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Another Amateur Radio Satellite 140
k4hg writes "Remember the US Naval Academy satellite with the measuring tape antennas?
Well, not only is it still alive after nearly four years in orbit (be sure to read the 2001 Slashdot articles to see who was right and wrong about it working at all!), but the latest satellite to come out of the same lab, called PCSat2, was installed Wednesday on the International Space Station. It is bolted to the space station on the P6 truss, but is otherwise independent, only benefiting from the high mass to drag ratio of the ISS to prolong orbital life. The satellite is alive and transmitting on amateur radio frequencies, I could hear it on a marginal elevation in the Florida Keys. When it come in range of a ground station with better coverage, the data will be viewable here in real time. This new system is in addition to the amateur radio station already operational on the ISS.
And yes, they used tape measure antennas again, you could see them deploy on Nasa TV!"
Heh... (Score:2, Funny)
Re:Heh... (Score:1)
Re:Heh... (Score:2)
Ham nerds (Score:5, Funny)
Re:Ham nerds (Score:2, Funny)
Re:Ham nerds (Score:4, Funny)
Re:Ham nerds (Score:2)
Re:Ham nerds (Score:2)
I tried to explain, briefly, why I was happy it was all working, but it sounded so trivial in 25 words or less and the reaction was...
Re:Ham nerds (Score:2)
Re:Ham nerds (Score:1)
I'll certainly look into it though. I use the Gimp already, just haven't delved into the script language.
Re:Ham nerds (Score:1)
I've got a big library of routines I put together over the past 4 years or so, which means I'm never starting from scratch. Anyway, when I'm not writing SF I actually enjoy writing freeware [spacejock.com] - it's a hobby, so I'm allowed to waste time on it for relaxation...
Re:Ham nerds (Score:1)
Re:Ham nerds (Score:1)
Re:Ham nerds (Score:3, Insightful)
Geeks like us appreciate not having to do the same thing multiple times, particularly if it's mindless work. You avoided mindless work by creating something which you can reuse later to continue avoiding mindless work. Sounds fine to me!
Price? (Score:5, Interesting)
Re:Price? (Score:1)
Re:hitching a ride is free you dorkwad (Score:3, Insightful)
I know replying to an AC is useless, but the assertion that extra mass means extra fuel isn't always true.
Many of the early small Amateur Satellites were launched for free as the ballast of larger commercial sats. Commercial launchers must add ballast to their payloads if the main payload's CG is not over its center. As long as the Amateur sat is space-rated and the right shape, size, and weight as the needed ballast, why not launch it instead of inert ballast that will just
marginal elevation? (Score:5, Funny)
Marginal elevation: Elevation due to a stick of margarine. The low cholesterol alternative to butteral elevation.
Re:marginal elevation? (Score:3, Informative)
More likely elevation as in "horizon at the bottom, zenith at the top." The higher the sat is above the horizon, the longer the pass, the shorter the radio path and the less atmospheric attenuation (for high UHF and above).
yeah (Score:2)
they have an interesting way of getting rid of trash here. they compress it and pile it up and then throw dirt over the top of it. it creates these MASSIVE pretty green hills as the natural tendency of any field or pile of dirt is to sprout grass.
my coworker here refers to the big one in south of miami in cutler ridge as 'mount trashmore'
Finally, a practical use for shuttle+iss (Score:2)
Yeah... (Score:2)
But, frankly, it seems the history of science in LEO is pretty poor. Aside from using LEO as a convenient spot to look down upon the Earth or up at the stars, that is...
Can any Slashdotters make a convincing case that science on the ISS is a vaguely good use of funds? In the sense of "the scientific payoff is likely wor
Re:Yeah... (Score:3, Informative)
Re:Yeah... (Score:3, Interesting)
Re:Yeah... (Score:1)
Orbital microchip factory.
Short pause to remember that when we started into space, one of the possible commercial exploitations that was mentioned was an orbital vacuum-tube factory.
