Gunstar Posted January 17, 2021 Share Posted January 17, 2021 (edited) I was skimming through my old Antic magazines yesterday and came across the September '86 issue (volume 5, number 5) with article, schematics and programs to build a WEFAX interface. Luckily, WEFAX is still in use for the maritime industry. I remember skimming over the articles back then, but it was before I knew anything about working with electronics so that was it. Today I just ordered the XR 2211 IC for decoding the signal and found a cheap shortwave radio with single side band (SSB) for $60 (most start over a $100 and go up from there, but his one should suffice for this project). I haven't ordered the radio yet as I'm going to see if there are any shortwave radio apps for my Android that have SSB. Anyone know of any? An app should work, since all I need is a headphone jack to plug it into the WEFAX interface. I think it will be fun to get weather info and satellite images on my Atari, and I'll finally have something to use my 24-pin dot-matrix printer too! Edited January 17, 2021 by Gunstar 3 Quote Link to comment Share on other sites More sharing options...
ivop Posted January 17, 2021 Share Posted January 17, 2021 I remember this was reprinted in the Dutch "Atari Magazine". It was one of the first DIY projects I tried to build, and I failed misserably ? Lets say my soldering skills were not developed yet/ I used a so-called "world" radio receiver. As a family, we used to take that one on holidays, and listen to Dutch radio, to the Tour of France, each day. Even when in France 2 Quote Link to comment Share on other sites More sharing options...
Gunstar Posted January 17, 2021 Author Share Posted January 17, 2021 (edited) 4 minutes ago, ivop said: I remember this was reprinted in the Dutch "Atari Magazine". It was one of the first DIY projects I tried to build, and I failed misserably ? Lets say my soldering skills were not developed yet/ I used a so-called "world" radio receiver. As a family, we used to take that one on holidays, and listen to Dutch radio, to the Tour of France, each day. Even when in France While looking for receivers on ebay and amazon I saw a lot ot the "world" radio receivers, but none of them had the SSB band (required for this project), There are plenty that do, but they aren't referred to as "world" receivers. did your receiver have the single side band? My family also used to have a radio that was am/fm/shortwave that we used to take on trips too. Though I don't know if it had SSB. I don't know what ever happend to that radio. Anyone have a used and working portable short wave radio with SSB and a headphone jack that they'd sell me for less than $60? All the ones on ebay and amazon were new, no used ones up for sale. Edited January 17, 2021 by Gunstar Quote Link to comment Share on other sites More sharing options...
ivop Posted January 17, 2021 Share Posted January 17, 2021 9 minutes ago, Gunstar said: While looking for receivers on ebay and amazon I saw a lot ot the "world" radio receivers, but none of them had the SSB band (required for this project), There are plenty that do, but they aren't referred to as "world" receivers. did your receiver have the single side band? It had long wave, short wave, and AM/FM. But I just read some wikipedia info on the matter, and SSB seems to be a different modulation technique. Not sure if our receiver had that. Perhaps that was why we didn't get it to receive weather images, and not my mediocre soldering skills 1 Quote Link to comment Share on other sites More sharing options...
Gavin1968 Posted January 17, 2021 Share Posted January 17, 2021 Yes! I built one! It worked pretty cool!!! What a blast from the past! Gavin 3 Quote Link to comment Share on other sites More sharing options...
Gunstar Posted January 17, 2021 Author Share Posted January 17, 2021 2 minutes ago, ivop said: It had long wave, short wave, and AM/FM. But I just read some wikipedia info on the matter, and SSB seems to be a different modulation technique. Not sure if our receiver had that. Perhaps that was why we didn't get it to receive weather images, and not my mediocre soldering skills It's easy to miss that it requires the SSB, it's only mentioned once across all the several articles about WEFAX in the magazine, stuck in the middle of a page and paragraph. I read it, but when I went back to look what band the project required again when looking for radios today, I had to practically read it all over again to find it. 2 Quote Link to comment Share on other sites More sharing options...
Gunstar Posted January 17, 2021 Author Share Posted January 17, 2021 1 minute ago, Gavin1968 said: Yes! I built one! It worked pretty cool!!! What a blast from the past! Gavin Awsome! Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 18, 2021 Share Posted January 18, 2021 SSB was chosen as it requires less power to transmit and at higher power transmits further. It this is possible because the method is not transmitting the carrier wave or other modulated signals on the other side of the carrier (since there were 3 parts, we refer to the whole wave including upper and lower modulation as a band of the radio spectrum), So you only transmit a single signal without the other two parts. To decode and make it natural sounding the receiver may inject it's own carrier wave at extremely low power use to make tuning the signal easier and more natural so you don't get distorted, muffled, or quacky, tinny, donald duck noises. The key here is long distance, low power usage. Those are the primary reasons for SSB. even if geologic or geographic features like mountain, valley's, water swells impact the signal wave causing compression or spreading of the wave, you can tune it back to the proper waveform to the point it is intelligible. this makes for a robust communication system using lower power across longer distances and was used for Marine, Air Traffic, and HAM radio among other applications. Short wave radio can utilize the method to it's advantage just like most other transmitted wave forms of radio and other coms. Perfect for WEFAX and while not on all SW radios today, it used to be on many, you may just have to look closely of the SW radio offerings of vintage receivers more closely and make sure it's there, most folks wouldn't even know to include it in an auction description. 1 Quote Link to comment Share on other sites More sharing options...
Bobofett Posted April 1 Share Posted April 1 (edited) Hey everyone, this ignited my curiosity (not hard to accomplish) so I used the original article to draw the schematic and produce gerber files for the project. Got the pcbs and it actually works. Here is a link to my repository where both gerber files and software are provided to make this happen. Hope they can be useful for anybody here. Disclaimer, I am no expert designing PCBs so I am sure you guys can improve upon my version. https://github.com/fcordov/wefax Edited April 1 by Bobofett typo 1 2 Quote Link to comment Share on other sites More sharing options...
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