, read and
perform the following tests…
If instead of the SynTalk dialog box, you get the error "Communications Error with the Syntor!!! Program Exiting.", then your computer is unable to establish serial communications with the SynControl System. Be certain that you are properly connected to the serial port specified when you installed the software, and that all cables are plugged in and that the transceiver has power applied. If you think you specified the wrong com port, you can manually select a specific port by editing the SynTalk.ini file located in the Windows Directory. If you double click the SynTalk.ini file, in the following path:
You will see the set-up parameters for the program. Under the category
of [Communications] there is a line that reads Comm Port (1-8) =1, where
the digit following the ‘=’ sign is the comport that the radio must be
connected to. You can manually change this digit if necessary. If this
digit is 0 then Comm ports 1-8 will be scanned to see if the Syntor is
on one of them.
If the radio fails to communicate with the program, after you are sure that you have selected the correct com port, you will need to perform a loop-back check on the specified com port. Start Hyperterminal:
Hyperterminal (click it)
Double click the Hypetrm.exe icon. This will open the New Connection Description dialog box. Type Syntor in the name field and press OK. Next, the Phone Number dialog box will appear, press the arrow to the right of the Connect using field. You may now select the appropriate Direct to Com for the port you are intending to use. Next press OK, the Comx Properties dialog box will appear. Select :
19200 Bits per second
8 Data bits
1 Stop Bit
Flow Control None (this is very important!!)
With these selections made, press the OK button. You will se a blank window with the terminal cursor in the upper left corner of the screen. If you press the ‘?’ key, with the SynControl system functioning properly, a string similar to:
Metering lead shown in the injection metering test point.
I have found that on most radios, the slugs on L1-L5 tend to end up in a position with 2 to 3 threads exposed above their jam nuts when the alignment is complete. This indicates that this would be a good position to start from when you attempt the alignment. Do not go wild screwing the adjusting screws all the way in or out during the alignment process. The front end of the Syntor was intended to have a maximum channel spacing of 2 mHz, although in practice you can get acceptable results with a bit wider spacing. I usually try to get my receiver aligned so that the best sensitivity is around the 147 mHz mark; sensitivity will fall off at the low end of 145 mHz but is still adequate.
The operation of the SynTalk program is quite intuitive and we encourage
you to experiment with its features. There are several points that need
amplification as follows:
Setting Memory Channel Data:
To set a memory channel parameter, use the main SynTalk Dialog Box
to input the desired settings, frequency, PL tone, channel skip , desired
offset and, in the box beneath the Update and Clr Skips buttons, any text
comment you would like to attach to this memory. After setting these parameters
press the Update button, this will bring up the Channel Manager Dialog.
To change a specific channel to reflect those parameters previously set
in the main SynTalk Dialog, select the channel by clicking on its line
in the channel descriptor list box and the press the Over Write button.
The memory channel will be updated with the parameters from the main SynTalk
Dialog. You can move a specified memory locations parameters up or down
to adjacent memory locations by highlighting the desired memories location
and then pressing either the Move Up or Move Down buttons. Pressing the
Delete button will clear the highlighted memory location to show a frequency
of 146.52 and remove its text identifier label. Pressing the Clr Skips
button will remove all channel skip information from the list of memory
channels. If a memory channel has a skip flag marked, as indicated by the
letter ‘S’ to the right of its channel number, this memory location will
be skipped during scan operations.
There are two ways to exit the Channel Manager, by pressing the Update
or Cancel buttons. If you exit by pressing the Cancel button, any changes
that you have made will be ignored. If you exit by pressing the Update
button, the changes will be written to both the radio and the channel file,
by default named VHFFreq.fdt. It takes two or three seconds to update the
radio and the file, so be patient.