Anyone priced a 6146 lately?
Re:Yeah... (Score:1)
Re:Yeah... (Score:2)
Re:Yeah... (Score:2)
"Gravity-less" is not correct. Even "microgravity" is a misnomer. "Micro-acceleration" would be a better term.
Stupid Question (Score:2)
02:11:26:12 : W3ADO-1]BEACON,SGATE,qAo,N1GAU-15:T#014,066,058,05 8,087,213,11111111,0001,1
Enlighten me, please...
Re:Stupid Question (Score:4, Informative)
When the checkout is complete and the satellite is opened for general amateur use, it will also relay position between two points on the earth (which is the main function of the first PCSat).
Re:Stupid Question (Score:2)
The original PCSat is an APRS satellite
Re:Stupid Question (Score:1)
Q: How can we listen to ISS/Shuttle comms? (Score:2)
Are there other interesting frequencies, or does the ISS/STS have to be "exactly overhead" in order to pick up on their transmissions? I presume that if Houston is able to pick them up, I should be
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1, Funny)
Re:Q: How can we listen to ISS/Shuttle comms? (Score:5, Informative)
On the upside it's got a higher power transmitter than other Amateur radio sattelites so it's a lot easier to hear. I regularly listen to it with just an HT and stock rubber duck antenna. 145.800 is the frequency of interest but what you hear depends on what they're doing with it.
Most often it's in packet mode so all you'll hear are bursts of data. They aren't very melodic but they do stand out above the background noise so you can tell you're hearing it. It's 1200 baud packet and with something like a $45 TNC-X hooked to your audio you could decode it fairly easily. The packet transmissions are a combination of APRS for position reporting on the earth and the BBS for sharing messages.
From time to time it gets put into cross band repeat mode where it listens on 437.800 and then retransmits whatever it hears on 145.800 I made a contact through it in that mode just a few weeks ago using nothing more than a homebuilt "J-pole" I usually use for communications on earth based repeaters. (They're real easy antennas to build, just takes one 1/2" copper tee 1 1/2" elbow and 10' of 1/2" copper pipe, lots of sites on the net with plans for them.) For my uplink I thought I was using a 440mhz Jpole I had build but not yet installed but later found out I was using my directional Yagi I built for listening to weaker satelites - amazingly I had that very directional antenna pointing nowhere near the ISS but was still able to get a signal through it very easily.
The third mode the ISS radio may be in is just a normal radio with an astronaut on the other end. I've yet to be lucky enough to hear it in that mode
However the radio is also off from time to time since it's not a primary mission of the ISS. It's always off when they're on spacewalks to keep down RF exposure.
The website www.issfanclub.com is a great place to check and see what the current status is. They have an area where people submit what they've heard recently so you can see what mode it's in. Though for some reason the site isn't responding today.
Because of the ISS's small footprint just knowing it's over NA isn't usually good enough. You'll need a way to check it's actual current position. On Windows I use a package called Orbitron which is postcardware and works great. amsat.org has links to a bunch of other sat tracking programs as well as a tool for finding passes through their site. Also because the ISS tends to move around more than most sats you need to make sure that your keplerian elements are up to date. Those are what the tracking programs use to determine it's exact position. Most sats are fairly fixed in their orbits but the ISS is adjusted from time to time espically when docking with a shuttle or other supply ship.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:3, Funny)
HT and stock rubber duck antenna
in packet mode
1200 baud packet
$45 TNC-X
APRS for position reporting
BBS for sharing messages
homebuilt "J-pole"
directional Yagi
RF exposure
make sure that your keplerian elements are up to date
Dude, I have no idea what any of that means.
The bold one's my favorite, though.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:5, Informative)
Just for reference when I say spacecraft I'm including unmaned satelites juts to prevent confusion before it starts....
