Tagged: discovery dish

Multiple Comprehensive Tutorials on Weather Satellite Decoding

Over on his website "Jacopo's Lair" IU1QPR (@original_lego11) who is also a developer for SatDump has written up many tutorials about weather satellite decoding that involve the use of SatDump. SatDump is a popular piece of software often used with RTL-SDRs and other low cost SDRs for decoding weather satellite images.

With a small satellite dish, feed, RTL-SDR and LNA+filter and the SatDump software it's possible and download beautiful images of the earth from many geostationary and polar orbiting weather satellites. We note that we are currently taking pre-orders on Crowd Supply for our Discovery Dish system, which is low cost hardware designed to help users get started with weather satellite reception.

Over on Reddit IU1QPR has created a listed summary of all the tutorials he's written. These are currently the most up to date and comprehensive tutorials that we have found on this topic. The tutorials cover everything from what satellites are available, what dish sizes you need, what SDRs can be used, what LNA+filter and other hardware you need, and how to use the SatDump software.

Satellite reception and decoding

Automated stations

SatDump usage

All have been moved to SatDump's documentation page

Satellite data processing and usage

From the HRPT tutorial: What various HRPT signals look like on the spectrum.
From IU1QPR's HRPT tutorial: What various HRPT signals look like on the spectrum.

The Biggest RTL-SDR and Related Stories from 2023

This year there were several interesting stories and product releases that we posted about on the blog and this post will be a brief end of year review of some of our most popular posts. We also wanted to wish everyone a Merry Christmas and Happy Holidays to every celebrating at this time of the year!

In January we saw that the popular ADS-B Exchange (ADSBx) ADS-B aggregation platform was sold to a private equity firm called JETNET. This caused quite a bit of outrage as many involved with the development of the platform were blindsided by the owner's sudden decision to sell. ADS-B Exchange is a popular ADS-B aggregator that uses RTL-SDRs and is known for it's hard no censorship policy, allowing it to be used in projects like "Dictator Alert" and to uncover immoral use of aircraft in policing and military "kill chains". Many of the original team have since started a new service at https://airplanes.live.

ADSBExchange.com interface
ADSBExchange.com interface

Next in February at the height of the "Chinese Spy Balloon" scare we ran a story about how the US air force had shot down an amateur radio 'pico balloon' called K9YO-15  , on the assumption that it could have been another Chinese spy balloon. Pico balloons are party sized helium balloons with a solar powered amateur radio transmitter attached. The fun of the hobby is seeing how far and long around the world they can travel for. A typical pico balloon could circumnavigate the globe several times over several months, all whilst transmitting it's position.

Rough trajectory overlay
Rough trajectory overlay

In April we saw the Flipper Zero go mainstream when it was reviewed on the Linus Tech Tips YouTube channel. The Flipper Zero is a small RF hacking device that gained high popularity on social media sites like TikTok. 

Linus Tech Tips Reviews the Flipper Zero
Linus Tech Tips Reviews the Flipper Zero

In June we saw a video from a YouTuber that appeared to show a Flipper Zero being used to wirelessly 'let the smoke out' and self-destruct an electricity meter which raised major infrastructure security concerns. However, this video appears to have since been removed, and there was speculation that the video was faked, or at least staged in some way.

In July we showed a video demonstration of how our KrakenSDR could be used to track down a low power FM transmitter station. In August we showed the KrakenSDR tracking down multiple GSM base station transmit towers simultaneously.

Later in August we also released the RTL-SDR Blog V4 dongle, a limited edition RTL-SDR that makes use of existing stockpiles of R828D tuner chips. It has improved HF performance thanks to an upconverter, and improved filtering on the VHF and UHF bands.

In September we saw crowd funding start for the RFNM, a device that promises to be a next generation software defined radio.

Finally in November we saw the release of the crowd funding campaign for our Discovery Dish project, a low cost and easy way to get into reception of L-band satellites, as well as Hydrogen Line radio astronomy.

Later in November we also saw a great technical overview of the Watch Duty wildfire monitoring project which uses multiple RTL-SDRs in their system.

