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VHF/UHF Syntor® PROM Editor and Intel HEX file generator program

The Motorola Syntor radio is a very nice synthesized radio. Many of these radios have 100 or 110 Watts of power output. One of the very nice things about this radio is that it can easily be modified to be capable of an almost unlimited number of channels. This software directly supports programming of 256 channels, but it is easy to use the software to program 1024 channels or more into one of these Syntor radios. Another nice thing about this radio is that they are readily available at hamfests or on the internet for a very low cost. Probably the nicest thing about these radios is that they were built with extremely high quality and are able to go into the most difficult radio environments and not suffer from "intermod", "spurious responses", etc. In addition to all that, they also offer an opportunity for the owner to exercise and advance their radio knowledge, ability, and expertise while having a lot of fun in the process.

This software is an inexpensive but full featured "do everything" Windows program that you can use to generate the Intel HEX files needed to program the Frequency and PL PROMs, EPROMs, etc. for use in the Motorola VHF and UHF Syntor® radios. Download a FREE DEMO version of this program.

All you need is this program, suitable PROMs (or EPROMs or EEPROMs, etc. and a PROM to EEPROM adapter), and access to a PROM/EPROM programmer and you can program an almost unlimited number of channels (see note below) into your VHF or UHF Syntor® radio. This is more than enough channels for all of the two meter repeater channels, simplex channels, repeater talkaround channels, even "reverse repeat" channels in the two meter FM band. Note that "Syntor®" as used here refers to the "original" Syntor® radio ONLY (and does not include Syntor® X, Syntor® XX, Syntor® X9000, etc.).

Don't have access to a PROM/EPROM programmer? I will provide FREE (for a limited time) EPROM programming to purchasers of this program who don't have access to an EPROM programmer. Moderate shipping and handling charges will apply (to cover the cost of returning your PROM/EPROM to you). Simply use this program to create the Intel Hex file for your radio and frequency list, attach it to an eMail message, and send it to me along with your order. I can also supply a suitable EPROM on request. I have a stock of both NEW and USED EPROMs.

On this web site there is also information about EPROM/EEPROM adapters for both the Frequency and PL PROMs used in these radios that you can make yourself. There is also information about EPROM/EEPROM adapters for the Frequency PROM that you can purchase.


The cost of this program is $25.00 for a single user license (see license details below). The program can be shipped via eMail, in which case the shipping is free. The program can also be shipped on a 3.5" floppy disk or CD-ROM. The cost is $5.00 extra for a floppy disk version, plus shipping costs (typically $9.50 to a commercial address, $11.50 to a residential address). Shipping cost can be reduced upon request to $5.00 for shipping via USPS priority mail, but this includes no insurance or trace-ability. NOTE: Shipping costs are higher outside the continental limits of the USA.


The FASTEST and LEAST EXPENSIVE way to order this software is to send your order via email and make your payment using PayPal. When you pay using PayPal you can pay using your credit card, your PayPal account, direct withdrawal from your bank account, or by eCheck (though paying with eCheck will cause a several day delay while your check clears through PayPal). There is NO EXTRA cost to you when paying this way.

Order Via eMail:

to order the software via eMail (go to HOME, then use "About Ries Labs" to send the email). Tell me what you want to order and and ask for my PayPal ID in your email. Ask to verify the total amount for your order, then go to PayPal and send your payment. Software sent via e-mail is now sent inside a "ZIP" file (since receiving "exe" files by e-mail is now impossible for many people - anyone using Outlook or Outlook express or restricted by corporate or ISP filtering). If you can't "un-zip" a zip file, please let me know when you order so that I can assist you. Windows XP will un-zip files for you but if you are using an older version of Windows you will need to use some other software to un-zip a file. There are several freeware programs that can zip and un-zip files.

Order Via regular Mail:

To order by regular mail.(go to HOME, then use "about Ries Labs" to obtain our address, etc.). Make the payment payable to Roger P. Ries. The payment should be a bank check or money order or a USPS money order. The payment must be in U.S. dollars. It is a good idea to verify the amount if you are ordering a floppy disk or CD-ROM version of the software since shipping costs shown on this web site are sometimes not CURRENT.


1.) Uses PROM data files which contain your frequency lists, PL tone lists, and also important information about your radio. These files can be Opened, Edited, and Saved using this program.

