Crossing a small bit of the pond...

I got into WSPR because I wanted to one day walk into my shack and be greeted by a Google map with big long lines showing my milliwatt signal stretching bravely across various oceans. That hasn't really happened yet, but I got a taste of it this morning courtesy of OY3JE's WSPR station. Jan lives in the Faroe islands, about 1600 miles from me. Last night at around 2300 UTC my 18 mw WSPR signal made it to Jan's location. I was 29 db below the noise. Thanks Jan!
(The images above and below are of Jan's locations in the Faroe islands (from his site).

WSPRing along at 27 db below the noise....

WSPR is fun. I haven't crossed any ponds yet, but the real- time displays of the reception reports are very addictive:
http://wsprnet.org/drupal/wsprnet/spots
Be sure to click on the map display also.

I was intrigued by the Signal to Noise ratio column, and wondered what the reference bandwidth for the noise was. K1JT's pages show the reference bandwidth is 2500 Hz, and that WSPR can decode signals that are as much as 27 db below that noise.

That's great. I guess I don't have to worry about the lower sideband of my 30 mw signal causing anyone any trouble. It will be very far down in the noise.

Are Diode Ring Mixers Fundamentally Different?

Joop, PE1CQP, and I have been discussing mixer circuits, especially the ever-popular diode ring.
Here is my latest e-mail to Joop. The RSGB diagram for the ring diode mixer appears above.

Joop: I think the way the diode ring mixer works is very different from the way a two diode singly balanced mixer functions. The effect, of course, is the same. But the polarity reversing element introduced by the ring configuration -- it seems to me -- makes this a very different circuit.

Attached is the RSGB Handbook diagram I mentioned. I like it, because you can really SEE how the actions of the diode ring produce the sum and difference freqs (you have to keep Fourier in mind, and imagine the results of filtering).

The two diode circuit simply "chops" the input signal at the rate of the LO. And it would even work in a non-switching mode -- you could, for example, use FETs instead of the diodes and bias them to operate in the non-linear portion of their curves, right? This makes me think that the diode ring mixer circuits (aka "polarity switching mixers" or "commutating mixers") are very different.

73 Bill

Balloon! Project Blue Horizon Reaches Mid-Atlantic

Wow, that's an exciting track. The intrepid radio amateurs at Cornell University have a balloon up over the mid-Atlantic. It is approaching my old stomping grounds in the Azores. Beacons are onboard and reports are requested. Here are some more details:

Balloon Launch - Assist in Tracking

The NS3 group of Cornell University engineering graduate students will launch PBH-9 (Project Blue Horizon) from Lockheed Martin in Owego NY on Sunday evening, 19 Apr 09, at approximately 21:00 EDT (Monday, 20 Apr 09, 01:00UT)

This ARHAB flight (Amateur Radio High Altitude Ballooning) will ascend and then float for up to 50-hours while drifting to the east.

The payload will include a KC2TUA-8 144.390 APRS beacon
(track via (http://findu.com/cgi-bin/find.cgi?call=KC2TUA-8)
and HF CW position report and telemetry downlinks on 7.104MHz and 10.148MHz.

The NS3 PBH-9 team requests distant ground stations receive and report HF telemetry via N2XE@arrl.net including reception UT date and time.

Distant receiving stations are welcome to also submit HF
reception reports to W0RPK@amsat.org for the ARHAB <50mhz href="http://showcase.netins.net/web/wallio/ARHABrecords.htm" target="_blank">http://showcase.netins.net/web/wallio/ARHABrecords.htm.

Additional PBH-9 information including HF telemetry transmit schedule and format is available via
http://showcase.netins.net/web/wallio/ARHABlaunchannouncements.htm.

Flight updates are available from the NS3 PBH-9 team
via http://twitter.com/pbh3.

WSPR Double Sideband Success!

Oh, how sweet it is. Today I finally got my WSPR station working. Before departing for Sicily, I installed a diode ring mixer (supplied by Jim, AL7RV) between my MEPT oscillator and my two stage 50 mw power amplifier. I thought I might have enough audio coming out of my sound card to modulate the transmitter, but I soon found out that I needed more AF. Lazy after a week on the road in sunny and snowy Sicily, I reached into the junkbox and pulled out the guts of an old computer speaker amplifier. Some really ugly jerry-rigging ensued. The amp is now sitting near the TX, powered by its own 9V battery. Looks like I'm getting about 25 mw out, but that's from both sidebands. So I'm guessing I'm at around 10 mw.

