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Ham Radio Repeater On The Moon?
kd5biv writes "QRZ.com has an interesting article on Martin Reeves' project to put a small amateur radio repeater on the surface of the Moon. The project includes a Surveyor-style lander with a UHF translator, a directional antenna aimed at Earth, remote controllable cameras, and some other interesting features.
If they can solve the basic problem of putting a package that size on the lunar surface, it will make moonbounce operations much easier and cheaper. Then again, a satellite about that size is still waiting for a ride on an Ariane-5 out of Kourou and it's only going to a sun-synchronous orbit .. we shall see how it works out .. "
The moon is a long way away, about 400,000 km. That's 10x the distance to geostationary orbit, meaning signals in each direction are 20 decibels (100 times) weaker than from geostationary orbit. The speed of light delay between earth and moon is 1 1/3 seconds each way.
It is far more costly in terms of fuel to land on the moon than to reach geostationary orbit. It's also far more technically demanding. The moon has no atmosphere to slow a parachute, so all that velocity has to be removed with retrorockets. Those rockets have to be controlled by landing radars. And a soft lunar landing is obviously a lot less forgiving than a geostationary orbit maneuver.
The surface of the moon is a far more hostile place for electronics than geostationary orbit. It's dark for two weeks at a time, when the temperature drops to hundreds of degrees below zero. Something has to keep your payload powered and warm during those lunar nights, and it's unlikely hams will ever get permission to fly nuclear power sources (the only practical way to do it). Lunar surface payloads that weren't nuclear powered (e.g., Surveyor and the Apollo 11 ALSEP) had very short life spans.
The trend is now in the other direction, from geostationary orbit to low earth orbit. Even though many more satellites are needed in LEO to provide global coverage than from geostationary orbit, the lower path losses and reduced propagation delays tip the scales in favor of LEO.
Phil Karn, KA9Q, AMSAT technical volunteer and former member of the board of directors
It amazes me that so many allegedly "educated" people have fallen so quickly and so hard for a fraudulent fabrication of such laughable proportions. The very idea that a gigantic ball of rock happens to orbit our planet, showing itself in neat, four-week cycles -- with the same side facing us all the time -- is ludicrous. Furthermore, it is an insult to common sense and a damnable affront to intellectual honesty and integrity. That people actually believe it is evidence that the liberals have wrested the last vestiges of control of our public school system from decent, God-fearing Americans (as if any further evidence was needed! Daddy's Roommate? God Almighty!)
.. the next time you're out in the backyard exercising your Second Amendment rights, the liberals will see it! These satellites are sensitive enough to tell the difference between a Colt .45 and a .38 Special! And when they detect you with a firearm, their computers cross-reference the address to figure out your name, and then an enormous database housed at Berkeley is updated with information about you.
Documentaries such as Enemy of the State have accurately portrayed the elaborate, byzantine network of surveillance satellites that the liberals have sent into space to spy on law-abiding Americans. Equipped with technology developed by Handgun Control, Inc., these satellites have the ability to detect firearms from hundreds of kilometers up. That's right, neighbors
Of course, this all works fine during the day, but what about at night? Even the liberals can't control the rotation of the Earth to prevent nightfall from setting in (only Joshua was able to ask for that particular favor!) That's where the "moon" comes in. Powered by nuclear reactors, the "moon" is nothing more than an enormous balloon, emitting trillions of candlepower of gun-revealing light. Piloted by key members of the liberal community, the "moon" is strategically moved across the country, pointing out those who dare to make use of their God-given rights at night!
Yes, I know this probably sounds paranoid and preposterous, but consider this. Despite what the revisionist historians tell you, there is no mention of the "moon" anywhere in literature or historical documents -- anywhere -- before 1950. That is when it was initially launched. When President Josef Kennedy, at the State of the Union address, proclaimed "We choose to go to the moon", he may as well have said "We choose to go to the weather balloon." The subsequent faking of a "moon" landing on national TV was the first step in a long history of the erosion of our constitutional rights by leftists in this country. No longer can we hide from our government when the sun goes down.
Ham radio had it's origins at the dawn of the discovery of radio. I.E. that you could send useful information by a wireless means. Experimentation was encouraged to find useful ways of sending information using this new technology. And, everyone was allowed to participate at that time free of licensing restrictions.
As the commercial implications of radio were realized, the government created the FCC to regulate both the commercial use of radio and experimentation in the field. This was to address issues and complaints of interference.
