The answer is that the current regulations do not adequately address the situation. There are those who would swear that D-STAR is Voice and those who would swear that it is digital. And I've had this discussion with a number of people who have assured me that their opinions have been confirmed by the FCC :).
So we've got a couple of options 1. Force the FCC to make a ruling, you know, those things that tend to make everyone equally unhappy. 2. Call if voice and live to within the voice rules. 3. Call it digital and live within the digital rules. 4. Or not make an issue out of it and play nicely with others so that it really doesn't matter ON VHF/UHF, the classification isn't a big issue, as both are usable in the same places. The issue is in HF where there is a legal line in the US. Basically there are two classifications Phone/Image and RTTY/data. And the problem really only exists on 10M. On 10M if you classify D-STAR as data, then run afoul of the following rule (4) Only a RTTY or data emission using a specified digital code listed in ยง97.309(a)<http://www.arrl.org/FandES/field/regulations/news/part97/onepage.html#309> of this Part may be transmitted. The symbol rate must not exceed 1200 bauds. For frequency-shift keying, the frequency shift between mark and space must not exceed 1 kHz. Since the signaling rate of D-STAR is faster than 1200 bauds, we have a problem. But if you classify it as voice, then there are really no issues. Now, one of the biggest things to think about is under what restrictions are Icom in making a radio. And basically the answer for this conversation is that just because an Icom radio CAN DO IT doesn't mean the it is LEGAL! From: [email protected] [mailto:[email protected]] On Behalf Of John Hays Sent: Friday, August 28, 2009 7:45 PM To: [email protected] Subject: [DSTAR_DIGITAL] Explain this to me (Was News on IC-9100) US Audience OK so I have been wondering this for awhile, but the announcement of the IC-9100 got me looking into it a bit further. The FCC Rule for voice/image transmission emission standard is: 97.307f (1) No angle-modulated emission may have a modulation index greater than 1 at the highest modulation frequency. 97.307f (2) No non-phone emission shall exceed the bandwidth of a communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission. Rules 97.307f (1) & (2) apply in the HF sub-bands for voice/image communications Rule 97.307f (2) applies to voice/image 29.0-29.7 mHz. Now I'm not expert on modulation, but this does bring up an interesting set of questions: * If we assume that DV is "Phone" communication, the D-STAR GMSK modulation index is 0.5 with a deviation of 2.5 kHz. occupying the approximate bandwidth of a 100% modulation (1.0 mod index) AM signal, which is generally considered a legal transmission in those bands. To my mind, that meets the requirements of 97.307f (1) and would mean that a D-STAR signal should be legal on most US HF bands. * If we assume that DV is all or partially a "data" signal, we run into a problem in the chart at 97.305c as the HF bands do not provide an overlap between "data" and "voice/image" communications. Except of course CW, which may be operated anywhere on the bands and that modern "image" (fax/sstv) transmissions often include "data" elements to designate modes - which I haven't seen any enforcement actions over. (Let alone some other mixed mode operations.) So, the big question is are people just assuming that D-STAR cannot run outside of the 29.0-29.7 mHz. segment because FM uses a higher modulation index and bandwidth or am I missing something in the regulations? (Since D-STAR would seem to meet 97.307f (1) and be about the bandwidth of an AM signal.) Certainly the AOR company believes their product meets the regulations (with a narrower bandwidth) -- see http://www.hamuniverse.com/aorard9000mk2.html Of course there is no indication that GMSK would do well in the HF environment where signal are often contorted and twisted on their journey. John D. Hays Amateur Radio Station K7VE<http://k7ve.org> PO Box 1223 Edmonds, WA 98020-1223 VOIP/SIP: [email protected]<sip:[email protected]> Email: [email protected]<mailto:[email protected]>
