11Mtr Packet - PSK31 - is anyone using it?

[MikeSierra]

Agreed, but one still needs a bit of a circuit made up to act as a buffer switch to operate the relay.
Summat like this =

Nice and working solution as long as VCC and GND are not the same that the radio uses. That could cause ground loops or partial grounding of the radio through the PC. RF can get into the PC, causing damage to serial port or sound card. Sound can get distorted and PTT control can get intermittent. And I suspect some people have yet to learn the importance of grounding the radio.
With a solid and grounded desktop PC it shouldn't be a problem, but I'd like to be careful with my HP elitebook laptop.

[ghost123uk]

Very good point, and one I hadn't considered

The more I think about this, the more I'm going off the idea, unless I just go and buy a box
Partially this is because there is likely no one using it anyway, plus, do I have the time to invest in it?

[MikeSierra]

The more I think about this, the more I'm going off the idea, unless I just go and buy a box
Partially this is because there is likely no one using it anyway, plus, do I have the time to invest in it?

Is there even one (interface) box ready to buy that just hooks up to a "normal" CB radio ext.sp. and 4- or 6-pin microphone contact without modifying something? I haven't found one yet. And that I think is the reason there are so few people doing packet radio on the CB band. We could have APRS, BBS, Weather stations, chatrooms, mailboxes etc. on the airwaves.

[ghost123uk]

Baycom?

[MikeSierra]

Baycom?

Baycom is ready for HAM radio, but not really doing the CB radio microphone switch thingy out-of-the-box.

My first trial was when connecting a TNC-X to an old Cybernet CB radio. I tried to do it like with a HAM radio - audio in, audio out, PTT and ground. The radio started smoking. I figured out that the TNC-X's output was active when in RX mode, the microphone line on the CB was connected to the audio amplifier when in RX mode, and the audio amplifier output was connected to a transformer. I didn't hear what was going on since I had the audio out connected to Speaker out jack. My shack could have burned down
That radio I modified by adding an internal relay which cut the microphone line while in RX mode.

Off topic rant: baycom kiss tnc's were popular during the MS-DOS era of PC's. They costed less than full-featured TNC's and communicated by bit-banging the control lines of a PC serial port.
Then came Microsoft windows, which did not allow programs to directly control the serial port control lines. A little later came the internet. It was the death of packet radio, until APRS came along. Nowadays there are drivers for baycom modems under both windows and linux. The race may be lost to digital radio systems like DMR, Fusion and D-star.

[ghost123uk]

With not much juggling at all, we used to use Baycom boxes on normal multimode CBs to good effect. We even used to send pictures to each other (Europe wide) using ascii to make up the pixels like these

If only there was a simple (cheap) RS232 to DPDT relay board using the fldigi industry standard DTR / RTS pins for "Hi-low" switching

I have, (as mentioned above) tested my (simple resistive audio attenuated) system on air, via fldigi under Linux (on a laptop) and it works fine. I'm just stuck with manual PTT switching via that toggle switch

[MikeSierra]

If only there was a simple (cheap) RS232 to DPDT relay board using the fldigi industry standard DTR / RTS pins for "Hi-low" switching
I have, (as mentioned above) tested my (simple resistive audio attenuated) system on air, via fldigi under Linux (on a laptop) and it works fine. I'm just stuck with manual PTT switching via that toggle switch

There might be a market idea for someone with some electronics knowledge. I have drawn a circuit board for the schematics I posted earlier. Things are still uncertain, like how to box the thing, can the components be bought locally, is it okay with vertical potentiometers etc. Who would make it, who would buy it. I would not have the time to produce it myself, and I already have too much money

CB_radio_PC_digimode_interface_PCB_v001.png

[ghost123uk]

There might be a market idea for someone with some electronics knowledge. I have drawn a circuit board for the schematics I posted earlier. Things are still uncertain, like how to box the thing, can the components be bought locally, is it okay with vertical potentiometers etc. Who would make it

Well, I tick all the boxes (40+ years of pro electronics work, up until about 8 years ago).

who would buy it.

That is the deal breaker

[Black_Pirate]

search ebay "psk31" from £27....does all digi modes

http://www.ebay.co.uk/itm/M0AQC-PSK31-D ... Swo4pYXPMN

not sure but I think its 9 pin seriel not usb you may need a adaptor...not sure...

[MikeSierra]

search ebay "psk31" from £27....does all digi modes
http://www.ebay.co.uk/itm/M0AQC-PSK31-D ... Swo4pYXPMN
not sure but I think its 9 pin seriel not usb you may need a adaptor...not sure...

Yes, you will need an adapter if your computer doesn't have a physical serial port.
If you are looking to buy one I suggest you contact the seller. He will probably ask you what radio you have and if there is sound from the speaker when the microphone is disconnected.

[Phoenix]

Brilliant subject guys and really interesting reading......Please keep this thread going as i do want to put a Packet Station on the air with a Uniden type radio but as above im struck as were to start.I do understand circuits and can solder and test..Photos of setups work good for me ..Videos of the same work great for me.

[MikeSierra]

I do understand circuits and can solder and test..Photos of setups work good for me ..Videos of the same work great for me.

m_DSCF6687.JPG

Galvanic isolator containing two audio transformers. http://en.4carmedia.com/product/4carmed ... 5000-01/11 ..and they are cheaper by the dozen.

m_DSCF6691.JPG

Once the encapsulation is gone there is a circuit board inside.

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Trimming the circuit board so it fits inside a plastic enclosure.

[MikeSierra]

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1N4148 diodes and optocoupler led series resistor on D9 connector.

m_DSCF6708.JPG

Potentiometers go in.

m_DSCF6717.JPG

Checking that the parts fit and connecting.

[MikeSierra]

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Placing PTT relay.

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Soldering microphone connector.

This is probably the most ugly prototype in the history of radio, but you all get the idea.

[MikeSierra]

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Finished interface is crammed into the box. My advice is to use a larger enclosure or lay out the components on a circuit board.

FLDIGI_CB.png

Now we can run Fldigi for a variety of digimodes.

soundmodem84.png

Or use UZ7HO Soundmodem84 to emulate a kiss packet radio TNC (type AGW on port 8000) for use with programs like UIVIEW, APRSIS etc.