Drive your Yaesu FT-757GX or similar transceiver using your Amiga and this program, compiled by Tom Moffat, VK7TM. == The following documentation is selected from an article published in Amateur Radio Action, Dec 1988, written by VK7TM.== .....So, what does the program do, you say ? Well............. 1 --Using the menu, you can type in a number that actuates any of the Yaesu CAT computer-controllable features. 2 --You can enter a new frequency directly into the radio simply by typing it on the keyboard. 3 --You can generate a list of up to 100 frequencies, with descriptions of what they are, on your computer, then send the list of frequencies to the radio simply by selecting the channel's number from the list on your screen. 4 --You can then edit the list and store it permanently on a computer data disk for later retrieval. You can, of course, keep many different disk files, each of up to 100 channels. 5 --You can 'read in' a channel list from a storage disk, then tell the program to make the radio progressively scan the whole lot of them. A 100-channel scanner! One problem with computer-controlling the original FT-757GX is its inability to change modes electronically; that's done by a mechanical rotary switch. So there's no way for the computer to change modes; back then you had to reach over with your left hand and give the switch a twist. It wasn't until Yaesu brought out the 'Mark II' version of the FT-757 that mode switching was made fully-electronic. This was. of course, in common with the ft-757's Icom competition of the time, the IC-730, which had both a mechanical mode switch AND a mechanical band switch. In fact, as far as I can tell, the IC-830 had no computer-control facility at all. Nevertheless, it was a ripper of a radio; I had one and I'm still kicking myself for ever selling it. The FT-757GX is capable of receiving commands from the computer, but it appears to be unable to talk back to it. This is a shame, because there's no way you can ask the radio what frequency it's operating on, or what its current mode is. --( The second-generation FT-757, the 757GX-II, does indeed have this facility. All the current operating parameters are sent to the "CAT" plug each time a change is made. Also, all of the other Yaesu "CAT" transceivers - including the FT-980, the FT-747GX - which is reviewed in the next issue of Amateur Radio Action, the FT-736 and so on - also have this 'two-way data' feature. The program therefore works equally well on those other transceivers. Ed. ) -- So the things you can remotely control on the FT-757DX are restricted to setting the operating frequency, and such things as swapping VFO's, switching between VFO and memory, and toggling features like the clarifier, dial lock, and split-frequency operation. THE INTERFACE UNIT. Yaesu produces a little magic box called an 'FIF-232C', which cam be used to connect any of its computer-capable radios to any computer using the 'RS-232' serial communication standard. RS 232 is available on just about every computer now made; it's the connection you use for such thing as serial printers, plotters, mice and modems. The interface unit comes with two cables, one to connect to an FT-757GX, and another to connect to the REST of Yaesu's radios. The FIF-232C does not need a special power supply; it's powered straight from the mains. THE FT-757GX COMPUTER COMMAND FORMAT. The computer needs to be able to send its commands to the radio at a speed of 4800 baud, or bits-per-second. Each data byte (which is an eight-bit, or eight character, hunk of information) consists of one start bit, eight data bits, one stop bit, and no parity. Each command sent to the radio consists of exactly five of these bytes, sent within 100 milliseconds of each other. The software assumes your computer is fast enough to work out the contents of each byte 'on the fly' , instead of calculating them all and storing them in advance of sending them to the radio. There's a fair bit of number-crunching to be done between each byte (in lines 1290-1350) of the program) but the three different computer and BASIC combinations I've tried all seemed to be fast enough. In 10 of the 11 computer commands for the FT-757, the first four bytes of the command are totally wasted, and the actual command code is contained in the fifth byte only. But for timing reasons, the other four must be sent; they are simply filled with zeros which the radio conveniently ignores. The only command to properly use all five bytes is the one to set the radio's operating frequency. Here, the fifth byte containes the command mode as before, but bytes one to four now contain numbers which represent the frequency being set. Each half byte, or NYBBLE, contains a hexidecimal representation of one of the decimal digits of the frequency being set. And just to make things interesting, bytes one to four are sent in reverse order. The five bytes decribing the frequency 12345.67 kHz would look like this, when seen in hexidecimal format: In an HF radio, with frequencies never going above 30 MHz, the first nybble in the fourth byte will always be 0. The other nybble is our '1'. Then, in the byte to the left, is '23', then left again for '45', and finally '67'. All together now... '01234567'. Got it? Good. The fifth and final byte is hexidecimal 'OA', which is the command code telling the radio what to do with the information it just received. In this case, it tells it to 'set the frequency'. The purpose of all the number-crunching in program lines 1290-1350 is to bust up a simple number into four arse-about bytes of hexidecimal digits. We enter the 'routine' with the frequency to be sent contained in the variable FREQ, and the function to be performed in the variable FUNC. These numbers are gathered either from a stored disk file or input directly through the keyboard, as we will discuss later. The little subroutine in line 1350 strips each digit off the number in turn. These are then converted to hex and organized two-to-a-byte in line 1300, where each byte is sent to the radio in line 1310. The procedure is finished off in line 1330, when the command code is sent out as the fifth byte. In the case of a simple command instead of a frequency-setting function, the FREQ variable is set to zero to fill the first four bytes with zeros, and FUNC contains the number of the command to be performed. THE PROGRAM. I won't attempt to explain how every step of it works; that would be the job of a textbook on BASIC programming. Those of you who are into BASIC should