[aprssig] mobile antenna for D7?
'Scott Miller' scott at opentrac.orgWed Mar 14 19:59:29 UTC 2007
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I wasn't aware of the D7 issue, but I know the Alinco DR-135 tends to get some noise on the speaker from the GPS serial data. There's definitely some crosstalk going on. Don't forget that even with low-speed serial data, you can have fast slew rates. A MAX232 will slew from -6 volts to +6 volts in about 1 microsecond. I wonder if adding some capacitance to the line would help... just dampen the slew rate out until it's just good enough for the RS-232 receiver in the radio to work reliably. Scott N1VG > -----Original Message----- > From: aprssig-bounces at lists.tapr.org > [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Mark Earle > Sent: Wednesday, March 14, 2007 1:24 PM > To: TAPR APRS Mailing List > Subject: Re: [aprssig] mobile antenna for D7? > > Tyson S. wrote: > > One thing to keep in mind is that NMEA data entering a D7 > from the cable will degrade your reciever. There are various > web sites that explain how you are usually transmitting > better than you think while mobile. But I use a regular dual > band antenna on my truck with an adapter from SMA to BNC and > it works pretty good. > > > > > Huh? I'm not trying to pick a nit, but low speed serial data causes > receiver degradation how? > > What do you mean degradation? Reduced sensitivity? Reduced > selectivity? > Intermodulation distortion? Overload? > > > > _______________________________________________ > aprssig mailing list > aprssig at lists.tapr.org > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig > >
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