A lecture on Radio Astronomy

The amateur can’t really afford a large enough dish to make Radio

Astronomy a good hobby

Joe Perry

August 2009

Wb6dco

What do we need to really receive noise from space atomic atoms that

vibrate

Moon Bounce EME

To quantify the path losses the distances and reflection efficiency of the Moon are required. The Moon is around 385 000 kilometers distant from the Earth. The surface of the Moon is also reflects only about 6% of the radio signal power that reaches it. Added to the path loss for the signal travelling to and from the Moon, the overall path loss is around 251 dB on 144 MHz and 270 dB on 1296 MHz.

The Dish, big and ugly

30” Dish is way too small

The Home big ugly dish (BUD) comes in sizes from 3 feet to about 16 feet.

The largest BUD’s are usable for Radio Astronomy or better

EME Moon Bounce

Parks 64 Meter Dish is really what you need to get those faint signals

Radio Wavelengths of Interest in Astronomy

Significant Radio Astronomy Frequencies

The following radio astronomy frequency bands were recognized at the 1979 World Administrative Radio Conference. Many are shared segments, not specifically protected from interference by other authorized users, but are nevertheless generally accepted spectral regions for radio astronomical observation. The lower two segments are generally used for solar and Jupiter observations; the 73, 150 and 406 MHz segments are quite popular for pulsar detection, and the 1400 MHz band is used for hydrogen line measurements. 13.36 - 13.41 MHz 25.55 - 25.67 MHz 73.00 - 74.60 MHz 150.05 - 153.00 MHz 406.10 - 410.00 MHz 1400.0 - 1427.0 MHz

Frequencies for Atomic AtomsSubstance Rest Frequency Protected Frequencies:

Deuterium (DI)327.3840 MHz327.0 - 327.7 MHz

Hydrogen (HI)1420.406 MHz1370.0 - 1427.0 MHz

Hydroxyl radical (OH)1612.231 MHz1606.8 - 1613.8 MHz3),4) Hydroxyl radical

Water vapour (H2O) 380.197 GHz 379.81 - 380.58 GHz

Carbon monoxide (C18O) 439.088 GHz438.64 - 439.53 GHz

Carbon monoxide (13CO) 440.765 GHz440.32 - 441.21 GHz

Hydrogen cyanide (HCN)797.433 GHz 796.64 - 789.23 GHz

Formylium (HCO+) 802.653 GHz 801.85 - 803.85 GHz

Carbon monoxide (CO) 806.652 GHz805.85 - 807.46 GHz

Carbon (CI) 809.350 GHz 808.54 - 810.16 GHz

Some Frequencies will be too noisy to record

Ham Band 1.2 to 1.3 Ghz (23 cm)

The all time best is the Hydrogen Line:Hydrogen (HI)1420.406 MHz1370.0 - 1427.0 MHz

Most BUD dishes can work easily in the 1 to 5 Ghz bands with the proper LNA or LNB receiver diode.

406-420 Mhz and 608-614 Mhz UHF TV old channel areas also can be used in Radio Astronomy.

General Setup for your Dish

The Receiver FM box tunes 1.420 to 1.665 Ghz

Pricey 1500$

But you still need more parts. You need the dish horn cover

and a receiver LNA

Feed Horn Cover for the LNA to help keep noise out 130$

A low noise amplifier diode LNA 130$

More Parts yet to come.

I don’t think you will be home brewing this low noise receiver stuff. 575$ for the converter

Here is a low noise amplifier 150$

Other test parts

• Calibrated Noise source to test your equipment.. Who’s noise is it! 95$

A narrow band pass filter will help also 130$

Books on Radio Astronomy• "AMATEUR RADIO ASTRONOMY"• SYSTEMS, PROCEDURES AND PROJECTS"• by Jeffrey M. Lichtman.• This NEW CD is the first all subject, all frequency range

compilation of amateur radio astronomyinformation. A timely collection of amateur radio astronomy projects from amateur radio astronomersand professionals. In addition, radio astronomy basics, antennas, construction techniques and signalprocessing techniques are covered.

• Over 200 virtual Pages.• This book is a MUST for your radio astronomy library. • PRICE: $ 17.00 + $ 5.00 Shipping / $ 20.00 Foreign (Air)

Now you need to record all this noise from space

• You need a good A/D recorder device for you computer.

• Then you need good software to run FFT’s to analyze the data.

Resolution in the SKY

• This will depend on the dish diameter.

• You would like the smallest width front lobe.

• You will need to correlate the pointing of the DISH to the Optical Sky map.

• Most just let the sky drift by and record the signal changes.

Dish sizes and Efficiency by N1BWT in 1997

Dishes suffer from many problems.

• The surface of the dish needs to be near perfect so that the signals from all over the dish do not null each other out.

• The dish suffers from spillover. This requires a good shadow Horn to reject off axis signals.

• You local EMI environment from power lines, Earth, Grounds, AM, FM, SSB, microwaves will all interfere.

Use UR BUD dish for EME off the moon

• We’ll when you get tired receiving noise all the time you can buy or make a 1296 Mhz ( 23cm) transmitter module.

EME

11 meter dish

By

OE5JFL

You have to have lots of power and

room for all the support

equipment. He uses 1 watt!

EME by K6PF

• Moon Bounce with 2m Yagi

• Antenna: KLM 13LBA or larger

• Az-El motor system to track the moon

• Yaesu FT-726R

• Time wave DSP-59+

• TE Systems brick preamp 180 watts

• Schedule with a ‘big gun’ receiver station

Love Thy Neighbor ( except in Palmdale )

EME using 2 metersUs 150 watts USB, bandpass off, AGC off, into a 2 m Yagi pointed at the moon.

