Project update 4 of 5
Discovery Dish is now successfully funded! We want to extend a big thank you every one who made this crowdfunding campaign a success!
We are now awaiting release of the funds, and shortly after we will begin ordering the dish stamping mold, molds for the plastic parts, and all the other parts that make up the Discovery Dish set. The molds will take about two months to be produced, and this time may extend a bit longer due to the looming Chinese New Year holidays in February, when factories typically shut down for a month. Once the molds are done, we will first be producing a number of final prototypes to make sure the manufacturing process is working well, before moving on to the mandatory regulatory testing and the first large production run.
During the production period we will take the opportunity to write tutorials, manuals, and notes about how to use Discovery Dish, so please keep an eye here for updates! We will also keep you posted on the progress of our upcoming rotator addon, which is currently in long-term stability testing at the moment.
We will take a rest from updates over the Christmas and New Year’s break, but will be back with some updates in January. In the meantime, below are answers to some questions we’ve received. Happy holidays everyone!
I have a HackRF and SDRplay Duo. Do I still need any feed at all with those two SDRs?
Yes, no matter what SDR you have, you will still need a feed. The feed is the antenna part of the system, and the dish is the reflector. Without a feed the dish by itself cannot be used to receive anything.
Do I need all three feeds to receive all the weather satellites mentioned in the last update?
No, if you only want to receive L-band weather satellites then you only need the L-Band weather satellite feed. The second feed we are offering is for hydrogen line radio astronomy which is a totally different application that is all about receiving a natural phenomena, not data transmitted from satellites. The third feed is for Inmarsat satellites which transmit data and voice only, not weather satellite images.
What is the maximum frequency that the dish is capable of effectively reflecting? Are there plans to make a solid dish for X-Band?
The hole size in the final version will be around 5 mm. The general rule is that the hole size should be 10x smaller than the wavelength being received to have no effect on the signal. Ten times our hole size is 0.05 m, which means that the dish should be able to support up to 6 GHz with an appropriate feed.
At the moment there are no plans to produce a solid dish, but if we find a popular use case for X-band we may look into it.
Is the dish easy to dissemble, store, and reassemble on the fly?
Yes, you can easily loosen the feed arm set screws, and remove the feed and feed arm from the dish. In this state, the dish should be easy to slide under a bed or store in a closet. If you need to make the dish even smaller for storage, you can remove the feed holder and bolts holding the three dish petals together.
If I was to get the dish, and L-Band feed, that does not come with the Raspberry Pi, correct?
The kit does not include a Raspberry Pi. You can use whatever computing you have available to you. I would recommend an Orange Pi 5, or a Pi 5 as those can run SatDump GUI directly on them.
And from what I can tell, I would need a tripod as well? If this is the case, is there a tripod that you would recommend purchasing?
Yes, you would need to way to mount the dish, be it a tripod, concreted pole, or an existing antenna mount on the side of your house or on your roof. I would recommend finding a local store that sells lighting stands, which can usually be found fairly cheaply.
Is it possible to mount your feeds (with adaptation of course) on a common and low-cost TV dish?
On a prime focus dish you could do so with your own 3D printed adapter. When we are closer to shipping, we will provide 3D printer CAD files for an adapter that will allow you to use the feed on Wi-Fi grid dishes that some people might already own. You could print something similar for a TV prime focus dish.
On an offset focus dish, results may vary as the feed was not designed for this.
I’m a complete beginner in this line of work and am wondering if I will be able to access all these different satellites from where I am in Brisbane, Australia. I’m considering getting the dish and all the line feeds, but I’m not sure if it’s actually going to work from where I am.
Not all geostationary satellites are visible from all locations. From Brisbane, you should easily be able to get LRIT from GK-2A and FengYun-4A. GOES-18 might be possible, but it will be quite low on the horizon at about nine degrees elevation only, which can be challenging.
I suggest downloading Gpredict or Orbitron, and having a look at where these satellites are in relation to your location. Also take a look at the SatDump satellite list.
For the polar orbiting satellites, like NOAA, Meteor, and MetOP, they can be received from anywhere in the world, since they orbit the earth and will pass over a couple of times per day. But for those you do need to hand-track them as they move across the sky, or use a mechanical rotator.
Also just a reminder, if you’re only interested in weather satellites, then you don’t need the hydrogen Line or Inmarsat feeds, as those are for other applications.
Discovery Dish is part of Qorvo RF Accelerator