SOxR interface

[kf0rt]

I'll go first...

I'm building a SOxR box (Single Operator multiple Radio). Got the CW and phone part working and got the parts for the digital modes this week. This will let me use one microphone, one straight key, a common keyer, etc. on my TS-570, IC-7000 and Drake stuff with the flip of a switch. It'll have a built-in soundcard interface when I'm done. I can't believe anyone spends real money on soundcard interfaces... they're SO simple.

I'll go first...

I'm building a SOxR box (Single Operator multiple Radio). Got the CW and phone part working and got the parts for the digital modes this week. This will let me use one microphone, one straight key, a common keyer, etc. on my TS-570, IC-7000 and Drake stuff with the flip of a switch. It'll have a built-in soundcard interface when I'm done. I can't believe anyone spends real money on soundcard interfaces... they're SO simple. That is really cool.

And I always thought that SOxR sometimes stood for Smart Ole XR when talking about me, and Stupid ole XR when talking about 3XR.

Anyway, I have some experience with designing FPGA's. Those things are really cool. Imagine a digital-only circuit and make the FPGA do that for you. Rather than using a micro-p, an FPGA can be your counters, gates, and flops in the size and shape you want them to be. If you need a 17 bit counter, put one in.

I have designed all-digital PLL circuits with sub Hz digital filtering. It is not that difficult. I had a blast learning that stuff.

Some FPGA's have micro-p's built in. Some of those can be pretty expensive, into the hundreds of dollars each. The ones I used were a few bucks each. They do have some in the sub-dollar region.

If anyone is interested, I can try to get them started on their way.

[kf0rt]

Neat stuff...

My work project uses an Altera Cyclone part -- I understand you can even drop a microprocessor core into those things these days and make it run code. One of the hardware guys does all the work on that, but the flexibility is amazing.

The SOxR project is really too simple to need anything like that, but it does have a built-in keyer. There are so many PIC based keyers out there that I really couldn't justify rolling my own. Originally, I was going to go with NØXAS's PicoKeyer, then I saw the K1EL stuff and ended up with a K40. The K40 has two PIC's and is a real "do it all" keyer -- interfaces to a 2x16 LCD display and has a built-in keyboard interface that takes a PS-2 type computer keyboard. The rest is just wire, switches and connectors. Oh, and a transistor buffer to grid-block key the Drake (I'm still not sure if a 2N2222 will handle the Drake's PTT; easy to fix if not).

Got all the parts in last week for the digital part of the box -- also, very simple. Just a couple switching transistors and telephone matching transformers for the audio. I'll get some pictures when I get back into it.

[kf0rt]

Lets try some pics... I think I have it working (but too late for the CQ WPX RTTY contest).

Here's the guts... mostly switches and connectors. The board at the upper left is the K1EL keyer. The perfboard holds a pair of buffers for grid-block keying the Drakes on the left and the audio interface for the soundcard on the right. I'm getting good audio from the Kenwood to the computer and good FSK (and PTT) signals from the computer to the Kenwood. Haven't tried the AFSK transmit interface yet -- someday when I want to try PSK31 or SSTV...
http://tatanka03.home.comcast.net/so-in2.jpg

Here's the proof, as seen on the IC-7000:
http://tatanka03.home.comcast.net/so-screen.jpg

The back is nothing but a heap of connectors:
http://tatanka03.home.comcast.net/so-back.jpg

And the front... From left to right, power switch (power for the keyer/display and bias for the grid-block transistors), the K1EL keyer display, keyer speed knob, microphone / key switch, PTT lock, Key lock, digital mode switch, PTT/CW switch for the computer interface.
http://tatanka03.home.comcast.net/so-front.jpg

What's it do? The mic/CW part switches a common keyer, straight key and microphone between 4 rigs. The built-in K1EL keyer supports memory, keyboard use, display and (most important) a speed knob that doesn't require menus to find. The digital part switches a single computer interface between three rigs and has all the matching stuff built in.

I still need to build the interface cable for the IC-7000 (this was the whole point).

[N1LAF]

Speaking of IC-7000 ... It can decode RTTY, but not encode from keyboard. Suppose I buy that $6.00 keyboard to serial device from K1EL, and connect it to an Actel FPGA, and modulate the FSK line, and output the transmit characters to a LCD display - two chip solution. N9XR, what do you think... do you have a RS232 9600 baud core? I did the hardware design for one for a class project, if I can find it, I can probably code it into VHDL. Now, if I can decode the keyboard directly to FPGA, then we have a one chip solution (excluding clock). With a RTTY encoder, a neat companion to the IC-7000. Good idea?

If there ever was a use for an FPGA, that would be it.

[al2i]

That is major sweet Rob. You are a certified ham.

[n4aud]

That's cool! I need something similar pretty badly, especially to handle mics and speakers. I built a simple speaker switch box a while back, but this makes that look like a stone wheel.