-very small footprint
The footprint is the area of the earth visible to the orbiting spacecraft. The higher the spacecraft the more of the surface of the earth that will be line of sight to it at any given time. That dosn't necessarially mean the spacecraft can only see the area in it's footprint, but it does mean only those in the footprint can see (and talk to or recieve transmissions from) the spacecraft. The ISS is the lowest orbit of any spacecraft carrying amateur radio so it's got the smallest footprint. That means the window that you can hear it durring is shorter than any others - but it also means the signal is louder and easier to hear.
-HT and stock rubber duck antenna
HT = HandiTalkie. A small low power handheld radio. "Rubber Duck" is a cheap flexible antenna with little or no gain, basically the bare minimum to recieve a radio signal.
-in packet mode
-1200 baud packet
-$45 TNC-X
Packet is a form of digital communication. 1200 baud is the speed it runs at. A TNC is to radio basically what a modem is to a phone line, it converts audio to digital information and vice versa. The TNC-X is a pic (small microcontroller populary with hobbyists) based TNC that you can assemble yourself for very low cost. It has USB capabilities but relies on the computer it's attached to do to much of the "thinking" for it.
-APRS for position reporting
APRS is a a position reporting system. Kind of like the Garmin Rhino only a LOT more powerfull. It uses 1200 baud packet to encode information and transmit over the air where it is picked up by other amateurs.
-BBS for sharing messages
Seriously, what the heck are you doing reading slashdot (a BBS!) if you don't know what a BBS is. This is the point where the troll starts to show...
-homebuilt "J-pole"
As explained in my first post, it's an antenna you can build yourself. Once again the trollishness is getting pretty bad.
-directional Yagi
A Yagi is a certian type of antenna, google is your friend. They're very directional meaning that they transmit a very directed signal and likewise recieve from a limited area. Omni antennas you don't aim, directional you do.
-RF exposure
RF = Radio Frequency. Come on, RF exposure has been discussed on
-make sure that your keplerian elements are up to date
Keplerian elements are descriptions of a spacecrafts orbit. They're used to calculate the position of the spacecraft. Most tracking software have built in utilities to download them on a regular basis to make sure you know where a spacecraft will be.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
I know what a BBS is, but I don't quite understand how a satellite would use a BBS for messages. Also, I don't really read into the stories that much, so I didn't really know what RF was.
Thanks for taking the time to explain things. It makes more sense and I'm actually interested in it now.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
Sometimes people forget that radio is usefull for more than just music and voice. You can also send data by encoding it someway.
Think back to the days of dial-up BBSes, only one user at a time so you do a store and forward type of deal. On radio it's the same. Only one person can use a frequency at a time so you can either have a single conversation or use a BBS to store messages and let multiple people send
Re:Q: How can we listen to ISS/Shuttle comms? (Score:2)
It is a technology developed over 20 years ago, at the time the typical radio amateur would have only a terminal or a very simple computer, and computers existed in very many variants so software development on home computers was a nightmare.
To make packet work, someone developed a small embedded system with modem and firmware running the protocol, and connected it to a serial port of a computer that would only be a terminal.
However, with the current state of the art you don'
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
Really?! The Linux kernel has a built-in soft modem? I thought it just understood the higher-level packet protocols like AX.25. All I can find is: Device Drivers > Networking Support > Amateur Radio support > Packet Radio protocols > Amateur Radio AX.25 Level 2 protocol . If it's not in the kernel, is there a software TNC/modem package for Linux?
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
The tricky part is getting the computer to actually turn on the mic (push the PTT button) on the radio before transmitting. This requires an interface between the computer's parallel or serial port, and the radio
Re:Q: How can we listen to ISS/Shuttle comms? (Score:2)
You need the AX.25 protocol as well.
When you have enabled the AX.25 protocol and the soundmodem, you can use various user-mode programs to display what you are receiving. In SuSE Linux, which I use, there are packages like ax25-tools and ax25-utils.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
It is? I grepped the kernel for soundmodem and only found one reference to it, in a file called hdlcdrv.c. The page for soundmodem suggests that it is a usermode program that integrates with the kernel AX25 stack. I'm confused...
