Billy alerted me to this TED Talk presentation on an MIT Media Labs project that used new "femto photography" techniques that allow us to watch -- in VERY slow motion -- a light beam pass through a bottle. Amazing. Makes me think about Einstein's old thought experiment about running alongside a light wave (but of course here they are slowing down time...)
I think I said before that Paul, NA5N, has one of those "dream jobs" for a radio amateur. Confirmation of this came in a message he posted to QRP-L today: We're running a special experiment today using the VLA antennas to observe at 74 MHz (a protected radio astronomy band) and at 327 MHz. We've hung dipoles just below the antenna subreflectors, acting as a virtual ground, and of course the 88ft dia. dishes to illuminate the dipoles. Picks up a lot more power from the sky than I would have thought (about 30dB gain over the same dipoles in free space). Anyway, about 0830 MST, suddenly the system temperature climbed about 200 deg. K. Our switched power calibration injected into the LNAs showed no shift, meaning the jump in power came from the sky, not from the electronics. The power plot looked just like a solar flare. Checked the NOAA site, and sure enough, we had an M4 solar flare from region 1618 ... about smack in the center of the sun. About 1530UTC=0830MST=1030EST, Wed. Nov. 21. NOAA has since measured the shock wave from the CME at 1918 km/sec. This is a fairly strong shock wave, and coming from the center of the sun means planet earth will be pretty close to the bulls eye. The first time in my life I witnessed a major solar flare in real time watching the "sky power" plots. Pretty neat. First time the astronomers involved in this experiment have witnessed a solar flare as well real time. Region 1618 has produced numerous C- and M-class flares past couple of days with high potentials of future activity. This will ionize our E/F layer for elevated MUF and weak signal reflection. Check the bands if you're not at work. This 1918 km/sec. shock wave headed for us will almost assuredly trigger a major geomagnetic storm in a couple of days. If it hits Friday evening, it will trigger likely aurora over northern U.S. It may hit Saturday. I'll check the NOAA predictions later today and post as to the expected shock wave arrival. 72, Paul NA5N Socorro, NM Currently inside of VLA antenna #5, west arm. http://www.vla.nrao.edu/
A short e-mail from across the pond. Thanks for sharing the VK3YE link, so impressed I was that I have built one.
It receives great and puts out a nice looking dsb signal, looking forward to some good qso's, ready to improve on it as we speak and looking to make a top band and 18m version also, love the site and keep up the good work...Ian
Peter Parker's amazing 8 transistor DSB rig (featured in an equally amazing YouTube video -- see earlier blog post) has sparked a worldwide resurgence of QRP minimalism. There is now a lot more activity on the "Minimalist QRP Transceivers" Yahoo group (be there or be square). Steve "Snort Rosin" Smith WB6TNL is minimalist mentoring to the max -- with his help it looks like more VK3YE transceivers will soon be on the air. Steve was kind enough to take the info from Peter's video and turn it into a .pdf schematic (see above). It is in the file section at the Minimalist QRP Transceivers group. I was, of course, pleased to see the inclusion of a robust 7 element low pass filter. Michigan Mighty Mites are also tickling the ether. I may pull out my single MPF-102 Yingling 80 meter rig. You can join the Minimalist group here: http://groups.yahoo.com/group/Minimalist_QRP_Transceivers/
We have kind of half a holiday today -- I have the day off, but the kids went to school. I made use of the additional shack time to test the feasibility Farhan-izing my old, not-so-beloved Heathkit SG-6 signal generator. I did a quick Manhattan build of the oscillator section from Farhan's sig generator (link in yesterday's post). Using an idea from an old 73 Magazine article on a similar project (thanks Clint!), I smashed the tube (appropriate, don't you think?) and connected (using the glass stump!) Farhan's oscillator directly to the pins that lead to the switchable coils and the variable cap of the SG-6. I just wanted to see if it would oscillate, and see if there was a big change in SG-6 dial calibration. Wow, it worked great! It oscillates very nicely on all but the upper frequency band setting (20-50 MHz). I feel confident that I'll get it to oscillate at least up to 30 MHz. Next I'll build Farhan's buffer and amplifier stages. The SG-6 had a switchable attenuator -- I want to include that feature in the solid state version. I'll have to give some thought to the audio modulation feature (nice for aligning AM receivers).
I've recently become acutely aware of the shortcomings of my signal generator. It is a Heathkit SG-6. It is really old. It has a selenium rectifier in it. It has one of those old mic connectors on it for the output. The output is very low. But I like the cabinet and there is a nice switchable coil/variable capacitor LC circuit in there (see above). In 2008 in Hyderabad, India Farhan went to McDonalds with his kids and went home with some straws. Soon the straws are chopped up and turned into coil forms for a signal source: http://www.phonestack.com/farhan/siggen.html
So here is my idea: de-tube the SG-6. Turn the selenium over to the HAZMAT authorities. Save the coils and the cap and most of what George Dobbs would call "the socketry." Use an MPF-102 for the oscillator, then make use of the buffer and feedback amp from Farhan's soda straw circuit. What do you guys think?
Another brilliant rig from DSB guru Peter Parker, VK3YE. I really liked this one.
I loved his drawing of the circuit diagram -- right there on the beach! Lots to be learned from this video. Thanks Peter!
In SolderSmoke 147 I mentioned that I had found some old pictures of AA1TJ's underground hamshack and workshop. People wrote in asking me to post them. Here they are. I still can't find the shot of the door surrounded by snow.
People have been asking about the DC to AC inverter that I have been using during the now frequent power outages (5 in the last two years, two of them since July 2012). With it I can easily keep the lights on in the house and even run the TV. Not bad for $69. Here it is:
In response to popular demand, "SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.
Here's the site:
For the print version:
For shipping from a printer in the U.S. (probably better for N. American buyers) Click here: SolderSmoke USA Version
For shipping from a printer in the UK, Spain, or the USA (probably better for UK and other European buyers)
Click here: SolderSmoke EU Version
The two versions are identical, except for a minor difference in the paper used. That's why the prices are a bit different.
Bill's OTHER Book (Warning: Not About Radio)
Click on the image to learn more
W4HBK's QRSS Grabber: The Amazing Pensacola Snapper (Live!)