HOMEBREW HERO: George Dobbs, G3RJV

This morning the mailing lists alerted me to a video of a recent talk by George Dobbs, G3RJV, of the G-QRP club. As I sat here in Rome and tinkered with my QRPp QRSS beacon, I went to the site, plugged in my earphones and was presented with a really wonderful, inspirational program. George has a truly unique way of combining the technical and the spiritual. (A while back he declared that my London shack had an element of "Wabi-Sabi" too it -- my wife heard this, did some research on Wabi Sabi, and found it very helpful in her garden design work.) In this talk, George reviews QRP construction techniques -- I learned about additional uses for garden slug tape, and heard for the first time of the new "Limmerick" PC board technique. George talks about the history and the evolution of some of the most well known QRP rigs (I builtone of those Sudden receivers!). And he talks about books for the QRPer (like me, he has a special fondness for SSDRA). Most important, I think, are George's comments about the spiritual, philosphical aspects of what we do, about why this hobby makes us happy.

So... run, don't walk to the British Amateur Television Site. Have a cup of coffee (or tea!) at hand. Have some rig to tinker with while you listen. You'll like it. How to get there:

Video of G3RJV QRP Talk

The talk given by Rev. George Dobbs, G3RJV, at the Lough Erne ARC Rally titled 'QRP Why and How' can now be watched on the BATC video site

To watch the video follow these steps:
Go to http://www.batc.tv/
Click on the 'Film Archive' icon at the top-left
Select G3RJV QRP Lecture from the drop-down list
Click on the > icon to start the player and click on the icon to the left of the volume control to display the picture full screen.

There is a link just under the player to save the video to your computer.

Videos such as this are examples of the wide variety of services offered by BATC to the amateur radio community. These include an excellent magazine. New members are very welcome.

Cyber membership, magazine by email, costs as little as £4.00 on-line. Membership gives individuals and clubs access to the BATC streamer allowing live webcasts from your shack or from a radio club display, talk or meeting.

British Amateur Television Club (BATC)
http://www.batc. org.uk/

QRSSuccess!

There it is. That's the rig we've been talking about. The astable multi-vibrator sits in the upper right. The Colpitts oscillator takes up most of the rest of the 9 square inch board. You can see the LED for the FSK circuit in the lower right. (I went with blue -- Jim, Al7RV, sent me that part.) (See that space on the lower left? I'm thinking that I could put in an SBL mixer and one stage of audio amplification to give this thing receive capability.)

After a bit of frustration during the building of the multi-vibrator, the initial on-the-air testing of this rig went amazingly well. I got home from work yesterday and finished wiring up the LED and a 5 pF cap for the FSK circuit. My frequency counter showed a nice 5 hz shift. Perfect. And the LED does flash a bit of blue light!

The sun was going down at this point, and I knew that 30 meters would soon be closed. But a quick check showed that the Belgian Grabber of Johan, ON5EX, was still picking up my QRO (20mW) rig. So I figured that this new rig (with around 10 mW) had a good chance of being received in Belgium. It took me a few minutes to spot it, but then I saw it. It was beautiful. Kind of a square wave with skirts, if you know what I mean. About 4 cycles per minute, and right on the freq shown by my counter. Here is a screen shot of the initial reception:

Nice, don't you think? One transistor, modulated by two others, making the trip over the Alps from Rome to Belgium. Here is a larger view of Johan's grabber screen. Time is marked along the bottom.
This rig will be on the air today. You can see Johan's grabber in the right hand column of this blog. Or here: http://www.on5ex.be/grabber/grabber.html
When the sun is up over Europe you probably should be able to see my signal.

Amazing: On the receive portion of this system we have billions of transistors (certainly millions in Johan's computer, and countless millions more in the internet). But on the transmit side we have only three.

Good Vibrations!

Somehow this goofy circuit diagram (sent to me by Mike, KC7IT) seems appropriate this morning. That is because, gentlemen, this diagram represents the kind of homebrewer I've been this week. After far too much struggle, and with the kind assistance of wizards from around the globe, I succeeded this morning in making an astable multi-vibrator do its thing. Not exactly a momentous achievement, I know. What you may ask, was the problem? Simple: Hans Summer's diagram called for 680K resistors from the power supply to base. But I somehow managed to put in two 68K resistors. This apparently results in an entirely different RC time constant!

Anyway, it is now percolating along nicely. The 2N2222s work fine, as do the two 10 uF electrolytics in parallel. It seems to produce a frequency of around one cycle every 15 seconds. That should be just about right for the QRSS FSK.

Thanks to all for the help and assistance provided. And thanks to xkcd for the cartoon!

Bad Vibes (No Vibes) :-(

Thanks for all the advice. I especially liked the LTSpice model -- it was good to get back to that great program. I plugged in the values that I am using (from Hans' circuit) and the 2N2222 transistors -- Spice says it should work. But no joy in the real world. I tried it with .1 uF caps -- nothing. I tried it with two fairly big 15 uF electolytics (as always, with the positive terminals to the collectors). No luck. Both collectors are just sitting there at .015 volts, both of the bases are at .6 volts. Sounds like both transistors are constantly at saturation, right?
Any other ideas? (I know I could do this with an IC, but I want to try to make it work with the simple two transistor circuit.)

Astable Multi-NON-Vibrator (Help!)

Having made good progress on my Ugly, Discrete Component, DC recever for 30 meters, this week I turned my attention to the little QRSS transmitter that I mentioned last week. The idea is to run this thing out at the country house. The inspiration here comes from Hans Summer's ultra-simple QRSS transmitter:

I ran into trouble this morning. The oscillator is running fine. But the little two transistor astable multivibator that is there to put some FSK on the signal is not vibrating. What am I doing wrong here? Instead of the BC-107s or 108s used by Hans, I'm using 2N2222s. Hans used 22uF caps. I didn't have any, so I just put two 10uF electrolytic caps in parallel. But nothing happens. It just sits there. Any ideas? Hans was running his rig off bleach batteries and was struggling to keep current low -- I don't have this constraint, so maybe by using lower value resistors to the collectors and bases?

Help me! Help me!

(I apologize in advance if this posting results in ads for other kinds of vibrators!)

