Does anyone have any suggestions for what to do with amateur radio astronomy? I recently looked into this a bit and came to the conclusion that to do anything actually interesting would require rather substantial investment in a big dish and having a place in the middle of nowhere away from interference. I had a hard time getting a list of interesting things you could do with more modest investments. Looking into Radio Jove and the Itty Bitty Telescope seemed like they would just be educational projects that wouldn't yield fruitful, long-term projects. Most projects seemed like just listening/watching to the Sun and Jupiter for various emission pulses, which seems like it would get boring pretty quickly after the initial learning exercise.
Although the more interesting of the two, radio astronomy, for the amateur, seemed like it wouldn't yield as interesting results as visible light astronomy.
The effort-to-results ratio is definitely better on the visible light side. Pictures are exciting, and much easier to explain.
A lot of smart amateurs discuss all things astro at the Cloudy Night forums; the subforum where topics such as radio astronomy are discussed is here: https://www.cloudynights.com/forum/88-scientific-amateur-ast... Could be worth a look if you're seeking ways to contribute to the area.
Take a look at the youtube channel "saveitforparts", he has been doing various satellite comms and recently radio telescope experiments with usually just saved or recovered parts. Much of it is him learning on the way, which for myself is neat to watch
1. Small apertures' one advantage is their being able to see a large amount of the sky at once. For any coherent aperture the larger it's span in a direction the smaller the beam pattern is in the perpendicular direction upon the sky. The bigger your collector the smaller your beamwidth the less you can see at once. Big dishes have small FOV and aren't good for monitoring the entire sky.
There are ways of getting around this: physically scanning the big antenna, multi-apertures for receive across the focal plane, or by abandoning actual imaging and measuring the correlations between arrays of lower gain (smaller) apertures.
But the best way (if the signal is loud enough) is just to have a smaller aperture. Real science monitoring for transient radio signals can and is being done with literally just using the feedhorn from a large dish by itself (with some precise clocks, expensive lna, receiver, and time stamping) to detect FRB (and other high power transients),
Multiple stare2 type instruments distributed around the world are likely to do real radio astronomy in the near'ish future. This is amateur scale possible. In the "Completely Hackable Amateur Radio Telescope" they're using a pyramidal dish because it's easier to construct but for trying to contribute to "real" radio astronomy you'd want a choke ring feed horn or at the very least a conical horn. The idea is to minimize sidelobes which otherwise prevent you from knowing for sure the signal you received came from the direction the horn is pointing.
2. Another low hanging amateur accessible "real science" is actually doing something when you're receiving solar radio emissions. Calculate the velocity of a CME shock by the frequency drift as it travels upwards through decreasing magnetic field. Or even more audacious, use a hackrf (or ettus usrp b200 or something) to frequency hop at 8 GH/s over a few hundred MHz bandwidth and record the fine structure present at milli and microsecond timescales precent in many types of solar radio bursts. Things like spectrogram zebra patterns and fiber bursts and other unexplained highly coherent fine timescale patterns which still lack accepted physical explaination today. Particularly in that their very short timescales indicate the emission regions have to be only ~a handful of kilometers in scale but outshine the rest of the sun. Whatever "small" solar features are making these short intense radio emissions are open to even amateur interpretation at this point.
Regarding your point 2 I don't think there is anything "amateur accessible" there. There are several groups looking into this using LOFAR which is a large radio telescope array with 52 sites all across Europe. E.g. the ref. below.
You don't need LOFAR scale aperture to receive solar radio bursts. I literally do it with a ~meter size antenna sitting outside on my porch. Seeing the frequency drift in solar radio bursts is quite easy all things considered. The lowest hanging fruit there is.
As for the fine timescale structure of solar radio bursts, depending on frquency, and for this you're probably wanting to cover all of l-band and up, you only need about a meter^2 of aperture. And to see the fine-structure you only need a fast enough receiver with wide bandwidth. That's a few hundred to a thousand bucks. And you definitely don't need to do any sort of imaging or array stuff. All you need is a single receiver and to look at the spectrogram with a time precision of milliseconds. It is very amateur accessible despite the fact that even the largest, most complex, radio telescopes are looking at it too.
I remember a fairly sketchy bit of gear at my old university that an amateur could have definitely made for themselves (if I recall correctly the dish was made with chicken wire). They used it for observing the Vela pulsar for a very long time (like years and years) and looked at how the pulses changed with time.
Although the more interesting of the two, radio astronomy, for the amateur, seemed like it wouldn't yield as interesting results as visible light astronomy.