Following guidance from Gene, W3PM (whose FB SSB rig inspired this effort), I set my oscillator at 10138700. That puts the upper sideband in the middle of the WSPR band.

Here's my first set of reports:

								Reported		Distance
Date	Call		SNR					by		km	mi
2009-04-19 18:32	N2CQR		-18					DL0TUH		1353	841
2009-04-19 18:32	N2CQR		-24					PA1GSJ		1343	835
2009-04-19 18:30	N2CQR		-19					DL0TUH		1353	841
2009-04-19 18:26	N2CQR		-22					DL0ODX		977	607
2009-04-19 18:26	N2CQR		-30					G8BKE		1519	944
2009-04-19 18:26	N2CQR		-26					PA1GSJ		1343	835
2009-04-19 18:24	N2CQR		-23					PA1GSJ		1343	835
2009-04-19 14:24	N2CQR		-22					M0WQR		1601	995

Hey, is this a first? Has anyone else run WSPR DSB?

Sicily, Mt. Etna... and The Godfather

Here's some Italy travelogue, well, actually Sicily travelogue. Above, our two heroes are seen with the Etna volcano in the background. Etna is Europe's largest active volcano. It was spitting out lava while we were there. The top is currently at about 10,800 feet (3300 meters). (It varies!) We went up to the 8200 feet (2480 meters) level (via cable car). Here is what it looked like from there:
It was COLD up there. We didn't stay long. Within 90 minutes of this picture being taken, the kids were back at sea level, and in the pool at 80F.

Here is a GoogleEarth View. The yellow marker shows the place at which we took the picture of us in the snow. (The Google shots were from May/June 2006).


Those of you who are fans of The Godfather movie will remember this scene:
Well, here we are, in the same place (but without the shotguns):

Francis Ford Coppola filmed most of the Sicilian scenes not in Western Sicily (where the village of Corleone really is) but in the East, near the beach resort of Taormina, in the village of Savoca. The Bar Vitelli is where Michael Corleone met Apollonia's father. Savoca also has the church where Michael and Apollonia began their brief and unfortunately explosive marriage.

We really liked Sicily. It is a beautiful place, rich in history, and with really nice people.

In Sicily

No posts to blog this week -- we are in Sicily, near the Etna volcano.
Beautiful place. Will talk about this in next podcast. 73

SolderSmoke Podcast #105

On #105: 

http://www.soldersmoke.com

Italy Earthquake
WSPR DSB, WSPR MP3
SBL-1 Blues
Clockwork minimalism
QST articles (design, HBR RX)
Marconi
Spring SPRAT
Blog stuff
ECHO-QSO with Mike, WA6ARA
MAILBAG

Happy Easter! 

Parachutes and QRSS

Kevin, AA7YQ, has made innovative use of a parachute. You are right Kevin, this must be a first:

Howdy Bill, It’s Kevin here in Montana, the ex-Smokejumper. I’ve been meaning to write again. Thanks for the nice comment on SS #100 I got a kick out of it. Anyhow, just thought I’d drop you a note to let you know I finally had a weekend to design and build up a QRSS beacon. I used a Cypress PSoC CY24123A uC to function as the Crystal Oscillator, and keyer. The final is two paralleled BS-170 MOSFETs running in Class-E mode to give me about 560mW out with a 7.5volt Lantern battery as my supply, total system power efficiency is about 63%(RFout over DC in), I’m sure this could be significantly improved, but good enough for now. After several hours of tweaking the capacitor values I finally got the oscillator to fall into the 100Hz window. That was MUCH harder than I had anticipated. With the original version I switched the PA on and off for true QRSS 3 CW, but found this made a significant frequency drift problem. So I added a couple parts and modified the PSoC code a bit, now its running CWFSK, switching about 1.1pF on and off one leg of the XTAL, shifting the frequency about 10Hz and much more stable.

My first tests were with the board sitting on the bench under the desk lamp. This caused all kinds of drift problems. I then put the beacon in a Tupperware container and placed it inside a soft case cooler. I was looking around the shack for a blanket or something to further improve the insulation, when low and behold sitting in a garbage sack… was a condemned FS-14 parachute (equivalent to the SF-10A) that I was planning using for something useful. So I wrapped the chute around the cooler and stuffed it all back in the garbage sack. Surprisingly, temperature stabilization was achieved, beyond my expectations.

