The tiny radio telescope

Details

The tiny radio telescope is an experiment based on the NRAO's "Itty-Bitty Telescope" design to see whether amateur astronomers can make useful observations in the radio spectrum. It is also a precursor project for our eventual goal of building a fully automated robotic telescope.

Like the Itty-Bitty, we're using a commercial satellite TV receiver as the telescope component, but we're taking it a step further by adding a simple motorized mount (to allow for computer-controlled target aquisition) and feeding the signal into a computer for real-time graphing of the signal.

If the project is successful, we will likely use it for science outreach demonstrations, and possibly build more to donate to school science departments.

Components

1 × Satellite dish the bigger the better

1 × LNB your standard satellite TV LNB will be just fine

1 × Satellite Meter Channel master makes a good one, but you can get cheaper ones too

1 × Lazy susan Hardware store

1 × Wooden mounts To put everything together

Project Logs

Collapse

SDR at last!
Paul Scott • 10/25/2015 at 13:39 • 2 comments

Big milestone reached! We actually managed to hook up the RTL-SDR dongle to the LNB with the inline signal booster too!
As a simple test, I tuned it to a local radio station...
MCX connector has arrived!
Paul Scott • 10/22/2015 at 11:33 • 0 comments

Finally! Some progress! Our RF coax F type cable to MCX connector has now arrived! We can now attach the RTL-SDR dongle to the satellite dish!
Old bicycle wheels
Paul Scott • 09/25/2015 at 15:52 • 0 comments

The sterling gentlemen at our local cycle shop (Linden Cycle) donated 2 old bicycle wheels for our project. They also threw in a cog and a derailleur sprocket for a spiffy 3:1 gear ratio.
The idea is to weld the spoked aluminium wheel to the lazy susan turntable top, with the big cog in between. A bicycle chain to a stepper motor will then rotate it, giving up a pretty sweet azimuth system, controlled by a stepper driver and a microcontroller.
The altitude system will work similarly, just a touch worried about getting enogh holding torque for it to be useful!
First successes
Paul Scott • 08/29/2015 at 09:16 • 2 comments

With the basic components here, we have managed a first successful test! This test officially puts us on par with the NRAO "Itty bitty" project!
Check out the pics for the "data" :)
First off, we pointed the dish (and attached LNB) to some relatively open sky. Unfortunately, I live in a townhouse complex, so open sky is a bit of a commodity here (hence the small reading). This was to calibrate the LNB to get a baseline "0" reading.
We then pointed the LNB near the sun.
Immediately the satellite finder lit up like a Christmas tree and gave us a much stronger reading. This is quite expected as the sun is a very strong RF source. I also pointed it at IS20 (found via a mobile Android app, and eyeballing where our regular TV satellite dish was pointing) and got about the same reading.
After about a minute, the sun started passing out of the dish line of sight, and the following reading was taken
This is great confirmation that, at least, the components are all working! I hacked an LNB power supply from an old Set Top Box that I had lying about (a proper one is on order, waiting for delivery).
Altogether, a great morning's work! Very pleased with the results!
Satellite meter
Paul Scott • 08/27/2015 at 14:38 • 0 comments

We have finally taken delivery of a satellite meter! This will aid us greatly in aiming the dish at objects, as well as with testing that everything is working correctly!
RTL-SDR first tests
Paul Scott • 08/18/2015 at 08:19 • 0 comments

Using an Android driver and RF analyzer app, we have now confirmed that the RTL-SDR dongle is, in fact, working correctly. This may be my last log for a while now, as we are waiting on delivery of the satellite LNB components. I had to order out of country for a powered multiswitch, as well as a heavy duty lazy susan for the base. Good thing though, is that the lazy susan is rated at 300 lb's so that should be good enough.
I will now also start designing the worm screw based altitude base, and figuring out any bugs with that too. I am unsure if I will go with the worm screw design, as I may decide to do a pair of stepper motors with LEGO tyres on them on a semicircular blade like design. Much in the same way that fairground roller coasters and things work with spinning tyres to accelerate the thing. Hopefully there will be enough grip to do it that way, as we will then be able to take full advantage of the 200 steps/rev on the steppers.
Satellite dish repainted and ready
Paul Scott • 08/17/2015 at 05:24 • 0 comments

Enlisted the help of my kids to get the satellite dish prepared this weekend. It is now rust free, painted and ready to go!
Getting all that rust off!
Corgi work inspector...
Done, and passed final Corgi inspection.
Signal Boosted!
Paul Scott • 08/14/2015 at 10:41 • 0 comments

Managed to get hold of an inline signal booster (line amplifier) at a local satellite TV shop. Relatively inexpensive and hopefully will make a huge impact on what we can detect!
Lazy Susan planetary gears
Paul Scott • 08/14/2015 at 06:55 • 0 comments

Designed and ready to print. I am not yet sure that the gear ratio will be high enough for a NEMA 17 stepper motor to drive it, but I suspect it should be OK. The antenna is not very heavy, but I am a little worried about possible wind damage....
Satellite dish acquired!
Paul Scott • 08/11/2015 at 12:48 • 0 comments

I managed to find a 1m satellite dish on OLX for only R200! Sweet!