WxSat
Short for Weather Satellite. This combines the radio and computing hobbies rather well. Receiving WxSat images is fairly easy, and there are a few satellites wizzing around the world that transmit some nice pictures. When the coulds clear you can sometimes see the outline of the UK!
All you need to receive WxSat pictures is a suitable receiver, some decoding software, and an antenna. The most common transmission format is called A.T.P. (Automatic Picture Transmission) this is a modified FAX style transmission.
Receivers can be almost anything from handie-scanners to custom built WxSat receivers. Almost anything that can receive in the 137Mhz sat band will get something. My setup is unusual in that I use the Amiga to decode the images. Decoding software is availabe for most computers, ranging from free to expensive. Just to give you an idea of what you can receive, here is an image I took back in 1993, one of the few images I have when it was nice and sunny over the UK!
21st May 2005 -
Noaa 18 is now in orbit, and here is one of the first images I have taken from this sat.
Equipment:
RX ICOM R9000 - Wide FM (30Khz) AFC on, JIM General Purpose pre-amp
Ant H/Brew Tall thin QFH approx 30ft upo - site located abt 15Km from centeral London
Software WxtoImg linux.
Note that I suffer from very very bad wide band noise, which normally means that sat reception is wiped out. Sometimes I the noise goes away and I get good images. There is only one big pager burst in this image. Apart from despecle and adding the outlines, this image is "as is"
Pass - 21st May 1302
NOAA 19
Noaa 19 was launched on Friday 6th Feb 2009, and is the last of the this series. This sat, has had a "interestiung" life, as it fell off the support table as it was being rotated. The cause was that the hold down bolts had been removed. The sat had to be extensivly rebuilt. However as it was the last in the series, many of the stockpiled and unused spares were available for use.
Note that at the moment, NOAA 19 is transmitting two visable light images, this will continue for several weeks untill the IR sensors are fully cooled and out-gassed. Once this is done, the transmission will revert to the "normal" IR and Vis image side by side.
The images below are from two passes over the UK on Sunday 8th Feb, one pass at 12:52, and the other (and better) pass at 14:34.
The on-screen images are approx 640 x 500 pixels wide. Clicking on the images will bring up the full size image. Be warned that the full size images are between 1 and 2Mb in size.
I have now changed the decoding system, using Linux rather than the Amiga., the images were recorded useing:
WxToImg software, (Linux version)
Receiver ICOM R9000 JIM general purpose preamp
Antenna Tall Thin QFH home made, image below.
12:52 pass.
This pass was a little to the east of the UK, and as you can see the UK is still in the grip of some rather chilly weather, with a lot of cold cloud cover. Also note the very poor reception to the south. N Africa is there, but the image is very noisy. This is due to two things. The first is that the antenna is screened slightly in that direction, and that there is a powerful paging transmitter on a nearby frequency that tends to degrade and desense the receiver.
The poor coverage to the north is due to a "hill" (Part of the A13 where it crosses a railway) and several tall buildings.
14:34 pass
This pass was well to the west of the UK and the first thing to note is that the coverage to the south is much better, purely due to the antenna having a clear view to the west. Also note the darker band at the bottom, extending up to the first white bar in the greyscale strip on the left hand side. This demostrates the difference between a receiver with a 15Khz filter. The dynamic range is reduced quite a bit. When I switched to the 30Khz filter the difference is very marked.
14:34 pass (2nd image)
This is the same image as the previous, but without the map overlay, and also processed with the "prestine" options of the WxToImg software.
12 Feb 2009 13:53 pass.
As NOAA 19 is still in the checkout phase, (the IR sensors are still being outgassed etc) it sends two vis light images. This allows for an enhancement not normally seen, which brings out vegiation rather more clearly. Of course the colours are all false...
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WAV File.
This is a LARGE File nearly 18Mb. It is a recording of the NOAA18 sat, on 26th October 2010 at 14:19 utc
This may be useful for testing decoding systems.