Amatuer radio operators (hams) also had to be regulated by frequency restrictions. Also, certain minimum standards were established to reduce interference with commercial interests. In order to become a licensed ham operator, you have to pass a license examination that requires some knowledge of radio, electronics and FCC regulations.
Today, Ham radio still has the same basic goal: To provide a hobby that enhances the technical art of radio, communications and electrical engineering. Many new modes of digital communication have been created recently. Packet radio--from the late-80's--simulates the function of a wide area network; whereas your own station can be a "router", a "client", or a "server" of sorts. Also, PSK-31 is a very recent mode that allows nearly error free weak signal communication in the extremely narrow bandwidth of 30Hz.
Hams also participate in emergency situautions where no other means of communication are possible. During hurricanes, earth quakes and tornadoes this invaluable service has made them known.
OK, a quick primer on ham radio for the uninitiated.
:)
The "ham" in ham radio is a strange abbreviation of "amateur." The amateur radio service is chartered by the FCC in America, and other government bodies in other nations.
The government has allocated parts of the radio spectrum for hams to use. It's not restricted to high or low frequencies -- there are ham bands up and down the dial, from a few MHz to the GHz range, and everything in between.
In return for getting radio spectrum, hams have a moral responsibility to further the radio arts and provide emergency communications in time of need. That's the spirit of the deal. In practice, a ham doesn't have to do anything he doesn't want to. Just obey the rules -- no swearing, no commercial use, no broadcast entertainment, ID yourself often -- and you are fine.
Most hams do often use their radios ("rigs") for the public good though -- calling in car accidents, stranded motorists, that kind of thing. I do that all the time. Used my HT (Handheld Transciever) once to call in aid for an injured mountain biker I found. Where I was there would have been no cell coverage, either.
You do have to take a Federal test to get your ham ticket, and there are harder tests required o get more privileges. But even the entry-level license lets a geek have a LOT of fun. If you have half a brain you can cram for the test in a weekend. If you have any electronics experience, you might be able to cram for it in a day.
When you pass your test you get a call sign. This is how you ID yourself on the air. Your call sign is analogous to a commercial broadcaster's call sign like KROQ or KNBC. The first call you get is long, like mine: KF6IYW. As you advance in the ham tests, your call gets shorter (provided there are vacant calls to move you up to). A ham with a call like NO6B is a stud.
Ham radio is cool because you have a lot of options and there are neat toys to buy. You can talk across town on a pocket-sized radio, or blacken the sky with a monstrous antenna over your home with which you talk to the other side of the planet. You can build a transmitter and try to get Morse code to the other side of the country with a few watts of power. It's about problem solving and electronics as much as communication for a lot of people.
Me, I like the pocket-sized stuff. Does it replace a cell phone? No, but it makes a damn good supplement -- and it doubles as a police scanner, FM radio, and TV audio receiver. You can't stay in touch with a mess of people at once, with no per-minute fees with a cell phone.
Last common question people have is "how far can that thing talk?" A small handheld radio -- cellphone sized -- can let you talk to someone 100 miles away, or more, if there are convenient repeaters. I commonly use an HT to talk to friends all over the LA area, sometimes farther. A powerful rig that operates on lower frequencies can talk to anywhere on earth, if conditions are good. Some nuts even put this stuff in their cars. That's too much for me.
There, all you ever wanted to know about ham radio...
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Yu Suzuki
Yu Suzuki
Deamcast. It's thinking.
quick, what was the first communications satellite? Nope, not Echo. That's right, it was the moon! For many decades people have been doing moonbounces, or EME (Earth-Moon-Earth).
It's a pretty cool way to talk to someone on the other side of the world (albeit probably one of the least efficient). You can actually notice the delay from the return trip time for the radio signal to travel to the moon and back.
In fact, about a year ago, the ARRL just awarded two hams for doing the first single-yagi to single-yagi moonbounce. A typical EME involves an array of yagi antennas aimed at the moon. Lots and lots of wattage, so a small reflecting amount can hit a receiver sufficiently. In reflecting radio waves, the amount of received power varies inversely as R^4, so the moon being pretty far away makes this vastly difficult.
But that's what makes it all the more fun! (although i must confess, i've never done it, it's one of my goals when I get around to it)...
But seriously, a repeater on the moon is pretty cool, it'll still be a good challenge to key it successfully. Maybe it'll offer real-time pictures of earth for packet download too...
make world, not war