Wednesday, February 20, 2019

The problem with the uranium at the Grand Canyon story

There's a hot story right now about three buckets of uranium ore that was stored at a museum at the Grand Canyon, with a claim of it being quite radioactive and a particular employee claiming the whole thing was covered up. The problem is the employee's numbers are off by a factor of 1,000. The presentation slide has the outside background rate at 2 mRem/hr. That's gotta be wrong; an average exposure in the Colorado Plateau is about 90 mRem per year, which would be something like 0.01mRem/hr aka 10 uR/hr. The buckets at the surface were really more like 300uRem/hr, or 3mRem/hr.

Saturday, February 09, 2019

Image received from the International Space Station

I received an image that was being transmitted from the International Space Station as it passed nearly overhead this evening. They broadcast at about 25W of power at 145.800 MHz; an amount that is easily heard and received since the communication is line-of-sight and only a few hundred miles away. They only use it on occasion so it was nice to hear they were planning on a few days of sending images. I used a generic SDR receiver and a simple dipole and piped the audio output to MMSSTV. Some of the noise in the center of the image was because I forgot to correct the receiver for the Doppler shift of the ISS as it passed by.

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() {
      
      digitalWrite(13,HIGH);
      delay (3000); 
      digitalWrite(13,LOW);
      delay (1500);
      dash();dash();dot();space();
      dot();dash();space();
      dot();dot();dot();space();
      dot();dot();dot();dot();space();
      delay(2000);
      
      
      pulseHigh(RESET); // off
};


void dot()
{
  digitalWrite(13,HIGH);
  delay(100);
  digitalWrite(13,LOW);
  delay(100);
  
}

void dash()
{
  digitalWrite(13,HIGH);
  delay(300);
  digitalWrite(13,LOW);
  delay(100);
  
}

void space()
{
  digitalWrite(13,LOW);
  delay(300);
}


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.