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Wednesday, March 31, 2010

SolderSmoke Podcast #123

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

SolderSmoke #123
Spring! Equinox! Sap in Vermont! Aurora in Norway! Birds singing in Rome!

SolderSmoke on Oprah. Program Schedule:

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

SolderSmoke--THE BOOK:

SolderSmoke--THE STORE:

Tuesday, March 30, 2010

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

Sunday, March 28, 2010

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.


Saturday, March 27, 2010

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

Thursday, March 25, 2010

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:


Thursday, March 25, 2010 9:52 PM
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.

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:

Wednesday, March 24, 2010

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.

Tuesday, March 23, 2010

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

Monday, March 22, 2010

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!

Sunday, March 21, 2010

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

Saturday, March 20, 2010

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

Thursday, March 18, 2010

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.

Wednesday, March 17, 2010

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:

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.

Mike, AA1TJ

From AA1TJ on March 3, 2010:

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.

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.

Sunday, March 14, 2010

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

Saturday, March 13, 2010

Hamfest tips, 12 Volt Tubes and Cigar Box Radios


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!

Friday, March 12, 2010

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.


- 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).


Thursday, March 11, 2010

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.

Wednesday, March 10, 2010

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.

Monday, March 8, 2010

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:

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.

Sunday, March 7, 2010

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.

Saturday, March 6, 2010

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

Thursday, March 4, 2010

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:
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.

Book Review (and a price reduction)

Lulu is having a sale this month. Just enter the coupon code IDES at checkout and save 10% on SolderSmoke -- The Book

Dale, G4IPZ wrote this review of the book:

It's not often that I've come across a book that combines the fun of Amateur radio along with understandable explanations of difficult technical concepts as well as being a damn good read.
This book not only achieves this but does it perfectly.
It's described on the back cover as "... the story of a secret, after-hours life in electronics." Why after hours? Well because the author, Bill Meara (N2CQR, M0HBR, CU2JL) is a diplomat, a consul for the United states of America, having been posted to such diverse locations as Rome, London, Panama, El Salvador, the Dominican republic and many other places.
During his career as a diplomat his hobby of ham radio and in particular QRP and home-brewing has followed him around the world.
He admits that he did take time out for a while on meeting his future wife and then marrying her. Then, as so many of us have done before, he began to be drawn back into the hobby; the warmth of the shack, where on a cold night, he could sit clutching a hot coffee, listening to the bands, talking to friends and surrounded by the smell of solder smoke.
During his years as a diplomat-ham he has spent much of his free time trying to understand some of the whys and wherefores of the circuits he was building, attempting to build and attempting to fault find when they didn't work. And so many of us have been right down that road!
And that explains what this book is; it's a form of diary of Bill's Eureka moments combined with an insight into his travels and life as a diplomat.
The technical range covered is quite large and despite all my years in electronics I found many of his eureka moments clarified some of my ingrained foggier thinking.
For example we all know how mixers work. Or do we? How many of us can actually explain what goes on even in the simplest of two diode balanced mixers? Most of us just accept that, by the black necromancy of radio in which we dabble, fearing the release the magical smoke at the wrong moment, it just mixes and that's that.
But Bill took time to ask, query and eventually, by making notes to himself, come to understand what was going on. And his explanations of mixers and other such subjects are indeed highly illuminating. He explains semiconductor principles (Do you really understand hole flow versus electron flow?). And how about resonant circuits for example? Bill explains these and much more in a refreshing new way along with capacitors, crystals, and a host of other often accepted but often not fully understood truths that we, as amateurs just take for granted.
This is an ongoing life's trip through the hobby which we all share with Bill, and remember that he is not a professional electronics engineer; he is a radio ham who wants to be more than an "appliance operator".
He enjoys tinkering and has stuck with some pieces of equipment for more years than I will mention but it hasn't stopped him working through the satellites and bridging the oceans on less watts than a nightlight.
And as well as his obvious love of his hobby, he introduces us to many of the other amateurs he has met on his travels and at his various postings. He paints a wonderful picture of the people that many of us may get to meet on the air but he's been lucky enough to meet face to face.
And as well as doing all this he also ventured into the world of Pod-casting and blogging, the outputs which has reached thousands world-wide on his SolderSmoke website.
I cannot recommend this book too highly and I found that it was one which I couldn't put down until I'd finished.
Dale Haines G4IPZ

Wednesday, March 3, 2010

Black Holes in Workshops?

Nigel (M0NDE), Ian (G3ROO), Tony (G4WIF) at Dover CC HQ

When I was out in Dover (UK) last week the fellows in the Dover Construction Club alerted me to a problem that has been affecting their workshop, and that may be causing trouble in yours: black holes. Apparently through some strange quirk of quantum physics, small black holes are sometimes generated in electronics workshops. They cause parts and tools to disappear. The quantum element of all this is readily apparent: only those parts and tools that you REALLY need disappear. If you don't need a particular part or tool, it will not be affected. The guys out in Dover recently lost a variometer this way, and while I was there a telegraph key briefly disappeared into the quantum mist. In a variation of this phenomenon, very small black holes sometimes pop out of the quantum vacuum when small parts are dropped to the floor -- that's why you often can't find them! SMT parts are especially susceptible to this (obviously because some of the damn things are getting down to quantum scale) . I don't really know what can be done to counteract this problem -- if you have any suggestions, please post a comment.

