KG2PM SETI Radio Telescope Project
Revision April 22, 2004
Initial test of
installation - Saturday, June 24, 2000
receiver is set at 1420.5 Ghz.
has received its initial test. In the evening, Mike and I installed
the feed, LNA, and receiver. The LNA gets power right out of the
receiver. The receiver
was modified slightly so that we could pull a DC signal from the
signal strength meter and run it to an F connector. The DC signal
then runs through a coax cable to a Tektroniks oscilloscope. Then we
simply ran a power cord to the receiver, which has a built-in power
supply, for the initial test.
in the shack, we turned on the oscilloscope and set it to read the DC
voltage coming from the antenna installation. We then used a sweep
generator to send out a very weak source to see if our scope could
detect it. It did, quite easily. The scope displayed nominal reading
with no signal applied, and a very definite signal response with the
sweep signal generator source.
For the time
being, this system will continue to use the DC voltage as the source
for analysis. We are awaiting the installation of the Radio Sky
Publishing's Data Collector Lite, which uses a dc voltage fed to the
computer through an analog to digital converter circuit. This will
allow us to generate graphs of the voltage variations, and we can
begin to start defining the noise of the system. We also intend to
test the system on natural objects known to exist and accessible to
small telescopes. In this way, we are attempting to duplicate the
approach used by the
University of Indianapolis Radio Astronomy Department.
real work comes now. Radio Astronomy seems to be a matter of spending
a great deal of time getting the system to hear something other than
its own noise, and if you can get it right, then you just might hear
some radio sources in the cosmos. For SETI it is even more difficult
because we don't know if the signal we're looking for even exists,
and we're not sure how to recognize it if it does. And it may be in a
form our telescopes can't detect as yet.
27, 2000 Software and A/D Converter Tests
the present time, tests are being conducted on an analog to digital
converter and software which will be used in the data logging and
analysis phase of the project.
converter was made from a Maxim 187 a/d chip according to
specifications supplied by Jim Sky of Radio Sky Publishing. The
schematic for the a/d converter is here.
The software is
Data Collect Lite, also by Radio Sky Publishing. Info on the software
At this point, technical problems are being sorted out, and info will
be posted here as available.
27 Power Supply Problems
project receiver, the SDR1000, has a built in power supply. In tests
with the sweep generator and oscilloscope, an ac ripple was detected
in the output. This noise level is not acceptable for our project, so
the internal power supply is being bypassed. The receiver has a plug
for an external DC supply. An external supply is being installed, and
further tests will continue to see if the AC ripple disappears.
1, 2000 Argus Telescope EL29 Now Operational
telescope is now operational and capable of making readings. The AC
ripple problem was solved with the installation of an external power
supply with better filtering. Although the initial ripple is reduced,
we think we still detect a small ripple, and will add a little more
filtering to the output for safe measure.
Data Collect Lite software is still not working correctly with the
Maxim chip A/D converter, so we installed the Radio Shack PC
interface multimeter (#22-805) and accompanying ScopeView logging
software to the system. The telescope is now capable of taking
voltage measurements from the receiver/LNA and logging them onto the
computer. Since we are not yet looking for information in the form of
a modulated message, this sytem is capable of detection of a carrier,
or hopefully, an other-than-noise signal. We will also test the
multimeter A/D with Data Collect Lite, and continue to troubleshoot
the Maxim chip A/D converter.
next step is to test the system against some astronomical objects. We
will use Radio Sky Publishing's Planetarium Software to locate known
objects in the 1420.5 MHZ neighborhood and see if the scope can
detect them as they cross its beamwidth. If we can detect them, then
we will know the telescope is functioning properly.
16, 2001 - New Receiver to be installed
Argus EL29 telescope has not proven useful after a year of admitedly
intermittent testing. The scope responds to test signals emitted by
our signal generator but to date has not detected even a hint of
astronomical rf. Mike, N5LHM, has recently donated a new receiver
which he obtained in his routine searches for interesting high tech
equipment on the surplus market. The new receiver is a MicroTel
Series 1200 Wide Range Receiver, designed for testing microwave
antenna systems. It covers 950Mhz to 150 Ghz. In it's present
condition it appears functional but the analog tuning dial needs a
new cable installed, which is presently being done. Once the dial is
repaired and the receiver calibrated, the MicroTel 1200 will replace
the SDR1000 data receiver currently installed. The MicroTel is
capable of detecting CW, pulse, or square wave modulated signals. We
need to devise a way to connect the output to the computer and
hopefully to a DSP program for weak signal detection. We may continue
to use the Radio Shack Multimeter and Scope program for tests, but
for the actual recording of astronomical signals, the DSP approach
will almost certainly be necessary. The receiver may also require
25, 2003 - After many months away from the project, I am now getting
back to the radio telescope. The Microtel receiver discussed in the
previous paragraph but has not been able to be calibrated. Attempts
will be made to get it functional, but for now it is definitely a
laboratory project. In the meantime, I have decided to put in a new
SDR1000 receiver, since I have several of these to work with. This
will be done within the next month. The LNA also needs to be tested
because the system was flooded out during a thunderstorm. It should
be waterproof, but we'll see when we throw the switch.
Entry April 22, 2004
marks the last entry for the Argus Station EL29 Test Log. Repairs on
the system have not been made due to a lack of time and funds. In
addition, recent thunderstorms brought down the wooden structure
holding the dish, so the project is in complete disrepair.
am still intensely interested in the SETI project and will devote
myself to exploring some of the more theoretical and methodological
problems of the SETI Search. For now, I will leave the hardware
science to those already doing an excellent job on the experimental
side of things, namely the talented amateurs of the SetiLeague and
the professional radio astronomers of the SETI Institute. I will post
ideas on SETI procedures, methodolgy, and theoretical concerns on
this site and on the SETILeague site as they deem useful.