[GreenKeys] Hello and Where to find PC to RTTY Interface?

[epvgk at limpoc.com]

Hi, 

Enough people have expressed interest that I'm going to do a small run of 
about 20 boards with a manufacturer I've used for work stuff in the past. 
It's about a two week turnaround, but super cheap. the bare boards will be
about $5, and will have solder mask and silkscreen with part markings. I'll 
also preorder all the cheap passive components so people don't have to order 
minimum quantities just to get one resistor, etc.. It's a small enough 
outlay that I don't really care if I end up with a pile of them unclaimed, as
I can always use more loose parts anyway. More info once the partslist is
all checked and verified. 

eric






On Fri, Dec 31, 2010 at 04:40:30PM -0800, epvgk at limpoc.com wrote:
> 
> Hi folks - 
> 
> A bunch of people have expressed interest in the FSK demodulator I made, one
> of which I gave to Paul Cembura. It's just a straightforward application of 
> the NJM2211 AFSK decoder chip pretty much right out of the datasheet, with an 
> optical current loop interface tacked on. 
> 
> Basically you give it power and an audio signal (ie from a computer playing 
> ITTY) and it keys a current loop circuit with the decoded data stream,
> suitable for directly driving an actual teletype machine. It does not include
> a loop power supply, as it's basically just an optical relay that opens and
> closes. It's also receive-only - it doesn't modulate. You can adjust the
> center frequency somewhat, and select wide or narrow shift. 
> 
> Paul and I have been using them for a while and it works fine for decoding 
> ITTY and various stuff I've found on the Ham bands, but is by no means a 
> sophisticated device. It does have the advantages of being tiny (2 by 2.5 
> inch board), cheap (<$20 in parts), and easy to assemble (30 components total). 
> 
> I'm including the schematic in PDF format, and the eagle files are at:
> http://xymoc.com/~eric/rttydemod/
> If anyone wants gerbers or some other format, let me know. 
> 
> I'm thinking of having a run of about 20 of the bare board manufactured, 
> which would run about $5 each at cost - if more than one or two people want 
> one I'll do this just to make it easy. I can also include with it a parts list 
> with Digikey part numbers so it's easy to order everything. Unfortunately I 
> am so busy with work these days I'm not going to realistically have time to 
> do preassembled ones. 
> 
> Anyway, I feel sort of silly putting this out there since it's a bit sloppy
> and not anything at all innovative, but i'm happy to contribute if people
> want it... 
> 
> eric
> 
> On Thu, Dec 30, 2010 at 02:08:52PM -0800, Bill wrote:
> > 
> > 
> > On 12/30/2010 10:37 AM, epvgk at limpoc.com wrote:
> > >On Thu, Dec 30, 2010 at 08:23:02AM -0800, Greg Farrell wrote:
> > >>Hi All,
> > >>
> > >>I am brand new to RTTY hardware and this group, first posting. Had a problem with my email address since I send from my native account, not k6sro at arrl.net and got a  message back I was not on the member list, but I am. Changed my email address to gregf at pon.net so hope this works.
> > >>
> > >>
> > >>Picked up a model 15 from Paul http://www.johnwhitney.com/misc/paul-rtty.htm yesterday.
> > >>
> > >>Thank you Paul.
> > >>
> > >>He demonstrated that machine with a little interface box from his laptop running ITTY.
> > >>
> > >>Where can I get this box or does anyone have a schematic/parts list for one?  It had an email address on it something like eric at linpoc.com but that doesn't work.
> > >>
> > >>TNX in advance.
> > >>
> > >>
> > >>Greg
> > >>K6SRO
> > 
> >     I would be very interested in this also.
> > Thanks
> > Bill Cain
> > >hi, that's me :)
> > >i can give you schematics and parts lists for that little box if you like, and if you have
> > >patience could etch you a bare pc board for it. you'd be on your own assembling it but it's
> > >a very simple circuit.
> > >
> > >eric at limpoc.com
> > >
> > >
> > >>-.- -.... ... .-. ---
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