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Wednesday, May 7, 2014
Parts Cost for BITX in India: $5 US (that's buying all the parts!)
I knew that in India you could build a BITX for a few bucks, but I thought that this cost estimate assumed a fairly well-stocked junk box. Not true! This morning an e-mail from Farhan points out that even if an Indian ham has to BUY all the parts, he can get all of them for the equivalent of 5 dollars U.S.:
"Less than half a cent per resistor, less than a cent per capacitor, two cents per npn transistor and 50 cents for the IRF510. We use 'tv baluns' and tap washers for coils."
And, from the original BITX design page:
"The purpose is to address the need among Indian hams in particular for an SSB rig that is easily and cheaply built. My original aim was to keep the price under Rs. 1000. The current design brings the cost to well under Rs.300 (less than 7 dollars)."
Now, when you are talking to someone using a new $10,000 Yaesu/Icom/Kenwood rig, it might be a bit unkind to mention that your rig can be had for $5.
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, May 3, 2014
The Guy who Invented the LED
I'm a big fan of Ira Flatow's "Science Friday" radio program (recommended!)
This week, while digging through the archives, I found this gem:
http://www.sciencefriday.com/segment/10/12/2012/fifty-years-ago-a-bright-idea.html
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
This week, while digging through the archives, I found this gem:
http://www.sciencefriday.com/segment/10/12/2012/fifty-years-ago-a-bright-idea.html
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
Labels:
LED,
radio history
Friday, May 2, 2014
Bert's EMRFD Direct Conversion Receiver
Very nice Bert. Sounds great. I like the pill bottle coil core. Lew McCoy used them in his designs. I do think that air core coils do provide better stability than ferrites or iron powder. I kind of like the SW broadcast background music. I also like the internal 9V battery. Glad to see someone else resurrecting an old DC RX 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
Labels:
direct conversion,
McCoy -- Lew,
NE602
Thursday, May 1, 2014
VFO for BITX 20/40
Here's the VFO I use in my BITX 20/40. IF is obviously 11 MHz. VFO normally tunes 3697-3859 kHz for 40 meters. Switching in that 220 pf cap lowers the range to 3292-3189 kHz for 20 meters. It workd very well. The coil is wound on a cardboard tube from a coat hanger. I will put this in the appropriate file on the BITX group site. I like the 20/40 band combination: Good DX possibilities on 20, with provisions (40!) for the low sunspot counts to come.
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
Labels:
BITX20
Wednesday, April 30, 2014
Manhattan meets Hyderabad: Pad Pattern for my BITX 20/40
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
Monday, April 28, 2014
Our New Robotic Overlords
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, April 25, 2014
Homebrew Blimp with paper-thin Arduino (Printoo)
More on Printoo (very interesting!):
https://www.kickstarter.com/projects/1030661323/printoo-paper-thin-flexible-arduinotm-compatible-m
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
Thursday, April 24, 2014
Hackers Recover 1960's Moon Pictures
http://www.wired.com/2014/04/lost-lunar-photos-recovered-by-great-feats-of-hackerdom-developed-at-a-mcdonalds/
Thanks to Mark, K6HX, for alerting me to this wonderful 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
Labels:
astronomy,
space program
Wednesday, April 23, 2014
Pete Juliano's Bilateral Rigs (with videos)
Hi Bill,
I was finally getting around to reading one of the recent SPRAT’s and saw a photo of your magnificent BITX17. Congratulations! A tip of the hat to Farhan for that very excellent design and it truly is a design that has traveled the world and made a radio available to many who otherwise would not be on the air.
It is a very robust design as I scratch built one in 2005 (or maybe 2006) and just for fun socketed every transistor so I could try various devices. I even had a bag of 2N706’s dating back to the late 1960’s. They all worked except for the carrier oscillator where I just couldn’t get enough swing in the oscillator to correctly place the CIO on the filter slope. That I attribute to the junction capacitance of the 2N706. By far the lowly 2N3904 that I bought for 4 cents each worked the best. Back when I built this I was W6JFR. Adding the EI9GQ frequency stabilizer really added a nice touch to the radio.
I should also tell you that when I built the radio my intent was to uses a piece of single sided copper vector board for the main chassis. It was the weekend and I didn’t realize the piece I had was not big enough for the project. So I took a piece of standard perf board and overlaid that on top of a piece of single sided copper PC board –AND hand drilled all of the holes – I went blind, cross-eyed and had a terrible hangover after consuming 6 beers in a short time span! See the photos below.
BTW I also built a 17M SSB transceiver using the bilateral amp stage from G4GXO as appeared in the SPRAT 128. That used a 4.9152 MHz IF and a 23 MHz Super VXO. In the case of the VXO I used 11.52 MHz crystals in the VXO and used a diode doubler to put the LO at 23 MHz. With the doubler –you get the bonus of 2X the frequency shift of the Super VXO. I also had made a custom set of crystals and used a small relay to switch those into the circuit and that essentially gave me almost the full SSB Band coverage. You can see that here
Also I have been using a simple bilateral stage consisting of a 2N3906 and 2N3904 and the results have been amazing. The latest work is a follow on to my shirt pocket transceiver and uses SMD components. See attached.
Here are some videos of the latest –which is now a two bander 40 and 20M. (Originally it was 75 and 40M)
https://www.youtube.com/watch?v=0UlBX7aznnM&list=UU4_ft4-oTdCMlWlL4XXHScg and https://www.youtube.com/watch?v=Wa5WiUZ9KoY
Have fun – this is such a wonderful hobby!
73’s
Pete N6QW
Labels:
BITX20,
Farhan,
Juliano -- Pete,
SPRAT
Monday, April 21, 2014
Clocks, CRTs, HV supplies: Eric has The Knack!
Nice interview by Jeri Ellsworth. This fellow definitely seems to have the Knack. At the end of the video he shows a high voltage supply that he is WEARING AROUND HIS NECK!
Here's Eric's site: http://tubetime.us/
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
Labels:
Ellsworth -- Jeri,
Knack Stories,
oscilloscope,
Tubes,
video
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