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. 

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

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.

 

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

 

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?

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.

 

 

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.

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?

On 6/2/2025 at 12:35 AM, simon43 said:

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?

I'm in Spain. My antenna was a dipol for 162MHz, now I cut new metal strips and checked resonance at 137 MHz with a VNA. Its probably the best I can get before making such a complicated antenna like yours. With the new antenna, there is sufficient signal. The signal can be seen in the waterfall right and left to the actual frequency, and audio can be heard. This was not the case with my old antenna. 

The pictures of the clouds only are not that interesting, but the satellite also measures infrared or something and then colors the rain clouds. These are really nice. 

Thanks for your help with this, and I put my antenna here not because it's beautiful, but that others will be encouraged to try. Its minimal effort to make one. 

Just to note that one of the US weather satellites that transmit in the 137 MHz band - NOAA-18, 'died' on 6th June after 20 years of operation.  The main data transmitter broke and NASA decided to switch it off completely.  It will still be listed on satellite prediction websites though until they update the status.

 

That leaves NOAA-15 and NOAA-19, both of which will no longer be supported for professional use by NOAA after June 16th.  In other words, they will still work.... until they don't!

 

Apart from that, there are 2 Russian weather satellites in the 137 MHz band that pass over Thailand.  Both of these have some problems, notably black bars that sometimes cut across the transmitted images.  They are also a little weaker in signal when compared to NOAA birds.

 

Anyway, the Russian Meteor M2-3 bird went over Thailand a few minutes ago and this is part of the image that I received (I cropped the image to remove the black bars).

 

On 6/5/2025 at 3:53 AM, TronxII said:

I'm in Spain. My antenna was a dipol for 162MHz, now I cut new metal strips and checked resonance at 137 MHz with a VNA. Its probably the best I can get before making such a complicated antenna like yours. With the new antenna, there is sufficient signal. The signal can be seen in the waterfall right and left to the actual frequency, and audio can be heard. This was not the case with my old antenna. 

The pictures of the clouds only are not that interesting, but the satellite also measures infrared or something and then colors the rain clouds. These are really nice. 

Thanks for your help with this, and I put my antenna here not because it's beautiful, but that others will be encouraged to try. Its minimal effort to make one. 

 

Which weather satellite was that image received from?  NOAA-19 has the strongest signal, so you can use the n2yo.com website to see when there will be a high elevation pass over your location.  You can also add a low noise amplifier to your system (they cost about $20 online and are powered by the SDR up the signal conductor of the coaxial cable).

15 hours ago, simon43 said:

Which weather satellite was that image received from?  NOAA-19 has the strongest signal, so you can use the n2yo.com website to see when there will be a high elevation pass over your location. 

Not sure anymore what satellite the previous picture was. The generated json always says noaa15, no matter which one passes. 

Thanks for the website, with this I could capture an 80° elevation pass of noaa19 today. However it gave me only a useful signal when the satellite was quite high, like above 30° it started to decode. Only received some clouds in Antarctica LOL.  Means my antenna is suboptimal. I'll try to play around with this antenna first, and then maybe the bandfilter with amplifier from Aliexpress. But over 20€ each! Glad that I'm not a HF affectionate, this must be quite an expensive hobby. 

I saw passive ones with only RLC which cost around 5€. That's tempting, but for 5$ I could order 5 PCB  in China and make it myself ... Would be a good justification to buy a set of smd inductors.

1 hour ago, TronxII said:

Not sure anymore what satellite the previous picture was. The generated json always says noaa15, no matter which one passes. 

Thanks for the website, with this I could capture an 80° elevation pass of noaa19 today. However it gave me only a useful signal when the satellite was quite high, like above 30° it started to decode. Only received some clouds in Antarctica LOL.  Means my antenna is suboptimal. I'll try to play around with this antenna first, and then maybe the bandfilter with amplifier from Aliexpress. But over 20€ each! Glad that I'm not a HF affectionate, this must be quite an expensive hobby. 

I saw passive ones with only RLC which cost around 5€. That's tempting, but for 5$ I could order 5 PCB  in China and make it myself ... Would be a good justification to buy a set of smd inductors.

Antarctica??  Something is not correct.  With these 137MHz satellites, you can only receive a signal as they pass over your location in Spain, because they are LEO (low-Earth-orbit) satellites and move around the Earth at a fast speed, (in order to cancel out the Earth's gravitational force which would otherwise pull them down).  So typically their signal can only be received for about 12 minutes as they pass over you.

 

I dropped the location of Barcelona into n2yo website and it tells me that NOAA-19 will pass over that location between 11.52am - 12.07pm today Thursday, peaking at 72 degrees elevation.

If you're using Satdump, your screen should look like this:

 

 

 

 

On the left is the progress of the satellite in its pass, showing the azimuth and elevation. The satellite signal is shown on the waterfall and if you have the audio playing box checked, then you'll hear the 'tick-tock' sound of the signal.

 

After the pass is completed, Satdump processes the data and adds the country overlay/underlay.  This is an image with rain clouds received 10 minutes ago from the above screen of NOAA-15, so you can see that the image map is of south-east Asia (I'm located in Thailand).

 

 

To avoid cluttering up GG's weather thread, I have created a new thread in the Sports and Hobbies subforum, for posting and discussing about space news, satellites, ISS, interesting signals and so on 🙂

 

The thread is here:

 

https://aseannow.com/topic/1363409-radio-comms-hobby-weather-satellite-and-iss-pictures-shortwave-radio-signals-space-news/