Sunday, October 23, 2022

Grabbing a NOAA weather satellite download

NOAA has a set of older LEO weather satellites that send an analog signal of the the sensor data they receive, one line at a time, and these are easily listenable with modest equipment. I picked up this image from NOAA 18 this morning, just by chance (I had just come in from listening to the ISS repeater and happened to leave the SDR listening on 137MHz). Recording via SDRSharp, WFM modulation, 35kHz bandwidth, gain at 30-40dB with a short vertical monopole indoors. Decoded with the appropriately named

Saturday, July 24, 2021

Compact Fluorescent Lifetime report #4

As previously mentioned, I've tried to keep track of CFL bulbs I used and how long they have lasted. Some have outlived some of the newer LED lights I now buy, which is related to the reduction of manufacturing cost by the makers of them. My early LEDs are still running from 2011, including the famous L-prize bulb won by Philips, in a torchiere conversion I did a long time ago and still use. This bulb was used for a several hours each day from 2008-2011, pretty much not used for two years, then was used for a short time daily and at most an hour or two weekly from 2013-2021 in the laundry room in a horizontal position. So, it probably lasted about 5000 hours. The bulb warranty was set as "guaranteed for 5 years at 4 hours each day" and labeled as 8000hrs.

Wednesday, December 16, 2020

Finding your USPS postal carrier route

If you are like me, you like to know how things are organized. What is my postal carrier's route? How many houses and businesses do they have on it? If someone else says they aren't receiving their mail, is that on my carrier's route as well? Searching for this info should seem simple, but Google guides you towards paid solutions like Melissa -- just like when searching for a weather forecast they'll send you to a commerical provider instead of the NWS. The USPS offers a service called "Every Door Direct Mail". You can deliver to them a stack of advertising mailers and they can deliver them cheaply to individual carrier routes. And so the information about the route is available.

Just visit and enter your ZIP code

. Carrier routes with demographics, incomes, numbers of business & residents are then clickable on the map. Enjoy!

Tuesday, February 18, 2020

1st Starlink sightings

I just caught the end tail of a pass of Starlink satellites. I haven't really tried to see them, but it was clear tonight and we had a convenient pass of a constellation of them. They were all from the Nov 11th 2019 launch and were brighter than predicted (3.0)--looked like about Mag 2 to me--but I wasn't checking very hard. Something like 5 in a row--had I started watching earlier would have seen 12. The chain I saw started with Starlink-1051, then 1012, 1026, 1013, 1009, and finished with 1015.

Tuesday, June 25, 2019

Meteorite detected in NEO survey before impacting in Caribbean

Meteorite detected in NEO survey before impacting in Caribbean Debris trail in atmosphere seen in weather satellite imaging about 3m diameter from rough infrasound measurement. H=29.3 from optical measurement would imply about a 4m diameter.

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 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.

Wednesday, May 04, 2016