Space Shuttle Over U.S. on Approach to Landing

This is an early Monday morning event. Lots of SolderSmoke fans within visual range of this flight path. (Somebody please alert Jerry, NR5A!) Spaceweather.com reports:

"Landing is scheduled for 8:48 am EDT, and it takes the shuttle about 35 minutes to traverse the path shown above. Observers in the northwestern USA will see the shuttle shortly after 5 am PDT blazing like a meteoritic fireball through the dawn sky. As Discovery makes its way east, it will enter daylight and fade into the bright blue background. If you can't see the shuttle, however, you might be able to hear it. The shuttle produces a sonic double-boom that reaches the ground about a minute and a half after passing overhead."

Please let us know if you see or hear it.

Colin's Power Meter

Hi Bill,

Thought you would be interested in the attached pics, one shows a power meter that a colleague made for me. I had mentioned to my colleague about the W7ZOI power meter after listening to SolderSmoke at work. A couple of days later I was presented with a power meter constructed from scrap parts! We work for a company that repairs cell 'phone base station equipment and the power meter was made from some scrap VSWR monitor circuits. My favourite part of the device is the heatsink fins on the 30dB attenuator along the top, which can be taken out of circuit by removing the SMA link. To use the meter, the 8V regulator is powered up and if any RF is present at the RF in, a voltage, which can be read by an external Volt meter, is output via the multiway connector. I use a ribbon cable, which has three connections used, DC (+&-) and meter test point. A graph plotting RF in against Volts out can then be used to determine measured RF.

The second pic shows a QSL card for a 17m CW contact I received for my contact with Ronny SM4RRF. I was using a low dipole and 500mW from an FT817! This was my 2nd ever CW contact.

73 and keep up the good work at SolderSmoke.

Colin M0CGH

Moonbounce Day!

Rafael in Mexico sent me some very interesting info about World Moonbounce Day. Today!

From: "MM"
Sent: Wednesday, April 07, 2010 3:06 PM
Subject: [amsat-bb] Arecibo on 432 MHz Moon Bounce

> Hi all:
> Here is a EME event you cant miss.
> Dust off your CW key, its time for Satellite, QRP EME.
>
> The 1,000 foot dish has 60 dBi on 432 mc and 400 watts.
> That comes out to be approximately 243,902,443 Million Watts ERP.
>
> enjoy
>
> wf1f
> www.marexgm.org
>
> (thanks to KB1MGI for passing on this data)
>
>
> Arecibo on 432 MHz Moon Bounce
>
> The Arecibo Observatory Amateur Radio Club will be putting the
> 1000-foot radio telescope on the air for 432 MHz EME from April 16-18.
>
> It can be heard with a small hand-held yagi pointed at the moon
>
> The scheduled times of operation are:
>
> April 16: 1645 - 1930 UTC
>
> April 17: 1740 - 2020 UTC
>
> April 18: 1840 - 2125 UTC
>
> Callsign: KP4AO
>
> Tx Frequency: 432.045 MHz
>
> Rx Frequency: 432.050 to 432.060+
>
> Tx power: 400 W
>
> Antenna gain: 60 dBi
>
> System noise temp: 120 K (cold sky)
>
> System noise temp: 330 K (when pointed at moon)
>
> KP4AO can be heard with a small hand-held yagi pointed at the moon and a
> good receiver. A 15 dBi antenna and 100 W will be enough to work us on
> CW.
>
> Operators at KP4AO will do their best to work as many stations as
> possible. Each session will start with a brief announcement and CQ in
> SSB. SSB QSOs may continue for 30 minutes to an hour, if the QSO rate
> remains high.
>
> The mode will be shifted to CW as soon as it is judged that higher QSO
> rates would result.
>
> We will listen for calls at frequencies 5-15 kHz higher than our own,
> and even higher if QRM warrants. Callers who s-p-r-e-a-d o-u-t are more
> likely to be copied.
>
> If you've already worked us in any mode, please do not call again --
> give others a chance.
>
> If we call "CQ QRP", we will listen for stations running 100 W or less
> to a single yagi. Please do not answer such a CQ if you are running more
> power or have a larger antenna.
>
> On April 18, if we reach a condition where most calling stations have
> been worked, and we judge that operating in the digital mode JT65B would
> produce a higher QSO rate, we will switch to JT65B.
>
> Note that any of these planned operating strategies may be changed as
> circumstances dictate.
>
> We are extremely fortunate to have been granted access to the world's
> largest radio telescope for this amateur radio good-will event. We look
> forward to working as many stations as possible in the alloted time!
>
> >From QRZ.COM

Homebrew Hero: Ed Roberts (RIP)

The Maker blog has a really great 20 minute podcast interview with Forrest Mims. He talks about his recently deceased friend Ed Roberts, founder of MITS and creator of the Altair 8800. The interview is really great. You guys will like it. Look for the little audio bar just underneath the article on this page:
http://blog.makezine.com/archive/2010/04/remembering_ed_roberts_the_father_o.html

Receiver Success! Combining Computers and Homebrew Radio

Well, it turns out that yesterday was a GREAT day for a new receiver. When I got home from work 30 meters was open. I fired up the new receiver and the FLDIGI program. Immediately I started to see and decode PSK-31 signals. I quickly switched over to the WSPR program and right away I could see the little two minute WSPR sigs. Here is what my screen looked like:

The program also began to automatically upload reports to WSPR HQ. Here is the report I found on the WSPR web site this morning:

I know all this WSPR and digi stuff often seems to be very computer-centric, and very "appliance radio," but I think this little project shows how we can have the best of both worlds: This rig combines a laptop computer and some pretty sophisticated software with a VERY simple, discrete component, homebrew direct-conversion receiver.

OK. So you see that I left a lot of space on the PC board. That's where the DSB transmitter (for WSPR and possibly PSK-31) will go.

BTW: You can keep an eye on my reception reports by going to the Database section of the WSPRnet site and plugging my call (I0/N2CQR) into the "reporting station" block. I'll leave the receiver on today.

