Radio Astronomy and SETI
Believe it or not, it is possible to do Radio Astronomy at home. Especially if you consider Radio Astronomy to include all frequencies from "DC-to-Daylight". But even if your idea of Radio Astronomy is searching for deep space objects at microwave frequencies, you can put together a complete radio telescope for a few grand, assuming you can scavenge a Big Ugly Dish (BUD) from a neighbor who once used it to get Satellite TV.
You can also do interesting work at lower frequencies, probing changes in the ionosphere which are affected by both solar activityand also possibly by Gamma Ray Bursts from deep space
VHF and Above
A few years back I built a system to receive RA signals at 408 MHz. It started with the SARA 408 MHz Quagi antenna, followed by an LNA and a home-brewed down-converter which shifted the 408MHz to 144MHz. This was sent down the cable to a receiver in the lab which was built around a military surplus ARR-52 VHF receiver originally intended to receive signals from Sonobuoys. Looking back, this was a masochistic thing to do, and I can't recommend that anyone else do it. I added some Radio Astronomy specific features around it and packaged it in a 3U rack mount enclosure. Here's a link to a few pictures and a block diagram of the Radio Astronomy Receiver.
I have since begun a total revamp of the receiver, which is still in progress.
One thing I found out was that the LNA needed to be temperature controlled to avoid losing the desired signal in the noise change caused by temperature swings at the LNA. Here in Santa Rosa, our temperature can change from the 50's in the morning to the 90's in the afternoon. To optimize the performance of the DEMI LNA that I'm using, I decided to use a Thermo-Electric Cooler (TEC) module and control the LNA temperature to 0 deg. C. Go here for details.
My project for 2010 and the start of the next Solar Cycle is the construction of a system to monitoring a variety of signals related to solar activity. So far I am monitoring for Sudden Ionospheric Disturbances (SIDs) at VLF frequencies and Decametric Solar radio signals at around 20MHz.
For more details, see my Solar Monitoring Pages
To monitor the results, I am taking advantage of spare channels in my seismic monitoring system to act like a chart recorder. This works very well. I have the seismic system set to sample the inputs 100 times per second, and then record the data to the hard disk. The software that came with the board allows me to view the data in real time or review it from the disk. Go to my Seismic Page for more information about the board and the software.
An important part of any monitoring program like this is to have good time references for the data collected. I have a very nice High Precision Time and Frequency Reference System for my lab.
Here are some great links to Amateur Radio Astronomy information:
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Last Revised: 23-May-2010