Transmitter guru needed

[NoobyMcNoobface]

Hi all,

I want to build a simple system that converts written text entered into a website, and transmits it into space. I truly have no idea where to start my research.

I guess the questions are:

1: What frequency
2: I was going to go for a small parabolic dish, under 30inch
3: Does what equipment is needed to connect it to the internet, to then receive the data.
4: How is the data converted from text input into a website, and transmitted?

I just need a starting point to look at. Any direction would help as while I'm techy, this is out of my comfort zone.

This is for a local school, so their kids can learn a little more about space, but actually enjoy getting involved in it as well. Makes learning more interactive.

Needs to be done on a tight budget as well.

Help is greatly appreciated.

[justron]

The radio side of your question is too open & makes it sound like in, licensing terms. That what you are proposing would be against the terms of your license. As broadcasting is not within the terms of the amateur radio license. You would need to have two way communication in mind to operate & that would mean a satellite, or moon bounce, if space & a transmitter was involved.

Nasa had some interesting information about radio & space when I was still licensed, as I helped to set up a school radio telescope & used a Nasa school specific project to do it.

Also what about an ARISS contact? We did that as part of the schools radio astronomy project. It took some time & a fair amount of work to set up & really needs a beam rotator that works on two axis to follow the ISS path. To make the contact work. Plus a radio that can be shifted to follow the doppler shift created. But it should be within the bounds of any amateur.

Another project we did with the school was a high altitude (near space) balloon with a tracker onboard.

[NoobyMcNoobface]

Hi, Thanks for the reply.

I guess what I'm going for is this: https://spacespeak.com/

A small 15 inch dish that transmits a message into space.

While we could simply use their free solution or even their API, I want to be able to physically show the radio dish to the kids. A more immersive experience.

RE a license, I didn't even know one would be needed. I'm in the UK, is it the same over here?

The radio side of your question is too open & makes it sound like in, licensing terms. That what you are proposing would be against the terms of your license. As broadcasting is not within the terms of the amateur radio license. You would need to have two way communication in mind to operate & that would mean a satellite, or moon bounce, if space & a transmitter was involved.

Nasa had some interesting information about radio & space when I was still licensed, as I helped to set up a school radio telescope & used a Nasa school specific project to do it.

Also what about an ARISS contact? We did that as part of the schools radio astronomy project. It took some time & a fair amount of work to set up & really needs a beam rotator that works on two axis to follow the ISS path. To make the contact work. Plus a radio that can be shifted to follow the doppler shift created. But it should be within the bounds of any amateur.

Another project we did with the school was a high altitude (near space) balloon with a tracker onboard.

[justron]

There are VHF/UHF license free options. But they are milliwatts so unsuitable for such a project & amateur radio options needs a license & that does not allow you to broadcast. So there would be no transmissions into space with those options. But you could research the options & potentially find an option that will work beyond those.

The best & simplest option would probably be a near space balloon. These allow you to use camera, which will show the earths curvature & for you to track it. But if you do not understand how radio works, then you will probably find such a project, especially with young enquiring minds, very hard work.

With any project that shows radio to the public, the hardest part is having the depth of knowledge needed to answer questions. Not only is it a breadth of knowledge that is needed, but also a ability to make that subject understandable & thus interesting. I used to train people for the RAE (Radio Amateur Exam.) And I have been involved in radio with youth groups such as the Scouts & the easy part is always the syllabus & the hard part is always the questions. I have never walked away from any form of training, without learning something new as a direct result of a question.

For example, try explaining harmonics, phase or resonance in radio terms to someone who understands music, but not radio. When you only understand radio, but not music. Do you know what an octave is in radio terms? I was once asked what an octave was by a young scout who had seen the term octave used to describe the bandwidth of a scanning antenna. A discone for example should cover 2 octaves. So if it works from 25 mhz it should stop working at 100 mhz.

[ChickenMadras]

I hate to break this to you.......

