Podcast QRM Culprit Found: WBIG-FM 100.3 MHz

Listeners noticed that recent SolderSmoke podcasts had some other audio playing faintly in the background. At first I though this must have been AM broadcast band breakthrough, so I built a little crystal radio, only to discover that the powerful AM stations here were not playing the ZZ-Top style classic rock that I was hearing in background noise. Bert, WF7I, suggested that I listen carefully to the QRM for a call sign. I tried that this morning. I couldn't get a clear call sign, but I picked up the unmistakable rhythm of Peter Frampton's "Do You Feel Like We Do?" Fortunately that song is 1) infrequently played and 2) quite long; I had enough time to take a spin around the FM radio dial. Sure enough, I caught the tail end of the Frampton song on WBIG-FM 100.3 A quick check of the web shows that this is a 50,000 watt station that has its transmitter within about 1 kilometer of my house. Bingo.
The mic cord is just about 1/2 wavelength. That would put the high voltage nodes at the ends, right? I notice that the interference drops noticeably if I wind up the cord, and increases a lot if I stretch out the cord.
I can hear some other stations in there also (one country station). It may be that there are multiple FM stations broadcasting from that antenna site. I can see the tower's red lights blinking from my front lawn.
Thank you Peter Frampton!

Regen Madness

How many times have I said "never again, no more regens"? I guess I need a twelve step program or something like that. This latest bout of regen fever started with the King's Speech movie. So I blame the Brits. All of them. Then this Belgian guy with the video comes along (see above). Now I find myself drawing out a schematic for the old regen that I picked up years ago at the Kemption Park rally in London. Someone please, STOP ME!

Job Opportunity: MAKE needs THE KNACK

Sounds like the folks at MAKE are looking for someone with THE KNACK. Check it out:
http://blog.makezine.com/archive/2011/03/awesome-opportunity-to-work-with-make.html

HomeBREW (literally!) Your Own Microphone!

During those dark days in which I was using my Astatic D-104 mic for podcast purposes (not a popular move) I checked on the mic element inside my chrome lollipop and found it to be the original crystal "Rochelle salt" element. I remember wondering about the Rochelle salt: What the heck was that? Well, this morning, the hippie technologists over at the Make blog explained it all to me via the above embedded video. It turns out that you can MAKE piezoelectric Rochelle salt crystals in your kitchen using -- get this -- soda ash, coffee filters, and -- wait for it: CREAM OF TARTAR sauce! I'm not making this up.

The Hobbit Hole

In the interest of preserving what I suspect will become an important piece of amateur radio history, I'm posting some pictures of the underground radio shack and workshop of Michael, AA1TJ.

Michael describes the facility this way: The shack is under two feet of snow at the moment, but from the surface it looks for the most part like any New England spring-box cover that you come across while walking in the woods. Only, when you lift this cover you discover Dr. Evil's secret underground radio laboratory, a re-creation of Hogan's Heros radio station, or what I affectionately refer to as the "Hobbit Hole."

The two of us burrowed down 13 feet, breaking up boulders the size of a VW Bug as we went. Aside from the pick and shovel work, I used both one and two-handed sledges along with an assortment of rock chisels and pry bars. Everything came up in 5 gallons buckets.

The lower-level slab used hand mixed concrete. The walls are 12" thick insulated masonry blocks; a Canadian-made product called, Sparfill, that's unfortunately no longer available here. We called in Ready-Mix for the concrete roof. The interior dimensions are a luxurious 2m square.

As luck would have it, I had just taken some photos of the interior for my pal, DL3PB. Please find them attached. Actually, in one bench corner you'll see the 2,400RPM AC induction motor and 400 pole stepper motor that I plan to use in the "Full Monty" version of the present project.

Mike has a wonderful posting on his blog today: http://aa1tj.blogspot.com

Shuttle and Space Station (and Sunspot)

Check it out! The ISS and the Shuttle Discovery captured by an amateur astro-photographer as they passed in front of the sun, with major sunspots nearby! Catalin Fus of Krakow, Poland, had his solar-filtered telescope trained on sunspot 1166 on March 7 and recorded this amazing conjunction. Thanks Catlin and thanks to spaceweather.com.

I had the whole family out in the front yard after dinner last night. ISS and the Shuttle made spectacular pass over the Washington DC area. We saw both rise up from the Northwest and then blink out after passing overhead. The shuttle (I think) was about one minute behind ISS.

40 years of Spice

Bob, W8SX, sent me an interesting article from EDN on the recent commemoration of the 40th anniversary of our beloved SPICE program. Check it out:
http://www.edn.com/blog/IC_Design_Corner/40584-SPICE_a_40_year_old_open_source_success_story.php

Watch the Shuttle fly with the Space Station

The two spacecraft are un-docked but orbiting close together. There is a good visible pass over Canada and the U.S. this evening (see above -- all times EST). Go to http://spaceweather.com/flybys/ to get the times for your location. Hurry, I think the Shuttle comes home tomorrow.