2.) This system is intended for use with the Syntor® radio and its normal complement of accessories (control head, control cable, Mike, Speaker, etc. -- including scan heads, etc.). with minimal modifications required only as needed to expand the number of channels available. While this program is oriented towards Syntor® radios with 16 channel accessory groups, the PROMs produced will also work fine in Syntor® radios with 1, 4, 8, or 12 channel accessory groups.

3.) Important details about your radio (its frequency RANGE ("SPLIT"), HI or LO side injection,VCO Offset, Number of Channel Banks, type of bank switch, etc.) are included in the PROM data files and can be easily edited also.

4.) This program includes a Bank Oriented Frequency List Editor which supports up to 16 banks of 16 channels each, and can be used to enter and edit channel frequencies and also PL tone frequencies.

5.) Text style frequency and PL tone lists (of up to 256 channels in 16 banks of 16 channels each) which you can create using your favorite text editor program can be Imported by this program and converted to PROM data files. This feature allows you to use your favorite text editor to prepare your frequency and PL tone lists, if you prefer.

6.) This program can also Export its frequency and PL tone lists to text files for printout, further editing, etc.

7.) This program includes a VCO Offset frequency calculator to help insure the most reliable results. This feature makes it easy to compensate for VCOs which are slightly off frequency due to age or other factors and eliminates the need to work on the delicate VCO circuit board. A simple measurement is all it takes and then this program can do the rest. (If the VCO is too far off frequency, it will need to be repaired first however.)

8.) This program also has provision for a completely "custom" VCO sub-range frequency list so you can use it to program radios that have use a modified or repaired VCO.

9.) This program allows you to select whether the VCO is programmed on the high or low side of the receive frequency (i.e. "high side" or "low side" injection). This feature makes it easy program PROMs for normal radios (ones used in their normal "splits") and also radios used outside their normal splits.

10.) This program generates the PROM data from the frequency lists and vital radio information, and writes the results to an Intel HEX file suitable for use with most PROM / EPROM programmers.

11.) This program includes an extensive HELP system to guide you while you learn how to use this program. The HELP system also includes information about how purchase or "home brew" an adapter so that you can use easily available EPROMs and EEPROMs with the Syntor® radio.

12.) Included with this program is a README file with much valuable information about programming the Syntor® radio and related topics.

note: The files maintained by this program can contain up to 256 channels, but it is easy to use the program to program several times this many channels into a Syntor radio. The number of channels you can program into the radio is limited only by the size of the PROM or EPROM/EEPROM used and the simple modifications you have made to the radio (added bank switches, etc.). Further information about this is contained in the "help" file and other documents supplied with the software.


This program is a 32 bit Windows application and is compatible with Windows 95, Windows 98, Windows Me, Windows NT, Windows 2000, Windows XP, etc. though I have no way to test it on all possible Windows platforms. I have tested the software most extensively on Windows 98 and Windows XP Professional. There are no special requirements as to the speed of the CPU, amount of memory, amount of disk space, etc. If your computer can run one of the above versions of Windows, it ought to run this software without difficulty.

You can download a FREE DEMO version of this software and verify that it works properly on your system if you like -- before you purchase. The FREE DEMO version of this software has all normal capabilities, but will not generate the Intel HEX output files. Go to Download SynPromW32 page.


In order to use the Syntor® radio with EPROMs, EEPROMs, etc. it is necessary to make or obtain a special adapter. This adapter plugs into the Syntor® PROM socket and provides a second socket where the EPROM or EEPROM (etc.) can be plugged. We sell inexpensive adapter circuit boards, adapter parts kits, and assembled adapters. The adapters we sell can be used with a large variety of 24 and 28 pin EPROMs (2716 thru 27512 variants) and EEPROMs (2804 thru 28256 variants). Information about how to "home brew" a suitable adapter is supplied with this program, and is also provided on this web site. The information supplied is adequate to allow a person reasonably skilled in the art of electronic construction to build a suitable adapter.

No adapter is required to use this program with normal (16 and/or 32 channel) Syntor® PROMs, though it must be mentioned that these PROMs are obsolete, becoming difficult to find, and can only be programmed one time so that a new PROM must be used whenever the frequencies are changed.