A Bad Day for a New Receiver

Here is the latest picture of my version of the W3PM WSPR receiver. You can see the Ugly Weekender AF amp in the upper left. No front end of any kind yet -- the sig goes right from the antenna jack into the RF pin on the SBL-3 diode ring mixer.
Turns out that this morning was a bad time to test a new receiver. Spaceweather.com reports that a big coronal mass ejection hit earth today, causing havoc in the ionosphere. I'll try it again later today.

G0UPL's Ingenious QRSS Circuit

Just look at that circuit! That's a complete QRSS beacon transmitter, including a multivibrator (the two transistors on the left) to generate a recognizable pattern on the grabber screens. This diagram appears in SPRAT 134. Hans Summers ran this rig with just a couple of volts from his homebrew bleach-based battery system back in 2008. I plan on putting a version of this rig into the solar powered lawn lamp I showed you two posts ago (scroll down).

In other news, I finished building the Ugly Weekender AF amp this morning, and it passed the smoke test. My WSPR system went toes up this morning, so today I am QRSSing on 30 meters. I'm running my usual upside down FSK. Please let me know if you see me.

Colpitts Mania! Two Rigs Under Construction

I'm really into Colpitts oscillators lately. I blame Gene, W3PM. He reminded me of the fact that these little one transistor stages can pump out the 7 dbm needed to drive a diode ring mixer. Gene sent me a note warning that I'd have to take special precautions to ensure stability, but I found that this circuit never strayed more than 20 hertz in the course of a full day of oscillating.

Above you can see my version of the Colpitts circuit that Gene has in his very nice WSPR transceiver. You can see the SBL-3 diode ring mixer above the oscillator in this picture. I still haven't decided on the audio amplifiers.

I'm working on a second Colpitts circuit. This one is for a QRSS transmitter, also for 30 meters. Here I took my inspiration from Michael, AA1TJ, who has been working DX with power levels similar to that of this little oscillator. Long-time blog fans might recognize this board, or at least the device that it was used in. This is the board from my "DaVinci Code" 30 meter frequency standard, so called because I used a paperback copy of the Dan Brown novel as insulation for this weird piece of test gear. With my Kempton Park Frequency counter working, I had no need for the DaVinci device. But the oscillator was a Colpitts, capable of pumping out 10 mW all by itself... I plan on building a Hans Summers-style multivibrator circuit to put a distinctive pattern on my QRSS sig. It should fit nicely on the same board. I have a case and a power source in mind: see below. See if you can figure out where I'm going with this.

Workbench/P! Taking Solder on the Road!

Sure, lots of guys carry rigs with them to the field, on vacations, etc. But how about taking your WORKBENCH with you on trips? Perhaps only truly hardcore homebrewers reach this extreme.

It may be that with summer approaching, guys are getting nervous about being away from their beloved workbenches... This week I got three e-mails related to portable workbench operations:

Jim, AL7RV, sent in a nice shot (above) of his most recent workbench location. Jim says while he does not have racks and racks of sophisticated test gear, he does have lots of fresh air (and a nice view) while working on his projects.

Nicholas, M1HOG, sent me a web page describing the portable bench he put together for use at his country cottage. While out there, he said he had "started to miss the delights of melting solder." We hear you Nicholas! Nice solution:
http://www.m1hog.com/projects/elecraft-kx1-building/elecraft-kx1.html

Finally, Rogier, PA1ZZ & KJ6ETL, reports on some very nice cabinets that seem ideally suited to this kind of work: http://www.gerstnerusa.com/

This is all great, but I think we have to draw the line somewhere. How about this: No soldering while driving!
No soldering while in flight on an airliner!

Soldering Irons to the Field! EXCELSIOR!

Success! Uganda WSPR Station On The Air!

Isn't it beautiful? Like an RF palm tree rising out of Uganda. That's a map display of the stations that have received the WSPR signals of 5X7JD in the last 24 hours. Not bad considering that Jack's rig is running one watt and that we are in the midst of a pretty massive geomagnetic storm.
This is a beautiful story for several reasons: Technically, the rig is very elegant. But even more appealing is the human aspect of this operation: This is a real "International Brotherhood of Electronic Wizards" story. First, Jack Dunigan goes to Kampala to help kids who are struggling with AIDS. Then Gernot, OE1FM, jumps in and designs and builds an ingenious rig that will allow Jack to run a WSPR beacon from Uganda. For more details, check out Jack's web site: http://hamradiosafari.com/ I got a kick out of his mention of a certain station in Rome that is running a 200 mW WSPR beacon. (And I'm looking forward to Jack's article on Kampala's "Radio Row" -- I suspect it will be a lot like Santo Domingo's.) Three cheers for Jack! Three cheers for Gernot! Three cheers for Joe Taylor! Three cheers for the International Brotherhood of Electronic Wizards!

SolderSmoke Book Helps With License Upgrade SAVE 10%!

Thanks to all those who are helping to get the word out about "SolderSmoke -- The Book." I put together a web page about the book:
http://soldersmoke.com/book.htm Lulu is running a sale: 10% off during April. Coupon Code: SHOWERS

I got a very gratifying e-mail from OM Walter. I was very pleased to hear that the technical portions of the book helped him in his license upgrade efforts:

Bill,

Just thought I would drop you a note to let you how much your podcasts and book have influenced my life (for better or worse). I have been listening to you podcast since last summer and have all of them on CD and have listened to them all. Living in Florida for the past 10 years I have not been active because I thought I could not get a proper station and antenna setup here (HOA restrictions). Boy was I wrong. Late last year I bit the bullet and bought a Icom 703+ QRP rig and hooked it to my computer for digital modes. Antenna of choice? A PAC12 vertical antenna kit. The antenna is indoors sitting on a small photo tripod.

With this setup using PSK and RTTY I have over 1/2 of the US confirmed and 8 countries including England and Germany. I am having a ball. My wife calls it "Playing with Radio's". At least she knows where I am...

Next steps is to get my code speed up and I have a couple of kits on order (QRP of course).

Your book was instrumental in me ugrading from General (N2LTB) to Extra (AJ4UM) in Dec 2009. Read your book and used the ARRL study guide. Your explanations hit home and I believe made studing for the test easier. Also very entertaining.

Thanks again for all you do for the Ham community and keep it up.