Scanning Memory Channels:
Scanning memory channels can be accomplished by pressing the Scan
button. When the SynTalk Program is in the scan mode, a green indicator
will appear above the scan button. The scanning mode may be terminated
by pressing most of the functions within the SynTalk Dialog Box, in particular,
a second press of the Scan button. While the scan mode is in operation,
channels will be consecutively accessed, unless its Skip flag is set, until
a channel with a carrier is reached. Scanning will stop on an active channel
until either the carrier drops on the channel or a Scan Hold on Signal
time out is reached. The Scan Hold on Signal Time is a parameter that is
defined in the SynTalk.ini file and by default is set to 5 seconds. If
the scan stops on a channel that you do not want to monitor, you may press
the Skip button. This will lock this channel from further scan access and
scanning will resume. By pressing the Clr Skips button, all channels will
available for monitoring in the scan mode, that is all skip flags will
be cleared. The skip flag status of any channel is temporary unless you
enter the Update mode and save the channel information by exiting from
the Channel Manager Dialog via the Update button. If the file data is not
recorded by this technique, the original memory channel data, along with
channel skip flags, will be retrieved the next time the SynTalk Program
The Setup button is used to enter the Setup Syntor Dialog. From this
dialog you can setup the transmit timeout timer, the signal meter zero
and full scale settings and the power up default settings for frequency,
volume squelch etc. You should have the parameters that you would like
for the power up condition of the radio selected in the SynTalk main menu
prior to pressing the Setup button. Once in the Setup Syntor Dialog, exiting
by way of pressing the Save button will set the power up defaults of the
transceiver to the current mode. If you wish to set the signal meter operating
conditions, it is a good idea to set the zero value, by pressing the Set
Zero button while in a no signal condition, before setting up full scale.
To set full scale, input a signal that you wish to save as the full scale
setting of the signal meter and press the Set Full Scale button. Good sources
of this Full Scale signal would be a very strong local repeater or a signal
generated by a nearby HT. The setup parameters will be saved in the SynControl
boards non-volatile memory when you exit the Setup Syntor Dialog by pressing
the Save button. If you exit by pressing the Cancel button, the parameters
will not be saved but will be in effect until the next time the Syntors
power is cycled.
SynTalkPS is a second program distributed on the standard installation
disk. This program is tailored for the Public Service users of the Syntalk
system. This program has the same basic functionality as the SynTalk program,
but is a bit more ‘Point and Shoot" than the standard program. In addition
the SynTalkPS program allows for priority channel scanning. In order for
a memory channel to be considered a priority channel, its information must
be moved from the Regular channel list to the priority channel list. Do
this by highlighting the desired channel and then pressing the <> button.
The SynTalkPS has a different .ini file from the SynTalk program.
It is located in the same directory as the SynTalk.INI file but is named
Note: The Win98 list animation mode adversely affects the speed of
scanning and should be turned off. Press:
Then make sure that the box marked "Animate windows, menus and lists"
is not checked off.
8 Pin Modular Connector pin outs:
SynTalk Control Head
The Syntalk Control Head / Microphone is intended to allow operation of the Syntalk converted Syntor transceiver without the use of a dedicated computer. Although the control head is primarily intended for channelized operation, it is capable of the following operations:
Installation of the SynTalk Control Head is very easy. There are
two connectors on the bottom of the control head. The 1/8 mono jack is
connected to the speaker circuit and you can use it for an extension speaker,
although it is preferable to use the speaker connections on the 9 pin MOLEX
connector on the SynTalk interface board. The 6 pin modular jack makes
all other required connections. Use the provided cable, the 8 pin side
goes to the SynTalk board, and the 6 pin side goes to the SynTalk Control
head. Only the first 6 connections in the 8 pin connector need to be carried
to the control head; keep this in mind if you decide to make your own modular
Even though the SynTalk Control head has only 6 buttons and a 2 digit display, it is capable of performing quite a few operations. These operations are explained in the order of their importance. It makes sense to master those operations at the top of this list before tackling the more complicated features. It is useful to know that:
Memory commands are numeric in both digits of the LCD display while VFO commands always have a letter in the LCDs left hand digit.
Upon initial power application to the SynTalk Control Head, the LCD display will show two dashes followed by either:
Mem / VFO Button:
The MEM / VFO button toggles the Control Head from the VFO mode to
the Memory mode. All Memory mode operations display numeric
values in both of the LCD digits, while VFO operations always display a
letter in the left most LCD digit. As previously stated, the display
will be in the VFO mode initially after application of power. If you press
the Mem / VFO button to enter the Memory mode the display will show two
dashes indicating that the control head doesn’t know which memory channel
is currently selected.
Memory Mode Operations:
Pressing the Mode key will move the Control Head to
its various operating modes. The mode key is cyclic, multiple presses of
the keys will cycle the Control Head through each of its various operations.
