[Big] old satellite dishes for radio astronomy?

[Rusted]

Hi,

I have collected several parabolic dishes for remote [British] satellite TV reception over the years.
Over time the Astra 2 footprint regularly shrank below worthwhile reception here on the Continent.
Unperturbed, I regularly increased the size of my [secondhand] "dishes" to achieve modest reception at specific times of the day.

I still have 1m offset. Plus 1.8m [GRP] and 2.3m prime focus dishes.
The latter a professional quality aluminium dish with reinforcing cage and massive altaz mount.
All are no longer required. So could become oversized [Olympic sized] bird baths.

Do any of these dishes have any value to amateur radio astronomers?
I'm thinking "free on collection" [bring your own labour!] Note that I live in Denmark now.
I know from personal experience that these dishes can safely travel in/on a car trailer if well strapped down.
It just needs several strong bods to lift them into the trailer.

 

[Peter Drew]

I believe they can be used for radio astronomy, we had on in the process of converting it for the purpose but were donated a professional bona fide  3.8M complete radio telescope in need of refurbishment.  This has recently been mostly completed and we expect "first sound" to be available shortly.  Images of the system are on our website.      🙂

[Victor Boesen]

These could have great value for amateur radio astronomy and weather satellite reception! I wish I could store these but I have to ask anyways, whereabouts in Denmark are you located(or how far from Frederiksberg)?

[Rusted]

Hi Victor,

I'm on Fyn.  About 120 miles or 200km from you.

[JamesF]

There was a school in Taunton (now closed, I believe) that had a very large dish in the grounds and I had thought about doing this sort of thing myself.  The dish appears to be gone now though.  Perhaps just as well, as I don't believe the WAF (wife acceptance factor) would be very high at all.  Not unless it got decent television reception as well, anyway.

James

[Victor Boesen]

7 minutes ago, Rusted said:

Hi Victor,

I'm on Fyn.  About 120 miles or 200km from you.

Quite a drive I must admit... In any case, I don't think my mom would agree to pick up such a large dish It looks really good though, and there are a lot of useful scenarios where it comes in handy! Out of curiosity, have you tried playing around with software defined radios with these dishes? With the large ones you could probably receive the geostationary satellit GOES-13 or even X-band low earth orbit one's with a resolution of 250m/px! The list goes on:)

[Rusted]

2 hours ago, Victor Boesen said:

Quite a drive I must admit... In any case, I don't think my mom would agree to pick up such a large dish It looks really good though, and there are a lot of useful scenarios where it comes in handy! Out of curiosity, have you tried playing around with software defined radios with these dishes? With the large ones you could probably receive the geostationary satellite GOES-13 or even X-band low earth orbit one's with a resolution of 250m/px! The list goes on:)

Thanks, but quite frankly I have little interest in radio astronomy. The dishes were a series of attempts to appease my wife as BBC TV slowly receded into the noise. Then came fibre Internet and streaming. British satellite TV became obsolete technology overnight as far as we are concerned.

My wife has now suggested that I make her a garden tool shed with a domed roof.  I wanted a giant bird bath in the lawn. With ducks, geese and swans... 

[Rusted]

3 hours ago, JamesF said:

There was a school in Taunton (now closed, I believe) that had a very large dish in the grounds and I had thought about doing this sort of thing myself.  The dish appears to be gone now though.  Perhaps just as well, as I don't believe the WAF (wife acceptance factor) would be very high at all.  Not unless it got decent television reception as well, anyway.

James

We once drove past a rural, Danish garden packed with truly vast netting dishes.
The problem with solid dishes is the wind. They have tremendous lift if the wind is just right.
These are strictly concrete pier jobs. Being pale in colour they can be seen for miles across the fields.
A huge, white caravan goes completely unnoticed but anything round is an eyesore.
The same problem exists with white domes. The wandering eye latches onto them.

[Ed astro]

5 hours ago, Victor Boesen said:

Quite a drive I must admit... In any case, I don't think my mom would agree to pick up such a large dish It looks really good though, and there are a lot of useful scenarios where it comes in handy! Out of curiosity, have you tried playing around with software defined radios with these dishes? With the large ones you could probably receive the geostationary satellit GOES-13 or even X-band low earth orbit one's with a resolution of 250m/px! The list goes on:)

Yep these dishes would indeed be great for amateur radio or radio astronomy! Such solid dishes would not only be useful for "regular" 21 cm work but also work well at cm wavelengths (unlike mesh dishes). These could for example be used for detecting and monitoring methanol masers at 6.7GHz or 12GHz, or maybe even water masers at 22GHz if the quality of the dish is good. Indeed one can make a very long list of interesting stuff to do with a large dish. 

 

[Victor Boesen]

3 minutes ago, Ed astro said:

Yep these dishes would indeed be great for amateur radio or radio astronomy! Such solid dishes would not only be useful for "regular" 21 cm work but also work well at cm wavelengths (unlike mesh dishes). These could for example be used for detecting and monitoring methanol masers at 6.7GHz or 12GHz, or maybe even water masers at 22GHz if the quality of the dish is good. Indeed one can make a very long list of interesting stuff to do with a large dish. 

 

Not to mention pulsars as well! Definitely something I want to try at some point.

[SteveBz]

On 05/05/2021 at 18:27, Victor Boesen said:

Not to mention pulsars as well! Definitely something I want to try at some point.

Wow Victor, I didnt know. Do you think my 1.3 m dish is big enough to get the Crab Nebula, for instance.  It would probably gave to be a bit more steerable than it is.

Kind regards,

Steve.

[Victor Boesen]

26 minutes ago, SteveBz said:

Wow Victor, I didnt know. Do you think my 1.3 m dish is big enough to get the Crab Nebula, for instance.  It would probably gave to be a bit more steerable than it is.

Kind regards,

Steve.

Not quite sure how powerful the Crab nebula pulsar is, however, I do think you may be able to pick up some of the easy ones. I still haven't done pulsars myself yet, so I can't quite share my experiences, yet....

Victor

[Carbon Brush]

Recently I assisted an amatuer radio club to get some 'surplus to requirements' dishes an SGL member was kindly offering.

The intended use is for 'moonbounce' more formally known as earth-moon-earth communications.

The idea is to transmit a narrow beam high power signal, which gets reflected by the moon.
A simlarly equipped station, potentially hundreds or more miles away receives the signal.
This allows 'over the horizon' radio links at microwave frequencies where this is normally impossible.

You should see the size of the mount they are part way through building! Makes any of the scope mounts I have seen look like phone selfie sticks!
Strangely (to me anyway) they thought that tracking the moon using a motor driven mount was more difficult than building something big enough for a 2M+ solid dish.

[Rusted]

The major problem is wind loading.

Here are some of mine.
Collected in a desperate attempt to watch UK TV from Denmark.
They kept shrinking the footprint.