Beginners Radio Astronamy

[boardy77]

Hi all just been asked by a friend... "what is the easiest and cost effectiveness was to get into Radio Astronomy" ?

[SilverAstro]

44 minutes ago, boardy77 said:

 to get into Radio Astronomy" ?

what does he mean by R A ?

detecting the sun ( at what wavelength ), SIDs,  detecting the Milky Way, or Cassiopeia A,  reflections off the aurora, off meteors (of amateur radio ops), VLF - ELF     etc&etc  ??

Most of that can be done with off the shelf gear, but the antennas need a bit of diy and having some real-estate well away from civilisation  helps.

 

[boardy77]

i will ask him thanks

[boardy77]

Hi SilverAstro

Spoke to my friend and its meteor side

 

[Way]

There is a big, helpful topic here: 

It's quite easy to start with meteors detecting. Your friend should buy a SDR dongle (I recommend RTL-SDR it's cheap and sufficient), build an Yagi antenna for 143MHz and start listen  

 

 

[Dave Simons]

Guys I'll be watching this thread closely.  I'm a science teacher in rural South Australia and have decided to 'have a go' at using Radio Astronomy to make wave theory a bit more exciting.  I thought we'd start with something a bit LF/HF to get some earth readings, then progress to FM to read meteorites.  Now I'm in the process of tracking down good day time falls as a 'hook' to get the kids interested.

Regrettably I'm a techno / electro component moron, so I'll be learning flat out myself.  I'll buzz you with questions and updates quite regularly.

 

Cheers Dave.

[Tomatobro]

On 3/8/2017 at 09:42, Way said:

There is a big, helpful topic here: 

It's quite easy to start with meteors detecting. Your friend should buy a SDR dongle (I recommend RTL-SDR it's cheap and sufficient), build an Yagi antenna for 143MHz and start listen  

 

 

Hi thought you might like to see my setup. Its based on a Gibertini 1 mtr dish on a alt az mount. will post more info if anyone is interested in learning more about it

[Dave Simons]

Please do post. Profoundly interested.

[Way]

Tell

On 1.07.2017 at 11:54, Tomatobro said:

Hi thought you might like to see my setup. Its based on a Gibertini 1 mtr dish on a alt az mount. will post more info if anyone is interested in learning more about it

Of course we are interested  What are You receiving with this setup? Make a short clip showing how this is working- I see that You use a linear actuator for elevation.  

[Tomatobro]

OK here goes.... where do I start!

Because navigation is key to finding objects its vital to know where its pointing in the sky. The beam width of the dish is 1.6 degrees. The large base protractor is calibrated due north using a good compass (with magnetic north offset). The base is levelled using a spirit level. The altitude setting requires that the dish offset is taken into account and this is done by a calibrated plate mounted on the tower left hand side (just below the cable) in the lower picture. I place a digital inclinometer on this plate and set it to zero. This is then transferred to a plate on the antenna so it reads the altitude of the dish beam. I use software called Radio Eyes to give me the Alt/AZ of objects of interest. The actuator allows course and fine control of elevation.

The receiver is based on an analogue Satellite finder (£5.00 Ebay). The finder has a moving coil meter showing signal strength and has adjustable gain. The meter is removed from the case so that the voltage can be picked up from the meter. This voltage (about 0.4 of a volt FSD) is then amplified and fed into an A/D convertor of a PIC processor. Software converts this signal into a numerical value which is then transmitted via RS232 to a laptop running Selmaware Makerplot. This is a graphing package that accepts RS232 data.

You have to think of this setup as a single pixel "camera". You position the beam a few degrees ahead of the object and let the earths rotation transit the object through the beam. The changes in signal strength indicate the passage of the object. The beam width and earths rotation should be reflected in the output trace providing the object passes through the centre of the beam. Also repeating the objects pass should give similar results.

The Sun is an easy object and gives a very characteristic trace. Other objects, particularly pulsars only give an indication on the trace as the signal processing prohibits capturing rapidly changing inputs.

The biggest problem is one of receiver stability due to temperature changes. To this end thermistors are glued to the processor on the Sat finder and software attempts to normalise the output. A fan blows air across the electronics. The Sat Finder has an LED for meter illumination as standard and the dropping resistor for the LED is the biggest source of board heating so this as been removed and relocated off the board.

I will post a couple of traces later....

[Tomatobro]

The lower traces are the receiver temperature variations. The upper traces are temperature compensated.

[Tomatobro]

Note the upper picture is of a Pulsar the lower one is the sun

[robin_astro]

On 7/12/2017 at 10:35, Tomatobro said:

Note the upper picture is of a Pulsar 

Really??   Are you sure?  Which one.   The difference in signal between the sun and a pulsar is huge.  What does your lunar signal look like?

Here are some of my plots with a similar setup

http://www.threehillsobservatory.co.uk/astro/radio_astronomy/radio_astronomy_1.htm

 

Cheers

Robin 

 

[JeremyS]

On 04/03/2017 at 18:51, boardy77 said:

"what is the easiest and cost effectiveness was to get into Radio Astronomy" ?

Edited March 4 by boardy77

The BAA Back to Basics Workshop at King's Lynn on Saturday Oct 7 has a talk on beginning radio astronomy. See https://britastro.org/node/8587

It's by Jeff Lashley, who runs the BAA Radio Astronomy group: https://britastro.org/section_front/24

Jeremy

[John101]

Hey guys thanks for sharing

lQQk what just followed me home

with gambles to follow Tomatobro,s setui example

John