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Thursday, April 15, 2010
Homebrew Hero: Ed Roberts (RIP)
http://blog.makezine.com/archive/2010/04/remembering_ed_roberts_the_father_o.html
Tuesday, April 13, 2010
Receiver Success! Combining Computers and Homebrew Radio
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
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.
Monday, April 12, 2010
G0UPL's Ingenious QRSS Circuit
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.
Friday, April 9, 2010
Colpitts Mania! Two Rigs Under Construction
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.
Thursday, April 8, 2010
Workbench/P! Taking Solder on the Road!
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!
Wednesday, April 7, 2010
Success! Uganda WSPR Station On The Air!
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!
Tuesday, April 6, 2010
SolderSmoke Book Helps With License Upgrade SAVE 10%!
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:
Geo-Magnetic Storm! Aurora as seen from orbit
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:
Monday, April 5, 2010
How much AF amplification needed between diode ring and a sound card?
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?
Wednesday, March 31, 2010
SolderSmoke Podcast #123
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
Tuesday, March 30, 2010
AA1TJ on Polyakov, Scrounging Parts from a Wehrmacht Tank, QRPp Success
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.
73
Saturday, March 27, 2010
Polyakov Plus! Dual-band Receiver with Subharmonic Mixer
Thursday, March 25, 2010
Sunspot 1057 Doing Good Work for US!
My e-mail inbox also had evidence of good HF conditions. Take a look at this from AA1TJ:
IZ0PEC de AA1TJ/QRPp
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
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
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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
Sunday, March 21, 2010
The FUNKY Keyer
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