The VHF and UHF bands have explicit bandwidth limits on data emissions and image has a bandwidth limit on HF. Unfortunately, image transmission benefits the most from increased bandwidth. This maybe a group concerned mainly with RTTY and data but there are other modes that woud benefit from changes in the rules.
73, John KD6OZH ----- Original Message ----- From: jgorman01 To: digitalradio@yahoogroups.com Sent: Tuesday, May 01, 2007 23:50 UTC Subject: [digitalradio] Re: New 200kHz Wideband Digital Voice on 20 meters in USA? This is exactly what I've been trying to say, there is no bandwidth limitations currently in the regs. Trying to argue that the ARRL's bandwidth petition screwed up experimentation and stops people from using newer, better modes just is not correct. The only problem I have with your example is justifying a 200 kHz bandwidth. With currently accepted standards like DRM there might be a little argument. However, if the FEC requires it so be it! Also, it might be difficult from a "spectrum efficiency" to justify that kind of bandwidth. You would have to convince everyone that the fidelity used was justified. The big problem I see is that the appliance operator using current amateur transceivers can't go much beyond 3 kHz. THAT IS where the big problem in experimenting comes from! Jim WA0LYK --- In digitalradio@yahoogroups.com, "expeditionradio" <[EMAIL PROTECTED]> wrote: > > Whether anyone supports "mixing" of digital and analog modes is not > really a matter for debate anymore in USA. The fact is, under USA's > present rules, digital and analog already exist sharing all the same > ham bands and subbands! > > The use of digital in all forms of ham radio communications will > continue to progress, whether that is text, data, image, voice, or > multiple simultaneous forms of content. > > Mere opinions, no matter how informed or ignorant, are not going to > stop these changes. > > Under the present antiquated USA FCC rules, there is no bandwidth > limit for digital signals on HF. > > As an example: > > If two Amateur Extra license operators want to transmit 1.5kW high > fidelity digital voice, 200kHz wide, centered on 14250kHz, it would be > OK under our present antiquated FCC rules. They could transmit such a > wide signal (14150-14350kHz) if it was needed to get the > communications quality they required at the signal to noise ratio at > which they would be operating. Perhaps they are 150 miles apart, and > the signals are weak, so they are using a very redundant FEC type of > transmission signal. > > All they need to do, is get up early in the morning when no one else > is on the band, and start up a good "ragchew" QSO. There is no time > limit on their QSO. They could continue to use a major chunk of the > 20m band, since they were there first. Under present FCC rules, > everyone else wanting to use the upper part of the 20m band would have > to avoid interference to their existing QSO, and wait until they are done. > > Hmmm... what if... these two hams started their 20m ragchew QSO on the > morning of a DX contest? > > Anyone like to set up a digi voice sked? > > ;) > > Bonnie KQ6XA > > . >
