Tuesday, November 20, 2018

CFL lifetime report #3

As seen previously, a series of CFLs I used starting around 2008 onwards failed at varying lifetimes. I report a third failure, of a Nvision 14W installed in June of 2011. It failed in May of 2018. That's just about 7 years of roughly 3-4 hrs of use daily. The lifetime estimate ranges around 8000 hours for that one.

Thursday, September 13, 2018

Visualizing a "How low can you hear?" test

A facebook link a friend shared mentioned a sound test and wondered if it was accurately matched to the listed frequency. I ran the sound through Spectrum Laboratory and then tried out making a desktop video with Open Broadcast Studio.

Monday, August 27, 2018

Burning Man in Synthetic Aperture Radar

I downloaded the Sentinel-1 Synthetic Aperture Radar data of the Black Rock area taken on August 19, and the start of Burning Man work is apparent. The colors represent different polarizations of the returns. This is a very small subset of the original 25000x16000 pixel image.
Also found this one from the 24th (horizontally flipped to correct)

Friday, July 13, 2018

Freighter visible on weather radar

The Terminal Doppler Weather Radar system for Midway Airport caught the freighter Stewart J. Cort traveling on Lake Michigan towards Burns Harbor, IN. It's the return out in the middle of the lake heading south. I ID'd the ship with AIS Boatnerd

Sunday, August 13, 2017

AM Broadcast Band, day vs. night

This is a comparison of the broadcast band during the day (at top) vs at night (bottom). Many stations are required to lower their power and/or change their antenna directionality at night because the absorptive D region of the ionosphere disappears and allow lower frequency waves to propagate via a skywave. Some stations, called clear channels, are allowed to maintain their high power at night. Chicago happens to have quite a number of them-- you can see them at 670, 720, 780, 890 and 1000kHz. Local stations including the clear-channels are marked (minus 1690). At night, you can see a carrier at nearly every 10kHz, showing many of the AM stations listenable at night from across the US. WSCR 670 and WBBM 780 are unfortunately also using HD Radio. Local switching power supply noise appears as very impulsive (fast horizontal bands) at about 615, 925, 975, 1090, 1230, 1500, 1550 and 1850kHz. The fundamental for some of these appears to be at 306Khz. You can see in the IF this signal, as well as the much weaker DGPS signal at 304kHz from Mequon,WI. This was taken with a simple indoor dipole of 42ft length (with some turns in it) and a RTL-SDR.com v 1.3 dongle with HF direct sampling (Q-branch) and AGC turned on.

Thursday, August 10, 2017

The radio satellite CUTE

The nanosat CUTE, or rather the CUTE-1.7 + APD II, sends out a beacon in morse code. I picked it up with a simple antenna and a SDR. Time increases to the right in the image and frequency is the vertical axis. It shifts because the satellite was moving away from me during the capture. Track CUTE for your location.

Monday, May 02, 2016

SAR image of the Calumet region of Chicago

I've been working on manipulating the large images offered by the Sentinel satellite. I found an image of the city of Chicago region on April 10th, 2016, and have been taking a look at it. The data image is 25000x16000. I grabbed the HH(the Horizontal transmitted, horizontal received polarization) and HV images (horizontally transmitted, returned vertical polarization), normalized them and made them R and B in an RGB set. The G I created by adding the two images together. Adjusting the hue allows for greater visual impact of the image. This is the Calumet region of southeast Chicago and Northwest Indiana, a heavily industrialized region. Lake Calumet, Lake Michigan, Wolf Lake, and the Calumet River/Cal Sag all show with no reflectivity at this normalization (you'll recall the previous post where Lake Geneva had some return from waves). The ArcelorMittal steelworks sits out on the right as a highly reflective region of pipes, stacks, rail cars and other industrialness, with the BP Whiting refinery to the left of it as another nearly continuous return. Long linear blue streaks are presumed oil or ethanol conveys consisting of mile-long packs of tanker cars that are bright in the HV channel. Shipping containers, barges, oil tanks and rail cars that are not tankers all reflect highly in the HH return. Even Binions Horseshoe floating casino shows up brightly. A bright return in the upper left I assume is the tower at Promet steel. blue-cyan-calumet

Wednesday, April 27, 2016

Synthetic Aperture Radar data of Lake Geneva, Wisconsin

I happened upon a nice description of how to grab data off of the ESA's Sentinel satellite via Evan Appelgate and there's a bunch of interesting things in the data. It was taken just this Tuesday morning at 7:11AM. The winds were out of the north at 8MPH and overcast. You can see in the image the effect of the wind creating a rougher, more radar scattering surface on Lake Geneva--dark at the north shore, transitioning to a very slightly rougher surface to the south.

Click to enlarge. There's a lot more interesting things to look at--that's just the first thing that jumped out at me.