The beacon is running good now, nice and stable. I’m fairly certain, that in the history of mankind, no one has ever used a parachute to improve the temperature drift characteristics of a QRSS beacon. Anyhow, I plan on having it fired up quite a bit, so that my antenna is actually put to some good use. It seems I rarely get a chance for one to one contacts anymore. Most of my free time is spent designing and building the radios I never use. Ha. I guess the design and building is the real fun for me.

Anyhow, I’ll talk to you later. 73s Kevin, AA7YQ

PS the Beacon is sending “AA7YQ” followed by a several second pause. It’s showing up on the K6HX grabber between 10.140050 and 10.140060.

2N35s, 1955... and some inspiration from AA1TJ

From Michael, AA1TJ:

Bill, I was re-reading Ade, W0RSP's "History of QRP" last night; especially that last chapter on transistor rigs. It dawned on me that the two 2N35 transistors that I'm presently using in my 40m transmitter were built two months before Bob, W7UUZ's famous, maiden transistor QRP contacts in August of 1955. While we can't go back and beat Lindbergh's first solo crossing of the Atlantic, for example, a fellow could re-live some of the excitement by building a replica of The Spirit of St. Louis and taking it up for a spin. If anything, it gives one a better appreciation of the hurdles those early trailblazers had to leap.

That's Michael's 2N35 rig pictured above. For more details see:
http://mjrainey.googlepages.com/80mqrptransmitter;circa1955

Michael also put a really great message on QRP-L earlier this week. I hope he reprints that on his blog.

SolderSmoke: On Sale on Thai Beaches!

An interesting e-mail from Thailand arrived this week. Excerpts:

Hi Bill Now for the full story

Life was so uncomplicated and peaceful before soldersmoke!

Last October I was lying on the beach in Pattaya City Thailand. I was just lying there enjoying a cold rice beer watching the various peddlers trudging along the sand. I wasn't bothering anyone and thought I was enjoying my retired life style. (Little did I know what was about to happen). Casually the wife reminded me there was a Ham club meeting in about three hours, I should hold off on another beer. Ok, I'll manage till later.

Pattaya Thailand has a great little Ham Radio club with locals from all parts of the world enjoying the one universal hobby without boundaries.

We showed up at the meeting on time and found a nice corner table. ( now the plug for the club - the meetings are the Friday after the first Sunday of every month and are held at Jimbos Bar). After about an half a beer a friend from England wandered over and sat next to me. He produced a CD from his pocket and said is was SolderSmoke, would I like to buy a copy for 100Baht. (approx. 3.00US) . As with most normal people, my first question was, what is soldersmoke? This was my first big mistake. I should have said not interested and looked for other friends that were arriving. But, no, I had to ask what was SolderSmoke.

My friend tried to explain, but feel short of being able to fully relay the meaning of the word SolderSmoke. If I remember correctly there were episodes 1 thru 80 something. I took the CD back to my house. and the next day spent over 5 hours glued to the CD player. My world was beginning to crumble.

I listened to more episodes. and started to think in terms of QRSS, QRPp, long wires etc. This new terminology was fascinating. I grew up in Idaho and was first licensed in 1963. I still have my first rigs that consisted of a Hammarlund HQ-100 and a Knight Kit T-60. I apparently had the knack at age 13 or so, but didn't know what it was called then. hi hi

In a couple of SolderSmoke episodes there was mention of a Drake 2B, a great receiver in all respects. I found myself wanting one (I sure didn't need one), and looking every where. I bought one in great condition with the original for sale tag still on it. It even had the crystal calibrator installed.

Now my vocabulary has expanded to whisperers, grabbers, mickums, reggies, knights of the realm and other terms before unknown to my vocabulary. Fessenden was a terrific individual although I'd never heard the name before episode 90 something. I started to build a QRSS beacon. I am in constant contact with Michael Rainey , AA1TJ. He is a great guy and has helped with a lot of questions.

For the first time in several years I am involved with something I enjoy. This is really fun I said to myself after fabricating a one transistor transmitter patterned after the discontinued ONER. 0-Yes let's not forget Mr. Doug Demaw, I bought the QRP notebook and Solid State Design (I didn't tell the XYL how much this book cost).

I've always been taught that addictions are bad things. I am in serious trouble now. I am thoroughly and completely addicted to SolderSmoke. I get impatient and unpredictable when the podcasts are a little late being posted on the internet. It's just like getting your fix for the week. Yes, fix for the week because it doesn't last the full two weeks. hi hi

I guess this is a non e-cursing thank you kind of Email. SolderSmoke has ruined my life, but my new life is much better with it.

