I wonder if this is similar to what Paul Lutus did to communicate from the open seas back to his Oregon home during his sail around the world?
Here is an excerpt from his book:
My ham radio link is working better than expected. Before I started this sail, I spent some time installing and testing ham radios and computers in both the boat and my house in Oregon. I wanted to be able to write a message here, transmit it by radio, and print it on paper in Oregon. At the Oregon end, because a normal person (not a radio nerd) has to be able to use the system, there's a simple "message screen" on display. A person just sits down at the computer and types a message, then presses a key that saves it. The next time I make contact I collect the messages.
Used to be. Honestly don't even remember my callsigns.
I became a Technician when I was in high school because I lived in NYC (went down to Varick street to take the test) but didn't know anyone who could administer the Novice test.
Built a small QRP rig but never made contact with anyone and lost interest.
A few years later I went back to get either my Extra or Advanced...who remembers. I did that more to see if I could copy code at the required rate than for any other reason. Actually I think my last license might be in the safe, I should take a look someday.
I was never that interested in being a ham and talking to other people; SWL was much more fun. I had QSL cards from all over the world.
I used to be. I got my technician class license at 14, just before morse code became optional (which I think they never should have done). In fact, I passed the 20wpm code test for general, but never took the written. My license expired while I was in the middle of graduating college, buying a house and having a kid. I had other priorities on my mind at the time, obviously, and didn't even think of it until the grace period had ended. I want to get back into it, but there are no longer any VE's in the area and it's just a lot of hassle to travel a long distance to take the test. The last time I checked, though, my call sign was still available (KE4BZY), and if I did test again, I'd probably pay the vanity license fee to get it back, if possible.
Low-code Extra here. I've got a couple Altoids tin kits, but I've never put enough time into code to really work CW QRP. I've worked some far contacts with 2-5 watt PSK though.
Reading this thread is giving me the bug again :-)
I might just go into the basement and put together a simple 40 meter receiver tonight just to see if there's any activity there and maybe build a small transmitter later.
ISTR that the FCC went to non-expiring licenses. My last one is from the late 80's/early 90's. Anyone know what the likelihood is that I still have a valid license?
3600 miles, 100 milliwatts, 5Hz of spectrum near 10MHz, rooftop mounted dipole, $25 of parts to make radio (including obligatory Altoids tin) => 0.05 bits per second.
hey there i'm kd8mek, i wrote a blog piece about software radios and such the other day http://verily.posterous.com there are a billion of these qrp small radio blogs out there, all kind of people dreaming up all kinds of things
While it is interesting I can't really get excited because to me a QSO is a two way conversation. Far more interesting to be running a few watts and be having two way conversations with people instead of being merely captured on their computer screens.
Why do they transmit a square wave, instead of just short and long dashes of a single frequency? Only the top of the square wave is the signal, the bottom is the 'negative' of it.
They are not transmitting a square wave. The square wave is the drive waveform that is modulating the transmitter. If you look at the square wave shot, you will see longer "high" periods (dash) and shorter "high" periods (dots).
In classic "CW" (continuous wave, aka. Morse Code), it would be keying the transmitter on and off. When the transmitter is on, it is transmitting a pure sine wave at the Tx frequency (10.140015 MHz). When the transmitter is off, it is transmitting nothing (duh).
Looking at the schematic, the kit in question is transmitting continuously and modulating the carrier to be slightly higher or lower in frequency based on the square wave modulation drive.
For a direct conversion receiver[1], (heterodyne[2] works the same way, but uses intermediate frequencies to improve selectivity) the receiver has an internal oscillator that is tuned to approximately 1000 Hz difference from the transmitter. By mixing the two signals in the receiver, it demodulates the transmitted signal into a 1000 Hz tone when the transmitter is transmitting and nothing when it is not transmitting (CW) or higher and lower pitches with the kit from the article.
The CW on/off modulation is what you hear (simulated) in the WW2 movies with the beeping ("dit" and "daaah") sounds.