Re:Q: How can we listen to ISS/Shuttle comms? (Score:2)
In 2.4 it was part of the standard source but of course it usually was not enabled in
Maybe they considered the audience too small...
But anyway, it is available for Linux.
In my own system I use a HDLC interface card that is driven by drivers/net/hamradio/scc.c and has external hardware modems, this was a solution popular between the TNC and the softwaremodem era. This driver is still in the 2.6 kernel, together with some others.
It scales a bit better because it
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
It's really a shame, because (/me just can't force himself to write "in this post 9/11 era")... well, because it is good to have a long-range, backup data network that can be driven by battery-powered portable devices and can route emergency position information across the nation (with VHF-HF digipeaters). It would be cool if packet had evolved into a parallel Internet, and hams could basically use the Internet (albeit at 9600 baud) anywhere near a digipeater.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:1)
JPole Source (Score:1)
Re:Q: How can we listen to ISS/Shuttle comms? (Score:4, Informative)
Once you get some idea of when the sat will be overhead, you can start tuning around the transmit frequency. You have to keep the squelch open, and it helps to have a continuous tuning receiver because it is easier to adjust for doppler shift [qsl.net]. I wouldn't think the NASA communications between the ISS and ground control is open for the general public (looks like the ground control systems are not easily heard by a scanner [klabs.org] anyway), but the HAM stuff is all just narrowband FM. Good luck.
Re:Q: How can we listen to ISS/Shuttle comms? (Score:2)
Here is the CHEAP answer:
YES
You should have no trouble hearing the ISS, The Shuttle or any satellites using Ham Radio.
How to do it
You need to know when to listen. Yes you can get keps and computer software and learn how to use it, however it's real easy for average Joe to just go to http://www.heavens-above.com/ [heavens-above.com] and look it up. They tell you when and in what direction. ---It's great because you can see the ISS and other orbiting things too.
These satellites use several frequecies accross several band
Re:Q: How can we listen to ISS/Shuttle comms? (Score:2)
I presume that since the shuttle is currently docked to the ISS, its passes overhead are concurrent with ISS. There is no pass listed over my area until 8 August, so I imagine that I should keep my scanner tuned to the local po-po trunk until then...
Thanks a
YAARS (Score:1)
Did someone miss a chance to add "Yet" to derive a "Yet Another Names Starting With Yet"
/.ed... (Score:1)
In case of slashdot... (Score:5, Funny)
Now I see. (Score:2)
02:03:26:44 : PCSAT2]APRLTM,SGATE,qAO,KC9XG:T# IGNORE ALogger A side test packet
???
Profit!
Re:In case of slashdot... (Score:2)
It's actually fairly similar to this.
Re:In case of slashdot... (Score:1)
Re:In case of slashdot... (Score:2)
For examples of what gets done with it see
aprsworld [aprsworld.net], an open source site and database of APRS location-based service data generated by and for hams.
You can see google map overlays, ACME.com topo map overlays, tracking data, historical events, and also other services such as weather reports from individual weather stations.
Re:In case of slashdot... (Score:1)
Re:In case of slashdot... (Score:2)
As for low tech, far from it. I just finished building a PIC-based microprocessor controled module for my radio; it's actually quite similar to the kind of experimentation that people do n
Re:In case of slashdot... (Score:1)
Well, it's an international limited resource
So are sidewalks, but I don't need a license to walk down the street. So is the internet, and where do you think the internet would be today if you had to take a test and get a license to use it?
It's actually fairly similar to certification exams for IT professionals, for MS developers, or DBAs.
Except that you aren't required by law to take those exams in order to be an IT professional, MS developer, or DBA.
As for low tech, far from it. I just finished
Re:In case of slashdot... (Score:1)
So, go check out QRZ.com for the Technician (no morse code required) test
Alright, how high do I have to score? I got a 60% on the practice test, and that apparently wasn't high enough.