The Discovery Dish
The Discovery Dish

Discovery Dish Updates and Some Cool Hi-Res Images

We have recently posted an update on our Discovery Dish crowd funding campaign over on Crowd Supply. Check it out on the update page, or on the repost down below.

Discovery Dish Teardown Session Livestream Recording

Thank you to Helen Leigh and Crowd Supply for featuring us on one of their Teardown Sessions live streams a few days ago. If you missed it, feel free to watch the recording below. On the livestream we discussed the Discovery Dish and talked a bit about the journey we took to get to the final product design.

Teardown Session 38: Discovery Dish

Enclosure Glands and Vents

We have decided to include a few cable glands and vents with the Discovery Dish Enclosure, as these will ensure that the bottom of the enclosure is protected against water jets and any splash back from the ground, as well as allowing the electronics inside to breathe a bit. Allowing waterproof enclosures to breathe is important in many environments to avoid condensation build up inside.

The glands and vents will be metal to ensure that RF tightness of the enclosure is maintained as much as possible.

The electronics inside can be passively cooled via thermal pads that sink all generated heat to the metal enclosure which acts as a large thermal mass and heatsink.

In the image below you can also see the mounting board. We are still planning to reduce the hole spacings on the board.

Rotator Timelapse

We’ve been testing an early prototype design of our upcoming antenna rotator for the Discovery Dish, and have created a quick preview timelapse of it running overnight. With mechanical designs like this it’s important to do some long-term testing, so we’re going to be running prototypes non-stop for several months while tracking many more satellites than would be typical.

DD Rotator Preview

 

Example Weather Satellite Images Downloaded

Some people have asked for high resolution examples of what can be received from satellites with the Discovery Dish. Below are a few samples.

GOES 18 Full Disk

Discovery Dish GOES 18 Full Disk Blend

 

GOES 18 Mesoscale

GOES 18 EMWINN

GOES 18 NWS

Metop AVHRR (Advanced Very High Resolution Radiometer)

Metop IASI (Infrared Atmospheric Sounding Interferometer)

GK-2A Full Disk

FengYun 4A Full Disk

Meteor MSU-MR (Multispectral Scanner Unit - Medium Resolution)

NOAA AVHRR (Advanced Very High Resolution Radiometer)

Crowdfunding Goals

We just wanted to clarify a point regarding how crowdfunding works. If the goal isn’t reached then everyone who ordered won’t be charged. We have had a few concerns from potential customers wondering if we will keep the money if the goal isn’t reached, but this is certainly not the case! In fact, credit cards will only be charged if we hit our funding goal. You can learn more in the Crowd Supply Guide.

The goal is set relatively high as this product requires a number of molds to be created for the dish and the various plastic parts, and molds typically have a high fixed initial cost. There is also a high minimum order quantity that we need to commit to in order to do a production run.

But the campaign is currently over 70% to its funding goal and we are expecting some large reseller orders to come in during the last few days of the campaign, so please don’t worry as the goal will almost certainly be reached with the help of just a few more individual supporters. If you have been on the edge, please consider supporting us to get this product started!

Customer Questions

In my environment temperatures get down to -20 to -30 degrees C. Will the electronics in the feed hold up?

The components used in the feed all have ratings down to at least -40 degrees C. In very cold environments, the one thing we would suggest considering is if a dish heater is required. These are heating strips that can be placed on the dish and can help melt snow/ice buildup.

What is the hole pattern on the dish?

The hole pattern on the dish has no specific function, the holes are simply used for reducing wind loading and weight. The manufacture of the prototype dish requires that the holes be cut by laser cutter, but the laser cutter we have available was not large enough to do the entire dish at once. So it was manually rotated around, and this caused an uneven pattern.

The production version of the dish will split into three petals, and each petal will be manufactured via a stamping process. Stamping is when a sheet of metal is placed under a heavy molded block of metal, and then that block of metal is pressed down on the sheet metal to create a desired shape. With this stamping process we will have perfectly neat hole patterns.

I suggest that the S-band version of the feed not use a downconverter, and just use an SDR that can receive S-band instead.

We currently have a similar opinion.

To explain this customer question/comment, we note that as mentioned in the previous update, we are planning to soon test an S-band version of the feed which should be able to receive S-band satellites.