Because it would be very difficult to decide if your box was not transmitting or just unable to be heard at any given time. The square, spread over a large time allows you to say with confidence, "yes I have received and yes its the bottom/top of a dot/dash".
[+] [-] euroclydon|15 years ago|reply
Here is an excerpt from his book:
My ham radio link is working better than expected. Before I started this sail, I spent some time installing and testing ham radios and computers in both the boat and my house in Oregon. I wanted to be able to write a message here, transmit it by radio, and print it on paper in Oregon. At the Oregon end, because a normal person (not a radio nerd) has to be able to use the system, there's a simple "message screen" on display. A person just sits down at the computer and types a message, then presses a key that saves it. The next time I make contact I collect the messages.
http://www.arachnoid.com/sailbook/Chapter_2_--_Oregon_to_Haw...
[+] [-] joshfinnie|15 years ago|reply
That begs a good question. How many hackers here are also hams? I'm W1OFZ.
[+] [-] HeyLaughingBoy|15 years ago|reply
I became a Technician when I was in high school because I lived in NYC (went down to Varick street to take the test) but didn't know anyone who could administer the Novice test.
Built a small QRP rig but never made contact with anyone and lost interest.
A few years later I went back to get either my Extra or Advanced...who remembers. I did that more to see if I could copy code at the required rate than for any other reason. Actually I think my last license might be in the safe, I should take a look someday.
I was never that interested in being a ham and talking to other people; SWL was much more fun. I had QSL cards from all over the world.
[+] [-] kellishaver|15 years ago|reply
[+] [-] ja27|15 years ago|reply
[+] [-] coffee|15 years ago|reply
[+] [-] a-priori|15 years ago|reply
[+] [-] joe_bleau|15 years ago|reply
[+] [-] wglb|15 years ago|reply
30m rocks for mobile as well.
[+] [-] charrington|15 years ago|reply
[+] [-] grandalf|15 years ago|reply
[+] [-] geofffox|15 years ago|reply
[+] [-] klinquist|15 years ago|reply
[+] [-] HeyLaughingBoy|15 years ago|reply
I might just go into the basement and put together a simple 40 meter receiver tonight just to see if there's any activity there and maybe build a small transmitter later.
ISTR that the FCC went to non-expiring licenses. My last one is from the late 80's/early 90's. Anyone know what the likelihood is that I still have a valid license?
[+] [-] jws|15 years ago|reply
[Edit: to lose that extra zero. Thanks Joe.]
[+] [-] joe_bleau|15 years ago|reply
[+] [-] th0ma5|15 years ago|reply
[+] [-] rmason|15 years ago|reply
[+] [-] Luc|15 years ago|reply
[+] [-] gvb|15 years ago|reply
In classic "CW" (continuous wave, aka. Morse Code), it would be keying the transmitter on and off. When the transmitter is on, it is transmitting a pure sine wave at the Tx frequency (10.140015 MHz). When the transmitter is off, it is transmitting nothing (duh).
Looking at the schematic, the kit in question is transmitting continuously and modulating the carrier to be slightly higher or lower in frequency based on the square wave modulation drive.
For a direct conversion receiver[1], (heterodyne[2] works the same way, but uses intermediate frequencies to improve selectivity) the receiver has an internal oscillator that is tuned to approximately 1000 Hz difference from the transmitter. By mixing the two signals in the receiver, it demodulates the transmitted signal into a 1000 Hz tone when the transmitter is transmitting and nothing when it is not transmitting (CW) or higher and lower pitches with the kit from the article.
The CW on/off modulation is what you hear (simulated) in the WW2 movies with the beeping ("dit" and "daaah") sounds.
[1] http://en.wikipedia.org/wiki/Direct-conversion_receiver
[2] http://en.wikipedia.org/wiki/Heterodyne see also http://en.wikipedia.org/wiki/Superheterodyne_receiver
[+] [-] noonespecial|15 years ago|reply
[+] [-] joshu|15 years ago|reply
[+] [-] Kilimanjaro|15 years ago|reply
Makes me think about an alternet for when they switch the internet down.