Ponticelli QRP Station Gets New Antenna

At the country place I now have a table on the front porch for the HW-8 and assorted gear. In the picture above you can see the Trastevere Flea Market Pi Section antenna tuner (upper left), a Japanese SWR meter (also from the flea market) , HW8 and Radio Shack speaker, Volkswagen Solar Cell, 12 Volt gel cell, key and cans...
I had been using a piece of wire just thrown up in the trees, but I thought I could do a bit better. I had some TV twin lead in the shack, and there was this useful-looking center connector... I had some AC line cord. Next thing you know I had a sorta-doublet antenna supported by a Roman Pine in Sabina (pictures below).
And it gets out! Worked IT0ULN in Sicily on 40 meters. Then I spoke to another QRP station, 2W0NNN in Wales, on 20. Also UU4JDD/P on Tuzla Island. Finally E53AX in Estonia.
Ioan, 2WONNN, sent this report:

Hi Bill, thanks for the email, I look forward to seeing the pics on your blog too. Very interesting reading, same goes for your QRZ page too. I had to laugh at your DX with an astronaut on Mir!!!

Your HW-8 and doublet is certainly working well; I remember you were completely readable with a good signal about 90% of the time, it was only the QSB that made it difficult. To be honest I was surprised to have a QRP QSO with someone in Italy. I was using my FT-817 with a new Par End Fedz that I'd catapulted over a tree. The top was about 15m high but oriented as a sloper to the north west. I've had a fair number of QSOs with East coast US stations so I thought I'd go for an over-the-pole route to the West coast... there in Italy you're pretty much spot on the opposite direction so I'm not sure it's all that directional!

73 and hopefully speak to you again for more QRP/QRP!

Ioan,

2W0NNN

Armadillo Aerospace Video

SolderSmoke Podcast #115

http://www.soldersmoke.com
Camping in Sabina
Michelangelo's late start
Anniversaries: Internet, SolderSmoke, Hack-A-Day
From Kitty Hawk to the Moon 
Carrington flares and childhood aurora
Calculating speed of light (using cheese)
Mythbusters
Hubble Space Telescope, Sliding Spring Observatory 
Europa
Transistor Museum
Understanding Mixer products
FALL SALE AT SOLDERSMOKE CAFE PRESS STORE! 
MAILBAG

Mixing it up

OK, enough of the pretty pictures from outer space, now it's time to go back to mixer math.

In the podcast, on this blog, and in the SolderSmoke book I have chronicled my efforts to understand how mixer circuits REALLY work. For some of us, the trig is just not enough. We want intuitive understanding. Ya' gotta draw us a picture. Mike KC7IT, and Dennis W6DWF, both alerted me to a good one. It is from a new book "RF Front-End: World Class Designs", Edited by Jane Sullivan Love. The chapter on mixers is available online here:
http://i.cmpnet.com/rfdesignline/2009/08/C0429pt1.pdf

I really like figure 9.6 (above). You can really SEE how the switching action that is driven by the LO kind of "chops up" the RF signal and produces the complex waveform that is the IF. The neat thing about the IF waveform in this drawing is that you can clearly see both the sum freq (the smaller squiggles) AND the difference freq (the overall movement inside which the smaller squiggles are present). Go ahead, count them up! Sums and differences!
This is a special kind of mixer: a polarity-reversing switching mixer. When the LO is negative, it inverts whatever is at the RF port. From this you can see why mixers are described mathematically as "multipliers." This mixer is multiplying the instantaneous value of the RF input by +1 (when the LO is positive) and then by -1 (when the LO is negative).
I think it is quite a bit harder to "see" the genesis of the sum and difference freqs when you are working with non-switching mixers, but this diagram is, I think, really useful in gaining an intuitive understanding of what goes on in the mixing process.

Hubble Space Telescope: New and Improved!

I know, I know, it is not exactly ham radio, but look at it this way: electromagnetic waves from far, far away! REAL DX. And some very cool gear to receive the signals. And some recent repair and modification work... So you see, this is really not so far afield after all.

I've been a big fan of the Hubble Space Telescope for a long time. When I was closer to the equator (in Santo Domingo) sitings of the HST were quite common. I'm glad to see that the recent repairs and mods worked out so well. Here is a really nice video on the new and improved Hubble: Hubble Space Telescope Video

Saving the world, finding comets....

Well I guess the hours are not great, but how about the job satisfaction! Rob McNaught works at the Sliding Spring Observatory about 400 km from Sydney, Australia. The observatory searches for comets and asteroids that could do to us what they may have done to the dinosaurs (see below). A significant fringe benefit of this job is that Rob gets to discover new comets. He recently set world record by finding his 50th. Congrats Rob!