However, the typical software defined radio used is an RTL-SDR, which cannot reach S-band frequencies like 2.2 GHz where most S-band satellites transmit. To get around this, we could add downconversion circuitry to the S-band feed, which would increase complexity and cost. This would convert the 2.2 GHz frequencies down to a frequency that the RTL-SDR can receive (below 1.766 GHz). Alternatively, we could simply recommend that customers interested in S-band reception instead use another SDR such as the HackRF, PlutoSDR, or LimeSDR Mini 2.0.

Once we have tested the S-band version of the feed, we will make a decision on if we should add a downconverter or just recommend the use of other SDRs that can reach the S-band.

Can any of the feeds be used for 1296 MHz EME (earth-moon-earth bounce communications)?

Sorry no, the feeds will not be suitable for EME, as that requires transmission which our feeds do not support.

I would like to use the dish on an astronomical mount. What is the expected weight of the dish and feed?

The dish itself weighs less than 1 kg (2.2 lbs). Together with the feed and mount we expect it to weigh a total of less than 1.5 kg. This is significantly lighter than a Wi-Fi dish which is already 1.6 - 2 kg (depending on the brand) for just the dish by itself.

Are weather satellites encrypted?

No, most weather satellites like this are not encrypted. Although these satellites come from various countries’ governmental space and/or military agencies, weather satellite data is generally considered public science. If it’s not necessary, adding encryption is undesired as it adds complexity to the system and increases the amount of data that needs to be transferred.

Obviously high-end military and commercial satellites are encrypted and we cannot receive data from those. It’s possible that future weather satellites could be encrypted, but given the current trend of new weather satellites being unencrypted this seems unlikely.

 

Crowd Supply Discovery Dish Teardown Session: Thursday 30 November Noon PST

Crowd Supply is hosting Teardown Session 38 on Thursday 3- November at Noon PST time which will feature the Discovery Dish. Join us for this livestream where I will be talking about and showing the Discovery Dish prototype.

Discovery Dish is currently being crowd funded over on Crowd Supply. It is designed to be an easy entry to the world of L-band weather satellites, hydrogen line radio astronomy, and Inmarsat reception. The Discovery Dish aims to be the start of an ecosystem of hardware designed to get users set up with satellite reception, including a planned companion light-duty antenna rotator.

Remember to click on the “Notify me” button on the YouTube link in order to be reminded about the stream!

Teardown Session 38: Discovery Dish

The Latest Progress on Discovery Dish

Over on Crowd Supply we are currently crowd funding for the Discovery Dish, a system that aims to help make satellite dish based radio projects more accessible for use with low cost software defined radios like the RTL-SDR. We've recently posted an update which we pasted below.

Discovery Dish: Simplified system for weather satellite reception and hydrogen line radio astronomy

The Latest Progress on Discovery Dish

First, we want to thank everyone who has purchased a Discovery Dish! We are about two weeks into the campaign now and we’ve reached over 30% of our goal. Please help us get there by sharing the campaign with anyone you think might be interested!

Progress Report

Here are the latest updates:

  • We’ve been working on getting manufacturing of the molds and electronics ready to go once we receive funding. We’re finalizing our CAD files and double checking everything so we’ll be ready to go once the campaign ends. We put six months as our target before shipping, but we’re hoping to actually get the product out sooner than that. The main delays in the timeline will be the Chinese New Year holidays early next year and the time it will take to sea freight our bulk production runs.
     
  • For the enclosure, we’ve begun getting samples of the general electronics mounting board. It will be made out of a conductive metal which is important for grounding RF noisy electronics to the enclosure, and will also allow heat to transfer out of the enclosure via a thermal pad underneath the board. Once we get our prototypes we will share more images.
 
  • We've also began considering how we might implement a 2.2 GHz S-Band feed for the Discovery Dish. The return-loss characteristics of the feed were designed to be good at 2.2 GHz, so we probably don't need to change much of the core feed design. The main question will be if it's feasible to implement a downconverter for use with RTL-SDRs (which have a maximum frequency limit of 1.766 GHz), or if it's better to just use a HackRF for this band. Updates on our investigations will be provided as we test further.
  • We are also actively working on our rotator prototype which we hope to release next year as a companion product to the Discovery Dish in order to make reception of polar orbiting satellites easier and more accessible. We don't want to release too much information on the rotator at the moment as things could still change a lot, but currently we are ordering samples of some custom parts that we need to test a production version. We are also developing the microcontroller firmware so that it will be compatible with the EasyComm II rotctl protocol.

