Thursday, October 31, 2013
Brooklyn Bike Generator -- Want one!
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Wednesday, October 30, 2013
The New "Gold Standard" in QRSS Grabbers
Bill
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
I just discovered Scott Harden's "QRSS Plus" grabber aggregator...
Check it out - it is the new "Gold Standard".
73, Paul
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
An Interesting Idea for Checking Crystal Filter Passbands
Today at 9:37 AM
Hi Bill,
Just listened to your last soldersmoke blog with reference to xtal filter checking using a DDS and scope. What do think of this idea to check filter performance?
Logical, relatively easy to build and NO digital electronics to deal with. 
Best 73
Rick G6AKG
PS keep up the great work, love the Blogs.
Monday, October 28, 2013
Slide Show of BITX 17 Build
As I was building this rig, I periodically stopped and took a picture of the board. I think the resulting slide show is kind of fun. Check it out: There is a button to launch the slide show.
http://www.flickr.com/photos/106886073@N04/sets/72157637045750216/
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
http://www.flickr.com/photos/106886073@N04/sets/72157637045750216/
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Book Review: "Bunch of Amateurs" by Jack Hitt
The title held a lot of promise, but the subtitle ("A Search for the American Character") hinted at the main problem that I had with the book: the author (perhaps driven by his editor) seemed to be struggling to prove that there is some uniquely American elements to amateur science and technology. Early on, Mr. Hitt, makes the preposterous claim that "the rest of the world doesn't have amateurs." He goes on to write that "In Europe and on other continents, the word hints at class warfare... Amateurs may be taken seriously, but, almost by the power of the word, are kept in their place: isolated outside some pre-existing professional class, some long-standing nobility. In America, amateurs don't stay in their place or keep to themselves."
What a load of rubbish! This claim directly contradicts what many of us have been finding out in the quintessentially amateur world of amateur radio: as we travel around the world (in person, or via the ionosphere) we find, all around the globe, guys who have followed shockingly similar paths to ham radio. From Sudan to Switzerland, from India to Indiana, the story is much the same. And I'll bet you'll find similar similarities in just about every serious sci-tech hobby (astronomy, photography, etc.). To claim that there is something fundamentally exceptional about amateurism in the U.S. is, I think, ridiculous. Mr. Hitt should have spent some time looking at the amazingly diverse and vibrant world of British amateur science and technology. That alone would have prevented him from straying into these silly claims of American amateur exceptionalism.
But, all that aside, there is a lot of interesting material in the book. I liked his description of John Dobson and the amateur telescope builders. And, somewhat surprisingly, Hitt's description of the DIY Biology movement (these guys are playing with genetics and cooking up new organisms) seemed to capture very well the creative joy and satisfaction that amateurs find when working (just for fun) on their projects. I was kind of surprised when I found myself identifying with the DIY Biology folks. Their basement labs sounded a lot like our radio shacks.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
What a load of rubbish! This claim directly contradicts what many of us have been finding out in the quintessentially amateur world of amateur radio: as we travel around the world (in person, or via the ionosphere) we find, all around the globe, guys who have followed shockingly similar paths to ham radio. From Sudan to Switzerland, from India to Indiana, the story is much the same. And I'll bet you'll find similar similarities in just about every serious sci-tech hobby (astronomy, photography, etc.). To claim that there is something fundamentally exceptional about amateurism in the U.S. is, I think, ridiculous. Mr. Hitt should have spent some time looking at the amazingly diverse and vibrant world of British amateur science and technology. That alone would have prevented him from straying into these silly claims of American amateur exceptionalism.
But, all that aside, there is a lot of interesting material in the book. I liked his description of John Dobson and the amateur telescope builders. And, somewhat surprisingly, Hitt's description of the DIY Biology movement (these guys are playing with genetics and cooking up new organisms) seemed to capture very well the creative joy and satisfaction that amateurs find when working (just for fun) on their projects. I was kind of surprised when I found myself identifying with the DIY Biology folks. Their basement labs sounded a lot like our radio shacks.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Saturday, October 26, 2013
BITX BUILD UPDATE #17 Arv's Discrete AF AMP
I've been kind of cheating with the audio output from my BITX17: I've been using one of those little battery-powered computer speakers. It sounded fine, but hey, this is supposed to be a homebrew project right? I've already noted my ideological objections to the use of the LM386 CHIP. The files of the BITX20 yahoo group provided a very promising and completely discrete AF amp circuit by Arv Evans, K7HKL. I used a 2N3906 and a 2N3904, with a 2N2222 driving them. It works like a charm. Not a bit of feedback or motor-boating. It sounds great. I've already had a contact with it: Jack, W7YUM is a builder of big amplifiers out in Salt Lake City. He seemed very impressed with the BITX concept so we may have a Utah BITX in the works.
book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Friday, October 25, 2013
Words of Wisdom (on Amplifier Stability)
From "A Simple SSB Transceiver" by Ashhar Farhan:
"What if your transmitter is unstable? Don't curse your fate. All transmitters start out as unstable beasts. Relax." Farhan goes on to provide some good pointers on how to tame the beast.