Walter

AJ4UM

Geo-Magnetic Storm! Aurora as seen from orbit

Batten down the hatches my friends. The solar wind is blowing, and we're in a geo-magnetic storm. Well, we were anyway, yesterday. Astronaut Soichi took this amazing picture of the resulting aurora.
No WSPR spots of my little signal this morning -- I blame it on the storm.
You can see some interesting discussion of the storm conditions on the WSPR live-chat system. Here is a sample of last night's commentary:

How much AF amplification needed between diode ring and a sound card?

Progress continues on my WSPR direct conversion receiver. The Colpitts oscillator is working nicely and is very stable. Yesterday I glued an SBL-3 diode ring to the board and hooked it up. With my 'scope and sig generator I can see it turning 30 meter RF into audio. So far so good.

Now it is time to build the AF amp. Here's my question: How many db do I need? The standard 100 db DC RX AF Amp seems like a bit of overkill -- this thing won't drive a speaker or a headphone, but instead, a computer soundcard. What do you guys think? How many db?

SolderSmoke Podcast #123

Listen at: http://www.soldersmoke.com

SolderSmoke #123
4/1/2010
Spring! Equinox! Sap in Vermont! Aurora in Norway! Birds singing in Rome!

SolderSmoke on Oprah. Program Schedule:http://www.soldersmoke.com/oprah.html

Special Report from MASSCON QRP Convention by Mark, NX1K
Propagation improvingWSPR as a personal sunspot detector
Building the W3PM WSPR rig
Colpitts oscillators
Polyakov's "Russian Mixer" BANDSWEEP: A low-frequency sweep by Chris, KD4PBJ
EMRFD on Direct Conversion and Direct Aversion
Faraday's toroid diagram
NA5N's ISBN
MAILBAG
SolderSmoke--THE BOOK:
http://stores.lulu.com/store.php?fAcctID=3999032
SolderSmoke--THE STORE:
http://www.cafepress.com/SolderSmoke

AA1TJ on Polyakov, Scrounging Parts from a Wehrmacht Tank, QRPp Success

Caro Bill, FB on your 20mW DSB WSPR DX! I've never actually been on the air during the upside of a solar cycle. This is wicked exciting! Thank you for the nice write-up on your Soldersmoke Blog, OM. I heard back from Fabio this morning; he seems to be as excited as I am (please see his message below). Italy is my fourth DX contact and third country with 10mW. Two weeks ago I worked F5NBX twice and FM5LD once. Again, all great fun... I'm glad to hear of your interest in the Vladimir Polyakov's mixer. I can attest to Vlad's claim about its resistance to SWBCI. So far, I've used silicon and germanium diodes, MOSFETS, and even a saturating inductor for the subharmonic, commutating switches. I haven't mentioned it till now, but leading up to my Gigi regenerodyne receiver, I built Polyakov reflexed 40m receiver that was lots of fun. The RF input signal first passed through a simple BPF on its way to the cathode of a triode, grounded-grid RF amplifer. The amplified signal next passed through the Polyakov anti-parallel diodes. The resulting AF signal was then re-injected into the grid of the same triode (now working as a common-cathode amplifier). In typical "reflex' fashion, the same tube amplifies first at RF and again at AF. Looking at my notebook entry, I was able to "plainly hear" a 1.0uVrms signal and in a week of operation I hadn't noticed any SWBC breakthrough. Actually, the subharmonic mixer was well-known by 1976, but I'd never seen it used by hams at HF until Polyakov popularized the idea. Our Eastern European comadres took a liking to it right away but it took some time before it finally caught on in the West. By the way, I had a short email exchange with Vladimir a few months ago. I'm pleased to report he's a really nice fellow. He happened to mention that his first amateur radio transmitter was built using parts that he salvaged from an abandoned Wehrmacht tank. It seems radio components were extraordinarily hard to come by in those days. Amazing... Have fun, Bill! Mike, AA1TJ ---------- Forwarded message ---------- From: Fabio Ventrone Date: Sat, Mar 27, 2010 at 9:16 AM Subject: Re: IZ0PEC de AA1TJ/QRPp To: Michael Rainey Dear Michael, Many many compliments for your qrpp station! Really exciting to have qso in this conditions... It's actually the first time I can connect qrpp oversea... Unbelievable, something we can tell our friends forever!!! I was transmitting with 4 el antenna and something more than 100w. I will have to take back my 817 and try to call dx as you bravely did!!! Best 73 qsl Fabio de IZ0PEC 2010/3/26, Michael Rainey > Dear Fabio, > > Thank you for your patience in copying my signal on 20m CW this evening. I > had been calling DX stations for several hours but you were the only one to > answer. My homebrew rig has an output power of only 10mW (0.010 watts). The > distance between us is 8793km; nearly one million km per Watt!. The antenna > here is simply an end-fed wire. > > I am amazed that you heard my 10mW signal in Rome. It's fantastic! > > Again, thank you for patiently listening for my weak signal, OM. It would > not have been possible without your very kind efforts. > > Ciao, > Mike, AA1TJ

Building W3PM's Colpitts Oscillator

I took a break from all the computer stuff and decided to melt some solder this weekend.

W3PM has a neat WSPR rig on his site. I decided to build at least parts of it. Today I put together the Colpitts oscillator. I really like this circuit -- it produces enough power to drive a diode ring mixer directly. Mine went together very smoothly. Sure enough, mine produces about 10 mW.

It was good to get back to solder melting. I used circular pads sent to me by Jerry NR5A. And parts sent by Jim AL7RV, and by Mike AA1TJ. EMRFD provided very useful background info on the circuit. I powered the prototype up with my Kempton Park power supply with the current limiting chip provided by Tony G4WIF. So it was a like a team effort. Thanks to all!

I'll try to get the next podcast out mid-week.

