Perhaps there are those that think that there are more limitations than actually exist in the FCC rules, but there are differences that should be remedied. PDFs can be defended as being images, but many other types of files are clearly prohibited as they aren't formatted to print on a page. Any type of file should be able to be sent as can be done in many other countries. There are also bandwidth limits on VHF bands that clearly prevent the use of wideband modes where there is space for them.
73, John KD6OZH ----- Original Message ----- From: [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Thursday, May 03, 2007 03:43 UTC Subject: Re: [digitalradio] Digi Voice: No Bandwidth Limit After all the claims of how we are somehow being held back from new technologies, it is interesting that there is nothing but silence from the folks who claim so many others can do all these new things that we supposedly can not here in the U.S. I am hopeful we have some honesty about this in the future and not just theoretical claims. I have wondered why no one has asked the FCC for an interpretation of our ability to use mixed modes in the phone/fax/image portions of the bands. 1. It seems to me that sending a picture, FAX, diagram, with text mixed in but in a form such as a pdf, doc file, or even better an odt file (which is a fraction the size), would be the same thing as a FAX transmission and is completely appropriate within the voice/FAX/image data portions of the bands. 2. Ideally, if you are going to be using mixed operation on 160, it would be nice to see an area where it is approved in the band plan so there is no question. The ARRL's band plan says "SSB, SSTV and other wideband modes from 1.843 - 2.000. Since I don't really consider this "experimental" I don't think one should have to resort using the 1.995 - 2.000 experimental band plan frequencies. I think you will find WinDRM to work quite nicely to send documents. I have copied many SSTV signals from the digital groups and if you lose a block, you can request a fill after the fact so that you can get a perfect document. This is used in an unconnected mode from one to many. If someone developed an ARQ mode then it should work in a similar fashion. The main problem with WinDRM and other programs using this form of OFDM is the requirement for a very high S/N ratio in order to get anything to go through. It needs something around 7 db S/N or thereabouts and that is not easy to do on a consistent basis. If we could get a mode to work just a few db under the noise, and not slow down too much, that would indeed be a breakthrough. Perhaps something along the lines of 141A FAE ARQ mode in Multipsk. It would require a VERY long time to get a message through that is 30 to 70 kbytes as a lot of even simple docs tend to be. 73, Rick, KV9U Leigh L Klotz, Jr. wrote: > I would like to try some of the DRM-based modes which allow you to send > voice, pictures, and text. > I suppose I could do thos on 160m, now that I think of it. > > 73, > Leigh/WA5ZNU > On Wed, 2 May 2007 7:58 am, [EMAIL PROTECTED] wrote: > >> If it is true that others are not being held back, what actual new >> wideband HF modes have been developed that we can not use in the U.S.? >>
