Merely reporting the weather in my area.....

[TronxII]

4 hours ago, simon43 said:

I just bought a 7 foot diameter satellite dish to receive the weather images from a geostationary satellite (GK-2A), which produce the 'whole Earth' view (well, one side of the Earth) as shown in one of my previous posts. 

 

 

Before this dish, what antenna and software did you use for the previous pictures?  I played around with this stuff some months ago, IIRC the frequency was around 160MHz ? , made only a simple dipole  but could not get any good reception with the SDR. 

[SkyNets]

Using Satdump at the moment on a SDR dongle, had some cool images but mostly random ocean.

[simon43]

15 hours ago, TronxII said:

Before this dish, what antenna and software did you use for the previous pictures?  I played around with this stuff some months ago, IIRC the frequency was around 160MHz ? , made only a simple dipole  but could not get any good reception with the SDR. 

OK, there are 2 different systems:

 

1 - Low earth orbit (LEO) weather satellites at about 450km above the Earth, such as NOAA 15, 18 and 19, and the Russian birds Meteor 2-3 and 2-4.  They transmit around 137 MHz. These are the images that I've been posting (except for that single whole-world image).

 

Since they are close to the Earth, these satellites move faster than the Earth is spinning, meaning that they orbit the Earth every 90 minutes.  In other words, you will only receive an image when the bird is passing over you, and at other times no image is possible since the bird is somewhere else over the Earth.

 

Luckily, NOAA-15 passed over my location just 15 minutes ago, and here's one of the images received, with the intensity of the rain shown in colours:

 

 

I use an SDR to receive the satellite signal and Satdump free software to decode the satellite signal.

 

2 - Geostationary weather satellites are about 50,000 km away from the Earth, in an orbit which means they move at the same speed as the Earth turns, meaning that they are visible all the time and always show the same area of the Earth. To decode these images, you can use Satdump again, but you need to use a dish antenna and feed horn to actually receive a strong enough signal.  So that's the fun challenge for me 🙂

 

If you want to receive weather satellite images, using an SDR dongle and Satdump is fine.  The easiest and strongest signals come from NOAA 18 and 19, but you do need to mount your receiving antenna clear of buildings/trees etc - my antenna is on a 6-metre pole.  A simple dipole antenna should receive some signal, but a 'QFH' antenna works much better - see my photo of this kind of antenna that I built in a few hours from some wire and water pipe.

 

[simon43]

Saturday morning, and last night's rain has stopped, but bad rain storms in Yangon region...

 

[TronxII]

On 5/28/2025 at 2:43 AM, simon43 said:

I use an SDR to receive the satellite signal and Satdump free software to decode the satellite signal.

Could you have a look how your waterfall compares to mine? I seem to get a weak signal, and sometimes it decodes, but I feel there is something missing. This morning, I also had the automatic thing connecting when the satellite passed, but only grey in the decoded picture. At the moment I think, maybe my signal is too weak?

[simon43]

3 hours ago, TronxII said:

Could you have a look how your waterfall compares to mine? I seem to get a weak signal, and sometimes it decodes, but I feel there is something missing. This morning, I also had the automatic thing connecting when the satellite passed, but only grey in the decoded picture. At the moment I think, maybe my signal is too weak?

I can't see all of your Satdump screen, but the step by step process is:

 

- start Satdump with your SDR and antenna connected

- make sure you have added your latitude/longitude under the General Settings tab

- in 'Recorder' tab, click on 'File Source' and select your SDR type and click on 'start'

- make sure that the SDR gain slider if turned up to about 35dB

- you can adjust the FFT settings to get a visible trace

- click on 'tracking' and then click on 'Schedule and Config'

- Add NOAA15,18 and 19 to the 'Search selected' list

- Click on 'Engage Autotrack' and you should see all 3 satellites graphically displayed for their next visible pass times.

- Now disengage the autotrack and add the frequency 137.620 for NOAA-15.  Click on 'Live' and select 'NOAA APT' as the processing type.

- repeat for NOAA-18 (137.9125) and NOAA-19 137.1)

- engage autotrack again and close that pop up window.

 

Now the 'autotrack engaged' should be a green 'yes' and your tracking display should show the next time to acquire the 1st of these 3 satellites (AOS).  When this happens, the Satdump should start to show the received signal.  After about 12 minutes, it is loss of signal LOS and then Satdump will automatically process and save the received images in the directory that you specified in General Settings.

 

Why might you receive nothing?

1 - You forgot to enter your lat/long or entered them incorrectly

2 - Your SDR/cabling has a fault

3 - Your antenna is not suitable (what antenna are you using?)

4 - Your view of the sky is obscured by trees, buildings etc.

 

Let me know how you get on!

 

To show what is possible, I received this image today when NOAA was only 5 degrees above my horizon, passing over India.  The image is not perfect, because it was way off 'illuminating' Thailand.

 

 

[TronxII]

6 hours ago, simon43 said:

I can't see all of your Satdump screen, but the step by step process is:

 

....

 

Why might you receive nothing?

1 - You forgot to enter your lat/long or entered them incorrectly

2 - Your SDR/cabling has a fault

3 - Your antenna is not suitable (what antenna are you using?)

4 - Your view of the sky is obscured by trees, buildings etc.

 

Let me know how you get on!

 

To show what is possible, I received this image today when NOAA was only 5 degrees above my horizon, passing over India.  The image is not perfect, because it was way off 'illuminating' Thailand.

 

 

 

OK thank you for the instructions. Following these guidelines, I did receive something from noaa15, although no idea where this is, and no idea, if this picture is from the satellite or if this is some map overlay from the software. 

The next satellite noaa19 gave some islands which I cannot identify either.

Therefore I imagine that "3 - Your antenna is not suitable (what antenna are you using?)"  is the next thing to address. I'm using a dipole built some time ago for 162MHz for AIS ship position, which worked well for that purpose. So the SDR and cables might be good and I'll remake the dipole next.

[simon43]

That's the map overlay produced by the software itself.  I see no sign of a signal (eg clouds). The overlay should generally be your region, since the satellite passes over your position, taking about 10 minutes to do so.  Whereabout in the world are you?

 

A simple, fixed dipole is not the best antenna, since the satellite passes over and above you.  Are you able to physically hold the antenna to 'aim' it at the satellite position?