The AM Forum

A new digital voice mode...Frequency Division Multiplex Digital Voice

http://n1su.com/fdmdv/

There's a couple of threads on QRZ.com where guys have posted some sample sound files.  Judge for yourself.

http://www.qrz.com/ib-bin/ikonboard.cgi?act=ST&f=3&t=176625

http://www.qrz.com/ib-bin/ikonboard.cgi?act=ST&f=3&t=177183

Obviously, lots of "growing pains" yet to come, but I think you can guess where this kind of stuff will lead.

I'm not against new technology, but that certainly does not mean we should abolish what we have today.

It made sense to kill spark.  It does not make sense to kill any of the modes we use today.

I know I'm preaching to the choir, but it really burns my onion that a few connected individuals can take it upon themselves to declare that older, but still very useful technology should be done away with or severely restricted.

AM and digital modes are at the opposite ends of the technological spectrum, and are practiced by only a very small percentage of the total ham population, but they BOTH have a rightful place in our hobby and deserve the right to exist equally and peacefully among those using more popular modes.

Downloaded the software a couple of days ago. I'll let you know how it works if I get a chance to play with it this weekend.

I tried WinDRM, but it is not robust enough to ensure that you doo not experience drop-outs, at least with my equipment and with the received signal strengths at my location. The FDMDV is supposed to be a more robust application under poor signal-to-noise conditions. We'll see...........

FDM voice is nothing new....

For sure, when you are talking about taking numerous voice channels and multiplexing them. It was the first type of multiplexing the phone company did way back, like in the 20s.

The FDMDV - Frequency Division Multiplex Digital Voice posted is just one voice channel, divided up into 15 separate carriers (14 QPSK and 1 BPSK) using the MELP codec.

Interesting. The audio files I've heard are pretty robotic sounding. Anyone who has used MELP or CELP based systems in the past will find the sound familiar. I know you will Johnny.

Ah yes, I prefer pdm myself.
I was watching digital TV on the ferry today. It was a bit choppy. I noticed the video breaking lock a couple times. I prefer snow over stuck blocks.

Ya FDM voice - now everyone can sound like "Robbie the Robot".

who will be the key man...

20-20khz
S/N 90db or better
thats what i expect from digital  :)
i'll wait till they improve it a bit more

How many people can or will actually build this technology? ...why? so we can stuff more people into a given band. What a pile of cow-dung.
I could see it now...multi-plexed, processed, condensed, chopped and seasoned audio. Forced in to buying technology that serves no other purpose than to pack em' in. I digress...a reference to the IARU and bandwidth :P

 I can understand technology marches forth, but some of these applications are pertinent to the commercial market and seems to be out of place in amatuer radio world.

I agree. The real problem isn't band crowding, it's bad operators. There's plenty of space now to talk, but for some damn reason, people like to set up right next to each other. This is mostly slopbucket behavior lately, but there are some am'ers that do the same thing. If your freq agile, move around a bit, if your rockbound, update the gd damn thing. This is 2008, not 1935, and if your smart enough to keep that old rock rig running, then make a simple vfo so it can cruise around a bit for Christs' sake.

1100hz bw digi-crap signal so you sound like some cheap voice synthesizer? What are they going for, to get every single station all stuffed into the same 20kc and then sell the rest.

SKER*





*SKER; Stop Key, End Rant. ;)

LOL i say the same thing  ;D
just plug it into the xtal socket.

"yea back in the mid 20'th century they invented these things called VFO's, check it out sometime they are quite convenient"  :P

I hope this won't be a repeat of the high pressure salesmanship campaign of the late 50's and early 60's that attempted to force everyone to abandon AM and buy a slopbucket appliance, which ignited the infamous AM vs Slopbucket Wars, and brought deliberate QRM into the mainstream of amateur radio, something from which we have never fully recovered.