Mike, You are comparing "apples to oranges" when you say that there should be a conversion from Perseus WAVs to FLAC or MP3. These audio formats are NOT the same as the data recorded on the special WAVs that Perseus generates (same thing with the SDR-IQ's files...they are not audio). The data on the waves have what's called I & Q (in-phase and quadrature) information that represents the RF spectrum at the bandwidth and frequency range chosen. It's much more complex, but that's my low-tech explanation. You might want to look at Gerald Youngblood's pioneering first article on SDR technology: http://www.flex-radio.com/Data/Doc/qex1.pdf See page 4 in particular.
Chuck mentioned in effect that you can't practically listen to all the frequencies of a full night of recording on a Perseus, and should just collect a few minutes on the hour and half-hour. My preference is to capture a continuous stream if possible, especially if conditions are looking good. What you do is apply a strategy for review; you don't actually listen to ALL minutes of ALL possible MW channels. One approach (and I think the quickest) is to tune a single frequency at the start of a session, and quickly skip ahead every 3-5 minutes, keeping an eye on the waterfall display for any sign of signals that may be breaking into audio (~10 dB s/n on Perseus, for intelligibility). If something appears or I see an indication of a co-channel fading in, I stop and listen for a bit. The Perseus files are recorded sequentially so it is easy to skip ahead while remaining tuned to s single frequency. I pay particular attention to the hour and half-hour for IDs, and give more attention to all parts of the hour when it's around that crucial "max dawn" period of sunrise enhancement (when conditions can change quickly). After you pretty much exhaust a single frequency of the DXpedition in this "fast forward" method, you start on the next frequency and repeat the technique. I review faster and skip more minutes, between the hour and half-hour; but the data is always there for checking another time if I want to dig deeper. I think it's better to be safe and have captured "everything" so that you can throw away "anything" later, than to have not recorded the band continuously. Hard drive space is cheap these days... 73, Guy Atkins Puyallup, WA http://fivebelow.squarespace.com > From: Mike Hawkins <[email protected]> > To: Mailing list for the International Radio Club of America > <[email protected]> > Subject: Re: [IRCA] Laptop computer requirements for an SDR or similar > receiver. > Message-ID: > <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1 > > I've been out of work for almost a year. I've got time...sadly. If I had > something like that for FM when there's skip (or meteor showers), I'd be in > heaven. I still think there needs to be an on-the-fly conversion to MP3. > > Mike > > _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