73

Polyakov Plus! Dual-band Receiver with Subharmonic Mixer

I found it! SPRAT 110, Spring 2002, page 5. A short article by OM Rudi Burse, DK2RS. This is the variation on the Polyakov Russian Mixer that I mentioned a couple of days ago. I'd been digging through piles of books and old magazines looking for this. My wife thought I'd gone nuts. (Well, nuttier than usual, actually.) It didn't help that I responded "The Polyakov Russian sub-harmonic mixer circuit with two band application!" when she asked what I was looking for. Of course, I should have known that it was in SPRAT. It just happened that the issue with this article was piled under a lot of junk on the workbench. I really like this circuit. Ingenious. And now that I have come to understand mixers a bit better, I can appreciate this one more. Here's how I'd explain it: With the switch closed, the signal from the LO "opens" one of the diodes on the positive peak, and it opens the other diode on the negative peak. So that RF signal from the antenna is getting sampled and mixed twice each cycle of the LO. The resulting complex waveform has sum and difference frequencies of RF+2LO and RF-2LO. With the switch open, you only have one diode sampling the RF, and it opens only ONCE each LO cycle. So the complex waveform that comes out of this single diode had frequencies of RF+LO and RF-LO. This opens the possiblity of DC receivers for 80/40, 40/20, 20/10 meters, etc. I guess a key adjustment in this circuit would be getting the LO level just right. Thanks SPRAT! Thanks Rudi! Thanks Vladimir Polyakov!

You'll see in the comments attached to my last blog post that our man on the left coast, Steve Smith, gave that cute little Doug DeMaw/Vlad Polyakov receiver a name that might set American-Russian hamrelations back a bit: He called it "Vlad The Inhaler." Good one Steve! (But you might want to stay out of the diplo game!) 

Check out "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm

Sunspot 1057 Doing Good Work for US!

I got up early this morning, and so did 30 meters. Take a look at the WSPR signal reports that greeted me (below). My 20 mW DSB signal was making the trip to Norway and the UK through most of the night. And at 0256 W1BW picked it up. A visit to the excellent spaceweather.com website reveals that this is probably the work of sunspot 1057. Rogerio Marcon took this picture of that sunspot on March 24 from his backyard observatory in Brazil. (This and a recent thread started by Chris Trask on QRP-L make me think that I NEED a solar telescope.)

My e-mail inbox also had evidence of good HF conditions. Take a look at this from AA1TJ:

IZ0PEC de AA1TJ/QRPp

Thursday, March 25, 2010 9:52 PM

From:

"Michael Rainey"

To:

f.ventrone

Dear Fabio,

Thank you for your patience in copying my signal on 20m CW this evening. I had been calling DX stations for several hours but you were the only one to answer. My homebrew rig has an output power of only 10mW (0.010 watts). The distance between us is 8793km; nearly one million km per Watt!. The antenna here is simply an end-fed wire.

I am amazed that you heard my 10mW signal in Rome. It's fantastic!

Again, thank you for patiently listening for my weak signal, OM. It would not have been possible without your very kind efforts.

Ciao,
Mike, AA1TJ

Polyakov's Russian Mixer

I'm planning on building a DC receiver for use with the WSPR system. I will probably follow W3PM's lead and put a crystal filter between the antenna and the mixer. This will be a fixed frequency receiver aimed at one 200 hz slice of the 30 meter band.

Of course, the big question is what mixer circuit I should use. I'll probably go with an SBL diode ring, but while perusing the literature, I again came across "The Russian Mixer" of Vladimir Polyakov, RA3AAE. Michael, AA1TJ, is a big fan of this circuit, and has been talking about it on Radio Havana Cuba. What a cool circuit it is! Just two diodes in parallel, cathode to anode. RF from the antenna goes in one side, and the local oscillator signal is placed at the other end. The LO signal causes the diodes to turn on and off on voltage peaks, effectively chopping up the incoming signal, producing sum and difference frequencies. LA8AK's drawing of one version of this circuit appears above. (Obviously OM AK didn't like this configuration, but it gives you the idea.)

The really cool part is that because you have two diodes, the "chopping" takes place at TWICE the LO frequency. This happens because on a positive LO peak one of the diodes conducts, and then, on the negative peak, the other conducts. So it is as if the mixer gate is opening twice each LO cycle. This allows you to run the oscillator at half the operating frequency, with advantages for stability and for the effort to eliminate common mode hum.

A while back I saw (somewhere!) a clever use of this circuit. LO was running at around 3.5 Mhz. With the two diodes in the circuit, it was a 40 meter receiver. They had a switch that could remove the second diode from the circuit. By throwing this switch, the RX went to 80 meters.

Does anyone remember this circuit? Where did it appear? SPRAT? QQ? Tech Topics? I can't find it.

I had the impression that OM Polyakov was active in the early days of radio. But some Googling shows that he is of much more recent vintage, still active and listed on QRZ.com. Here he is:

Was Marconi the First Radio Amateur?

Steve, WG0AT, posed this question in the title line of his latest (excellent) video. I really liked the recordings of Marconi speaking in English. (I'd heard him in Italian, but never in English.)

So, was he one of us? I say yes. Definitely. Why? Because he very clearly had what we would call a shack. This is discussed in SolderSmoke -- The Book. When his mom saw that his tinkering with electricity had some potential (!), she had an attic room in the family home near Bologna configured as a workshop for her Knack-afflicted son. And there he tinkered. Just as we do.

Dino's Awesome Workbench

People send me these images, and they are so good that I feel compelled to put them on the blog. From Dino:
-------
Ok, can't stand it anymore....had to show off my workbench as well. BTW, will be making a presentation at Dayton Hamvention in May on "Building Your Ham Radio Workbench." So if guys have any great ideas to pass along would love to hear them and include as possible. Am gearing this toward the beginner and focusing on basics, soldering equipment, tools, safety, the bench, parts accumulation, etc. Over the past two years have made pitches at Hamvention on Test Equipment and Station Engineering Manuals....always lots of fun.
73 -- Dino KL0S

AA0MS's FB Workbench

Doug, AA0MS, sent us this nice picture of his workbench and operating position. (That looks like a nice oscilloscope!) Doug is blogging at http://aa0ms.blogspot.com/ Lots of good stuff there about his electronic adventures. I liked the pictures of the old homebrew gear that his dad built. Thanks Doug!