Sunday, March 06, 2016

A really bad soldering iron

I picked this soldering iron out of the ewaste recycling stream that students dump at the end of the year, figuring I could use another iron. I knew it ran hot. Yesterday I was attempting to create a data cable between a PC and a radio and was annoyed at how quickly oxidized the tip had gotten. After cleaning it and trying again (failing ultimately because the PS/2 keyboard connector happens to not use one of the pins) I noticed a subtle warm color to it--and thinking it was just the orange light pollution reflecting off of it, but then I put two and two together and realized it was black body radiation. And that means this soldering iron is really really bad.
The camera appears to have a fairly good IR block filter on it, so the colors match better to the eye's response. On a weaker camera I would expect a purple appearance to it as the blue Bayer filter will pass IR circa 900nm.

Thursday, February 11, 2016

long term survelliance flights over Chicago

Perhaps you've heard of constantly circling Cessna planes, spending hours circling high above US cities. http://www.washingtontimes.com/news/2015/jun/18/fbi-surveillance-flights-by-the-book-rarely-track-/?page=all Today I happened to see many of them over Chicago. Looking at FlightRadar24's live feed I saw two. Their data is much more complete than my limited ADS-B receiving capability. The first was a Cessna, high at 9,000ft. It looks like it came from DuPage County airport, and has done a number of similar flights in the past few days. I was able to spot it in binoculars, and in doing so also picked up an identical looking plane holding an identical path, but not on ADS-B. I presume I was seeing a shift change, but one never knows. It had the 4414 squawk, and matched the false front company 'OBR Leasing'. Not only Cessnas, but a Bell 407 helicopter was hanging around too at a lower altitude further west, closer to Midway.

Wednesday, June 24, 2015

Morse code over laser light with an Arduino

19. After another of my famously lavish parties, I sometimes walk alone out to Promontory Point at exactly 10:00 p.m. Thursday and glance lakeward, out at a blinking light on some distant shore, and think of Daisy Buchanan. That light winks on and off, unattainable, a powerful metaphor for|wait, is that Morse code? [5 points for lights over a mile away; 15 points for lights over 5 miles away; 0 points for lights that are only metaphors] For this Scav Hunt item I used an Arduino to turn a laser pointer on and off in morse code:
#define pulseHigh(pin) {digitalWrite(pin, HIGH); digitalWrite(pin, LOW); }
#define RESET 13  // Pin 13 

void setup() {
pinMode(13, OUTPUT);

void loop() {
      delay (3000); 
      delay (1500);
      pulseHigh(RESET); // off

void dot()

void dash()

void space()

I checked and saw at http://www.heywhatsthat.com/?view=PKDC86DD that the path from Adler Planetarium to the Point was just a touch over five miles and free. I could identify the Point fairly well in binoculars; I aimed the laser pointer by fixing to a tripod, testing the aiming by hitting nearer objects (a beach buoy nearby happened to be retroreflective which helped quite a bit) and then carefully moving the system towards the Point. I turned it off whenever boats went near the beam. To prove it was me, the judge requested I manually hit the key a few times--since I had only a programmed 'SCAV' (yes, it says GASH above), I manually connected the pointer to 5V & ground on the Arduino. It was powered via a 12V battery and a cigarette lighter USB charger to provide 5.1V.

Friday, June 20, 2014

insect on clematis

insect on clematis insect on clematis A cute colorful insect hanging on out a clematis vine. Graphocephala coccinea, red-and-blue leafhopper.

Monday, March 17, 2014

Hyde Park Hum

Background: Hyde Park Residents Puzzled by Mysterious Noises, Vibrations, Loud Hum at Night.

Some random thoughts:

I hear a vague distant sound sometimes, like a locomotive engine that never leaves. It came up earlier in the year, but beyond suggesting it sounded like it was coming from the SE from my location, didn't do anything else. Recently it came up again, and evidently for some people, is intolerable. These people live east of the Metra Electric tracks in various high-rises and other multistory buildings between 51st and 56th St (specifically, people in the Windemere, 1700 E. 56th, 5490 South Shore, 5479 S. Hyde Park, and 51st and East End have mentioned it). People on the west side of 1700 E. 56th higher up (like 28th floor and above) seem to have it the worst--and they claim their management have turned off every system in their building to prove it wasn't local to them. I originally thought it was related to the opening of Earl Shapiro Hall on Stony Island, to the SE of me.

I went wandering around a few weekends ago on a slightly breezy and roughly about freezing 0C evening with an ipad running a tuner app that offered a fairly nice spectrum analyzer and I could see a prominent tone at about 85Hz that came and went, and varied in intensity. It turned on and off with a period of several minutes. I saw it best in quiet places. I saw it underneath the Metra tracks at 57th. I did not see it get any louder when I pressed the tablet against the UC maintenance building on Stony Island between 56th and 57th. I saw it at 54th and Cornell. I did not see it at 53rd and South Shore. I saw it in the alley between Everett and Hyde Park Blvd between 53rd and 55th. I see it in front of the home at 5522 S Hyde Park Blvd. I see it quite strongly in the alley between Cornell and Hyde Park Blvd between 55th and 56th, strongest at the back of 5528 S Hyde Park Blvd. It is quite strong there and next door at 5540 S Hyde Park Blvd, the Poinsettia Apts and Broadview Hall, respectively. Given that, I wondered if my aural direction of SE is real, or some reflection from Vista Homes.