The mission of the Siding Spring Survey is to contribute to the inventory of near-earth objects (NEOs), or more specifically, the potentially hazardous asteroids (PHAs) and comets (PHOs) that may pose a threat of impact and thus harm to civilization. The identification of the iridium anomaly at the Cretaceous-Tertiary boundary (Alvarez et al., 1980) and associated Chicxulub impact crater (Hildebrand et al., 1991) and perhaps recently the Australian Bedout crater (Becker et al., 2004) associated with the Permian- Triassic "great dying" (although the presence of shock metamorphism has not yet been adequately demonstrated), strongly suggests that impacts by minor planets play an important role in the evolution of life. These are a natural result of the accretionary process that formed the Earth and planets. Indeed, the 1994 impact of D/Shoemaker-Levy 9 on Jupiter provided tangible evidence of this. Although the collision frequency is much lower than in the past, the question is not whether there will be other impacts, but when.

Early Crystal Set in Altoids-like Box

Even way back then, British homebrewers had an affinity for Altoids-like boxes!
David, M0VTG, sent me the above pictures, and this description:

I enclose some pictures of a kit produced in the early to mid 1900s of crystals and a holder for use in a crystal radio; unfortunately the cats whisker is missing! The box is marked:

Front: NEUTRON Back: Neutron Ltd

Trade Mark Sicilian House

Wireless Crystal Southhampton Row

1/6 Phone Museum 2017

Catswisker and

Directions Enclosed

The 1/6 refers to the price (one shilling and six pence) pre-decimalization and converts to seven and a half pence today (although the half pence has been dropped thorough inflation). I should add that the box measures about an inch and a half in length.

Carrington Flares, Aurora, Where were you on August 4, 1972?

Greg, KC2DWF, sent me a really interesting story about the work of the English solar astronomer Richard Carrington. He discovered a kind of solar flare (named for him) that comes along every few centuries and could knock us all off the air.

As I was reading the article, I started to think about a childhood event that I think I mentioned in one of the podcasts. I have vivid memories of a summer night in which the skies were filled with really bright colorful lights. The article about Carrington notes that there was a major solar flare (but not of Carrington levels) on August 4, 1972 that caused auroral displays far into the southern part of the USA. The year is a bit later than I thought (I was 13 at that time) but the time of year is correct. And that flare was big enough to have caused really vivid aurora over New York.
The NASA site "Brushfires in the Sky" provides this very helpful list for people, like me, trying to figure out what we saw, and when:

The Aurora Watchers Handbook lists the following "Great Geomagnetic Storms" of the 20th century when auroras were seen much farther south than usual. If you have a childhood memory of aurora borealis, it may have come from one of these storms.

• October 31 - November 1, 1903
• September 25, 1909
• May 13-16, 1921
• April 16, 1938
• February 11, 1958
• July 8, 1958
• August 4, 1972
• December 19, 1980
• March 13-14, 1989

Looks to me like my event was August 4, 1972. Anyone else have memories of this storm?

Here is the article that Greg sent:
http://science.nasa.gov/headlines/y2008/06may_carringtonflare.htm

The Transistor Museum

Wes, W7ZOI, relayed to us this great site found by from Jeff Damm, WA7MLH. This is a real treasure trove of transistor history:
http://semiconductormuseum.com/Museum_Index.htm

Alaska QRSS Grabber Controlled from CHINA!

Our friend Laurence leads an interesting life...

http://www.kl1x.com/

Hi Bill and greetings from the NE coast of still summery China - actually its cooling down a bit from boiling over to just cooking.

Just been home to Alaska. Whilst and between lumberjacking 20 dead trees on the property I had a few mins to throw up a K9AY and connected it via 250ft of Walmarts best RG6U into the R75 - with a little help of Ham radio delux, Citrix and Skype I have control of the radio from here in China - Mostly on 30m but really shoved it up for the winter lf/mf season but of course WSPR and visual modes have proved very popular. So until a moose walks thru, a Wolf chews threw or wife cuts thru the antennae wire it will be up.

Here in China I'm sporting the second r75 and this supplements the SDR IQ - my antennae are gradually getting blocked towards the states and Eu by every rising high rises just in front and I can actually measure the increasing losses at LF and HF as the beast rise. Still looking for your WSPR signal and keep up the good work.

Regards
Laurence G4DMA et al - KL1 X and in BY3A

A Good Old VFO (by Rick, KK7B)

