DIY Radio Astronomy

algwat (Alan) · #1 15-10-2013, 09:11 AM

Another interesting use of USB TV dongles. regards Alan.

http://rishi-patel.blogspot.co.nz/20...a-project.html

Terry B · #2 15-10-2013, 11:06 AM

Very interesting.

bojan · #3 15-10-2013, 02:48 PM

Working on similar project.. details will be published here when I have some results (in a week or two).

Barrykgerdes · #4 16-10-2013, 09:06 AM

I am interested in any results you get.

I started to revive the ASNSW radio astronomy project about three years ago. We have a 16ft dish and steerable aerial ex Fleurs Mills Cross. I refurbished the main dipole and checked out its performance using a test signal and spectrum analyzer. We purchased a new low noise amplifier to use in front of a spectrum analyzer. However the low noise amplifier was unstable when connected to the dish aerial although it was quite stable connected to a test dipole. At this stage we had not detected any signals from the H2 emissions from the sun.

I was not able to carry on the testing from here as the project became too heavy for my physical capabilities due to age and the project once again has become dormant.

Barry

Poita (Peter) · #5 16-10-2013, 10:50 AM

Where is that based Barry?

Quote:

Originally Posted by Barrykgerdes

I am interested in any results you get.

I started to revive the ASNSW radio astronomy project about three years ago. We have a 16ft dish and steerable aerial ex Fleurs Mills Cross. I refurbished the main dipole and checked out its performance using a test signal and spectrum analyzer. We purchased a new low noise amplifier to use in front of a spectrum analyzer. However the low noise amplifier was unstable when connected to the dish aerial although it was quite stable connected to a test dipole. At this stage we had not detected any signals from the H2 emissions from the sun.

I was not able to carry on the testing from here as the project became too heavy for my physical capabilities due to age and the project once again has become dormant.

Barry

bojan · #6 16-10-2013, 03:03 PM

Last weekend I obtained the dish on ebay - C-band mesh for satellite reception, for $160 (just a 2.3m dish, no electronics.. still a good buy because it is easy to assemble the contraption in a backyard).
Then I stumbled on this website:
http://www.haystack.mit.edu/edu/unde...srt/index.html
This is almost exactly what I had in mind.. I am not the first one here ;-)

Currently I am building the LNA and BPF filter.
For the receiver and recorder I will use SDR# and SkyPipe.. I tried it in a dry run, and it works OK (RAW signal, my audio card passes DC signal to recorder it seems..)
Anyway, I am hoping to at least detect the 21cm line, and it seems it will be possible to even do some doppler measurements (I have high stability frequency reference, so it won't be hard to calibrate the TV stick properly).

Barrykgerdes · #7 16-10-2013, 05:35 PM

Quote:

Originally Posted by Poita

Where is that based Barry?

Up your area. It is at Wiruna.

I use the 3rd harmonic from a hand held CB for testing. Its frequency is 1429 Mhz. However the spectrum analyzer is calibrated and can see -117dbm at maximum sensitivity. The LNA givers an additional 30 db and the dish should eventually add another 24 db when it is repaired.

The spectrum analyzer is old but good, a HP 141 main frame with 8552B and 8555A plug ins. It is at Wiruna

I also have an 8558 Spectrum analyzer (1 to 1500 MHz). I have this one at home for testing but it is not as sensitive.

Barry

PS I have built transmitters and receivers for the 1296Mhz Ham band 45 years ago when we had to work with valves. I was the first one to get a working system going and as I was "The contest Committee" I organized a contest with cross band allowed and naturally the scoring was biased my way. However I let Dick 2ZCF have my receiver and he eventually won.

mswhin63 (Malcolm) · #8 16-10-2013, 07:30 PM

I have had one of these dongles for a while, I will start with Pulsar measure on 411MHz then expand further if the dongle proves any worth.

It does not have exceptional front end but it maybe useful for a starter application.

Barrykgerdes · #9 21-10-2013, 11:37 AM

If you are contemplating building a horn antenna like in the reference. There is some design information in this file

http://barry.sarcasmogerdes.com/qb64...ttenuators.zip

The source code is in BASIC modified for QB64(gl). The exe files are compiled with QB64(gl) and will run on a 64 bit computer. I have had the BASIC source for 30 years but could never get the Horn.exe it to run properly. It took me two days to debug and find the very simple syntax error

Barry