Radio Astronomy Forum?

Pablo,

I would be interested in this forum.  I've been wondering whether it is possible for an amateur to observe bright variables in the radio part of the spectrum.   Experience from others in radio might help me to decide what the possibilities are.   The forum idea could be useful.  I don't own a telescope but I do own antennas and radios.   Why not see what my technical limitations in the radio are?   I visually observe my bright variables with binoculars.  I want to learn some more about your 1420 Mhz setup and will email you.   Thanks for posting this information.

Rich Glassner GRIB

Pablo,

I also built a hydrogen line radio telescope over the Covid shutdown last spring-- instead of a parabolic reflector, I used a small horn antenna (I have a much larger horn constructed, but haven't tried to use it yet.  It looks like I used the same software that you did as well as the same SDR dongle and I did get similar results.

I think that a radio astronomy forum would be a great idea and would try to contribute to it.

Coincidently, I also belong to an astronomy group called SARA (Southeastern Association for Research in Astronomy), which is a consortium of mostly southeastern universities.

Tom

This is an interesting coincidence! I have recently been thinking about proposing a radio astronomy forum/observing section. Obviously the average amateur doesn't have a radio telescope in their back yard, but it makes sense to have a forum to at least discuss things and share information.

I too was a member of SARA (the amateur group, not the Southeastern group) until a few years ago and was considering rejoining. I wrote a couple of papers for their journal. I became Section Leader of the AAVSO HEN Observing Group earlier this year and significantly updated the website which was seriously out of date. As part of the new website, I included a section on multimessenger astronomy with links to several radio observatories.

I also built a radio telescope receiver a few years ago from some spare parts left over from a Navy contract I was working. It worked functionally, but suffered from poor sensitivity and would have required large antennas to get enough gain.

Anyway, I would be very interested in being involved in any radio astronomy activities thru AAVSO.

Dave

A few cents worth from the AAVSO Solar Section Chair.  I've built two different solar radios in the microwave frequencies 2.8 GHz and 12 GHz looking for flare activity and proxies for sunspot counts. These radios used 90 cm satellite dishes.  Both had severe disruptions because of how close these frequencies are to satellite communication networks and internet routers. 

Other than that, we would be looking at the OH (Hydroxl) frequencies at 1.6 GHz. This would be for comparing the LPV Mira stars that have OH masers, R Aql, W Hyd, etc.  HOWEVER, these are weak signals and would need a dish in the 25 meter size to detect these masers.  There are folks in the SARA group who do have access to these size dishes.  I would point you to the SARA web page:  https://www.radio-astronomy.org for discussion of this sort.  

We do have an active VLF group who contribute their monthly recordings of solar flaring to the Solar Section, if that is of interest then post ideas and requests to the Solar Section forum.  

Rodney

I had a different crazy idea that also overlooked the sensitivity issue:

0-3 GHz reciever on heliax to a fast photodiode on the optical scope.

Three problems right away

Expensive, $4000

Poor sensitivity for fast photodiodes. You gain sensitivy and slow response by adding capacitance. Fast photodiodes can see fast laser pulses but not daylight.

A brief literature search for stellar emissions in that band did not turn up much.

So it's on the back burner until I can find a PD that can see 100 photons at 0 to 6 GHz, or I get time on a 30 meter scope.

Ray

This is from my homebuilt Hydrogen line radio telescope, it's a slow start on purpose..Notice the doppler shift as the radio telescope detects several spiral arms moving towards us and away from us. I am now detecting hydrogen line signals way past the spiral arms in several instances as clearly depicted on this video which includes 2 days of drift scanning.

I have 2 Nooelec Sawbirds in series (dc blocks included) and that has given me a LOT of gain. (The video of the antenna is live and the setup is fully steerable, my next project is to get signals from different parts of the Galaxy and make videos for people to enjoy).

https://www.youtube.com/watch?v=lFTI-BJnbns

What I did was to improve on the following system with a larger dish and an extra LNA. Read the following article which includes the software I use. https://www.rtl-sdr.com/cheap-and-easy-hydrogen-line-radio-astronomy-with-a-rtl-sdr-wifi-parabolic-grid-dish-lna-and-sdrsharp/

Thanks!

Pablo LPAC (WA6RSV) at The Maury Lewin Astronomical Observatory