Here is another really great message from Rick, KK7B, sent to the emrfd yahoo group: [emrfd] A Good Old VFO Saturday, August 22, 2009 10:29 PM From: Rick To: emrfd@yahoogroups.com For several critical receiver applications in my lab I've used old Collins PTOs converted to solid state (I just replace the triode in the classic Hartley circuit with a J310 and run the circuit from a 9 volt regulator). I have half a dozen of them in dedicated propagation study receivers, and one SSB exciter I occasionally use on UHF. The other day I was changing something else in one of my receivers and connected the solid-state PTO to the frequency counter on my bench. The PTO was set to 3.100000 MHz. From a cold start (it hadn't been turned on for years) it drifted three Hz over the first ten minutes, and then a total of 10 Hz over the next few hours. When I calibrated one of my 144 MHz propagation study receivers 25 years ago, total frequency drift was <18Hz/hour. I expect most of that was aging of the overtone crystal oscillator in the premix circuit. Old Collins PTOs are common (someone at Dayton this year had a box of unknown ones in decent shape for $10 each, and there are R390 PTOs in the current Fair Radio flyer). I've never had one fail, tuning resolution is infinite, phase noise is low, digital noise is zero, and once I build one into a receiver, that part of the project is done--no improvements, software upgrades, needed. My research receivers are connected to a baseband Fourier analyzer (yes...even 25 years ago). The finest resolution I've used for serious experiments is 10 milliHertz, but more often I use 1 Hz resolution, with 1024 channels in the output spectrum. I often average spectra for more than a minute, so frequency drift needs to be less than 1 Hz per minute. The solid-state Collins PTO is much more stable than needed even for those critical experiments. This is not a fluke. Every Collins PTO I've converted to solid state using a U310 or J310 has had similar performance. Sometimes it is useful to remember that the major benefit of digital frequency synthesis is that it is quick, cheap, and frequency agile. No commercial manufacturer could afford to build a transceiver with a Collins Mil-Spec PTO in it these days. But for an amateur with mechanical skills or access to surplus hardware who needs just one good oscillator, the venerable Hartley with a temperature compensated tuned circuit and a JFET can provide outstanding performance. In music, art, architecture, automobiles, motorcycles. .. there are recognized "golden eras" where some combination of factors resulted in technical hardware that is widely recognized as being superior to what is being produced today. Often the difference is directly related to the amount of skilled labor needed during production. As technical hobbyists, we automatically assume that new is better, but as experimenters, we should be open to the idea that sometimes the technology, ideas, and block diagrams of an earlier era are superior to the cost-driven disposable technology coming off fully automatic assembly lines in some out-of-the-way place with inexpensive labor and attractive business tax codes. The idea that old technology designed decades ago by retired guys might be better than new technology is a radical concept in electronics. But NASA is using a brand new, hand built, Traveling Wave vacuum tube in the current Moon exploration mission. After 100 years of radio experiments- -it is fun to look back and find old technology that might actually work better than some of the new things we've been inventing recently. Best Regards, Rick KK7B

Sonya's Rig

Stewart, G3YSX, provided us with Part II of his article on the espionage radio work of the Soviet spy Sonya (who had the Knack).

Sonja Continued

A few days after my article on Sonja the Spy was published in the September 2004 edition of the CARC newsletter, I received a letter from club member Eddie Ramm
DK3UZ filling in a few additional details.

The Fuchs antenna that Sonja used was first described by Dr Josef Fuchs, OE1JF, in 1928 and is a half-wave end-fed design.

End-fed half-wave antennas are very efficient and do not need a particularly good ground, but they are very high impedance and need a suitable matching circuit. For a spy the use of a simple, but efficient, antenna of this type would have its attractions.

Eddie then pointed out that the design is of current interest to the QRP community by pointing me to the following URL: http://www.qrpproject.de/UK/fuchs_ant_.htm. This describes a 5 band portable QRP antenna designed by Frank, DL7AQT, based on the Fuchs design. The antenna is a 40m to 42m length of wire and the ATU is a parallel tuned circuit using a pair of toroids and a 200pf variable capacitor. It is worth reading the English version of the manual, which discusses the issue of self-resonance in these high impedance matching circuits. Matching circuits of this type only function correctly below the self-resonant frequency. Frank used of a two toroid arrangement to the move the self-resonance from 18MHz to 60MHz, thereby producing an ATU that operated correctly from 80m to 10m.

The second point that Eddie raised was the term “Three Point Oscillator” that Ruth used to describe her (Sonja’s) transmitter. The German term is “Dripunktsender” (three point sender), which Eddie tells me is the term was used to describe both the Hartely and the Colpitts based transmitters. Both oscillator designs are similar in the way that they use the reactive components in the tuned circuit as an impedance transformer to provide the coupling between the tuned circuit and the amplifier, so the use of the common term makes sense. He included an article dated January 1939, which shows a 3W automatic transmitter for maritime use, which is of the Hartley design and is described as a Dripunktsender. The article can be found at http://www.radiomuseum.org/funkschau/1939/funkschau_12jg_0339_1v2.pdf and the Hartley transmitter circuit is shown above.

We have no way of knowing which type Sonja actually used, although, as I suggested before I would suspect that it was the Hartley. This is likely because the Hartley was popular in the amateur radio world at the time and we know that she improved here spy transmitter by using amateur radio techniques. Secondly, because her transmitter had to fabricated, without raising suspicion, using material found in the field, a Hartley would seem to be the preferred design. A Hartley has no critical capacitors, just a coil which can be fabricated out of an “innocent” piece of wire or metal, and adjusted to give both the right inductance and the right feedback.

Stewart G3YSX