On Fri, May 11, 2012 at 2:14 PM, Bruce Perens <br...@perens.com> wrote: > The reason that SSB transmission is in general not offered on HTs is that > much of the power of a linear PA ends up being turned into heat.
Hm. I thought it was also because they don't have stable and accurate oscillators (because doing them in confined space/ highly variable temperatures is costly). This is less of an issue for us I think— because snazzy DSP can track frequency drift and capture even if the tuning isn't dead on. It's not like a HT has room for nice output filters to prevent OOB splatter from an excessively non-linear power amplifier. Would any customer protest if that their SSB mode lost 3dB output power vs FM mode? In any case, being _easy to use_ will mandate running inside some HT's FM modulation— and that basically precludes being more narrow-band or working when the signal is very weak. At best you can get better multipath/picketfensing survival by slapping on a lot of FEC and a handy data side channel. The people pushing dstar have the advantage of selling hardware adapted to it to a market eager to buy from them (even absent the dstar support). It's simply not possible to be competitive with large entrenched hardware companies. You can't innovate at the modem/RF layer because there is little installed base of SDR compatible VHF/UHF hardware, so if you try you fail at ease of use. If you make it to be easy to use (just AF input on a FM radio) then you'll suffer on performance. You can have superior performance or you can have ease of use, but not both ... and even if we somehow solved that problem, dstar comes _built in_ at _no extra cost_ in popular radios whos makers have many sales people and no problems manning a booth. The fact of the matter is that in the US, and I assume everywhere else, the proprietary and trade secret encoding used by dstar violates both the letter and the spirit of the law. If you want to compete with dstar— go get a statement from the FCC clarifying its unlawfulness to everyone who's been happy pluging in black boxes and not worrying about the encrypted data coming out of it. ... but without that, I think trying to outdo dstar at its own game is just a losing battle and it distracts from making the best codec and modem that can be made— and making displacing dstar the goal makes the whole process non-fun: How many people want to work on a project whos success or failure is uncorrelated with how well they do? ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
