Multi antenna as one!!

Hi all,
I wondering if I could connect many antenna as one for better results on receiving. For example nasa connect lots of radio telescopes and with phenomenon of contribution the get better results.
Thanks for your time.

I must admit it's not often we get posters who think they can think they can do anything NASA can do. Let me be blunt. Are you nuts ? Let's forget about NASA for a moment. Since you are posting on the General Electronics topic , let's pretend you are simply asking the question:

Can a radio tranmitter or receiver ( you didn't say which) use more than one antenna ? (if not why not?)

Answer: No
Reason: Antenna is designed to match impedance of transmitter or receiver. Placing two or more antennas in parallel is like putting two or more resistors in parallel. Google " parallel resistance formula". If the impedance of the antenna is not matched, neither a transmitteror a receiver will work ( correctly).

Good luck with your DIY Mars rocket.

I wondering if I could connect many antenna as one for better results on receiving.

Basically no, you can not do it.

I am not saying it can't be done but you have to know what you are doing, like having a lot of expensive test equipment and have studied RF at degree level for three years. You can't just slap them together.

When you combine them it becomes one and the elements have to be in the right relationship with each other. This is often called a phased array. It is like a squashed balloon, any increase in gain in one direction and you get a reduction of gain in another. This means that high gain antenna are directional, the higher the gain the more directional they are.

For example nasa connect lots of radio telescopes and with phenomenon of contribution the get better results.

Better? They do this not to increase signal strength but to get better angular resolution. That is to determine the signals location more accurately. This is done post detection

No need to tell him off instantly. RF/aerials is not an easy subject for a beginner in (RF) electronics.
And yes, arrays used to increase gain at the cost (or benefit) of opening angle.
Plenty of gremlins there to get the waves in phase and with the right impedance to the receiver.
Not sure if you want that "tunnel-vision".

What frequency are we talking about.
What is the range now, and what range are you after.
Can the aerial be directional (arrays usually are).
What aerial/receiver are you using now.
How far between aerial, receiver, and/or other digital gear
Give us the full picture. There might be other solutions.
Leo..

No need to tell him off instantly

I wondering if I could connect many antenna as one for better results on receiving. For example nasa connect lots of radio telescopes and with phenomenon of contribution the get better results.

Ok, what's the chance he has a radio telescope and needs to post of the forum because he doesn't know anything about antennas ?

Answer: 0

That being the case, wouldn't you expect a question about antennas to start by identifying the radio, , receiver , frequency , and any other relevant details before presenting the question ?

ie:
"

I have a 433 Mhz receiver, etc etc etc"

or,

"I have a 5.8 GHz receiver , etc ,. etc., etc,"

or ,

"I have a spread specrum receiver, etc "

but ,

"Hey, NASA does this [etc] . Can I do that too ?"

Really ?

How about posting on the General Electronics (Not "Space Exploration") Topic by just saying:

"Hey, I have this [XYZ] antenna for my [XYZ] radio. Is there anything I can do to improve reception ?"

(and just leave NASA out of the question)

For example, IF the OP has said he wanted better reception for his 5.8 Ghz antenna, we could have referred him to something like this:

As a kid (in the seventies) I had great fun connecting four big UHF yagi aerials in an cubic array.
I had the best reception of distance TV stations in town.
Learned a lot about joining aerials the hard way, without any specialised gear.
Dream a little, experimant a lot. One day you might work for NASA.
Leo..

As a kid (in the seventies) I had great fun connecting four big UHF yagi aerials in an cubic array.
I had the best reception of distance TV stations in town.
Learned a lot about joining aerials the hard way, without any specialised gear.

If you still have it then you have the best HDTV antenna in town.

DimitrisTzam:
I wondering if I could connect many antenna as one for better results on receiving. For example nasa connect lots of radio telescopes and with phenomenon of contribution the get better results.

Certainly...
http://radiojove.gsfc.nasa.gov/telescope/ant_manual.pdf

Well, it is a good solution if you want to receive radio waves from Jupiter. You may have to make some alterations for whatever signals you hope to capture.

My aerial bible in the seventies was "Karl Rothammel's antennenbuch" (in German).
Double hard, because I was Dutch.
No internet and no technical books in the local library.
Leo..

My aerial bible in the seventies was "Karl Rothammel's antennenbuch" (in German).
Double hard, because I was Dutch.
No internet and no technical books in the local library.

Yeah, no internet, no smart phones, no smart phones, no ipads, no cds, no Hubbel Space Telescope.

Frankly I don't know how we survived...

I was lucky. I lived close enough to "The Op Amp Technical Book Store" (Hollywood) to go there in person. I don't remember what I bought but it might have been Walter Jung's "Op Amp Cookbook"

Computers and smartphones are timewasters.
You had shiploads of time in those days to experiment.
Leo..

raschemmel:
Ok, what's the chance he has a radio telescope and needs to post of the forum because he doesn't know anything about antennas ?

Answer: 0

Um, actually amateur radio telescopes are quite popular. They tend to be mostly antenna, with a receiver attached. The kids in our astronomy club just built one to monitor Io's orbit around Jupiter. It uses a 1/2 m diameter circle of copper wire placed about 30 cm above a backplane of chicken wire.

Point it in the general direction of Jupiter, scan around 20-21 MHz, listening for pops and squeels. They only occur when Io is not obscured by the planet.

There are also solar experiments, that need a different antenna.

Take a look at NASA's Radio Jove website.

I think the correct search terms here is "antenna diversity" and "phased array". Normally collecting
lots of antenna together in a phased array is a lot more expensive than using a single high-gain (ie
directional) antenna, but allows software control of the beam direction.

So this sounds like the xyproblem, and you are looking for a high gain antenna...

Nasa uses more than one receiver dish because the earth is not flat. (Unless you mean
radio telescopes, which are phased arrays)

It's possible to build an antenna array for example on 2.4ghz?

DimitrisTzam:
It's possible to build an antenna array for example on 2.4ghz?

Yes.
But before you get to the stage of using an array there are lots of designs of antenna with high gain to explore and fail to get working.

At a minimum you will need a SWR meter that works at these frequencies.

The radio amateurs handbook is probably a good place to start looking.

The place to start is Google:

"2.4 GHz antennas"

Just for the record , 2.4 GHz is not a Radio Telescope, so I doubt that the NASA reference is relevant.
If you have a radio telescope it implies you would have a (very expensive) Spectrum Analyzer , being as the whole point of a radio telescope is to capture all the fequencies. ( so the array type would probably be very different for 2.4 GHz.)
Check out L-Com.com's sectarized 2.4 GH array.

RF is not my area of expertise so I wouldn't know. Russelz would probably know.

DimitrisTzam:
It's possible to build an antenna array for example on 2.4ghz?

Only one question answered from post#3. The frequency.
Yes, I would be able to build an aerial for 2.4Ghz. Not sure if you can.
At this frequency things get reasonably small.
A dipole (e.g. for a phased array) is about 60mm long.
A vertical 1/4 wave is about 30mm.
Leo..

What ? We're on Reply#18 and ALL we know so far about the application is the frequency. What part of "we need more information " don't you understand ? Why bother posting on the forum if you are not going to tell us anything ?

I want to thanks all of you for your replies.
This post is much more educational purposes than practical. I want to learn more about antenna array but on the Web I can't find helpful information. Then maybe I would try to make one as a project. I want a receiver antenna array to receive video on 900MHz-5.8ghz.