On a related subject, Jim Miller sent us this:

Tools Explained

DRILL PRESS : A tall upright machine useful for suddenly snatching flat metal bar stock out of your hands so that it smacks you in the chest and flings your beer across the room, denting the freshly-painted project which you had carefully set in the corner where nothing could get to it.
WIRE WHEEL : Cleans paint off bolts and then throws them somewhere under the workbench with the speed of light. Also removes fingerprints and hard-earned calluses from fingers in about the time it takes you to say, "Oh, shit!"
SKILL SAW : A portable cutting tool used to make studs too short.
PLIERS : Used to round off bolt heads. Sometimes used in the creation of blood-blisters.
BELT SANDER : An electric sanding tool commonly used to convert minor touch-up jobs into major refinishing jobs.
HACKSAW : One of a family of cutting tools built on the Ouija board principle. It transforms human energy into a crooked, unpredictable motion, and the more you attempt to influence its course, the more dismal your future becomes.
VISE-GRIPS : Generally used after pliers to completely round off bolt heads. If nothing else is available, they can also be used to transfer intense welding heat to the palm of your hand.
OXYACETYLENE TORCH : Used almost entirely for lighting various flammable objects in your shop on fire. Also handy for igniting the grease inside the wheel hub out of which you want to remove a bearing race.
TABLE SAW : A large stationary power tool commonly used to launch wood projectiles for testing wall integrity.
HYDRAULIC FLOOR JACK : Used for lowering an automobile to the ground after you have installed your new brake shoes, trapping the jack handle firmly under the bumper.
BAND SAW : A large stationary power saw primarily used by most shops to cut good aluminum sheet into smaller pieces that more easily fit into the trash can after you cut on the inside of the line instead of the outside edge.
TWO-TON ENGINE HOIST : A tool for testing the maximum tensile strength of everything you forgot to disconnect.
PHILLIPS SCREWDRIVER : Normally used to stab the vacuum seals under lids or for opening old-style paper-and-tin oil cans and splashing oil on your shirt; but can also be used, as the name implies, to strip out Phillips screw heads.
STRAIGHT SCREWDRIVER : A tool for opening paint cans. Sometimes used to convert common slotted screws into non-removable screws and butchering your palms.
PRY BAR : A tool used to crumple the metal surrounding that clip or bracket you needed to remove in order to replace a 50 cent part.
HOSE CUTTER : A tool used to make hoses too short.
HAMMER : Originally employed as a weapon of war, the hammer nowadays is used as a kind of divining rod to locate the most expensive parts adjacent to the object we are trying to hit.
UTILITY KNIFE : Used to open and slice through the contents of cardboard cartons delivered to your front door; works particularly well on contents such as seats, vinyl records, liquids in plastic bottles, collector magazines, refund checks, and rubber or plastic parts. Especially useful for slicing work clothes, but only while in use.
Son of a bitch TOOL : Any handy tool that you grab and throw across the garage while yelling, "Son of a bitch" at the top of your lungs. It is also, most often, the next tool that you will need.
No trees were killed in the sending of this message.
However, a large number of electrons were terribly inconvenienced

Tuesday, March 2, 2010

Mars Express Phobos Fly-by (Wednesday)

The European Space Agency's Mars Express probe will be doing the closest ever approach to the Martian moon Phobos. On Wednesday night the spacecraft will come within 67 km of Phobos. They will use a very cool radio technique to gather data about the internal structure of the object (see below).
Mars Express carried the Beagle II lander to the red planet. I was in the UK when they made that brave attempt to put the probe on the surface, and shared in the disappointment when no signals came back. Later, I had the privilege of meeting Beagle II's creator, Colin Pillinger. Colin gave me signed copies of his wonderful books on Mars.

Here's some more info on Wednesday's fly-by (from ESA):

1 March 2010
ESA’s Mars Express will skim the surface of Mars’ largest moon Phobos on Wednesday evening. Passing by at an altitude of 67 km, precise radio tracking will allow researchers to peer inside the mysterious moon.

Mars Express is currently engaged in a series of 12 flybys of Phobos. At each close pass, different instruments are trained towards the mysterious space rock, gaining new information. The closest flyby will take place on 3 March at 21:55 CET (20:55 GMT).

From close range, Mars Express will be pulled ‘off-course’ by the gravitational field of Phobos. This will amount to no more than a few millimetres every second and will not affect the mission in any way. However, to the tracking teams on Earth, it will allow a unique look inside the moon to see how its mass is distributed throughout.

How will the ground teams make these tremendously sensitive measurements? Ironically, they will turn off all data signals from the spacecraft. The only thing that the ground stations will listen out for is the ‘carrier signal’ – the pure radio signal that is normally modulated to carry data.


Preparing for closest approach to Phobos
With no data on the carrier signal, the only thing that can modulate the signal is any change in its frequency caused by Phobos tugging the spacecraft. The changes will amount to variations of just one part in a trillion, and are a manifestation of the Doppler effect – the same effect that causes an ambulance siren to change pitch as it zooms past.

After the closest flyby, the work is not over. Mars Express will sweep past Phobos a further seven times before the campaign is complete. In addition to the tracking experiment, known as MaRS for Mars Radio Science, the MARSIS radar has already been probing the subsurface of Phobos with radar beams. “We have performed a preliminary processing of the data and the Phobos signature is evident in almost all the data set,” says Andrea Cicchetti, Italian Institute of Physics of Interplanetary Space, Rome, and one of the MARSIS team.

MARSIS completely deployed
The MARSIS radar is already taking data

“All the experiments on Mars Express have something to say about Phobos,” says Olivier Witasse, Mars Express Project Scientist, ESA. This is a bonus for science, considering that none of them were originally designed to study Phobos the moon, only Mars the planet. The science results from these flybys are expected in subsequent weeks or months, when the various teams have had time to analyse the data.

All photos from ESA.
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column