View Full Version : CTCSS tones for an IC2AT

10-25-2002, 01:17 PM
I have had an IC2AT for years and have recently decided to bring it out of retirement. It appears that it needs CTCSS tones added. Has anyone had a good/ bad experience doing that and what kit would you recommend?

Paul K4JAZ

10-25-2002, 05:12 PM
There's no room inside the IC-2AT for a tone board, which is why thousands of them were sold "used" nearly 20 years ago, when most metro areas in the U.S. went to full-time, all-PL repeaters. (That's when I sold my IC-2AT, IC-3AT and IC-4AT.)

However, since that time I did modify one for a friend: Using the Com-Spec P/N SS-64 DIP programmable encoder (0.66" x 1.08" x .21" thick) and miniature #28 gauge ribbon cable to connect it to +, - and audio, I laid the board inside the HT behind the existing Icom main board, insulating it with a piece of 2" x 2" mylar film tape. Nothing holds the board in place at all except the pressure placed on it by sandwiching the board between the rear case and the main board, which is quite sufficient. Access to the DIP switches is provided by a hole drilled into the rear case and filed into rectangular shape with a small file. The rectangular shape required is about .375"w x .200"h.

The whole process took me about two hours because it was pretty experimental, but I could probably do it a bit faster a second time!

73 & good luck!

Steve, WB2WIK/6

10-25-2002, 07:51 PM
Actually, Communications Specialists make a tone board that DOES fit into a 2AT. I have one installed in mine. Sorry, I forgot the model number. Tones are set by DIP switches. Only problem is that you have to open up the radio to change tones.



10-25-2002, 08:08 PM
Or, you can do what I did with my old Kenwood TR-7850: Although there is provision for a single tone board to be installed inside, I bought a Communications Specialists TE-32 which costs $49.95 plus about $4 shipping (they are on the Internet and have an 800 number for orders). This has all 32 of the standard CTCSS tones plus an "off" switch and requires really only 3 connections (+9 to 16 volts DC, ground, and the tone output). There is a level control on the board to set the tone deviation so that it does not exceed +/- 0.5 KHz (1/10th the system deviation).

Thus, all you have to do is to set the knob on the TE-32 to the desired tone frequency and key the transmitter. It comes with leads plenty long enough for any rig (I cut off most of them when I mounted it on my TR-7850). You can use a piece of double-sided foam to attach the tone encoder to the rig or use the "gimbal" mount that comes with the unit.

Glen, K9STH

10-25-2002, 09:47 PM
KA0AZS, the Com-Spec P/N I referenced in my original post is the one with the DIP switches that you're thinking of. If you jammed it inside an IC-2AT (well, so did I, eventually&#33http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif, then you know it's a pretty tight fit.

Glen, I've used TE-32's on various rigs for many years, but didn't think it was so appropriate for an IC-2AT, since the tone generator would be about the same size as the rig!


10-25-2002, 11:50 PM
Yes, I agree about the size, but not having to keep a chart handy with the DIP settings for the various frequencies as well as keeping the little tool handy is worth the size! Also, I have found that the DIP switches don't take too kindly to repeated switching. If one only needs a single CTCSS tone, then the TE-32 is definitely not the way to go. However, it is really "cheap" when you consider the versatility of the unit when you have several CTCSS tones to access local repeaters and have one of the older rigs.

The actual size of the board and switch are less than 10 percent of the bulk of the unit. I actually considered mounting the board inside the TR-7850 and the switch on the top cover. But, so far, I haven't done it!

Glen, K9STH

10-26-2002, 02:37 AM
I have an IC2AT with a tone board inside. I don't remember for sure, but I think the current model number in 1981 was SS32M or something. It was programmable, but to do so required soldering across terminals on the board to make the correct binary choice. So if you only needed one single tone, that was the way to go. The board mounted between the circuit boards of the IC2AT. The wiring was done and the board installed between the circuit boards while the radio was opened like a book.

So yes, such a thing did exist, but it wasn't easily reprogrammed, certainly it couldn't be done in the field. Commspec does indeed have similar gadgets now, so worth a look at their site.

Good luck,


10-29-2002, 03:44 PM
Thanks guys! I suspect the SS-64 will fill the bill for me. It just seems a shame for that old radio to lay around and not be usable. When I get one installed I'll let you know how much luck I had.

Thanks again for your responses and help.
Paul K4JAZ

10-29-2002, 07:53 PM
OK, I am disappointed now. I asked for the same help on a different radio, and well... anyways I have a DRAKE UV-3 and while i have all the nice books and binders for it, I am lacking the tone board. no one has even heard of a board for this radio, but apparently, one was conciderds as it tells and shows how to hook one into the rig. it even has a nice little plug already mounted and wired. so now, does anyone know where i may find a decent tone board, that will get plenty of abuse in a moble inviroment.

10-29-2002, 09:05 PM
KF6NFW - I think this thread will point you in the proper direction also. CommSpec makes a wide variety of tone boards. I'm sure if the UV3 was designed for a tone board, CommSpec may likely even have application notes for that rig.

I'd suggest looking at their website or calling them.

Good luck,


10-29-2002, 09:33 PM
The main problem with the older rigs that allow for a single tone board is that in today's world, there are often several different tones used in even the same basic locale. Communications Specialists makes all sorts of encoder and encoder/decoder boards. You do not need to get a board that also serves as a decoder since most repeaters do not transmit the CTCSS tone, only is needed to open the repeater receiver. Even if the repeater does transmit the tone, you do not need a decoder to receive the signal.

Most of the ComSpec boards use DIP switches to change the tones and supply a chart with each board showing how these are set for each tone. Unfortunately, these switches are not really made to be switched a considerable number of times since commercial applications are just "set and forget". That is one advantage of the TE-32 model which has a rotary switch that takes care of the various combinations to set the tone frequencies. It takes about a minute using the tool supplied by ComSpec to change the tone frequency of the encoders that use the DIP switches. This is fine if you are sitting in your shack. But, on the road, this is impractical.

The size of the TE-32 is much larger than the actual board and switch contained in the unit. It would be very easy to move these to another housing, or, the housing that is supplied can be reduced in size by at least 75 percent. I use the TE-32 since the price is right ($49.95) and since it definitely does the job.

One thing about the ComSpec boards is that they work on voltages from about 8 VDC to about 20 VDC without modification.

You should not run a CTCSS tone in through the microphone jack. The best place is to run the tone into the "IDC" (instantanious deviation control) and adjust the tone level to a maximum 1/10th of the maximum deviation of the radio. For amateur operations this means a maximum of +/- 0.5 KHz deviation. I like to run between 0.4 and 0.45 KHz deviation as measured on one of my service monitors.

There are several other manufacturers who make tone boards. However, Communications Specialists has been around for over 2 decades and their products definitely work.

Glen, K9STH

10-30-2002, 06:35 PM
http://www.com-spec.com is the website.