AA1TJ's Dream: No Tubes, No Transistors... ALTERNATORS!

Treat yourself today to an experience in radio enthusiasm and innovation: Go to AA1TJ's blog and read about his latest creation: The Schmidtschem. Michael begins his post this way:

I've dreamed and schemed, off and on, for the last twenty five years over the prospect of constructing a complete, high-frequency (HF) amateur radio station without the use of vacuum tubes or semiconductors... Having considered and subsequently rejected a number of esoteric possibilities, I eventually concluded that a system based on electromagnetic alternators was the most promising.

He has a prototype on the air, using it with a no-gain receiver, and he is making a lot of contacts. Check it out: http://aa1tj.blogspot.com/

Crystal Radio Sleuthing

As part of my effort to stamp out broadcast interference to the SolderSmoke podcast, this weekend I reassembled the crystal radio that Billy and I had built in London. It is REAL simple: Just a parallel LC circuit with a germanium diode detector and some high impedance phones. (I also put a chunk of galena and a cat's whisker on the board -- that's for when I get the urge to form my own PN junctions.) As expected, I immediately heard two AM broadcast stations: WFAX 5 kw 1220 kHz (religious) and WUST 20 kw 1120 kHz AM (mostly foreign language). I found out the hard way that these stations reduce power at night: I was bragging to my wife about the EXCELLENT reception I'd been getting on the crystal set, but when, after dinner, I brought her into the shack for a demonstration, she could barely hear anything. Oh well...

But here's a surprise: These are NOT the stations that are getting into the podcast! With the crystal radio in operation, I did some audacity recording and then quickly checked to see if the breakthrough sounded like what they were playing on WFAX and WUST. NO! The breakthrough was ZZ Top! I'm guessing that the breakthrough was from an FM broadcaster. I note that the length of the cord to the microphone would seems like it would be a nice antenna for the FM broadcast band... What do you guys think?

Whatever the source, I think I have taken care of the problem. I got big ferrite toroid core and wrapped about ten turns of the mic cable through it. No more broadcast breakthrough.

The Knack in Mexico, Engineer and Inventor

Our correspondent in Guadalajara, Roberto XE1GXG, had earlier posted a comment on Guillermo Gonzalez Camarena, an inventor who worked on color TV. This morning I had the chance to check out the Wikipedia article on OM Guillermo. I was struck by the telltale signs of The Knack. This is further proof that the phenomenon is truly global. Excerpts from the Wikipedia article:

Guillermo González Camarena (February 17, 1917 – April 18, 1965) (aged 48), was a Mexican engineer who was the inventor of a color-wheel type of color television, and who also introduced color television to Mexico.

Born in Guadalajara in 1917, his family moved to Mexico City when Guillermo was almost 2 years old. As a boy he made electrically propelled toys, and at the age of twelve built his first Amateur radio.

In 1930 he graduated from the School of Mechanical and Electrical Engineers (ESIME) at the National Polytechnic Institute (IPN) with an engineering degree; he obtained his first radio license two years later.

He was also an avid stargazer; he built his own telescope and became a regular member of the Astronomical Society of Mexico.

González Camarena invented the "Chromoscopic adapter for television equipment", an early color television transmission system. A U.S. patent application (2,296,019) states:

“

My invention relates to the transmission and reception of colored pictures or images by wire or wireless...

”

On August 31, 1946, González Camarena sent his first color transmission from his lab in the offices of The Mexican League of Radio Experiments, at Lucerna St. #1, in Mexico City. The video signal was transmitted at a frequency of 115 MHz. and the audio in the 40 meter band.

He died in a car accident in Puebla on April 18, 1965, returning from inspecting a television transmitter in Las Lajas, Veracruz.

A field-sequential color television system similar to his Tricolor system was used in NASA's Voyager mission in 1979, to take pictures and video of Jupiter.^[1]

In 1995, a Mexican science research and technology group created La Fundación Guillermo González Camarena (The Guillermo González Camarena Foundation), which benefits creative and talented inventors in Mexico.

At the same time, the National Polytechnic Institute began construction on the Centro de Propiedad Intelectual "Guillermo Gonzalez Camarena" (Guillermo González Camarena Intellectual Property Center).

The King's Speech Regen

In SolderSmoke 131 I talked about this old homebrew receiver. I picked it up at a radio rally in London and almost sold it at a hamfest in Virginia. A fit of UK nostalgia provoked by a screening of "The King's Speech" caused me to hold onto it. Now it is luring me into two areas that I don't really want to get into: high voltage and regeneration. But here we go... I turn now to our British cousins: What can you tell us about this receiver? 1920s? 30's? What tubes should I be looking for? How would they have powered this receiver? Does anyone have a schematic that might describe this device? (Or something close?)