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Receiving Weather Images. Receiving NOAA Weather Images. Why?. Offered as a free service by NOAA No license required Inexpensive Requires no infrastructure Satellite Receiver Good learning experience for new amateur Cool ?. Receiving NOAA Weather Images. Information Sources
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Why? • Offered as a free service by NOAA • No license required • Inexpensive • Requires no infrastructure • Satellite • Receiver • Good learning experience for new amateur • Cool ?
Receiving NOAA Weather Images • Information Sources • NOAA Publications • Various amateur internet sites
NOAA Publications • Website • http://www.noaasis.noaa.gov/NOAASIS/ml/satservices.html • User guide (PDF)
Receiving NOAA Weather Images • APT Images • Automatic Picture Transmission • HRPT Images • High Resolution Picture Transmission
Receiving NOAA Weather Images • We will discuss APT • 137 MHz FM • Infrared and visible images • Provided by polar-orbiting satellites
Polar Orbiting Satellites • What does it mean to me? • Satellite will be visible twice a day for ten minutes • Satellite will not always be in the same location in the sky • Need omni-directional antenna
The Signal • ~137 MHz FM • RHCP • Right-hand circularly polarized • +- 17 KHz frequency range • Subject to doppler shift
Equipment Needed • Suitable Antenna • Receiver/Scanner • Produces an audio stream • Method of producing the image • Converts audio stream to image • Free software packages available to do this
Antennas • Turnstile Antenna
Antennas • QFH • Quadrifilar Helix
Software Defined Radio • Can replace scanner with SDR device • Basic idea: replace some of the hardware with software
Ingredients List • QFH Antenna • Antenna Cable • RTL-SDR Receiver • USB Extension • Software • SDR Sharp (Controls SDR device) • Virtual Audio Cable • WXtoImg (Manages recording and image creation)
Next Steps • Resolve registration issue • Antenna placement • Improved antenna feed • Replace the SDR# software • Try a LNA (Low Noise Amplifier) • Try out new antenna • Learn the software better
Future • Learn more about antenna construction • Design • Antenna Feeds • Dish? • Learn more about SDR • Inexpensive approach to many radio applications