Hope this epistle hasn't bored you to much. Your providing a great focal point for fellow knack victims.

Only thing left to say Bill, is KEEP ON SMOKIN!


Thanks for SolderSmoke

73 de
Stephen (Himself) (seems like everyone has a nickname)
HS0ZHB / NM7J

More Seismic Action

Two more fairly strong jolts today, both from the same region NE of here. The 4.9 was very noticeable at 11:25 am local time, and the 5.6 really shook the apartment at 19:47 local.
The USGS site is really very useful and up-to-date. Lots of data. For example, we learned that the compression wave from the 5.6 jolt took about 15 seconds to reach Rome. The people up in Abruzzo are really suffering and each one of these aftershocks makes things worse for them.

	MAG	UTC DATE-TIME y/m/d h:m:s	LAT deg	LON deg	DEPTH km	Region
MAP	5.6	2009/04/07 17:47:38	42.349	13.405	13.1	CENTRAL ITALY
MAP	4.5	2009/04/07 17:32:53	32.984	47.833	10.0	IRAN-IRAQ BORDER REGION
MAP	5.0	2009/04/07 15:18:41	37.620	-17.441	8.3	AZORES-CAPE ST. VINCENT RIDGE
MAP	4.7	2009/04/07 14:50:02	46.099	151.609	58.1	KURIL ISLANDS
MAP	2.9	2009/04/07 14:46:42	33.883	-116.872	14.4	SOUTHERN CALIFORNIA
MAP	4.5	2009/04/07 14:20:10	-7.970	122.916	236.7	FLORES SEA
MAP	5.1	2009/04/07 13:29:48	-6.976	129.425	69.7	BANDA SEA
MAP	2.9	2009/04/07 13:10:43	19.256	-65.076	63.6	VIRGIN ISLANDS REGION
MAP	2.9	2009/04/07 10:08:55	32.209	-116.626	0.0	BAJA CALIFORNIA, MEXICO
MAP	4.9	2009/04/07 09:26:31	42.336	13.360	10.0	CENTRAL ITALY

Earthquake Hits Central Italy

A 6.3 earthquake woke us up last night. Rome was shaking quite a bit. Looks like the epicenter was up in Abruzzo, near L'Aquila. News reports indicate that buildings have collapsed and people have been killed up there.

Deep Solar Minimum

Farhan alerted us to this. From the NASA website:

April 1, 2009: The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower.
2008 was a bear. There were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days: plot. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.
Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87%).
It adds up to one inescapable conclusion: "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of the Goddard Space Flight Center.
"This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center.
For the rest of the article:
http://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm?list830785

The Siren Song of WSPR...WSPR DSB?

Man, that's the kind of map that I want to find on the screen when I walk into the shack in the morning. Or maybe on my Blackberry at lunchtime. Above you can see the WSPR spots for Jeff, KO7M. You can see Jerry, NR5A, in there, proudly representing South Dakota. Buried under the Northeast calls is K1JT, the only Nobel Prize winner in the group.
This morning I downloaded K1JT's WSPR program and was very pleased to find that it runs nicely on this old, rickety Windows 2000 machine. (I pushed the envelope a bit and tried to get it to run on my recently revived Toshiba Satellite Pro 400CS, but it didn't seem to like Windows 3.1. ) I have on the workbench the plans for W3PM's bare bones WSPR transceiver and the WSPR care package sent over by Jim AL7RV.
Here is my plan: Make W3PM's rig even simpler. TX only (at first) and Double Sideband. Maybe I'll just put an SBL-1 mixer between the oscillator and the RF amp in my current Visual MEPT transmitter. (I'll make it switchable so that I can go back to our beloved visual mode whenever I want.) Then add W3PM's audio amplifiers between line out on the sound card and the audio input port on the SBL-1.
What do you guys think? WSPR DSB? The other sideband should fall FAR outside the band, and it will almost certainly be completely down in the noise for anyone not running ARGO or SPECTRAN-like software.

Amazing NASA site: Audio from Apollo Landings

Akshay, VA7AAX, sent me a link to a truly amazing site. NASA has pulled together a huge amount of data on all the moon landings, and they have made it very accessible. Included is a LOT of the raw audio of the communication between the spacecraft and ground. They even have the internal communications inside the lunar lander. If you guys are looking for something to put in your MP3 players (in addition to SolderSmoke, of course) this is the place to go. It is also a great site for audio to be played in the shack while building something. It is really inspiring. This morning I listened to the Apollo 11 landing.