In the Memory mode, the allowed operations are Channel Selection, Volume
VFO Mode Operations:
Again, pressing the Mode key will move the Control
Head to its various operating modes. When you enter the VFO mode, by pressing
the Mem / VFO key, the allowed operations are Frequency, Tone or Offset
F4 F6 F5 F2 F0 F(blank)
This display will be continuously repeated, the F(blank) being the key to the start of the end of the displayed number. Although this may seem to be a bit clumsy, the display is very easy to read with just a small amount of adjustment time by the operator! Pressing the Up key increases the frequency in 5 kHz increments while the Down key reduces the frequency a like amount. It is not necessary to wait for the display between subsequent presses of the Up or Down key. That is, if you want to increase the frequency by 15 kHz, press the Up button 3 times, the display will begin showing the new frequency.
t0 t8 t5 t(blank)
Pressing the Up or Down keys will change the transmit tone frequency. As with the frequency change command, you don’t have to wait for the display between subsequent presses of the Up and Down keys.
oP Transmit is offset higher in frequency
o0 Transmit and receive are operating on the same frequency
oX Transmit and receive are on different frequencies but not a standard offset.
Changing a frequency, offset or tone is temporary. If you leave the frequency mode and change to another channel and back you will be returned to the original channel settings. You can permanently update a channels settings by performing the following steps:
The scan mode may be entered by pressing the scan button
from either the VFO or Memory mode. When you enter the scan mode
the SynTalk Control Head will enter the memory mode and begin scanning
the memory channels sequentially until an active channel is located. When
an active channel is located the scan mode will wait approximately 5 seconds
and then begin scanning again. The scanning sequence is terminated
when any key is pressed, including the PTT key. The key that is
pressed to terminate the scan operation will be ignored, except to stop
the scan operation. So, if you use the PTT key to terminate the scan operation,
the transceiver will not enter the transmit mode until the PTT key is released
and then pressed again.
Displaying Signal Strength:
The signal strength mode may be entered at any time
by pressing, the releasing, the Mem/VFO and Mode key simultaneously (notice
the S between these two keys). When in the Signal Strength mode,
the display will show values between 00 and 99 to indicate the relative
signal strength of the currently received signal. The Signal
Strength mode is terminated when any key is pressed, including the PTT
key. The key that is pressed to terminate the signal strength mode
will be ignored. So, if you use the PTT key to terminate the signal strength
mode, the transceiver will not enter the transmit mode until the PTT key
is released and then pressed again.
You can swap the transmit and receive frequencies, as well as swapping
the offset direction, by simultaneously pressing, then releasing, the Up
and Down keys (notice the In silk screened between these two keys). This
mode is handy to see if you can hear someone on the input of a repeater
or to communicate with someone if the repeater goes down. Repeat the process
to return back to the normal mode. The input mode switches the SynTalk
Control Head to the VFO frequency display mode.
The SynTalk Control Head may be used to transfer channel data between
the computer and a remotely located computer. In order for
the computer to communicate with the SynTalk Control Head, the control
head must be connected to the same serial port used to communicate with
the Syntor transceiver with the optional serial / power adapter.
This optional power adapter board is connected in series between the control
head and the modular DB9 serial adapter plugged into your computers serial
port. In addition, the power adapter must be connected to a suitable, supplied,
wall transformer. Upon application of power to the SynTalk Control Head,
you will first see two dashes on the display, followed by two error codes,
and finally two dashes again. The error codes indicate that the control
head can not communicate with the Syntor transceiver, and are normal with
You should use the SynTalkPS program version 1.01 or later, as previously
described, to create / modify your channel list. If
the SynTalkPS program doesn’t see a Syntor radio on any of the computers
serial ports it will respond with:
After you press the OK button, the program will continue in the Stand
Alone mode. In the Stand Alone mode you are allowed to maintain the channel
database in the normal fashion. You can transfer the channel information
to the control head by pressing the ‘Update’ button followed by the ‘Copy
File to Radio’ button in the Channel Editor Dialog. If the SynTalkPS program
is in the Stand Alone mode, the Copy File to Radio routine knows to try
to communicate with the control head instead of the Syntor transceiver.
Alternatively, you can use the SynCtrlHd program to send .fdt channel database
files to the control head.
During the download process, the SynTalk Control Head will briefly
show dL on its display, followed by the numeric value
41. The 41 indicates that 41 memory channels have been loaded into the
SynTalk Control Heads non-volatile memory. The control head may now be
disconnected and moved to the transceiver site.
The upload process from the control head to the Syntor transceivers memory is accomplished by:
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