1. anybody have any links to any sites that describe how to make a packet radio transmitter/receiver? I found some sites that say you can use your sound card, but they weren't really reliable.

Posted at 2:57PM on Oct 4th 2007 by Alexander

2. Damn this guy is just waiting for an apocalypse to show he can still talk and find his way around.

F3

Posted at 4:21PM on Oct 4th 2007 by Fqubed

3. I think the reason we don't see many self contained circuits being published on the Internet now days is we've all became lazy over the past decade.

For example if you go search for single board computers with NTSC or PAL output most of the designs stopped being published in the late 90's. I guess that's when the analogical tide broke and everyone signed contracts with big company's that licensed there employees creativity as there own.

It's cool to see more RF devices being made. It'd be even cooler to see something like 12Mhz shortwave digital packet protocols being implemented in non-commercial circuits. Even better would be AES or triple DES shortwave protocols.

Posted at 5:59PM on Oct 4th 2007 by TJhooker

4. GPS in a post apocalypses?

Don't count on it, these machine rely on frequent maintainance. Also its likely to be shut down during a apocalypses, by the American government to civilian applications.

Packet radio soulds pretty good... Packet Usenet anyone?

Posted at 9:57PM on Oct 4th 2007 by crackerjackel

5. As I understand it, many of the circuits aren't published anymore because it's usually accomplished via software. Sound cards are wonderful things, and as long as you connect it directly to your radio, you don't need any additional, expensive components. It's also more flexible.

One good example of this is Digital Radio Mondial. As far as I know, there are no DRM decoder chips, or at least none that are widely available. If you want to listen to DRM, you need to first mod your receiver to output 12kHz, then feed it into a computer and decode it there. Eventually it will be moved into hardware, but doing it in software is more flexible.

Posted at 11:42PM on Oct 4th 2007 by sean

6. It's not that we're not being "creative" anymore, it's that hobby single-board computing isn't as fun as it used to be. You used to be able to make something only slightly slower than a commercial machine, and do useful computation on it. Nowadays you're mostly stuck at the same level people were in the early 90's/late 80's (try breadboarding a 386!), which isn't nearly as fun. That, and FPGA's have removed the need to wirewrap 50 discrete IC's (Verilog is WAY easier than wirewrapping!).

Posted at 11:49PM on Oct 4th 2007 by chris

7. I have a USB dongle that gets pretty good MPEG over different satellite bands, but it doesn't make me want to stop messing with AX.25 and obscure spectrum hardware.

Also FPGA's are pricey as hell even on an engineers salary. Some of us stick to salvaging components as a necessity. In a post apocalyptic state the yuppies and the consumers would perish after going on parasitic rampages.

Posted at 6:02AM on Oct 5th 2007 by TJhooker

8. Seeing the hardware it looks like from 1970 or earlier... not a very modern approach.

Anyways, this guy really understands RF electronics.

Posted at 8:49AM on Oct 5th 2007 by Lupin

9. I wouldn't really call FPGA's "pricey as hell" nowadays (certainly years ago). You can get a breadboard-able ~1 million gate Spartan3 with LED's, switches, 32MB of SDRAM and an on-board flash chip for about $200 (http://xess.com/prod035.php3 - I have one, they're great). No JTAG programmer or anything needed (just over parallel).

On the bright side, you can now design your own processor that can achieve ~20-50 MIPS, which was just about impossible even 10 years ago =)

Posted at 1:39PM on Oct 5th 2007 by chris

10. This is from 1991, when commercial GPS receivers cost $1000s. Very nicely done!

Posted at 2:27PM on Oct 5th 2007 by Henry

11. You all have plenty of time to build this. I won`t have the apocalypse ready for another month at least.

Posted at 3:11PM on Oct 5th 2007 by Seedy-ROM

12. Alexander- A transceiver suitable for telephony will work for packet. On consideration for packet would be it's RX to TX turn around time. Because my old TNCs are still functioning, I have yet to use a compter/sound card with the AGWPE utility program. Those I know who do haven't mentioned any problems other than it may take a bit of futzing to get all the components to like each other.
Sean- While software is playing a larger role, we still need the RF circuitry for the software to have something to do.
Post-apocalyptic? Chances are the first radio comms. will be by CW operators using Morse Code. I'm no Morse Code forever type, but CW equipment is simple and can do more with less power than any other wireless mode. Even it requires the most powerful computer yet, the human brain.

Posted at 5:16PM on Oct 7th 2007 by static

13. Bring it to the people, alexander!

CW FTW!

(73 DE N2NLQ!)

Posted at 8:35AM on Oct 8th 2007 by strider_mt2k

14. are bhosdiwalo kuch DOWNLOAD section to rakho isme.
sirf ise dekhkar kya lauda hilayenge

Posted at 9:28AM on Oct 8th 2007 by ragra001

15. bluetooth gps receiver doesn't seem that expensive now, right? :)

Posted at 2:24PM on Oct 8th 2007 by mure

16. crackerjackel, that is why it is using both GPS and Glonass... If either the US or the Russians (or their satellites) survive, it will still be usable!!

lol

Posted at 12:57AM on Oct 9th 2007 by kn0t