But almost any radio signal will make its way up into space. That includes the kids chatter on their own mobile phones (which have relatively powerful 2 W transmitters), their toy walki-talkies and home Wi-Fi routers. There is no magic. My typing right now is making its way into space from my laptops built in WiFi

If you want to build a website sending data into space, just have the server forward data over Wi-Fi (a plug in wireless card will do). If you want to drive the point home to kids, replace the Wi-Fi antenna on the card with a Wi-Fi dish antenna or a "cantenna" pointing up

As an aside, the majority of radio systems that you can access (without an amateur radio licence) are "type approved" meaning it is normally illegal to modify antennas. This includes the kids walki-talkies and their phones. Wi-Fi is one exception to this, and given you want to run this as a website, sounds like the way to go.

[justron]

I hate to break this to you.......

But almost any radio signal will make its way up into space. That includes the kids chatter on their own mobile phones (which have relatively powerful 2 W transmitters), their toy walki-talkies and home Wi-Fi routers. There is no magic. My typing right now is making its way into space from my laptops built in WiFi

Space is defined as the area 62 miles (100 km) & more above earth. During lifts signals may travel long distances, by bouncing off, or within the atmosphere. Or off things such as satellites, aircraft, meteor tails or even the northern lights. But 2 watts of mobile phone into a poor antenna, or milliwatts of wifi router with a good antenna, are going to struggle to reach space.

The average power used by a communications satellite is between 1 kw for a low earth orbit, up to a maximum of around 20 kw. A friend worked on a amateur radio project for a small low earth orbit satellite & that used 20 watts.

[Transwarp]

I hate to break this to you.......

But almost any radio signal will make its way up into space. That includes the kids chatter on their own mobile phones (which have relatively powerful 2 W transmitters), their toy walki-talkies and home Wi-Fi routers. There is no magic. My typing right now is making its way into space from my laptops built in WiFi

Space is defined as the area 62 miles (100 km) & more above earth. During lifts signals may travel long distances, by bouncing off, or within the atmosphere. Or off things such as satellites, aircraft, meteor tails or even the northern lights. But 2 watts of mobile phone into a poor antenna, or milliwatts of wifi router with a good antenna, are going to struggle to reach space.

The average power used by a communications satellite is between 1 kw for a low earth orbit, up to a maximum of around 20 kw. A friend worked on a amateur radio project for a small low earth orbit satellite & that used 20 watts.

Voyager 1 space probe - 7 billion miles away using a 23 watt transmitter - just saying.

[ChickenMadras]

During lifts signals may travel long distances, by bouncing off, or within the atmosphere. Or off things such as satellites, aircraft, meteor tails or even the northern lights.

"Lifts"are atmospheric phenomena and more likely to hinder, not help a signal getting into space

But 2 watts of mobile phone into a poor antenna, or milliwatts of wifi router with a good antenna, are going to struggle to reach space.

It'll get > 100 km alright!
Weak, but it will be there. Plug some numbers into Friis to see the proof: https://en.wikipedia.org/wiki/Friis_tra ... n_equation

The average power used by a communications satellite is between 1 kw for a low earth orbit, up to a maximum of around 20 kw. A friend worked on a amateur radio project for a small low earth orbit satellite & that used 20 watts.

Christ mate! We aren't talking about the Tx needed to drive multiple high bandwidth data channels to a bird in GEO Milliwatts can carry a single basic signal a very long way. (Terrestrially, look at the crazy distances WSPR achieves).

For some space examples; plenty of people (including me) have worked lossy analogue voice FM amateur birds in LEO, ~400 kM up running just 1 Watt earth-to-space from a handheld and 'arrow' antenna.
Going the other way, GNSS birds are in MEO, 20,000 km up (a damn sight more than 100 km high !) and run just 25 Watts space-to-earth. Their signal on Earth is below the noise floor, but perfectly usable, even with poor antennas and consumer grade GPS/Galileo chipsets found in cheap mobile phones. (Move up to professional grade kit, and as Transwarp says, it is possible to recover a basic signal sent using just 23 Watts from the Voyager space probe)

Besides, OP is just looking to do a proof of concept. It isn't like anybody is looking to receive and is struggling to decode OP's signal

[justron]

Christ mate! We aren't talking about the Tx needed to drive multiple high bandwidth data channels to a bird in GEO Milliwatts can carry a single basic signal a very long way. (Terrestrially, look at the crazy distances WSPR achieves).