[kf0rt]

Speaking of IC-7000 ... It can decode RTTY, but not encode from keyboard. Suppose I buy that $6.00 keyboard to serial device from K1EL, and connect it to an Actel FPGA, and modulate the FSK line, and output the transmit characters to a LCD display - two chip solution. N9XR, what do you think... do you have a RS232 9600 baud core? I did the hardware design for one for a class project, if I can find it, I can probably code it into VHDL. Now, if I can decode the keyboard directly to FPGA, then we have a one chip solution (excluding clock). With a RTTY encoder, a neat companion to the IC-7000. Good idea?

Keep it small and low power. You could build it right into a keyboard that would plug directly into the back of the 7K. How cool would that be? (I guess the LCD might be an issue...)

It's hard for me to conceptualize doing this in an FPGA -- you'd have to decode the keyboard, buffer it, encode the buffer to RTTY, plus drive the display. FPGA's are definately not my forte. It'd be a slam-dunk with a PIC, though.

Was just looking at the documentation on the K40 -- it'll transmit FSK/AFSK RTTY, but with an add-on board. The add-on is mostly audio decode and encode for AFSK -- seems odd that the FSK part wasn't included in the keyer itself.

[N1LAF]

Speaking of IC-7000 ... It can decode RTTY, but not encode from keyboard. Suppose I buy that $6.00 keyboard to serial device from K1EL, and connect it to an Actel FPGA, and modulate the FSK line, and output the transmit characters to a LCD display - two chip solution. N9XR, what do you think... do you have a RS232 9600 baud core? I did the hardware design for one for a class project, if I can find it, I can probably code it into VHDL. Now, if I can decode the keyboard directly to FPGA, then we have a one chip solution (excluding clock). With a RTTY encoder, a neat companion to the IC-7000. Good idea?

Keep it small and low power. You could build it right into a keyboard that would plug directly into the back of the 7K. How cool would that be? (I guess the LCD might be an issue...)

It's hard for me to conceptualize doing this in an FPGA -- you'd have to decode the keyboard, buffer it, encode the buffer to RTTY, plus drive the display. FPGA's are definately not my forte. It'd be a slam-dunk with a PIC, though.

Was just looking at the documentation on the K40 -- it'll transmit FSK/AFSK RTTY, but with an add-on board. The add-on is mostly audio decode and encode for AFSK -- seems odd that the FSK part wasn't included in the keyer itself.

I saw the K40 stuff too. But I think you suggested an excellent idea, putting the circuit inside the keyboard. Downside would be if the keyboard goes bad, it would have to be 'extracted'. I think we can make a small enough board that it would not be a clunky dongle. FPGA devices comes in all kinds of sizes. I have dealings with the BIG devices, maybe Todd can make a recommendation on a smaller device.

[KF5ER]

Speaking of IC-7000 ... It can decode RTTY, but not encode from keyboard. Suppose I buy that $6.00 keyboard to serial device from K1EL, and connect it to an Actel FPGA, and modulate the FSK line, and output the transmit characters to a LCD display - two chip solution. N9XR, what do you think... do you have a RS232 9600 baud core? I did the hardware design for one for a class project, if I can find it, I can probably code it into VHDL. Now, if I can decode the keyboard directly to FPGA, then we have a one chip solution (excluding clock). With a RTTY encoder, a neat companion to the IC-7000. Good idea?

Jeez you guys are good! After reading and trying to understand what ya'll were talking about
I just had to get up and hug my old DX-100. :roll:

[kf0rt]

Speaking of IC-7000 ... It can decode RTTY, but not encode from keyboard. Suppose I buy that $6.00 keyboard to serial device from K1EL, and connect it to an Actel FPGA, and modulate the FSK line, and output the transmit characters to a LCD display - two chip solution. N9XR, what do you think... do you have a RS232 9600 baud core? I did the hardware design for one for a class project, if I can find it, I can probably code it into VHDL. Now, if I can decode the keyboard directly to FPGA, then we have a one chip solution (excluding clock). With a RTTY encoder, a neat companion to the IC-7000. Good idea?

Keep it small and low power. You could build it right into a keyboard that would plug directly into the back of the 7K. How cool would that be? (I guess the LCD might be an issue...)

It's hard for me to conceptualize doing this in an FPGA -- you'd have to decode the keyboard, buffer it, encode the buffer to RTTY, plus drive the display. FPGA's are definately not my forte. It'd be a slam-dunk with a PIC, though.

Was just looking at the documentation on the K40 -- it'll transmit FSK/AFSK RTTY, but with an add-on board. The add-on is mostly audio decode and encode for AFSK -- seems odd that the FSK part wasn't included in the keyer itself.