The FUNKY Keyer

Paul up in Manchester has some really intriguing ideas on CW and keyers. He likes highly personalized CW from straight keys, and thinks he can even hear the influence of Latin-based languages when receiving signals from stations in France and other Romance language countries. (Like me, he also thinks a bit of homebrew chirp adds some character to signals. ) Automatic keyers seem to squeeze all of the individuality out of CW. So Paul has written some computer code to put that individuality back in! Can we get a "Lake Erie Swing" option Paul? Check out Paul's blog. Interesting stuff!

Hi Bill

Further to the kind words of introduction you gave me as a “new homebrewer” in Soldersmoke 104, I’m writing to let you know about a little project of mine which I think you might appreciate…

I made a h/b keyer a while back and recently added the ability to send automated 3*3 cq calls (and cq FISTS calls).

On doing this, I realized how much I HATE the sound of machine generated CW – so mechanical and lifeless. I want to hear a real fist – preferably with some chirp and drift thrown in for good measure!

So – I’ve come up with an alternative – The FUNKY keyer!

It adds some random timing "jitter" to each automated cq call, to simulate the sound of a real fist on a straight key.

You can read all about the Funky Keyer on my blog, http://m0xpd.blogspot.com

The blog also documents some of the other outcomes of my personal puffs of solder smoke, including the “Funster PLUS” 40m CW Transceiver and the “Not-so-superhet” experimental valve receiver. There’s some operating stuff, including WSPR on 40 and 80m with my Softrock SDR and I was inspired by Soldersmoke to include some travelog – ZL, VR2, BY, HB, etc.

Hope you enjoy it.

Let me take this opportunity to thank you for all the enthusiasm and inspiration you continue to give us in Soldersmoke,

73 de Paul, m0xpd

Paul Darlington

Vernal Equinox!

Today marks the Vernal Equinox, an important day for QRP radio amateurs. In the Northern Hemisphere, conditions usually start to improve. And this year's equinox is accompanied by higher sunspot numbers. So cheer up guys! Better conditions are on the way.

The equinox comes at 1732 UTC today, 20 March 2010.

Spring seems to be getting off to a good radio start here in Rome. My 20 mW WSPR signal made it across the pond this morning, 8289 kilometers to W3HH (see below). This was the first signal report of the day. I only seem to cross the pond around my local dawn -- never around sunset.

Date/Time TX station SNR PWR RX Station Grid km az
2010-03-20 05:44 I0/N2CQR -7 0.02 PE1DCD JO21fu 1262 334
2010-03-20 05:44 I0/N2CQR -20 0.02 DF6DBF JO31si 1116 342
2010-03-20 05:42 I0/N2CQR -17 0.02 PE1DCD JO21fu 1262 334
2010-03-20 05:40 I0/N2CQR -15 0.02 PE1DCD JO21fu 1262 334
2010-03-20 04:40 I0/N2CQR -29 0.02 W3HH EL89 8289 296
2010-03-19 21:22 I0/N2CQR -28 0.02 LA6TPA JP54rl 2512 359
2010-03-19 21:16 I0/N2CQR -30 0.02 LA6TPA JP54rl 2512 359
2010-03-19 20:54 I0/N2CQR -29 0.02 LA6TPA JP54rl 2512 359
2010-03-19 20:02 I0/N2CQR -29 0.02 G4KFK IO91pk 1457 321

Look West OM! (For Venus)

Billy and I were crossing the Tiber River's Garibaldi Bridge yesterday at sunset. Off to the West, with St. Peter's Basilica in view, we go a nice view of Venus under the crescent moon. Venus is now back as our "evening star." Also visible from the bridge is the "lighthouse" up on the Janiculum ridge. It's like a real light house, but it flashes the colors of the Italian flag. Very nice.

G.W. Pierce and the AA1TJ GiGi

Mike, AA1TJ, continues to provide the global solder-melting fraternity with large doses of QRP/homebrew inspiration. And, as usual, his latest series of messages to QRP-L contain interesting references to the radio pioneers who laid the ground work for his low power exploits. This time, it was G.W. Pierce.
-------------------------------------------------------
From AA1TJ on March 8, 2010:

Fellers,

It was an exciting QRPp afternoon here on 20m. It started off well
with a ten minute contact with G3MJX. Tony was running 5w to a dipole.
I'm still using the breadboard, two-tube, 250mW (Gigi) station that I
wrote about last week.

KB0PCI in Minneapolis was my next contact. Wayne was using 5w to an
indoor loop. I thought that was pretty cool.

Things seemed to be going so well that I felt the urge to further
reduce my output power. Dropping back to 56mW, I soon snagged Jack,
W7CNL. He's out in Boise with 5w and a five-element Yagi. It was a
great contact with 579/539 reports.

After we signed I resumed calling CQ. Sometime later I heard my call
coming back at me; always a happy moment when you're running QRPp. But
wait...he's signing DH1BBO...Holy Toledo!

With a pounding heart I sent off a 559 report. Olaf came back with a
529 for me, and get this...he says he's running 300mW to a windom! The
first round was an easy copy for both of us, but thing got a little
rougher after that. Still, we were able to hold it together through
the finals for a complete QSO.

Again, my transmitter circuitry is right out of 1928; a
crystal-controlled, push-pull oscillator using a single, 3A5 (a
twin-triode introduced by RCA in 1942). The receiver uses a second
3A5. The first triode forms a crystal-controlled autodyne converter.
The second stage is a standard regenerative detector driving the
headphones directly. My antenna is an end-fed wire at 35'.

Anyway, it was one of those QSO's that I dream about; QRPp on both
ends from start to finish, wire antennas at both stations and an
ultra-simple rig from the days of yore. It was Olaf's first QRPp DX
contact ever, and 57mW now stands as my lowest USA-to-Europe contact
power (230mW was my previous best).

As for working a 300mW German station with a receiver made from a
twin-triode; I think it's a testament to what these little
regenerative detectors are capable of. I was awestruck at the age of
12 or 13; having built my first genny. I love 'em no less some forty
years later as they truly are a beautiful technology.

73/72,
Mike, AA1TJ


From AA1TJ on March 3, 2010:
Bill,

Gigi worked AA7VW (running 5w to a Moxon) in Oregon today with 250mW.