understand how the program works. There are no tricks, not even anything fancy, so it's all very straightforward. The first section of the program generates a menu of all the functions the program can perform, and then lets you select a function by number, 'Chinese restaurant' style. Most of these items are SIMPLE functions, requiring no parameters. They are sent directly to the radio, with zeros in the parameter bytes. Item 10, entering a new frequency, first asks you to type that frequency and then sends it directly to the radio. BUT NOTE WELL: Within this program, frequencies must ALWAYS be expressed in KiloHertz. If you select items 12 or 13, you are first asked to supply a file name, and then the program continues on with the selected procedure. Every file name used with the program must have the extension'.CHL'. (That means CHANNELS, you dummies!). If you don't type any file extension, or you type somthing other than .CHL, the program will force the extension to ,CHL. For item 12, to read, edit, or use a disk file, the program begins a new file if the one you specify canot be found. If the one you specify cannot be found, it then sits there on channel 1, waiting for action. You are shown the channel number, and then prompted to enter first the frequency and then a description of what the channel is used for. The program keeps showing new channel numbers and prompting for inputs until you hit the RETURN key on its own when asked for a frequency. The program then asks if you would like to save the file you have just typed in, and then returns to the main menu. If, in response to the description prompt, you hit RETURN on its own, the program just keeps going, assuming you would rather pass over the description for now and add it later. NOTE: This ENTERING feature is included mostly to allow you to type in a few new channels at the end of an existing file. The best way to build a file from scratch is with a text editor or word processor such as WordStar. Here, you can type in your channels with gay abandon, zipping around the screen to correct any mistakes. There are a couple of rules, though... You do NOT enter channel numbers. These are computed automatically by the program as you use the file. Using an editor, all you need to type in is the frequency, followed by a comma, and then a description, one channel per line. Every line MUST have a frequency and one comma. Otherwise this program will go crash-bang-boom. You must also ensure that the list is not terminated with a extra blank line, otherwise TROUBLES as above.... Here's how a file containing Hobart's broadcast stations would be typed in using a word processor : 585,7ZL ABC Radio National 729,7AP Parliament 864,7HO Pop music for the masses 936,7ZR ABC local service 1080,7HT Pop music and lots of horse racing 1620,7RPH Radio Print Handicapped. So, there is your little file of just six channels, ready to be read into -- and acted on by -- the program direct from the disk. When displayed on the screen, the channels will automatically be numbered from one to six, and the frequencies and comments will be in nice neat columns. If you look again at the file after it has been saved from within the program, you will discover that a space has been added before and after each frequency. Big deal. Right! Here's what happens when you ask for item 12 and the file name you specify already exists on the disk: The file is read into the computer's memory all at once, and the computer's memory all at once, and then displayed on the screen 20 channels at a time. After each screen-full you are given the choice of setting the frequency into the radio by typing the channel number, or changing the displayed frequency or description. After any of these operations the screen is updated, showing any changes. If you then simply hit RETURN, you're given ANOTHER 20 channels. If you get to the end of the file and hit RETURN again, you are asked if you want to save the file, after which you go back to the main menu. However, if you get to the end of the file and then select a channel number higher than the ones that already exist, the next number in line will be assigned and the program then will jump back into the 'enter' mode as described above, one again showing channel numbers and prompting for frequencies and descriptions. Selecting lucky item 13 on the menu gives you MOFFAT'S MAGIC-YOU BEAUTY-HUNDRED-CHANNEL-SCANNER. You will first be asked for a file name. If you give it a bodgey one the program will vomit you back to the BASIC command level (we can't be all user-friendly!. If the specified file does exist, it will be read into memory and will then wait for you to type a key. If the key is ANYTHING BUT "C" (for continuous), the program will step along through each channel in turn, giving a new one for each press of any key. This means when you get sick of one station you just tap the keyboard to change to the next station. When you get to the end of the file it all starts over again. You can stop the pain by pressing the 'escape key' , which is sensibly marked , of course sends you back to the main menu. The interval between each new channel in the continuous mode is determined by the number after the word 'TO' in line 1110 of the listing. Tntering '5000' seems to give a pleasant delay on each channel for an IBM PC with an 8 MHz clock speed. You can make this number anything you want to allow whatever time-delay suits your computer -- and your taste. I would suggest that scanning through a fully-laden 100-channel file might get a bit tedious. To make life easier you might want to run off a renamed copy of the 100 channels, and then use your text editor to prune the copy back to 10 or 15 of the most interesting ones. That way you will get to hear each one more often. Note that there is no facility in this project to make the scanner stop on busy channels, as 'proper' scanners do. If the FT-757GX supplied a 'mute open' signal, things might be different. If, by the way, 100 channels per file isn't enough (you glutton), then you can allow for a bigger size by changing the DIMension statements in Line 90. You could also make them smaller, of course. ............... So there you have it, my friends, yet another way to convince yourself and your family that your computer is really useful for something after all. Just watch those channels stream down the screen.! And just watch those frequencies flip over on the radio's dial as it steps along from station to station! ..And just listen to your wife say " So what?" ..