|Subject:||Re: [Discuss-gnuradio] This is nice|
|Date:||Thu, 22 Mar 2012 11:06:20 -0400|
I also have a trio on order. The issues I can see surrounding this approach are:
o Consumer electronics parts lineups are capricious and unreliable--the target device may use the "SDR-capable chip" this month, and next month, they've found that they can shave $0.35 of off the B.O.M. by going with a totally different parts line-up they will, even though it will cost them $50K in engineering costs up front--they sell thousands and thousands a month. There are already *TWO* versions of this dongle, one using the "good" RTL2832U chip, and the other using an Afatech chip (AF9015 or AF9035). The "magic sauce" that Antti discovered in the RTL2832U chip to do "raw samples" is peculiar to the RTL2832U chip, and doesn't necessarily map on to other DVB-T digital demod chips on the market.
o The 28.8MHz master oscillator is a very cheap 100PPM part, which will produce unpleasant frequency offsets, and phase-noise to match
o Not sure how good the noise figure is, since there's no LNA in front of the E4000 tuner chip.
o Don't know how they implement re-sampling. If it's not done right, then there'll be nasty aliases in the passband handed to the host
None of these are fatal, but be aware that the approach of "re-purposing" consumer electronics is fraught with dangers as described above.
On Thu, 22 Mar 2012 10:53:13 -0400, Tom Rondeau wrote:
Andrew and Sean, Glad to hear you both thinking about doing this! Coordinate as you can and keep us up to date on the progress. Tom On Thu, Mar 22, 2012 at 10:45 AM, Nowlan, Sean <address@hidden> wrote:Funny enough, a coworker mentioned it to me yesterday morning and then it popped up on discuss-gnuradio. He must have seen it on Reddit as well. I have one on order too, and I was also contemplating a GNUradio driver... let me know if you want to coordinate. Sean -----Original Message----- From: address@hidden [mailto:address@hidden] On Behalf Of Andrew Davis Sent: Wednesday, March 21, 2012 9:34 PM To: David Kierzkowski; address@hidden Subject: Re: [Discuss-gnuradio] This is nice Saw it on Reddit a couple days ago, already have one on order. Then I might work on making a GnuRadio driver or something for real-time use. On Wed, Mar 21, 2012 at 3:17 AM, David Kierzkowski <address@hidden> wrote:_______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradioThe osmocom guys are using a 20$ USB catv tuner as a RF source in gnuradio. 3.2MS/s ! http://sdr.osmocom.org/trac/wiki/rtl-sdr _______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio_______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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