I've been reading a bit of history here in preparation for my
presentation at MassCon next week. For example, I've traced the
crystal-controlled, push-pull transmitter (used in Gigi) as far back
as 1928. Cady and Pierce did their ground-breaking work on quartz
crystal-controlled oscillators in 1923, so it didn't take long for
hams to jump on this one. BTW, Professor George Washington Pierce
("G.W." to his friends) was a real character!

I send my best wishes to you and the family, Bill. The sap has just
started flowing here this week. It's Maple sugaring time in Vermont
again. Spring can't be far away now.

73/72,
Mike, AA1TJ

----------------------------------------------------------

Here is a bio on Pierce: http://profiles.incredible-people.com/george-washington-pierce/

This all makes me want to reconsider my opposition to regens... Maybe they are NOT possessed.

Online Preview of SolderSmoke -- The Book, SALE!

I was working on the websites for SolderSmoke -- The Book, and I managed to set it us so that you can get a preview of the first part of the book. Just click on one of the links on the upper right hand side of this blog page, and look for the preview link (under the picture of the front cover). Lulu is running a 10% off sale this month. Use the coupon code "IDES" when you check out. (Very approriate - tomorrow marks the Ides of March.)
SolderSmoke Store on Lulu: http://stores.lulu.com/store.php?fAcctID=3999032

Hamfest tips, 12 Volt Tubes and Cigar Box Radios

Bill,

Enjoyed very much listening to your adventures in the UK - I very much want to visit Faraday's lab!

When going to the next radio rally/hamfest, can I respectfully suggest the following:

A jacket or waistcoat with lots of pockets, the bigger the better. A backpack with some more bags inside. An idea also would be some kind of lock or restraint so that you could lock a full bag to a post or something out of the way in case you buy something heavy - I usually ask a stall-holder to look after a bag which they are often willing to do after I have made a reasonable purchase from them!

In one of the pockets put a small multimeter with a working ohms range - to test transformers, coils, valve heaters, etc. before purchase.

In another pocket put valve/transistor (or whatever you are interested in) data books or have a handheld thingy (iPhone, etc.) with a working Internet connection where you can look up such things.

In another pocket put a calculator (not needed if you have a handheld thingy) and a small notepad and pen/cil to make notes and work things out and compare prices from competing stalls.

A camera to take pictures of beautiful things you have no money for or intention of buying.

Some personal news:

Currently building a one-valve BC FM receiver - lots of fun. Recently built a MW 2-car-valve superhet which I listen to the World Service on here in Brussels. I build them into Cuban cigar boxes my missus gets free from tobacco shops around the city and in airports.

The fridge broke down and I discovered it was the thermostat and so I decided - foolishly - to spare the money for the replacement part (unemployed) and build one from components I already had in the radio room. Big mistake. I have been fiddling with different resistor values, broken Veroboard tracks and recalcitrant 740 op-amps for weeks now. Managed to freeze an entire bag of perfectly good carrots! I think I am on the tail-end of the prototype development process now and the production model should emerge in a week or so. The missus was initially impressed but now, sadly, not so. C'est la vie.

I experimented with QRSS using a simple PIC-controlled single car-valve crystal-regulated transmitter and a crystal immersed in a large jar of water for temperature stability. I managed to get seen by various grabbers and so am moderately happy. WSPR might be on the boards next, if I can do it with a PIC and a valve...

Good luck with the RC aeroplanes - try and keep the propellor pointed away!

73 cheers
Nick on4Nic / m0NjP

PS Car-valves are designed to operate from 12V only - heater and HT. Great fun for fiddling around with and completely safe - so long as you don't break them or burn yourself on the glass!

Cool Phobos Picture

This one is not from the recent fly-by. This one was taken by ESA's Mars Explorer in January 2007. I thought it was a very nice picture. There should be new close-ups of Phobos coming out this week.

Windows 2000, SMT, Olive Oil, Difference Engines

Hi Bill:

Just finished listening to SS 121. Fascinating as usual. In no
particular order:

- Microsoft is ending all support for Windows 2000 effective July
13th of this year. For us little guys there's only one impact, but
it's a doozy: no more security patches. My bench computer is still
Win 2k, so he'll either be losing his connection to the interwebs or
get replaced (don't think his little brain would take the current
Ubuntu release, but perhaps I'll give it a shot.) I'm a pretty tech
savvy guy so I've got no problem moving on, but I hate to toss
perfectly good hardware. Heck, I've got a 1965-vintage USAF surplus
VOM and a Fluke LED readout DVM on my bench (both relatively new to
me!) The scope, power supply and sig gen aren't much newer. I
think the odd duality of hams you pointed out (tech forward and also
sticks-in-the-mud) is another expression of an engineering mindset
that doesn't accept that the new must devalue the old.

http://blogs.technet.com/lifecycle/archive/2010/02/25/end-of-support-for-windows-2000-and-extended-support-phase-transition-for-windows-server-2003.aspx

- I'm starting to think the Sun has dropped life-cycle support for
HF, effective when I got my HF privileges. I'm following your weak
signal work with a lot of interest.

- I think I mentioned previously that I got to see the Babbage
Difference Engine #2 last fall. After hearing your Dobsonian
maintenance story using "API Grade Extra Virgin" olive oil, I thought
you'd be amused to hear that the BDE is lubricated entirely with corn
oil, which is apparently available in a variety of SAE weights. I
thought they should put a Bunsen burner under the drip pan and make
popcorn in there, but the docents weren't too impressed with my
engineering suggestions.

- SMT: I got my first serious taste of SMT while building, of all
things, a Nixie clock. It had two large quad flat pack (QFP) chips.
They weren't involved in the processing (which was done by a proper
DIP packaged PIC chip) but were the HV drivers (apparently actually
intended for use in a plasma TV). The manual instructed me to tack
down the corners, verify the alignment of all the unsoldered pins,
then just heat 'em and solder 'em down, ignoring pin-to-pin shorts.
After soldering all the pins, it then said to lay a piece of
desoldering braid on top of each run of pins, and heat it until the
excess solder wicked up. I was dubious, to say the least. But to my
complete surprise not only did the clock work on the first try
(meaning all 80 pins had been soldered correctly) but the chips
actually looked pretty good, too. Still a bit nerve wracking!