The above adapters are similar to an adapter described elsewhere for 2716 EPROMs (which is compatible with the output of this program). Note that the output of this program MAY or MAY NOT be compatible with adapters described by other authors.


I maintain a list of email addresses of customers (except any who have requested NOT to be on it). I use this list exclusively to send free updates of this software to customers whenever I make any significant changes, repair any problems found, etc. Note that these updates are sent via e-mail and these updates have the software installer program enclosed in a "ZIP" file - so it is necessary to first "un-zip" and then install the software. This has become necessary since many users can no longer receive "exe" type e-mail attachments.


If you purchase and install this program, you implicitly agree to the terms of my license. Briefly, you agree that you will be the only user of the program if it is installed on more than one computer system OR you may install it on only one computer system that may be used by multiple users. You may make one or more backup copies for your own exclusive use. You agree not to make any other unauthorized copies, nor to provide copies to any other person, organization, etc. without the written authorization of Roger P. Ries, the author of the program. You also agree to a disclaimer that is part of the license agreement. The full license agreement is supplied with the program -- including the FREE DEMO version.


1.) You need to understand that you are buying a program that has not been tested by many users other than by myself. I have tested the program extensively, but it is possible that you may find a flaw (or flaws). If you report any problems, I will try to correct them and provide you with a "fixed" version of the program. I will also provide (via eMail) updated versions of the program from time to time including fixes for any problems discovered by you or others -- to all purchasers except those who request NOT to receive this service. This will be done at no extra charge (within the constraints of my schedule, which places undue importance to other things such as my "day" job, etc.)

2.) I will not be responsible for any incidental or consequential damages that might result from the use of this program, including (but not limited to) PROMs lost due to incorrect programming, damage that might occur to your radio, etc.


The images below show some of the screens from the VHF/UHF Syntor® PROM Editor and HEX file generation program.

The above image shows the Syntor Software after the "File" menu has been opened.

The above screen shows the Radio and PROM information editor when a "new" file has just been started. The "new" file is "preset" for the Range 3 VHF radio and the other settings as shown. This is just a convenient starting point and the user is free to select whatever items match up with the radio to be programmed. Several extra options are present to provide the software with the flexibility necessary for almost any concievable situation - but these can be ignored for the more common situations. An extensive HELP program is part of this software -- to help the user learn to use the software, even the advanced features. An example of one of these features is the Receiver L.O. Injection option. The Syntor radio uses "low side injection" when operated according to the original design, but it is possible to operate the radio shown (Range 3 VHF) in the 144 to 148 MHz amateur radio band without having to modify the radio if "high side injection" is used in the receiver. Selecting the "High Side Injection" button (as shown) frequencies in this "ham" band can be programmed. The only change to the radio that is required is to re-align the radio to the new frequencies.

The above screen shows the Radio and PROM information editor after one has selected the Range 3 VHF radio, enabled the Custom VCO Frequencies option, and then set the Custom VCO Default Frequencies - which are the normal VCO sub-range frequencies for the Range 3 VHF radio, but which can now be edited as desired. This feature is not needed for most programming, but is very handy when the user wants to operate the radio slightly outside the design range - or when programming a radio which has been modified, etc.

The above screen shows the bank selector screen as it looks when a radio with four frequency banks has been selected. This screen is used to select the Frequency bank to edit. If the "Bank 1" button is pressed, the screen changes to the one below.

The above screen shows the frequency list editor being used to edit the TX and RX frequencies and PL frequencies in Bank #1 of a Range 3 UHF radio (450 to 470 MHz). This radio is being programmed with frequencies in the 3/4 Meter Amateur radio band. This radio works nicely (without the need for any modifications) on the 3/4 M Amateur radio band when "High Side Injection" is used. All that is necessary is to program the radio and re-align it to the new frequencies. This shows the radio being programmed with "slaved" PL (the PL frequency changes when the frequency selector switch is changed -- which is normal for the Syntor radio). For this example, the receiver is operated using carrier squelch on all channels - but it is also possible to program PL (tone squelch) on some or all of the receive channels. It is also possible to program some or all TX channels with no PL tone simply by programming "CSQ" for the TX squelch. Note that the PL must be entered by the PL tone frequency for the Syntor radio - rather than by the "PL Code" (i.e. 1A, 3B, etc.).

Note: Syntor® is a registered trademark of Motorola, Inc.

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