Us the RigBlaster for the digital communication mode, CW , Rtty, PSK, WSJT, JT65B, MAP65, WSPR

Get K1JT software http://physics.princeton.edu/pulsar/K1JT/

You need a computer to run RigBlaster and Software

EME path loss is 240 db or more on the propagation

Best time for EME is the moon at Perigee (closest)

A low temperature Pre-amp will help also

A 12.5 dBd or 14.6 Dbi gain horizontally polarized (not circular) antenna yagi

LM400 or Belden 9913 coax. Do not use RG’s of any type

Antenna Tracking software, W5UN Skymoon and others

KB8RQ has a big Gun Array

Some Hams just got to have bigger is better

I don’t see any small Dishes? So, BUD’s probably don’t work that well

The Milky Way in RF

Where is Mr. SETI

The amateur level of SETI looking in RF Frequencies is out of the

question.

For SETI, Size Matters….

100 foot Arecibo Dish in Puerto Rico

The New SETI is looking at stars for Photon modulations

Almost any telescope of amateur size can be used for photon monitoring of the stars.

Presently there is a Space Satellite pointed at one small region of the galaxy in hopes of recording photon changes that are of human nature.

The current sky conditions around the world are making astronomy a fading sport.

• Is Amateur SETI Even Possible?by Dr. H. Paul Shuch, Executive Director

• Recent link calculations have revealed what should not particularly surprise experienced weak-signal radio amateurs: the best ham SETI station we can assemble appears unable to communicate with its counterpart at the distance of the nearest star. This finding has generated concern within the SETI community. "If your system wouldn't detect the strongest signal the ETI might radiate," SETI pioneer Dr. Bernard M. Oliver told me recently, "even if it came from the nearest star, then years of listening, or thousands doing it, won't improve the chance of success. To cross the Golden Gate, we need a bridge about 10,000 feet long. Ten thousand bridges . . . one foot long won't hack it." I must admit, Barney makes an excellent point. And yet I am not discouraged. Why? In part, because the Golden Gate Bridge analogy assumes a serial process, whereas SETI may indeed prove a parallel enterprise. In addition, the crux of his argument seems to rest on how we define "the strongest signal the ETI might radiate." And this is so entirely unknown as to make speculation futile.

• What happens to our range, for example, if a ham SETI station tries to receive not itself, but a MegaWatt signal from an Arecibo-type antenna? The additional antenna gain at one end of the path increases system range by perhaps two orders of magnitude, to tens of light years. And what if the ETI possesses a Cyclops? Now our potential contact range increases another order of magnitude, into the hundreds of light years. Is amateur SETI futile? Not if our galactic neighbors are more successful than we in getting their governments to fund large-scale antenna arrays. So ironically, it just might be the distant success of Oliver's own brainchild which gives hope to amateur SETI.

• Hams have always been innovators, and one cannot begin to anticipate the spin-off technologies which might result from the search. Just as the thousand monkeys at a thousand typewriters might some day write out the whole Encyclopedia Galactica, might not a thousand digital signal processing experimenters, pushing a thousand different algorithms, someday find the key to digging another 20 dB into the noise? It would seem that amateur SETI is a no lose scenario, even if we hear not a peep from the stars.

From: http://www.setileague.org/editor/possible.htm

• I think this puts to bed the idea of doing any type of deep space receiving by an amateur station. Most areas would be way to EMI noisy and may not allow extensive arrays of antenna. Feed line loses are too great for most any setup.

• So, think astronomy photon counting.

Review of Radio Telescopes

Arecibo Observatory Radio Telescope in Mountain Side in Puerto Rico, 1963, 1000 ft wide

Jodrell Bank Radio Telescope

Jodrell Bank England, UK, 1945, 250 Feet,

U S Naval Laboratory

Some where back east I think was this telescope of the 1950’s. 80 footer.

The SETI Radio’sFollowing a recent demonstration of a 10-dish element of the Allen Telescope Array, the U.S. Navy has signed off on a $1.5 million agreement to use the array along with another 10-dish installation to be developed in the near future. When complete, the ATA will consist of 350 20-foot (6.1-meter) dishes. Twenty dishes are currently online at the observatory with a 42-dish array total to be completed near the end of the year. Though the project is slightly behind schedule due to the recent heavy northern California winter and the usual challenges of engineering a radical new technology, one of the project’s leaders is particularly pleased by recent progress.

Green Bank of West Virginia

300 Foot, 1950’s, this one fell down in 1999.

New Green Bank TelescopeOrganizationNRAO

LocationGreen Bank, West Virginia, USA

Wavelengthradio telescope and microwave band

Built1991-2002First light August 22, 2000

Telescope style Parabolic off-axis reflector, Gregorian optics

Diameter100m Collecting

Radio Telescope at Harvard

60 footer.

Cornwall Goonhilly, UK Radio Telescope

Now, Amateur Built Radio Telescopes

5.2 meter, for 1420 MHz neutral Hydrogen listening.

New Mexico Institute NRAO

In a cooperative effort with New Mexico Institute of Mining and Technology, NRAO has built the N2I2: NRAO/NMT Instructional Interferometer. It is a 2-element adding interferometer located at the Etscorn Campus Observatory at New Mexico Tech. The dishes were purchased from CASSI, are 10' in diameter, 25 meters apart on an east/west baseline, and use the SRT pointing software. The 21cm receivers are from Radio Astronomy Supplies.

Chippewa Valley Astro Society

5 Meter,

Parabolic Horn PA0AVS, The Netherlands

Goldstone Apple Valley, CA.

How about a tour of this site?

Contact JPL?

CalTech Ownes Valley, Bishop, CA.

40 meter

Solar array