I've had very good luck with the PA in the BITX -- very little cursing of fate on this project.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
"What if your transmitter is unstable? Don't curse your fate. All transmitters start out as unstable beasts. Relax." Farhan goes on to provide some good pointers on how to tame the beast.
I've had very good luck with the PA in the BITX -- very little cursing of fate on this project.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Sunday, October 20, 2013
BITX BUILD UPDATE #16 -- FIRST QSO!!!!!!!!!!!
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
BITX Build Update #15 -- Necessary Mic Amp Mod
I was having trouble with the mic amp on my new Manhattan Discrete BITX 17. I had it wired as per the schematic, but it just wasn't working right -- I was getting very little DSB out of the balanced nodulator, but everything worked fine if I 1) unbalanced the bal mod or 2) injected audio (from a sig generator) directly into the audio in port of the balancec modulator. Clearly something was wrong in the mic amp circuit. I noticed the collector voltage seemed quite low.
Some quick Googling revealed that others had struggled a bit with this problem also. Nicolae's note was especially illuminating and useful:
http://users.tpg.com.au/nfieraru/Electronics/BitX20_Mic_Preamp.htm
As Nicolae noted, the 10K value may have worked with lower gain transistors. We must remember that BITX was (very admirably) designed for minimal cost and maximum use of scrounged parts.
I swapped the 10K resistor for a 39K and all is right with the world. The band is not yet open here, but I bravely called a European aeronautical mobile station, hoping that he would be my first QSO on this rig. I think he heard me, but no QSO (yet!).
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Some quick Googling revealed that others had struggled a bit with this problem also. Nicolae's note was especially illuminating and useful:
http://users.tpg.com.au/nfieraru/Electronics/BitX20_Mic_Preamp.htm
As Nicolae noted, the 10K value may have worked with lower gain transistors. We must remember that BITX was (very admirably) designed for minimal cost and maximum use of scrounged parts.
I swapped the 10K resistor for a 39K and all is right with the world. The band is not yet open here, but I bravely called a European aeronautical mobile station, hoping that he would be my first QSO on this rig. I think he heard me, but no QSO (yet!).
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Saturday, October 19, 2013
BITX Build Update #14 -- STABILITY!
Good news on the BITX. I think I have solved the low frequency oscillation problem in the power amplifier. I tried running the PA off a separate power supply -- the oscillations disappeared leading me to conclude that the feedback was taking place via the power supply lines. I put a 22 uF cap to ground from the top of the PA's RF choke. With this cap in place I can dispense with the separate supply kludge. The amp is stable.
This morning I also resolved a different stability problem. I'm using a relay for T/R switching. One set of contacts controls the DC power, the other set was supposed to disconnect the receiver input from the antenna/lowpass filter when on receive. But I had positioned the relay too far from the LP filter and RX input, so I ended up with this long piece of coax that was hanging off the PA output terminal and carrying lots of RF on transmit. Yes, this led to oscillations. I thought about repositioning the relay, but I think part of the problem is that even if optimally positioned, the long unshielded contact levers inside this relay would be radiating a lot of RF and causing stability problems. So instead I put a small reed relay very close to the PA out and RX in connections. It carries the signal to the receiver when in R mode, and disconnects the RX when in T mode, without any long coax lines or unshielded relay levers. It works.
I still have a few things to do:
-- I need to build a proper speaker amplifier so that I can dispense with the amplified computer speakers KLUDGE.
-- I need to get a 3 pole double throw switch and some crystal sockets so that I can switch crystals from the front panel. Three rocks will cover all of 17 meter phone.
-- I have to build a case for this rig. I'm thinking wood, with tin or aluminum sheeting glued to the inside (for shielding).
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
From Bits to Atoms -- Software vs. Hardware
I thought this was pretty good. On Hack-A-Day.
http://hackaday.com/2013/10/18/guest-rant-from-bits-to-atoms/#more-105097
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
http://hackaday.com/2013/10/18/guest-rant-from-bits-to-atoms/#more-105097
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Friday, October 18, 2013
Feynman at G-QRP Convention!
What
do Richard Feynman and the G-QRP club have in common?
The
answer is an annual pilgrimage to Ripponden in Yorkshire, England. The G-QRP
club have their convention in a local school and Feynman went there every summer
to visit his wife's family. Here's an interview with Feynman filmed at
the Old Bridge Inn which is about a mile from where the G-QRP club gather:Is this enough to make Ripponden the Knack Centre of England?
Regards, Alan
G0RWB
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
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