The noise source is here!

I just got Jan's noise source (well, yesterday actually, I just opened it tonight)!


The noise source, 9V battery clip, attenuator, and antenna.

This is an extremely useful tool for measuring things like the radiation pattern and gain of the radio telescope (as well as the receiver electronics, I need to make a cage for the TV tuner to block out external RF, and a noise source is invaluable to determine if its good to go), as otherwise I would have to depend on the Sun as a noise source. The noise source can also be tweaked to different output levels, via the use of an attenuator (these are particularly useful for calibration). Jan has supplied me with a -10dB attenuator as well to that end (thanks again Jan! :) ).


Merry Christmas to you too Jan, and thanks a bunch! :)

Anyway, I will have the receiver built in a week or so (when I get time to clear off the bench in my garage and solder it together) and some kind of transit mount for the antenna ready by January.

Cheers,

KM

The feed is in and... pictures!

I attempted to load these on my website, but I can't login for some odd reason so... here they are:


As you can see, a lot of blockage, but I did a short test with an old TV set and, lets put it this way, I got channels I have never seen in this area (I think one was from Tucson, and it came in full color and almost completely clear!) right through the my garden gate! The directivity seems to be what I expected, and I was able to aim it over the fence and pick up even more signal and it faded to static after a very slight tip in either direction (elevation). It is also more directive in azimuth then elevation (faded in and out with a little shake right and left), which was also expected. The front-to-back ratio is phenomenal, I couldn't get anything out the back (turned it away from the gate completely). Anyway, a real test will have to wait until the receiver is built and I get Jan's noise source. Here are more pics:

The feed.


The parabolic curve of the cylinder.

Close up of the feed, showing the TV splitter used a the combiner for phasing the elements in the line feed together.

Well, that's it for now, the next steps to take are building a meridian transit (drift scan) mount, building the receiver, and of course, testing it. Future plans are a tracking system involving beam shaping the elements by using phase shifters, and then making the telescope remotely controllable over an http interface (I'm learning Java for that purpose now) and doing a collaborative study with those who would like time on the telescope over an IRC channel on the freenode IRC network (I currently run that channel for general discussion purposes, #radioastronomy on irc.freenode.net port 6667).

All this having been said, you can visit my website,

http://channel37.110mb.com/

to find a list of places to contact me with questions, suggestions, etc. other than comments posted to this blog.

Cheers,

KM

The feed is in! And, a little problem...

Just put the feed in tonight! Just need to adjust the focus and hammer out some stuff in the parabolic curve, and its ready to go, for testing anyway. The nice thing about using TV antennas is the fact that I can test the antenna on TV stations nearby to the RA band (Channel 37) to see what kind of reception I can get and (roughly) test the -3dB beamwidth(s) before I assess the performance on cosmic sources.

On a darker note, I just received and replied back and forth to a fellow by the name of Joel Gonzalez, saying that he has been problems with the receiver kit I am going to be using,

http://www.mtmscientific.com/tuner.html

regarding the IF output of the tuner. Before anybody who bought this begins to chew their fingers raw, I'm gonna build the thing. Hopefully Joel is having a localized problem with the board or something and not the tuner itself, or if is the tuner, maybe a bad batch. However Mr. Gonzalez has pointed out that you can also use the AFT pin (basically an S-meter voltage) to perform total power measurements. However for my purposes, I need the IF for further downconversion to a narrowband receiver, for when I have an L-band converter block at the front end (spectral line measurements), and for SETI. Tsk tsk, eek... :P

Anyway, I will post pics of the feed in the morning, as its about one o'clock in the morning at the time of this writing.

Cheers,

KM