Friday, October 31, 2008
IK0VVE has a nice grabber aggregator site that includes a sun clock. Here it is:
Just see if the sun is shining here, then scroll down and take a look at either PA1SBD's site or ON5EX's. Sometimes I can also be seen on I2NDT's.
You should see my signal around 10140055 Hz. It looks kind of like a square wave. Read the Morse along the bottom (my FSK is upside down).
For extra credit, see if you can see Paolo's solar beacon. It too looks like a square wave, but with no Morse. He's running 2.5 milliwatts.
Please let me know if you succeed in seeing our sigs.
Thursday, October 30, 2008
Sunday, October 26, 2008
Friday, October 24, 2008
Check it out: http://ea3fxf.googlepages.com/flea
Thursday, October 23, 2008
I really enjoy your Solder Smoke show and news feeds. Great stuff that has got me back into ham radio again. Your note about optical comms got me fired up enough to add some notes that you might not be aware of.
There is a substantial worldwide community playing with optical communications and they have achieved some amazing records using simple off the shelf components – mostly big Luxeon LEDs which have some (debatable) advantages over Lasers. The most sophisticated component in typical systems is the Fresnel lens – which can be obtained at office supply stores or ebay as “page magnifiers” for a couple of bucks.
There seem to be about four major groups:
The Radio and Electronics Association of Southern Tasmania has an active bunch and they have achieved some great distance records with (QRP) LEDs. They have also been bouncing signals off of geographic features to establish communications paths. They are also doing some cloud/sky bounce things that are quite amazing. The REAST web site has lots of well documented test data that’s really interesting to read.
K3PGP has an exceptional web page full of test reports and construction details. His K3PGP preamp/receiver (and variants) are the basic building block for most systems. It uses a $1.00 pin diode, a MPF103 FET and a handful of common parts to get some almost fantastic performance.
Yves, F1AVY has a strong theoretical background and has been doing interesting stuff in France for quite a while and his web page has lots of interesting technical details.
Clint, KA7AOI has a very comprehensive web page. Clint holds the record for long distance communications (173 miles) and describes much of his equipment and testing. There is also a bunch of historical material that is very interesting.
There are probably a bunch of folks I have forgotten, but all of them are noted in the many and varied links found on these web sites.
I think that the most interesting thing about the activities is how the teams have adapted available technology to an interesting problem. Much of the work resembles current amateur weak signal activities. In fact, Spectran and WSJT are part of almost every activity. Much of the work is unique outside of the academic community and might even be called groundbreaking in some areas.
We have a small group here in the Raleigh North Carolina area, but so far we haven’t done anything of note other than build equipment and play in the local park. The fact that this sort of thing must be done outside at night draws all kinds of attention – some of which is not necessarily good. …a bunch of strange looking guys running around in the dark with strange flashing red lights…. I have a special cap that I wear for the occasions.
Keep up the good work.
Monday, October 20, 2008
Bob, Kd4EBM, sent me some really good info on laser safety. Bottom line: For the time being anyway, Billy will be limited to the <5mw href="http://www.earthsignals.com/Collins/0036/index.htm">http://www.earthsignals.com/Collins/0036/index.htm
Their rig is pictured above.
And here is one that is really mind blowing: A while back we discussed the laser reflectors left on the moon by the Apollo astronauts. Well, apparently there is an intrepid amateur out there who has been shooting his own lasers at the Sea of Tranquility, and seeing reflections come back. Visual EME. Check it out:
Wednesday, October 15, 2008
HB Pi Network Tuna (with mystery)
Hamfest report from Belgium
Space Hackers removed from
FB Italian ham magazines
I shift to FSK on 30 meters
QRSS QSY woes
Jerry NR5A Back in action
Scott KD5NJR on Space Hacker controversy
Steve WB6TNL on the different flavors of solder smoke!
Paul WA1MAC labled PC boards with SSDRA page numbers
Ramakrishnan VU3RDD getting back on the air
Jim K9JM had 60 POUNDS of 2N2222
Jim AL7R listening from Yuma
Wes W7ZOI on plumbing washer toroids
Paul WA5WCP on
Terry G4GHU also went to KSC on honeymoon
Tuesday, October 14, 2008
Sunday, October 5, 2008
I used a fairly standard approach to get the FSK, but with a twist: I added the usual LED and a cap to the oscillator circuit. Now, on key down, the positive voltage from the keyer causes the LED to conduct, putting the additional cap into the circuit. But here is the twist: for the capacitor, I just used some of that twisted-up two conductor insulated wire that often comes with cheap old (mono) ear phones. In the old days this would have been called a "gimmick" capacitor. I started out with 3 or four inches. Using Spectran to monitor the amount of shift, I just cut off bits of the wire until the shift was at the desired 5 Hertz. I just clipped away at the wire until the shift looked about right.
The rig is now key down all the time, and even though power out is still only about 20 miliwatts, I have the final in Class A, so I actually had to put a heat sink on it. But there is still no need for a muffin fan, or liquid cooling or anything like that!
Five hertz isn't much of a shift. I think I can hear it, but barely. Shows up nicely on the grabber screens.
It was a lot of fun to start out with a vision of what I wanted the signal to look like, then actually make it happen.
Friday, October 3, 2008
Last Sunday's "Flea at Trastevere" (I'm the only one who calls it that) was a huge success for me. Minutes after arriving, amidst all the junk, Billy and I found this homebrew Pi network antenna tuner. The guy who sold it to me told me he had built it himself. The workmanship is top-notch. The quality of the parts is superb. There's a built in SWR meter and a 10 db attenuator.
When I started drawing out the schematic I noticed something weird: As the front panel indicates, it is a Pi -network, but for some reason the builder has the input variable cap floating. The physical connection to the chassis is via insulators. The other variable cap has the standard mechanical and electrical connection to chassis ground. That input cap needs to be grounded too, correct? Why would this builder -- who obviously knows his way around a soldering iron -- go to the trouble of allowing that input cap to float?
(Note to lawyers: I did not post the videos on YouTube.)
Wednesday, October 1, 2008
Controversy or no controversy, I still liked the videos and admire the efforts of the two intrepid brothers from Torino.