Hi All I've got to throw this out from a broadcast engineer's perspective. Since Paul mentioned HD radio, in a manner that implies that he listened to the AM HD signal, it may be that the HD process is responsible for the noise. FM HD works real well (or at least it did until the programming people heard the 96K bit stream could be divided into two 48K streams to give them something else to sell), BUT.......the AM HD process throws out raspy, buzzy, etc. garbage 10 - 30 KHZ either side of the main carrier and trashes adjacent carriers in no uncertain manner, especially if they're weak. We're being forced to implement the AM version against a lot of our better judgment. A number of AM's have turned the HD off until someone at Ibuquity (the patent holder) comes up with a better codec. As it is the FCC only allows HD on AM during the day because of sky wave causing excessive hammering of on channel stations. Just a thought.
Bill AD5OL >>> Paul Shaffer <[EMAIL PROTECTED]> 03/28/06 07:32PM >>> I need an idiots guide to AM reception. Even the strongest local stations have a hum or buzz in the audio through sdr-1000. I would like to get the great audio others are hearing and must be doing something wrong. I've tried SAM mode, no help. The buzziest local am broadcast station is the only jazz station in town. They just went to HD Radio. It sounds ok on a regular receiver, but not on sdr-1000. http://radio.boisestate.edu/stations/DigitalRadio.asp " Little or no change in listener behavior will be required since all local radio station dial positions will remain the same. Listeners will simply tune to their favorite programs and stations and receive them in either a digital or analog format depending on their radio. Because stations will begin digital broadcasting using a "hybrid mode," transmitting digital and analog signals simultaneously, listeners with analog receivers will still be able to pick up the broadcast and will be able to seamlessly upgrade to digital at their own pace." -------- Original Message -------- > From: "Jerald Jones" <[EMAIL PROTECTED]> > Sent: Tuesday, March 28, 2006 5:59 AM > To: "Mark Ericksen" <[EMAIL PROTECTED]>, <FlexRadio@flex-radio.biz> > Subject: Re: [Flexradio] SDR-1000 and AM Reception > > Mark, > > This is normal. What you are seeing is the AM station carrier beating > against the SDR (just like an analog receiver with the bfo on). If you > switch the SDR to SAM mode it will sync the SDR and the carrier and you will > have great sounding AM. > > Jerry WK0J > > ----- Original Message ----- > From: "Mark Ericksen" <[EMAIL PROTECTED]> > To: <FlexRadio@flex-radio.biz> > Sent: Tuesday, March 28, 2006 12:06 AM > Subject: [Flexradio] SDR-1000 and AM Reception > > > >I have had my SDR-1000 for a few weeks now and I am learning all of its > >"bells and wistles." I am currentlly putting up a new Ham antenna and in > >the mean time I am just using a wire strung around my den as an antenna. I > >have been listening to AM stations as well as ham stations. I have noticed > >that while listening to AM stations if I switch the display mode to Scope I > >see the detected AM audio riding on a low frequency sin wave. As I detune > >the radio the frequency of the sine wave increases. The audio from the > >station is not modulating this sin wave but simply adding to or riding on > >it. I have performed the Frequency, Level, and Receive Image Reject > >calibrations using an Elecraft XG2 test oscillator. I get this behavior > >regardless of the version of PowerSDR. > > > > Can someone tell me what I am seeing and why? Is this normal? > > > > Thanks > > > > Mark Ericksen > > AD4MA > > _______________________________________________ > > FlexRadio mailing list > > FlexRadio@flex-radio.biz > > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > > Archive Link: > > http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ > > FlexRadio Homepage: http://www.flex-radio.com > > > > > > > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