Then, assuming I read up on a few things, and can get a passing score, all I have to do is go to one of the places listed at http://www.arrl.org/arrlvec/examsearch.phtml?State =FL [arrl.org] , give them $14, and take the test? I guess that isn't too bad. Not sure how useful it'll be, though, especially since I live in an apartment
Re:In case of slashdot... (Score:2)
You can try hamtestonline.com as well, which has a study guide (free for the first 15% of the questions or so) and see if that fills in the gaps.
You don't need roof access to get to a satellite, you can do it from outside.
Send me mail please if you want to go further and I can hook you up with people to help.
(That goes for anyone.)
Antenna Picture (Score:4, Informative)
Re:Antenna Picture (Score:2)
Why? Because it is so simple. It can hardly fail.
Try it yourself with a 50cm (20 inch) piece, you will see it always rightens itself no matter how you hit it.
Under wightless conditions, any length reasonable for an antenna will behave the same, and still can be packed in a small space.
Compare that to an automatically extending car antenna. It is complicated, uses a lot of current, and can get stuck anytime.
Re:Antenna Picture (Score:2)
ATV (Score:3, Informative)
The good thing about a HAM transmisison (Score:2, Funny)
Re:The good thing about a HAM transmisison (Score:2)
Obviously because I am posting I have no mod points, but someone should hook it up
Here's an actual link (with images) (Score:3, Informative)
You can kind of see it mounted on the ISS.
What Type of Tape Measure (Score:2)
Because I'm in Europe, and need to know if I'll be able to listen in.
Jolyon
Re:What Type of Tape Measure (Score:2)
But It's Only A Couple Hundred Miles (Score:2)
Re:But It's Only A Couple Hundred Miles (Score:2)
It's not all about distance in Amateur Radio. In this instance you're talking with a box in space and that's exciting for many. I have a commercial $2K HF radio, but I get more kicks out of operating a $300 kit radio and little flea-powered circuits I design and build.
Re:But It's Only A Couple Hundred Miles (Score:2, Interesting)
Re:But It's Only A Couple Hundred Miles (Score:2)
(I've looked at some of those so-called "invisible" and other antennas marketed at apartment and condo dwellers, but I'm pretty skeptical. There's never any discussion of their abilities on the receive side of an exchange. Just how good at reception can a few feet of wire hidden on a balcony really be?)
Re:But It's Only A Couple Hundred Miles (Score:1)
HF, yup, you're kinda stuck with larger antennas. I have seen some pretty nifty setups where the antenna is dangled out of a high window, and it's rolled up after the transmission is done. If conditions are right, you can talk pretty far with a pretty minimal setup.
If you want to do VHF (or UHF) the antennas are a little smaller AND there's a pretty good chance that there's a repeater near by.
That's one of the neat things of radio - getting by with what you have. Any twit
Re:But It's Only A Couple Hundred Miles (Score:2)
When my father was a kid, in the American midwest, he was into SWL'ing. He used a Hallicrafters that was about as big as two microwaves; a big, heavy, solid metal box. His antenna was a longwire that ran down the street on the top of telephone poles for three blocks -- about 1000 feet. His interest was MW, and he had QSL's from 10-watt MW stations in the middle-of-nowhere Australia and others in that ballpark. Kinda difficult to repeat now, I su
Re:But It's Only A Couple Hundred Miles (Score:1)
Re:But It's Only A Couple Hundred Miles (Score:2, Interesting)
Only A Couple Hundred Miles...Straight Up (Score:2)
Imagine trying to get a signal from Key West to a point equally far away, but without any repeaters or being able to use longer frequencies for the HF advantage -- that's more
tape antennas (Score:3, Interesting)
Microstrip antennas (Score:2)
Here [mit.edu] is a good wideband VHF/UHF microstrip antenna example.
Re:The Death of Mary Jo (Score:1)
Re:The Death of Mary Jo (Score:1)
Re:"When it come in range of a ground station"? (Score:1)
User links to a site that does malicious things to the browser(Firefox)