Survivalism & Self Sufficiency Topics > Amateur Radio How-To's

How I setup a 1986 TNC to send VHF packet email on a 1996 radio

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Smurf Hunter:
What you'll need:

1) a VHF mobile radio (while it's theoretically possible to do this with an HT, it's not recommended).

2) a TNC - I paid $20 for an old Kantronics KAM at a ham swap meet. An hour later a friend of a friend paid only $10 for his.

3) sacrificial ethernet cable (for this how-to we will assume the mobile radio uses an RJ-45 style mic jack)

4) DB9 male connector kit (you might consider hacking apart an old serial cable and splicing the raw wires as an alternative)

5) heat shrink tubing (for style and safety)

6) the only thing I recommend splurging on and buying new is the serial to USB interface.  This one is a known good chipset and is almost guaranteed to work perfectly.  You can spend a few $$$ less but dork around with driver software for an afternoon if you prefer.
7) DB9 to DB25 adaptor.  This goes between the USB->serial cable and the TNC

For reference this is similar to what we'll be making:

Like any radio interface cable, the single most important thing is understand your radio's pin outs.  Every radio manual I've ever seen includes this.
Memorize this, write it down 10 times, or whatever it takes to not goof it up.  It's easy to do!!!

Step 1 - get the TNC connected to your PC
Plug in the USB to serial adapter into a USB port.  After the driver installs, goto Windows device manager and note the new COM port.
In my case it's COM14 (a virtual COM port if you are being precise).
This cable goes into the DB9 to DB25 adapter, and that plugs into the DB25 female port on the back of the Kantronics TNC.
So far any monkey with an account should still be okay.

Step 2 - make sure the TNC is alive and your PC can talk to it
The easiest way to do this is using RMS express.  If you have that installed, in the base directory is an executable
--- Code: ---RMS Simple Terminal.exe
--- End code ---
Run that, and specify the COM port from Step 1.  alternatively if you install the old MS windows HyperTerm.exe (for dialup modems) you can do similar.

Once you run your terminal program, connect to the TNC using the appropriate COM port and baud rate.  You may need to power cycle the TNC, but you should see output resembling this.

I'll post more soon...

Smurf Hunter:
Now onto the interface cable.

You'll need to connect pins 1,3,5,6 form the TNC to the radio

--- Code: ---TNC                        Radio
1 AFSK Out              Pin 6 (Mic Input)
3 PTT                      Pin 4 PTT
5 Audio Receive        *Connect this to the center conductor of a mini-mono plug and connect to the audio jack on the back of the radio
6 Ground**              Pin 7
**Tie this in to the ground on the mini plug as well
--- End code ---

Pin 8 and 9 on the TNC are also grounds, so I connected those to the ground (shield) of the speaker line out. 
TNC 6 to Radio 7 and use TNC 8/9 to connect the ground to the mono plug.
In my case I used a stereo plug, that has 3 conductors like this:

Since my mobile radio speaker out is mono  (no left + right stereo signals) I shorted out the tip and ring to pin 5 on the DB9.
Also, I shorted out pins 8 and 9 on the DB9 together, and connected that to the shield of the phono plug.

Make sure you use a multimeter and use the Ohm meter to test out the pins on the RJ45 and write down which color wire they're connected to.

Here was my cheat sheet.  I personally find I understand things like this better if I write it down on paper.  It also was more convenient to take a piece of paper to my work bench.

Details about soldering best practices can be found else where, but I highly suggest you wrap each individual pin on the inside of the DB9 with heat shrink tubing after soldering.  Plan ahead, cut to length, but this will add some strength and durability.

Here's the final product.

You got some skills dude.

Smurf Hunter:

--- Quote from: PrepperJim on April 01, 2016, 12:56:10 PM ---You got some skills dude.

--- End quote ---

Thanks, but I knew none of the is two years ago before I became a ham.


--- Quote from: Smurf Hunter on April 01, 2016, 05:14:34 PM ---Thanks, but I knew none of the is two years ago before I became a ham.

--- End quote ---

Who ever elmered you did a great job... 8)


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