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Friday, March 6, 2009
Lots of Great Old Radio Books FREE!
http://tinyurl.com/cvc4qd
That link led me to Project Gutenberg where I plugged in the word "radio" and was instantly given a list of really nice old books, including the Radio Amateur's Handbook by A. Frederick Collins of Congers N.Y. (my home town). Here it is:
http://www.archive.org/details/theradioamateurs06935gut
Thanks Greg!
Wednesday, March 4, 2009
Italians at the Forefront of QRSS
Born in 1944, in Lucca, Tuscany, Italy. Got a Doctorate Degree in Physics at the University of Pisa. Since then worked for IBM, with various responsibilities. Radioamateur since 1966, active on most bands, from 160m to 23cm. Lately experimenting with 137 kHz, recently allowed in Italy with 1W ERP.
Studying and applying DSP and digital techniques in general. Author of Winrad, SDRadio, Spectran, Jason, Argo and Hamview, widely diffused programs for SDR (Software Defined Radio), spectral analysis and real time filtering of audio signals, received with a radio and routed to a PC equipped with a soundcard.
Despite the age, open to learn new techniques and theories. *Not* a tube (or valve, depending on the side of pond you are reading this) nostalgic.
73 Alberto, I2PHD
Home page http://www.weaksignals.com
ET Phone Home! With Minimalist QRSS!
G'day Bill,
Thanks again for noticing my QRSS signal making it through to Europe.
Your talk about mechanical solutions for QRSS modulators immediately
made me recall "E.T. the Extra-Terrestrial". The "Phone Home" device he
built had a modulator based on a sawblade IIRC - its been years since I
watched that 1982 classic.
One easy hack might be to use an AC synchronous motor out of a gobo
rotator (for example, I got one out of a fibre optic christmas tree that
expired from overheating). Its reduction drive results in a fairly slow
rotation which might drive a modulator plate. You could do the pickup
optically using a LED/photodiode (or transistor, or even an LDR I guess)
transmission pair. Electrical contacts would work too, but doing it
optically probably means it would have a longer life.
A tape loop system might also be practical and would allow long
modulations to be encoded at reasonable tape rates. A syncro-drive gobo
has to be turned fairly slowly and pushes the "density" of the data
fairly high so the mechanical or optical sensor gets harder to just
throw together. I am sure a clockwork driven disk could be made to
work, it just might have to be fairly large.
Mechanical readout might be a microswitch and holes in the plate, or
even using PCB material with the pattern on it (etched or masked), and a
brush contact. To minimise wear a brass small roller held against disk
with spring tension would work. Oxidation on aging might become a
problem - yeah the more I think about it I am liking optical better.
You can also do it electrically using a diode matrix which can be read
out with some counters. Of course that defeats the original purpose
which was to make a single transistor QRSS beacon with a mechanical
modulator.
One completely insane idea that just occurred to me is to build a slow
mechanical oscillator (say driven by a Stirling Engine or a Curie Point
Pendulum heated by a small candle) and modulate the RF oscillator with
that. The mechanics or thermal system might directly effect the RF
oscillator frequency. Who will make the first candle-powered QRSS
beacon with thermopile PSU? :-)
Regards,
Alan
http://www.vk2zay.net/
Monday, March 2, 2009
Homebrew WSPR from W3PM
I had mentioned all this on SolderSmoke, and this morning Gene, W3PM, came to the rescue. He sent info on a really interesting and very simple SSB transceiver. Take a look at the block diagram. On transmit it is essentially a DSB rig with a filter at the operating frequency to knock down the unwanted sideband. On receive it is a Direct Conversion receiver preceded by a narrow filter that allows the WSPR frequencies through. It uses the familiar SBL-1 mixer. The filter has only one crystal. And --icing on the cake -- Gene built his version in modular form, with each module in an Altoids tin. Clearly, this is the WSPR rig for us!
Gene provides a very nice write up on his project here:
http://www.knology.net/~gmarcus/WSPR/wspr2.pdf
Sunday, March 1, 2009
Gil Cartoon of W7ZOI on the Mountaintop
I thought that Steve, N0TU (now WG0AT !), would find this especially interesting.
SolderSmoke Podcast #102
http://www.soldersmoke.com
For the new SolderSmoke Store:
http://www.cafepress.com/SolderSmoke
In SolderSmoke 102:
In the shadow of Vesuvius...
...then back to the "laboratorio."
-------------
QRSS musings:
1 transistor for transmit, 100 million for receive.
We need a low tech beacon generator -- maybe mechanical clock driven?
QRSS on "Hack-A-Day."
VK2ZAY QRSS booms into Europe.
Soul in the New Machine: Billy's oscillator.
ON5EX's grabber on SolderSmoke blog.
Italians at the forefront of QRSS.
--------------
T-shirt news: "Menus are for restaurants!"
"QRSS Ops Do it Very Slowly"
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Using iGoogle for ham radio.
USENET is going strong!
Back on Echolink.
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Minimalist Radio:
The Gnat! The NS-40!
I add a second transistor to my ET-1 (and hang my head in shame).
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MAILBAG:
Jim, AL7RV, developing smoke generator for LTSpice.
Randy, K7AGE, sent Empire of the Air video -- Thanks!
Jim, K9JM, prescribes higher Q for regen rx. "Never will be a 2B!"
Rye, K9LCJ, "Low Space Means Fine Teletype."
Alan, W2AEW, Listens to SS while on the road with Tektronix.
Dave, W8NF, "Armstrong, A Man of High Fidelity." Indeed.
Mark reports W7ZOI releases new EMRFD software.
Jonathan, KB1KIX, Shep fan, has good Smith Chart stuff on his blog.
Jerry, NR5A, building a QRSS beacon.
George, K8VU, Dilbert has "utter social ineptitude."
David, VK6DI, moving East.
Paul, K3PG, took Willamette project on ski trip.
Steve, WA0PWK, Gil cartoon about Wes.
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Saturday, February 28, 2009
Out of the Ozarks... The NS-40!
http://www.wa0dx.org/wa0itp/ns40.html