I like the live.365 system for the audio -- you can listen to it in streaming mode, without waiting for a long download.

Here is the site:
http://www.hq.nasa.gov/alsj/frame.html

Thanks Akshay! Thanks NASA!

SolderSmoke Podcast #104

http://www.soldersmoke.com

1 April 2009
Rome Marathon
Billy climbs Vesuvius!
Fixin' up old Toshiba laptop
Solar Power from Donuts and Tea!
Eldon's MEPT ET Phone home machine
More Catalan minimalism: The MOSquito
Book:  Thunderstruck! Marconi history
SPECIAL ECHOLINK QSO WITH NIGEL, M0NDE
MAILBAG:
Paul M0XPD new homebrewer, Funster 40, Paraset, and SDR
Preston WJ2V on REAL solder vacuum pumps
Ted AA5CK keys MEPT with iduino
Ken KG6PO on obit of TV pioneer Thomas T. Goldsmith
Art W2HQQ: "Man of High Fidelity" lacks knack
Scott KD5NJR on Sputnik 4, NASA comms
Alan W2AEW Don't smother MEPT oscillators! Books
Steve GOFUW Old Book recommendation. Building WARC rig
Jacki (XYL of KL7R) says hello from volcanic Alaska
Jeff KO7M  Why FSK on QRSS?
Jim AL7RV Sends WSPR care package.  (Thanks!) 

Solder Smoke Cologne! New!

As mentioned in SolderSmoke 104. Check it out! Here is the link:

Solder Smoke -- From the Men at Work Collection

Troubleshooting and Simulations

Alan, W2AEW, roams the Northeast USA as a Field Application Engineer for Tektronix. This week he sent me an e-mail with some words of wisdom about simulations and troubleshooting. Thanks Alan!

An excerpt from Alan's e-mail:

Funny you mentioned about LTSpice, and wanting to have that puff of soldersmoke whenever you place a component. It reminds me of something that I'd often tell new-hire engineers. Many times, engineers fresh out of school have never touched a resistor - they've often spent their entire education doing bookwork and simulations. I would always caution engineers about this, and try to illustrate that the simulation is only as good as the model you give it. If you ask the simulator to exercise the model in a way it wasn't designed for, it won't tell you that, it will just lie to you. YOU have to be smart enough to recognize the lie. For example, the simulator has no problem putting 10,000 amps through a 1N914A diode - it doesn't know that you'll let the smoke out of it! The simulator must be considered a tool, just as you VOM, scope, counter, finger, nose, etc. are all tools. Each can give you valuable information (and can lie to you). You have to learn to know what you can believe, and what you have to question - and you need to develop ways to look at strange behavior in a number of ways to figure out what is happening.

It reminds me of a story that Jim Williams wrote many years ago (you mentioned Jim Williams in a previous SS episode). He described how, as a child, he was playing with circuits at his neighbor's, and using his (neighbor's) oscilloscope to examine a circuit he was working on. He was getting all kinds of strange behavior, and couldn't make heads or tails of what he was seeing with the scope, VOM, etc. The neighbor (who was definitely afflicted with the Knack) came by and, with moistened fingers, probed around in his circuit for a few minutes. He then grabbed a small value capacitor and soldered it judiciously in the circuit, and everything worked fine. Jim was flabergasted and demanded an explanation. The neighbor said that he suspected that the circuit was oscillating at several hundred MHz, and used his finger's capacitance/loss/etc. to damp this behavior. He continued to explain that since the oscillation frequency was so high, the scope couldn't "see" it. Jim complained that this "wasn't fair"! The neighbor concluded the lesson about how important it is to not-only understand what our tools can do for us, but it is really more important to understand their limitations - because it is when we ask a tool to do something that it can't do, it often won't complain, it will lie. The same holds true for nearly every tool we use, and is a lesson well learned. This story is included in his chapter entitled "Should Ohm's Law Be Repealed?" in his book, "Analog Circuit Design: Art, Science and Personalities" from 1991.

Alan has a lot of great stuff on his web site. Check it out:
http://www.qsl.net/w2aew/

Marconi's Big Ears

Thunderstruck by Erik Larson has countless gems about Marconi. I thought I would share one with you this morning.

When Marconi was born on April 25 1874, an elderly gardener saw the new baby and exclaimed, "Che orecchi grandi ha!" ("What big ears he has!") Marconi's ever protective Irish Mom, Annie, took offense and replied:

"He will be able to hear the still, small voice of the air."

Indeed.