This is plainly false though. You're saying beats can't be localized to less than one second of precision (regardless of track length, which already smells suspect). Humans can localize a beat to within 50ms.
There's a concrete ship wrecked just offshore of Cape May Point in NJ. It has been deteriorating for many years and soon nothing will remain above the waterline.
I did raise eyebrows once of the person in the row behind me. I said I was listening to ATC and that seemed to placate him. I do believe most airlines have a blanket ban on radio equipment, even receive only. Some even ban using GPS!
A photodiode (BPV23NF iirc) connected straight to the dongle's SMA connector. Yes, I believe it would be operating in photovoltaic mode, where the incident IR light from the remote control will induce a small voltage. Yes, I had direct sampling mode turned on (but the rtl-sdr.com V3 can do this through the normal antenna port). I pointed the remote at the sensor (admittedly quite close) and saw a signal centered on 38 kHz in the waterfall, and was able to export the binary pulses.
Here are some more things you can do with your RTL-SDR after the first 50:
Meteor weather satellite reception (Russian counterpart of the NOAA satellites, but digital, so higher res and in color)
Digital Radio Mondiale -- digital radio but for shortwave
Analog TV -- if you're in an area that still broadcasts this (unlikely), you can receive a black & white picture and closed captioning. If no OTA broadcasts remain, you can use the analog output of a VCR or DVD player
GPS -- rtlsdr is capable of decoding GPS, Galileo, and BeiDou! (Likely not GLONASS since each satellite uses a separate frequency, spreading the signal beyond the sdr's bandwidth)
Hidden secondary audio broadcasts inside FM radio (like the stereo audio hack, but using higher frequencies in the demodulated stream)
Brazilian outlaws and UHF pirates using open repeaters on US military satellites launched in the 70s
TEMPEST / "Van Eck phreaking" where you can remotely read a nearby screen due to leakage from the monitor or video cabling
Instrument landing system -- if you're near an airport you can tune to a runway's ILS frequency and see the signal change as you move from the left side of the runway to the right
Infrared remotes -- stick an IR photodiode in the antenna port and you can demodulate codes from remote controls
Passive radar -- Tune into a very narrowband signal like a VOR or ATSC pilot signal, set your decimation extremely high (i.e., trading bandwidth for dynamic range) and you can see nearby planes in the area from their doppler-shifted reflections of the main signal
Specifically mine deals with what you'd hit looking across the ocean from a coast. I had long wanted to make mine an interactive app but could never fully motivate myself to do it, so congrats for shipping.
Ah yes, I have seen those before (quite rare). IIRC they don't have holes for the grounding prong, which should prevent plugging in any modern 240V appliance.
I think you're confusing a NEMA 5-20 (120V, 20A) and NEMA 6-20 (240V, 20A). Each has one blade sideways but they're mirror images of each other. T-slot varieties of both outlets are common, which can accept both 15A and 20A versions of their respective voltages. You won't find outlets that can accept both a 120V and 240V plug.
I just had some fraudulent withdrawals on my bank account pretending to be paypal. They did the two sub-$1 authorization transactions, then took out $400 then "reversed" it by putting it back into my account... maybe to attract less suspicion and execute a larger fraud later?? Anyway, my bank reversed the withdrawals and I just got to keep the $400 the scammers deposited in.
In my dabblings with SDR, playing around with analog video was one of the highlights. Something about this technology that was such a prominent yet opaque feature of my youth and now being able to control it from the inside out felt extremely empowering.
I wrote my own decoder in python (nowhere near realtime) because at the time I couldn't find one that handled color. The deep dive on the design tradeoffs and signal processing hacks for NTSC was fascinating.
A walk down memory lane for sure... I loved my Eee PC 901 and still have it. I used it to build a 'carputer' / navigation system before I had a smartphone. http://mrgris.com/projects/birdseye/
I remember becoming disillusioned that the netbook branding pivoted to "cheap" rather than "compact". The 9" series was quickly abandoned, with much more expensive 10" models becoming standard. An "almost laptop"-sized laptop for "almost laptop" prices wasn't really compelling. The 901 was adorably small and only cost $400 iirc.
It is quite difficult to visualize and it took me a long time to "get it".
The path of the sun's annual motion relative to the stars is determined solely by my physical progress in orbit around the sun. A planet's axial tilt only changes the 'direction' I'm looking in and thus the reference point of my celestial coordinate system. The sun's path will always be a great circle on that celestial sphere (and always the same relative to the fixed background stars) regardless of which reference frame I choose. I think this is enough to surmise that the sun's angular speed on the celestial sphere is constant regardless of axial tilt (assuming a perfectly circular orbit).
Taken to an extreme, imagine a planet with 90° tilt -- the sun would move vertically and pass directly over the pole, making a constant 'horizontal' motion literally impossible.
I'm not sure what your tidally locked example is meant to demonstrate, since that's literally what the analemma is -- the path the sun would make in the sky once you subtract a planet's local axial rotation, i.e., tidally locking it to the orbital parent.
It's a misconception that the figure-8 shape is due to the eccentricity of the Earth's orbit. Most of the variation in the sun's horizontal apparent motion is also due to Earth's axial tilt. Orbital eccentricity only contributes the slight asymmetry seen in the final analemma. See my reply to the sibling comment for more detail.
This is incorrect. The analemma would still be a figure-8 even with a circular orbit, but it would be symmetric -- the orbital eccentricity only adds the asymmetry we see in Earth's analemma.
This is because the sun on an axial-tilted plane 'lags behind' then 'catches up' to the ideal 0-tilt sun over the course of the year. At the equinoxes, the sun's motion has a significant vertical component. Therefore, it's horizontal speed is slower than an untilted sun (both suns still travel through the sky at the same speed of 360/365 degrees per day), so it will lose ground and drift back. At the solstices, the sun moves horizontally, but at an higher latitude (equal to Earth's axial tilt) on the celestial sphere, covering more degrees of longitude for the same speed than the ideal sun moving along the equator, hence making up the lost ground. This variation in horizontal speed throughout the year creates the figure-8.
I used the typical GDAL tools -- gdalwarp, gdaldem, with some associated scripts of my own. I recall not using GDAL's image pyramid builder as I ran into some issues with wrapping at the int'l date line and in general wanted more fine-grained control over the process.
This could be rendered dynamically using the elevation tile services now available from mapbox, et al. I wanted to use Jon de Ferranti's dataset specifically though due to his commitment to uniform global quality.
An additional issue is since the color ramp is quite jagged, aliasing would be quite unsightly when zoomed out. You'd need a hefty amount of supersampling to get back the desired smoothness... not sure the tile services can support that easily.
