Easy build radio telescope.

[mikemasey (Mike)]

Hi all,
I have been given one of those roof mounted TV dishes and I want to see if I can use it to listen to the sun or Jupiter, or any other easy to find target.
I have an AM coms receiver just collecting dust with a range of 0hz to 30Mhz.
Will this be ok and will I need wave guide from the antenna to the receiver of just some coax.
The websites that I have found all talk about low noise amps, are these needed and doesn't the radio already have them?
Simple questions I know and probably some obvious answers!
Thanks for any help.

mike.

[cometcatcher (Kevin)]

Hi Mike, I'm a bit rusty on this subject, but you can use one of those dishes with a working LNBF that they use for Foxtel to receive Sun noise at 12 GHz. If you have a set top box still, all you need is a satellite finder meter like this one http://www.ebay.com.au/itm/Satellite...item2a27eeb04e. If you don't have the STB, you need to power the meter with 12V somehow. Someone sells one that is powered but it's a bit pricey http://www.ebay.com.au/itm/Satellite...item4acc00370d

The meter is very basic, has a scale of 1 to 10 and a buzzer when you find either Ku band satellites or Sun noise at 12 GHz. The Sun is usually much stronger than any satellite signal. Remember also that those dishes are offset so rather than pointing them directly at the source, you point them at the offset angle which can be up to 30 degrees or so.

You will also find some satellite signals but without a decoder box you won't know which ones unless you do some geometry using Lyngsat, or get an STB. There are cheapish decoders available for free to air signals from other countries, which is a whole other hobby of it's own.

The roof dishes are small and don't work for C band or L band signals, so unless I'm mistaken the Sun and other Ku band sats are about it.

[cometcatcher (Kevin)]

Just been googling HF and Jupiter. It seems these signals can be picked up between 5 and 40 MHz. Never done it myself, but how hard can it be? .

I've been able to receive meteor pings on VHF. The most simple way, if you have a sensitive car radio, is to drive to a hill and pick a frequency on the FM band that has no stations. Make sure you tune to a potential station though using odd frequency channels. Early mornings seem best for this. I often hear Sydney ABC FM pinging in the mornings.

Another thing, though not strictly radio astronomy, is to listen for natural Earth sounds on VLF. You have to be away from powerlines to do it though. One can hear noises from our magnetosphere. Google "Steve McGreevy" for some excellent recordings.