Kenwood TS-711 CTCSS

[Cookie_Crunch]

After a long break from amateur radio I finally got around to dusting off my old TS711 and then realised that in the meantime someone changed the repeater access method from tone burst to ctcss . I did the usual Google to find the mods and it pointed me here. I followed most of the instructions down to making a replacement TU5-S lookalike board.

However, I really wanted to know how to enable the tone during repeater offset and tx only. I played with the diode matrix and came up this:

Insert D31 (it had been cut out in mine when new)
Remove D33 (this auto enables tone when offset is selected but just gives a 1s burst)
Remove D34 (this gives volts on TH pin during offset and tx)

I left D16 in as it doesn't actually do anything to affect what we want.
I didn't cut the PCB track and bridge the tracks behind the switch. I just swapped the orange and brown wires in the 5 way connector on the switch PCB.

The above keeps the radio compliant with UK band plans and achieves the required result.

Hope this helps somebody.

I have made a table of what the diode matrix does if anyone is interested.

[Radio Wrangler]

Not only have they changed the access arrangement, they've also cut the deviation for 12.5kHz channels.... even channels on the 25kHz numbers. Repeaters are required to dump you if your deviation isn't to the reduced standard.

Frustratingly, the change to 12.5kHz was never needed. The numbers of users fell, instead. It has, however locked out a lot of good old equipment that could have got beginners on the air.

David

[Cookie_Crunch]

Ah yes, I'm sure there's a lot more re-alignment to check after the kit's been sitting idle for all those years.

I've also got a TS430 with intermittent switches. I've soldered up the PA transistors and that bit now works. The rubbery felt pads around the switches behind the front panel have started to decompose into some sticky black goo . I always fancied the TS440 so might start looking out for one now.

[SiriusHardware]

I don't have one of these but it would be useful if CC could attach his mod details in a .zip file to a post here because someone might surf onto this thread maybe not now or next month, but in 3-5 years time looking for exactly that info.

I agree (and thought even at the time) that the change to 12.5Khz channelisation was a waste of time, the only upside being that most ex-PMR equipment suitable for conversion to 2m was already filtered for that channel bandwidth.

Unfortunately a lot of repeaters have since been allocated the channels 'in between' the original R0-R7 frequencies so we can't just ignore them the way I do for simplex operation. I think at least one repeater in CC's area is on an 'in between' frequency, GB3IR (Richmond) output on 145.7625MHz, CTCSS 88.5Hz.

It may be necessary to turn down the deviation a little in order to work through repeaters without your TX audio conking out on audio peaks. However, try it first and if everyone says you sound fine through repeaters, don't fix what isn't broken.

[Malcolm G6ANZ]

From what I can tell from what I've heard 2M seems to be all repeaters. The upper half at least.
I listen with a TS700G and the only simplex is from the RSGB news on Sunday mornings.

[SiriusHardware]

The outputs of conventional repeaters will only be found in the range 145.6000 to 145.7875 on 2m. You might also hear what sound like repeaters on the 'in between' 12.5Khz frequencies above 145.2000 - these will be internet connected 'gateways' which operate on a simplex frequency but are accessed, like repeaters, using a CTCSS tone. I don't imagine they existed when CC was last using his TS-711.

I still mainly use ordinary simplex myself but I have no objection to these particular innovations if they create a bridge between far-flung amateurs who otherwise would not be able to reach each other (not everyone uses HF or has the space for aerials for those bands).

[Cookie_Crunch]

I'll do a full write up soon. I'm just looking to see if anything else needs doing to get it to full functionality. I bought the rig new and haven't abused it but after such a long rest period I was expecting electrolytics failing (none found faulty yet).

I normally used simplex but the local radio club, which I've yet to join, have a club net on the local repeater so it would be nice to join in sometime.

[M0AFJ, Tim]

Originally Posted by Malcolm G6ANZ

From what I can tell from what I've heard 2M seems to be all repeaters. The upper half at least.
I listen with a TS700G and the only simplex is from the RSGB news on Sunday mornings.

Still a lot of activity on the weak signal modes, SSB, CW, Digi, just need an a horizontal antenna

[Cookie_Crunch]

Here is the promised write-up of what I did:

First acquire or make a TU5 tone board. I made one by copying the service manual. Simon_V correctly noted here that the schematic is wrong but the PCB layout is ok. (I have attached Kicad and pdf files in zip)
All work can be done by removing just the top cover.

1. Remove the 2 connectors at the rear of the control board.
2. Remove the original tone board (X52-1290-60)
3. Remove the 2 screws on the side which locks the cooling plate to the chassis.
4. Remove all screws (9) which hold the control board to the chassis. (this allows the control board to tip forwards)
5. Open up the 6 solder holes and solder a 6 pin header with a pin length of 12mm.
6. Remove R55 (22k) near J9
7. Insert jumper wire W2. This crosses one end of the removed R55.
8. Insert C56 (470pF ceramic capacitor).
9. Remove D33 & D34 (these are at the front of the board near J1)
 Removing D33 enables the tone whenever the offset is active.
 Removing D34 enables continuous tone rather than 1s tone burst.
10. My rig had D31 removed. This had to be re-inserted to achieve 12.5kHz channels. (if needed use one of the removed diodes).
11. Refit control board and add the TU5 or lookalike
12. The “Tone” switch is used to select the CTCSS frequency. Other people have modified the PCB under the ON/OFF switch (see photo from PE0SAT ). I left the PCB alone and unplugged the 5pin connector. Using a fine point jeweller’s screwdriver to slightly lift the pin locking tabs I removed and swapped the orange and brown wires. I found this much easier than cutting and bridging PCB tracks.
13. Power on the radio while holding the A=B button. This resets the memories and causes the cpu to read the diode matrix.
14. Set deviation of the tone using RV1 on the new add-on board.

[Hobooldman]

Interesting.

I wonder if something like this would be possible on an Icom IC271e?
Different beast I know but it's something I'd like to be able to access through my radio.

[Cookie_Crunch]

The Icom is covered on GitHub here.. I suspect there will be different challenges. An interesting project though.

[Hobooldman]

Thank you Cookie Crunch.
I may try this one.
http://www.zl2pd.com/CTCSS_encoder.html

Kind regards.