I saw the K40 stuff too. But I think you suggested an excellent idea, putting the circuit inside the keyboard. Downside would be if the keyboard goes bad, it would have to be 'extracted'. I think we can make a small enough board that it would not be a clunky dongle. FPGA devices comes in all kinds of sizes. I have dealings with the BIG devices, maybe Todd can make a recommendation on a smaller device.

My problem anymore is cord overload -- anything that gets rid of extra cables and little widgets adds about 10 db of gain to a project. :)

Have you done any playing with the PICs? (Not pushing or anything...) It seems like this could be done with a $3 part plus a minimal amount of support electronics (connectors and an oscillator, mostly). Of course, the challenge would be in writing the code, but you'd have that with the FPGA, too. Are FPGA's reasonably cheap and easy to program at home without expensive development software and hardware?

Just starting to think about another project here; half thinking of doing an intervolometer for my digital camera -- turns out someone already makes one, but it's a bit pricey.

[N1LAF]

My problem anymore is cord overload -- anything that gets rid of extra cables and little widgets adds about 10 db of gain to a project. :)

Have you done any playing with the PICs? (Not pushing or anything...) It seems like this could be done with a $3 part plus a minimal amount of support electronics (connectors and an oscillator, mostly). Of course, the challenge would be in writing the code, but you'd have that with the FPGA, too. Are FPGA's reasonably cheap and easy to program at home without expensive development software and hardware?

Just starting to think about another project here; half thinking of doing an intervolometer for my digital camera -- turns out someone already makes one, but it's a bit pricey.

I have the PICDEM 2 Plus board that I bought from Digikey for $210 that includes the USB ICD2 programmer. The chips I have used is the 18F452 and the 18F8720 ($19.50). I just had some boards made up that has PS/2 connector and interface chip pads, and to support the 18F872x devices, and a USB interface board. All two sided, so I took advantage of the 3 for $99 deals (PS/2 and USB were break-offs, and all three count as one. I will be using the 18F8722 next, because it has a built-in clock oscillator, how cool is that?

The 18F872x is a surface mount device, and the biggest 8 bit that they have. Most cases the 18F452x will suffice.

[kf0rt]

I have the PICDEM 2 Plus board that I bought from Digikey for $210 that includes the USB ICD2 programmer. The chips I have used is the 18F452 and the 18F8720 ($19.50). I just had some boards made up that has PS/2 connector and interface chip pads, and to support the 18F872x devices, and a USB interface board. All two sided, so I took advantage of the 3 for $99 deals (PS/2 and USB were break-offs, and all three count as one. I will be using the 18F8722 next, because it has a built-in clock oscillator, how cool is that?

The 18F872x is a surface mount device, and the biggest 8 bit that they have. Most cases the 18F452x will suffice.

I've got a PICKIT 2 programmer here; came with a handful of PIC parts and an experimenter's board. I think I paid $50 for it on a promotion Newark was having some time ago.

So far, the only PIC project I've done is a somewhat elaborate digital clock (made two; one for the living room and one for the shack). This used a 16F917 because I needed a lot of I/O -- it's a full-size 40-pin DIP. I think the 917 has a built-in oscillator too, but it wasn't fast enough or accurate enough for what I wanted, so I clock it externally using a little 20 MHz half-size oscillator. This lets the chip run at 5 MIPS if I recall correctly. I'll have to dig up the pictures, or take some more.

Fun stuff, though. I've been using ExpressPCB for boards (the whole TWO of them that I've had done). They'll do 3 (2.5" x 3.8") boards for $59, including 2-day shipping.

My other PCB project was an RF remote controlled screwdriver antenna controller. Kind of a failure that I need to get back to one of these days. It uses the Lynx receiver module and a little keyfob transmitter (433 MHz). It worked fine, but once I put it in an enclosure, the range dropped to almost zero.

That 18F8722 is a brute! Unlikely I'd ever need anything that big for a home project.

[N3ATS]

KF0RT, I bow to you, almighty homebrewer man!

I am just starting the planning for a homebrew PSK interface. I want something where I can adjust TX levels both incoming and outgoing without having to dig out a screwdriver (knobs). I want a monitor out jack for outgoing audio, a mic jack for WinDRM, a PTT switch, and it all has to fit in a small box.

[kf0rt]

What's WinDRM?

The PSK interface should be real easy. It's mostly just a rig / sound card interface, right?

When I first started playing with RTTY, I got one of those Buxcomm RASCAL interfaces. Couldn't believe how much I spent for what amounts to $5 worth of parts. There's really nothing to the sound card interface. Keying the PTT line is a 20 cent transistor and a 2 cent resistor.

Do it right, and most of your cost will be in the box and connectors!

[KG4CGC]

Nice work 0RT.
I need to do a project.
I always end up buying a new soldering iron when I do.

[N2RJ]

What's WinDRM?

WinDRM software used to implement DRM. (http://www.drm.org/)

The hammie version is narrower than broadcast.