You too can receive these NOAA APT satellites.
Here is a good link
to get you started or at least better informed.
That Saturday I went out on my observation deck with a old Uniden handheld scanner, my old tv
rabbit ears and a laptop running Windows XP with the free satellite data capture application
APTDecoder.
Below is one of the better data capture results.
If it is not obvious, looking at the visual image
on the right half, you can see the Baja peninsula below California on its left. Across the mainland
of Texas and Mexico you can see the Gulf of Mexico.
This improved antenna along with some minor mods to my receiver, an old 1985
Uniden Bearcat BC100XL
scanner have made for a modest improvement in my received images.
Another option I am working on now, late August 2011, is to modify a digital tv tuner to be a
50mHZ through 800mHZ receiver with a computer control for the satellite reception program
control. This tuner will require some aditional circuitry to allow it to fine tune to these three
satellite frequencies. More on this later.
A third option would be to purchase a kit designed just for receiving these satellites.
But that is still between $200 and $300.
Another of the Hurricane Saturday Saturday Aug27, 2011. I highlighted the eye of the hurricane in red.
I'm still working on better image acquisition. This probably means better antenna and receiver.
The Independent Organization for Weather Satellite and Earth Observation Enthusiasts.
A Quadrifilar Helix Antenna for 137 MHz. By George Goodroe, KF4CPJ.
? , 2010, 2011 Created: Tue Aug 02 17:14:12 CDT 2011, laste edited 04/01/2018 by Don Lewis
The left half is the Infrared (IR) image and the right is the visual. This image is loaded
with problems of lacking signal strength and signal to noise ratio(snr) problems. Remember, I was
standing on the deck with a cheap TV rabbit ears trying to keep a physical position
that delivered the strongest signal.
Meanwhile I have built a better antenna, a tall narrow 90 degree Quadrifilar Helix antenna (QHA) at a
center frequency of 137.50mHZ using the fine article
A Quadrifilar Helix Antenna for 137 MHz. By George Goodroe, KF4CPJ.
A little info on why this antenna style:
The satellites use a similar style antenna to transmit the signals down to earth. The transmission is
of a spiral counter clockwise rotation. This antenna matches the satellites signal phase.
Another plus of the antenna is that it performs best for horizon to horizon coverage as
the satellite passes.
All I did was tap onto the audio out pin of the integrated circuit top right with a small resistor
connected to the yellow wire going to the earphone jack. I simply removed the two leads for the
earphone, connected them together and taped them. This was a unused pin on the IC and provides
unfiltered / unmodified audio. This unfiltered audio then connects to the input of a computers audio
for decoding and image processing.
APTDecoder running on an older PC with XP Pro does the image acquisition. Through my network
I pull the acquired images from the capture PC to my main desktop Linux PC and further process the
images using WXtoImg. This program can also acquire images but is not as full
featured as APTDecoder unless one purchases the "Enhanced" version.
The Uniden scanner's shortcoming is that there are three good working satellites I use to
get images. If I leave the scanner in scan mode to receive all three, weaker signals are missed or broken up.
Therefore better images are gotten if the scanner is set on a single channel. My goal is
to either modify the Uniden by attaching a circuit to the keypad input that can then connect
to the capture computer. This will allow APTDecoder to switch channels as different
satellites are in range thus getting more images and a chance for some good ones.
August 26th, 2011, I left the receiver and computer in the observatory running with the receiver set to the
NOAA 19 satellite frequency and managed this image of hurricane Irene.
The image is time stamped 110825 185556 UTC.
Here are other images that turn out fair. Tropical storm Lee, Labor Day weekend 2011
credits:
For more information Email Don