Codec2 Project Asks FCC To Modernize Regulations

Bruce Perens writes "The Codec2 project has developed FreeDV, a program to encode digital voice on two-way radio in only 1.125 KHz of bandwidth. But FCC regulations aren't up-to-speed with the challenges of software-defined radio and Open Source. A 24 page FCC filing created by Bruce Perens proposes that FCC allow all digital modulations and published digital codes on ham radio and switch to bandwidth-based regulation."

About Codec2

[thatkid_2002]

For those interested in knowing what Codec2 is, there's a video from Linux Conference Australia 2012 which gives a pretty good (and gentle) overview.
http://mirror.linux.org.au/linux.conf.au/2012/Codec_2_Open_Source_Speech_Coding_at_2400_bits_and_Below.ogv [linux.org.au]

Re:good luck with that

[Dan Dankleton]

This will affect the amateur HF bands, not the agency bands. At the moment, US rules have separate sub-bands for voice, data and image transmissions. This does not really fit with how modern digital schemes transmit - there could be a lot of metadata carried with digital voice signals, for example. What this proposal does is do away with the rules which say where you can transmit voice and replace it with rules which say you can transmit any signal which takes less than X khz bandwidth in this segment.

I agree with the end goal, Bruce

[Muad'Dave]

The end goal of moving toward more spectrally-efficient digital modes for all forms of communication is laudable, but I think that there still needs to be some 'semi-official' protection for the traditional SSB phone modes while they're still in widespread use. Most robust digital modulation schemes are fairly immune to interference from adjacent SSB voice transmissions; unfortunately the converse is not true - my Mark I ears are not immune to nearby digital interference. As long as we still have band plans that encourage the separation of all digital modes from the analog modes, I fully support your proposal.

A question, though: How does spread-spectrum fit into your bandwidth-based plan? Do you consider the bandwidth to be what's used by each individual chip or the SS signal over all its carriers?

How do you feel about introducing a CDMA-esque automatic listen-before-transmit rule for computer-based digital modes, particularly with the growth of unattended stations?

PS - There's a typo in item 79 in the 20m, 6kHz section of the proposed bandwidth table - you have the lower limit as 1.150 MHz instead of 14.150 MHz.

73 de K4DET

Real World Demo

[pavon]

And here is a recent demo [youtu.be] of real world performance. Compared to SSB the encoded voice is more artificial sounding, but there is no background noise (hiss and clicks) and it uses less than half the bandwidth to transmit. There is more info and a large playlist of demo/tutorial videos on David Rowe's blog [rowetel.com] (the creator of codec2).

Not an issue in Canada

[ubergeek65536]

In Canada any codec can be used in ham radio as long as the signal fits in the allocated bandwidth for the frequency and no encryption is used. The restriction is that you must publish the method before going on the air.