The iPad software is limited to being sensitive to approximately 40Hz and higher, with a realistic limit of about 60Hz.

Things it is not: It is not related to the power grid, which mostly produces noise at 120Hz, with 60Hz appearing occasionally, plus all harmonics. I am very familiar with that noise. It is not a moving train. When a freight train goes by, the locomotive produces several harmonics in the sound area while it passes, but they have a Doppler component. The freight component offers deep rumbling at 9 to 11Hz. Metra trains produce lots of frequencies between 100-200Hz.

I have a PC laptop at home with a microphone running Spectrum Laboratory and Spectran, which I can vary the FFT size, sampling rate, and other variables which allow me to get much lower in frequency. The practical limit is 10Hz which seems to be the microphone's limit. That software is not calibrated, and I suspect it is off by 10Hz, since I see a discrepancy between the iPad, the PC, and what I expect to see.

I have seen it at home in the early evening, evening, at night, in the morning. I have not been at home during the day very much, but I suspect it is there then as well.

I embed an image of the monitoring software taken last night, 3/16/2014, between 10:30PM and 11PM below. Time is horizontal, frequency goes up vertical. Anything that is strongly vertical is likely me moving around, very local, moving the laptop, etc. Like at 22:37 I think I moved from my midlevel upstairs. You can see the "110Hz" horizontal line, which if my PC is off by 10Hz, could be the ubiquitous 120Hz AC hum omnipresent.

The thing I call the 85Hz noise you can see is recorded here between 70 and 80Hz. And it has some variance in frequency, always in the same pattern, always changing in a discrete manner. Another fairly signifcant tone is visible starting at about 22:31, in between 30 and 40Hz. It gets quieter when I go upstairs at 22:37. You see it changes discretely as well, but in a different way, than the "85Hz" tone. A discrete change like this is usually the sign of a controlled system.

The wispy, broadband thing at 22:52? I believe that was a jet plane. I don't recall that specific one, but that's what they look like.

A garbage truck going down the street looks like this: . The horizontal ticks are one minute apart here and with a different sampling rate and such the 120Hz appears to show up at 120Hz.

There's more on the flickr stream, if you take a look. I think this one https://www.flickr.com/photos/dwarmstr/13210307253/ is earlier yesterday evening and you can see more of the discrete hum changes, plus non-discrete changes, etc. It's hard to pin down.

I also was running spectran on some screenshots, showing lower frequency noises. You can see prominent tones at 46-47Hz and 29Hz: .

One question I do have is wondering if everyone is complaining or hearing the same sound. The different aspects of the "85Hz" tone vs the stuff at 30-40Hz is suggestive of two different systems, and yet they are both prominent. One could be the window rattler and the other could be the one you actually "hear". This is all speculation on my part. There's a lot of further investigating (and speculating!) to be done here, but it will take time. In an ideal world one would be able to visit the facilities of various buildings to see if the systems are there or not. Or have more time to measure the intensity in a number of places to get a better map. I thought I had found the source at 5528 because there is a metal chimney pipe the length of the building that seemed to be at the loudest area. In retrospect, there is a large pipe at Broadview in the rough area of the loudest ground signal, but it's elevated and away from easy access.

What is the source? Is it some fundamental of a system motor, it is a resonance of a exhaust pipe? Why does it change?

Atmospheric effects can bend sound down and return loud noises from the ground back to distant areas because the sound is gently bent from the change in the speed of sound with temperature. Are we hearing something more distant like a train switching station from somewhere else?

More speculation: I would bet the noises go away once it warms up.

Anyways, more to look at, more to explore.

Wednesday, September 18, 2013

random recent interesting titles

Oversharing: Yesterday's catalog search items that caught my eye. (My search was all T acquired in the past six months published in the past four years in English)

The future of post-human waste : towards a new theory of uselessness and usefulness / by Peter Baofu. http://pi.lib.uchicago.edu/1001/cat/bib/8956460

Masters of light : conversations with contemporary cinematographers / Dennis Schaefer and Larry Salvato ; with a new preface by the authors ; new foreword by John Bailey. http://pi.lib.uchicago.edu/1001/cat/bib/8956546

Chemistry of fossil fuels and biofuels / Harold Schobert. http://pi.lib.uchicago.edu/1001/cat/bib/8962902

Lightwave engineering / Yasuo Kokubun. http://pi.lib.uchicago.edu/1001/cat/bib/8968350

The diner's dictionary : word origins of food & drink / John Ayto. http://pi.lib.uchicago.edu/1001/cat/bib/8968910

Indigo : the colour that changed the world / Catherine Legrand. http://pi.lib.uchicago.edu/1001/cat/bib/9021426

The science of nutrition / Janice L. Thompson, Melinda M. Manore, Linda A. Vaughan. http://pi.lib.uchicago.edu/1001/cat/bib/9031178

The disappearance of darkness : photography at the end of the analog era / Robert Burley. http://pi.lib.uchicago.edu/1001/cat/bib/9032147