- In the "keeping old computers working" department I just ordered a
solid state drive to replace the oddball 1.8" drive in the little Dell
I use for travel. It runs Ubuntu pretty well, but I have to have Win
7 on there for work reasons, so I'm hoping the SSD will speed up the
latter (and not blow up the former - Linux and new technology haven't
worked out well for me in the past).

73,
Bob KD4EBM

Faraday's Transformer Diagram

Looks familiar, doesn't it? Reminds me a lot of the toroidal transformer diagrams that you see in the Doug DeMaw books. This is from an 1831 lab notebook of Michael Faraday.

Faraday's Shack and the First Transformer

In London, Billy and I visited Faraday's workshop in the Royal Institution. Poor Michael set up shop in the servants' quarters in the basement. The shop is still down there (behind glass and well-preserved now). The painting above depicts Faraday at work in his shack.

On display was the very first electrical transformer. And guess what guys: It was a toroid! Here is a picture of it:

I found one of Faraday's drawings of the toroidal transformer and its windings. It looks a lot like the drawings of Doug DeMaw! I'll scan it and post it tomorrow. Off to work now.

Pop Sci! 137 years of Popular Science. Free. Online.

I know I promised more about Faraday today, but I think Michael would agree that this story should take precedence. Niels, PA1DSP, reports that ALL 137 YEARS of Popular Science issues have been made available FREE ON-LINE. This is Billy's favorite magazine. Amazing. We're all going to have to quit hour jobs to have more time for this kind of thing! Three cheers for the publisher and for the boys at Google for making this possible. Here it is:
http://www.popsci.com/archives

At the Royal Institution

The Royal Institution in London is one of the world's most important scientific organizations. In the picture above, Michael Faraday delivers one of the famous "Christmas Lectures."

Billy and I visited the RI a couple of weeks ago and got to sit in the famous theater.

I even got to stand at the famous desk on which so much new science was presented to the world. More on the RI (and Michael Faraday) tomorrow.

Marconi's House in London

In London, the places where famous people lived are marked with Blue Plaques. I knew that Marconi's name was on the list, but I had never actually seen his plaque. When we were up in London last month we were staying in Marconi's old neighbourhood (Bayswater) so and Billy and I decided to take a look. Video by Billy.

This house is mentioned in the book Thunderstruck by Eric Larson and in Peter Jensen's wonderful Early Radio. Marconi lived here as a young man. His mother took him to London in order to get patent protection for his wireless invention. The way in which Marconi's mom watched out for her son's intellectual property rights reminds me of the way Bill Gates' dad watched out for his.

Marconi's arrival in the UK was a bit difficult. British customs officers were apparently very suspicious of the strange device being brought in by the young Italian. One book hinted that they might have thought that Marconi was involved in some plot to kill Queen Victoria. During the inspection serious damage was done to Marconi's rig.

Dover update: Falling from tree, B2 inheritance?, HB variometer

That's me (the new boy in the workshop) at the key of Ian G3ROO's B2 spy set. Beautiful rig. You will all, I'm sure, understand Nigel M0NDE's question to Ian (see below). The Dover variometer project is very interesting (picture at the bottom). Thanks Nigel! (Try to keep Ian at ground level, OK?)

Hi Bill, a Dover construction club update:

Ian was cutting down some trees in the garden this weekend, and took a tumble. As he fell I asked him if I could be left the B2, I can't tell you exactly what he said but you can imagine. Fortunately he was not injured as the ground was soft with all the rain we have had. The B2 remains in the museum for now.

The black hole has taken the variometer from us forever so a new one was made Thursday night at club. You got the blame tonight for anything that was not in its proper place when sought, the new boy in the workshop always takes the blame!

A length of plastic drain pipe was selected. A coil of about ten turns was wound around a large capacitor as a former and tied off with beeswaxed rafia then mounted onto a plastic rod. The plastic rod had a hacksaw slot put in it lengthwise to facilitate the copper wire exiting the plastic pipe. The plastic pipe was drilled and squeezed and the coil inserted into the pipe. The rod was held in place by friction fit brass washers. Two coils were wound around the plastic pipe,in similar directions. The wire is just tensioned by being passed though holes and threaded in and out of the pipe at each end. A plastic screw allows the inner coil to move through just 180 degrees. The first test showed two inductance ranges were possible 6-12 micro Henries and 12 to 21 mH. We will add additional coils up the pipe to give 21 to 30, 30 to 40 etc. A ten meter fishing rod will form the vertical element, with this variometer and switched coils providing the tuning. The experiment continues next Thursday night.

73 de Nigel Evans M0NDE QTH Dover

African WSPRs -- Homebrew, QRP, and International Brotherhood

Jeff, K07M, and others have noticed that the WSPR system's maps show very few stations in Africa. Gernot, OE1IFM, has launched a fascinating project to help fill this WSPR-gap. He has designed and built a stand-alone WSPR transmitter. No computer is required. It is all in two little boxes. It pumps out 1 watt of WSPR signal. And -- get this -- it jumps around from band to band, transmitting a sequence of WSPR signals on all of the HF ham bands. WSPR requires good synchronization. How, you might ask, does Gernot keep these rigs in synch without a computer and without the internet? No problem: He uses time signals from GPS satellites! Bravo Gernot! One of these rigs is currently on the air from Namibia (V53ARC). You can see it in the screen shot above (taken this morning).
Here is Gernot's creation. Isn't that beautiful? Note the "Homebrewed by OE1IFM" markings on the boards. Truly inspiring stuff!
But there's more: A while back we had a blog entry on Jack Dunigan, 5X7JD. Jack is in Uganda, helping kids who are living with AIDS. Today, one of Gernot's WSPR rigs is scheduled to be delivered to Jack. So soon we should be seeing WSPRs out of Uganda.

You guys should check out Gernot's web pages on this project:
http://www.oe1ifm.at/index.php?option=com_content&view=article&id=52&Itemid=53
His site is filled with really interesting technincal info on this amazing rig.

I found this endeavor to be inspiring at many levels: There is obviously a lot of Knack here, and this is a very good example of what the "International Brotherhood of Electronic Wizards" can do.