Hi Evans, With transmitting Dstar, changing deviation is as trivial as adjusting the baseband level: Both being audio, it was just a matter of setting the appropriate level (e.g. turning a pot.)
As mentioned, the phase modulator in the Mastr II was used for the voice tests and direct FM (on the compensation line) was used for the Dstar: The baseband levels were adjusted for +-5 kHz deviation for the voice, and +-1.2 kHz deviation (NOT +-2.5 kHz) for Dstar signal - and it was as simple as that. (If done properly, the occupied bandwidth takes care of itself.) I can't really comment on 900 MHz gear or its suitability. Since the discussion was based on using existing, readily-available analog gear on bands for which commercial gear is readily available, I haven't really thought much about trying it on a band for which there is no commercial Dstar gear at all. 73, Clint KA7OEI --- In [email protected], "Evans F. Mitchell KD4EFM / AFA2TH / WQFK-894" <[EMAIL PROTECTED]> wrote: > > I like your write up, BUT, there is something missing here. > > Are you switching from 5Khz deviation to 2.5Khz deviation while > doing your test??? > > D-Star transmits at 2.5KHz, not 5KHz. > There is a difference there... > > Focus needs to / could be with 900MHz equipment since it already > does 2.5KHz bandwidth, even though the lack of 900 gear, though > I would also like to see a 220 D-Star too, lots of band > but lack of equipment. > > Heck to make it worth while, for the HSMM junkies, > why not have a 1.54Meg BW 220MHz ID-220 ??? Think about it, > 2.4 has too much part 15 noise to say, but bring it down > where the Fresnel zone does not become an issue.... LONG DISTANCE > HOPS that are NLOS or NON-LOS for Emcomm use, NOW YOUR DOING SOMETHING! > > Evans > > -----Original Message----- > From: [email protected] [mailto:[EMAIL PROTECTED] > On Behalf Of cctbcn > Sent: Thursday, June 05, 2008 10:56 AM > To: [email protected] > Subject: [dstar_digital] Re: Maybe possible???? > > Hello, > > As part of our Dstar/Analog testing (see the thread posted several > months ago) we modified a Mastr II repeater to transmit, alternately, > Dstar and analog signals: For analog, we used the radio's phase > modulator and for Dstar, we used the direct-FM on the compensation > line. In our opinion, the Mastr II produced a better-quality signal > than the IC-91AD, mostly because it didn't suffer from the "PLL > Bounce" problem that the direct-FM modulated Icom radios have (e.g. > associated with the PLL trying to track the low-frequency components > of the modulation.) >
