Tired of only listening

[Radiorick]

Any ideas of a decent publication that covers decoding/demodulating digital communication signals. I'm using a IC PCR 1000. Granted the software will demodulate what it can, but am interested in viewing the
signal and attempt to classify and manipulate it. Also....have any of you
seen or heard of a library of signals (ie. tty/rtty/fsk ect) which will give
examples of set types. Thanks in advance.
Rick

 

[Radiorick]

An audible library so that I can train my ears....

 

[poltergeisty]

There is a web site for audio samples but I can't remember off hand. Maybe some one else dose. If all else fails do a search in this site. As to what digital coms. are you wanting to decode? If it's apco-25 or other trunked type digital system most can be decoded with a bc296d or a pro-96.

 

[Radiorick]

Tracking trunked conversation may be of interest down the road. Both those scanners utilize a "chip"...there has to be software that will do the
same. Right now though what I'm looking is a O scope displace or water
fall type display (Several software packages allow for this). .......couldn't
iDEN radios be scanned using a modded hand set?

 

[loumaag]

A good supply of digital signal sounds can be found at this link.

Good luck on your project!

 

[INDY72]

With apologies... If I remember right, iDen, and VSELP type digital systems from Motorola would require an actual vocoder which costs in the VERY EXPENSIVE range. As to trying to get a modded radio for these type of systems, you would need the radios programmed vias software to actually hear each system, and these radios are expensive (STX series, Saber series....etc....) Not trying to be negative here, but just letting you know the roadblocks you'll have to circumvent. As to monitoring IMBE vias oscilisope/cascade display systems, sounds like a good idea.... Not too sure you could do ProVoice type digital without a programmed M/A-Com radio (IE- Jaguar).

 

[N_Jay]

Tracking trunked conversation may be of interest down the road. Both those scanners utilize a "chip"...there has to be software that will do the
same. Right now though what I'm looking is a O scope displace or water
fall type display (Several software packages allow for this). .......couldn't
iDEN radios be scanned using a modded hand set?

I think the issue is deciding what you want to do.
Certainly a receiver and a modulation analyser will let you look at "pretty pictures" on the scope, but will probably not get you any further towards decoding the information.

Most of the RF modulation methods are public inforfmation anyhow.
Then you would have to decode the channel coding.
Probably a really good communications protocol engineer could do that with enough time, equipment and motivation.
Next would be reverse engineering the vocoder.
Again, I think most of these are patented so the base information is available.
If you could actually take a radio apart enough to inject a sugnal into just the vocoder, it would be a help. My guess is that most radios run the vocoder and channel coding algorithins from firmware (or flash loaded software) and breaking them apart is going to be well beyond most casual tinkerers abilities.

Another aproach would be to purchase the service equipment (Service Monitor or test set) for each type of system. This would give you a receiver with the channel and voice coding software ready to be used (or missused, as the case may be).

 

[Radiorick]

First thank you for you comments, secondly....The gent that commented on the analitcal aspect would all come down to finding commonality's (ie a artical about a group who found and monitored a Brazilan Naval traffic then decided to go further and start identify callsign...this was in this or last months issue of Monitoring Times). Eye candy is entertaining but
yes useless....anyhow nodal analsys does sound like it will require a lot
of background...but then again what hobby doesn't...