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Subject: | Re: [geda-user] [OT] Wireless communication 101 |
From: | "Chris Smith (space DOT dandy AT icloud DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com> |
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<CAOuGh88XMN_KjnUCBbLHiax0J0=3weeky=FU3Nm8w9_xhtnpPA AT mail DOT gmail DOT com> | |
Date: | Wed, 23 Sep 2015 15:55:00 +0100 |
Message-id: | <BB5DD20F-CAEA-4EF9-BCFE-391F019E510D@icloud.com> |
References: | <70C4A238-D361-4A6C-A81D-CBF019CADC4F AT icloud DOT com> |
<5601AE56 DOT 2050706 AT neurotica DOT com> | |
<0958473E-0115-4C08-860F-EF92B84B7404 AT icloud DOT com> | |
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> On 23 Sep 2015, at 13:06, Bob Paddock (graceindustries AT gmail DOT com) [via geda-user AT delorie DOT com] <geda-user AT delorie DOT com> wrote: > >> As I said, I can't influence the RF part, only the ones and zeros that are encoded onto the carrier. I also can't change at this stage the simplex operation. > > As in always TX -> RX or just one direction between the two at a time > (half duplex)? Strictly simplex, not half duplex. >> Thanks for the OT prompt. I've amended the subject line and will let the thread die out -- I wasn't looking for lengthy discourse anyway, just a few pointers. I will look at the ARRL handbook. > > While also at ARRL book store look at the Packet related items and at > the TAPR web site. Maybe you want to be in Chicago on Oct 9th for the > 2015 digital conference? https://www.tapr.org/ TAPR has lots of > Interesting Stuff. > > Also download and play with FLDigi http://www.w1hkj.com/download.html > Look through the modes such as PSK31 and BPSK63 et.al. on low > bandwidth (and slow) signals. There are bout 40 different > modulations, encoding etc. > Source code is available. > > AX.25 is the standard used for Amateur Packet Radio. > > I've had good results adapting the sliding-window protocol from Hydra > for my com applications over the years. It is based on the older > ZMODEM sliding window stuff. > Search for 'hydra' here ; http://archives.thebbs.org/ra90c.htm > > Also look up 'Error Correcting Codes' and CRCs (prepare for eye glaze > over if try to figure out the math of CRC Galois Fields of limited > Syndrome Length... Most people just copy the code found on Internet, > some of which is popular and mathematically wrong). Sadly I’m on the wrong side of the pond for TAPR, but thanks for all the links. Lots of reading ahead. :) Chris — Chris Smith <space DOT dandy AT icloud DOT com>
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