For some space examples; plenty of people (including me) have worked lossy analogue voice FM amateur birds in LEO, ~400 kM up running just 1 Watt earth-to-space from a handheld and 'arrow' antenna.
Going the other way, GNSS birds are in MEO, 20,000 km up (a damn sight more than 100 km high !) and run just 25 Watts space-to-earth. Their signal on Earth is below the noise floor, but perfectly usable, even with poor antennas and consumer grade GPS/Galileo chipsets found in cheap mobile phones. (Move up to professional grade kit, and as Transwarp says, it is possible to recover a basic signal sent using just 23 Watts from the Voyager space probe)

Besides, OP is just looking to do a proof of concept. It isn't like anybody is looking to receive and is struggling to decode OP's signal

My bird set up back in the 90's was a homemade 3 ele handheld beam, made from a length of tile batten & a couple of coat hangers, with a 5 watt handheld. But I have worked on lower power, but with a better antenna.

And whilst I accept that as a whole, any attempt at sending a message into space for reception by little green men is an exercise in futility. If the desired result is to inspire young people, then low power & unmodified off the shelf kit from Curry's is not the the way to go. Young people may lack knowledge on the topic, but they are still less green than the average Martian & the average young person is also VERY competent with google & more than able to ask the right (wrong) questions, so will probably realise any equipment's probable potential & lose any interest in the subject within 3 minutes. Especially if the person conducting the Martian broadcast is ill prepared & under equipped.

Very slightly modified satellite TV receivers used to make great SSTV receivers & could receive the video feeds from Police helicopters. And watching SSTV at a Scout event, I think from the ISS, made for some very impressed young people. So I do accept that it's not the value or the impressiveness of the kit Being used. But young people are far from stupid & are used to being expected to ask questions so they can understand something. And normally want to see results.

Schools today educate pupils about fake news, propaganda & misinformation. And a poorly conducted show of sending a message into space is likely to uninspire young people when it comes to space & science. Not inspire them.

I still think the easiest way to impress young people is to put a balloon up into low space. It's simple & reasonable cheap to do & they can be involved in the whole process from assembly, to launch, to tracking. And who knows, maybe a USAF jet will shoot it out of the sky, making it even more fun.

[ChickenMadras]

If the desired result is to inspire young people, then low power & unmodified off the shelf kit from Curry's is not the the way to go.

I take your point, though heartily disagree.

Inspiring kids works best showing them the tech behind day to day technologies they are familiar with, and letting them go from there..........

[justron]

I take your point, though heartily disagree.

Inspiring kids works best showing them the tech behind day to day technologies they are familiar with, and letting them go from there..........

Exactly, but you need to show them how it works. You need give them the tools to prove the point. Something which draws them in & allows them to see for themselves how it works. For example, a Scout talking to another Scout in another country, or by seeing an image from the ISS etc.

I used to take a few length's of wire, a torch type bulb holder & a 70cm hand held radio among my kit for things like JOTA. Then mid way through communication badge training. I would say something about the radio & explain there are two methods of defining the operating band. Frequency & wavelength. I would say the radio is on 433mhz or a 70cm wavelength. Thus a half wave is 35cm. I would ask them to find the two 35cm lengths of wire & connect those to the bulb holder, thus forming a 70cm full wave antenna, with a torch bulb at it's center. I would then show how the bulb lights up when the radio is keyed close to the antenna & the polarity is the same.


The invisible radio wave is proven to exist, as is wavelength & polarity. By the end of communicator badge training they may not understand everything about radio theory, but they know RF exists, they have seen it & used it.