|Subject:||Re: [Discuss-gnuradio] This is nice|
|Date:||Thu, 22 Mar 2012 15:15:56 +0000|
Worth taking a look for $19 right? The Elonics website claims there’s an integrated LNA in the e4000 but I can’t find the specs. http://www.elonics.com/product.do?id=1
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,
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