Customer Questions

Finally, we’ve received a few questions from customers which we’ll answer publicly below:

Inmarsat is circularly polarized. Is the Inmarsat feed circularly polarized?

Our feeds are all linearly polarized. But this actually does not matter much for Inmarsat because our dish is more than large enough for Inmarsat, and Inmarsat signals are relatively strong. Using a linear feed on a circularly polarized signal results in a 3dB loss which is relatively insignificant in this case. With a small patch antenna such a difference is significant, but not so with a larger dish.

Will this work with a SatNOGs rotator?

Yes, the Discovery Dish comes with a standard pole mount which can be used to mount it on the SatNOGS rotator arms.

What is the amplifier/filter architecture like in the feed?

The signal chain is as follows: Feed -> QPL9547 LNA -> SAW -> QPL9547 -> SAW -> SMA Output. So our feeds are dual-amplified and dual filtered.

Can the coax on the feed be swapped out for longer and lower loss coax?

Yes, the feed uses an SMA connector so you can swap out the coax cable if you like. Thicker cables may require different sized strain-relief at the end of the feed arm, though.

 

Discovery Dish Now Available for Crowd Funding! A Lightweight Dish and Feed for L-Band Weather Satellites, Hydrogen Line and Inmarsat

Today our Crowd Funding campaign for the Discovery Dish has gone live! Thank you to anyone who supports this project and our goal of bringing affordable products that make getting into various radio projects easier.

Our launch announcement reads:

We decided to develop Discovery Dish because we were disappointed by the lack of ready-to-use, low-cost, lightweight dish antennas on the market that are suitable for software-defined radio projects like receiving L-Band geostationary and polar-orbiting weather satellites, as well as for 1.5 GHz Inmarsat reception and 1.42 GHz hydrogen line radio astronomy. With excellent open source weather satellite decoding software, like SatDump, now available, it’s time for a complementary, easy-to-use hardware solution.

Through testing over several years, we chose 65 cm as the diameter, as we found that 60 cm is close to the minimum diameter required for perfect GOES weather satellite reception at 24° elevation, so this size should be suitable for most of the world that has GOES reception available. For LRPT satellites like GK-2A, and HRPT polar-orbiting satellites, it is more than large enough. We combined the dish with a carefully tuned feed that has a built-in low-noise amplifier (LNA) and dual filtering, which means there is no loss from feed to LNA. This also means we can use thinner and less stiff coax cable, which is a lot easier to handle and route. Finally we ensured that the entire dish and feed system is waterproof.

The only other ready-to-use dish offering we found is based on a modified 2.4 GHz grid Wi-Fi dish, which is still in our opinion too big and heavy. Size and weight is especially the important if you want to be able to use a low-cost, light-duty antenna rotator, which typically can only handle less than 1 kg in weight. We found that the grid Wi-Fi dish offering also has no solution for waterproofing the LNA, so the LNA needs to be placed indoors and very thick and unwieldy coax is used to avoid feed to LNA losses.

Other ways to receive these weather satellites and carry out hydrogen line experiments typically involve modifying a 2.4 GHz Wi-Fi grid antenna, or an old satellite TV dish. But these modifications can be time-consuming and difficult to get right, and even 60 cm satellite TV dishes are too heavy for light-duty antenna rotators.

Finally, we developed Discovery Dish with an eye toward it being used with a low-cost antenna rotator, and we are in the process of prototyping our own rotator design. Our antenna rotator is not ready for crowdfunding yet, as there are still some things to work out and long-term stress testing to be done, but please keep an eye out for it in 2024! An antenna rotator is a great addition if you want to use a dish antenna to decode images from the polar-orbiting HRPT weather satellites.

Note that you don’t need an antenna rotator to receive geostationary satellites like GOES, or to do drift hydrogen line observations. For polar-orbiting HRPT satellites, the lightweight nature of Discovery Dish also makes tracking the satellites by hand a much easier prospect.

Learn more about Discovery Dish on our main campaign page. Thank you to everyone who supports the Discovery Dish project in any way!

Discovery Dish: Simplified system for weather satellite reception and hydrogen line radio astronomy

 

Discovery Dish Pre-Launch: A Lightweight Dish and Feed for L-Band Weather Satellites and Hydrogen Line Reception

For the past few years we have been working on finding the best way to help beginners get started with L-band weather satellite reception and basic radio astronomy. We have now come up with a solution that we're calling the 'Discovery Dish' - a lightweight 65 cm diameter dish and active filtered feed set.

Discovery Dish: Simplified system for weather satellite reception and hydrogen line radio astronomy

The Discovery Dish will be crowd funded, and we currently have a pre-launch page set up on Crowd Supply. So if you are interested, please visit the pre-launch page and click on the Subscribe button for updates.

Discovery Dish is a 65-cm diameter aluminum satellite dish and active filtered feed designed for receiving GOES HRIT, GK-2A LRIT, FengYun LRIT, NOAA HRPT, Metop HRPT, Meteor M2 HRPT and other weather satellites that operate around 1.69 GHz. The dish is designed to weigh under one kilogram, and it splits into three petals, making it easier to ship worldwide. The 1.69 GHz feed contains a built-in LNA right at the feed point, as well as filtering, which means that there is almost no noise figure loss from cables or connectors.

Note that the prototype images show an early non-petalized prototype with rough laser cut wind holes. The production version will obviously be a lot neater looking! 

In testing the 65 cm diameter Discovery Dish with it's highly optimized feed has proven effective at receiving the GOES HRIT satellite signal with SatDump. We typically achieve SNR values of 3-4 dB to GOES-18 at 24 deg elevation, and with SatDump an SNR of 1 dB is about the minimum required to receive images so there is plenty of margin. It can also easily receive LRIT from GK-2A and Fengyun, and also when combined with an antenna rotator (or manual hand rotating) can receive HRPT weather satellites too.

The feed on the Discovery Dish consists of a tuned dipole feed with two 5V bias tee powered low noise figure LNAs, and two SAW filters (centered at 1680 MHz with 69 MHz Bandwidth). The feeds are also easily swapped out, and we will also be selling a 1.42 GHz Hydrogen Line feed for those who want to use the dish to get started with radio astronomy. Because the LNA's are right by the feed there is are no losses from feed to LNA, so we can use thinner and easier to handle cabling like RG58 without any loss issues.

In the past we've recommended and relied on 60 x 100 cm WiFi dish antennas for L-Band geosynchronous satellites and Hydrogen Line reception, but at 1.6kg these are too heavy, wide and exert too much torque for light duty antenna rotators to handle. At about half the weight of an equivalent WiFi Dish, the Discovery Dish is much easier to handle.

In the future we hope to be able to provide a low cost light duty antenna rotator that compliments the Discovery Dish. Currently we have tested the Discovery Dish with the AntRunner antenna rotator and found it to be light enough for that rotator to handle, versus a WiFi dish which is far too heavy for it.

Also when compared to a WiFi dish, the Discovery Dish is much easier to optimally set the offset skew as you can simply rotate the feed, versus having to rotate the entire dish at 45 degree increments.

We will also be offering an outdoor electronics enclosure that can be used to house a Raspberry Pi, RTL-SDR and other components like POE splitters. In our tests we have been running an RTL-SDR Blog V4, Orange Pi 5 and POE splitter in the enclosure, and running the SatDump GUI directly on the Orange Pi 5. This results in a neat contained system where only one Ethernet cable needs to be run out to the enclosure. 

As we are in pre-launch, pricing is not yet confirmed, but we expect the Discovery Dish to sell for less than US$200 with reasonable worldwide shipping costs. It will be a similar cost to what you would pay if you purchased a WiFi dish, filtered LNA and cabling yourself. Obviously please check what satellites can be seen in your region.

 

GOES HRIT
GOES HRIT
Meteor M2 HRPT
Meteor M2 HRPT
FengYun LRIT
FengYun LRIT