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Friday, December 6, 2013

"The Amateur Scientist" by C.L. Stong (FREE!)

This great book is available on-line:   You guys will really like it:

https://archive.org/details/TheAmateurScientist


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

Renaissance Man Illustrator for Scientific American


C.L. Stong wrote the "Amateur Scientist" column for Scientific American for many years.  When I was a boy, my mom saved up to buy me the anthology of Strong's columns.  It had a big impression on me -- I still have a copy on my shelf.  I never gave much thought to the illustrations, but I now realize that they were responsible for much of the impact that that book had on me.  The cloud chamber drawing was one of my favorites.  Note the use of peanut-butter jars.  Yea!  
 
This morning an article on the Maker blog focused on the genius who did all those wonderful drawings:  Roger Hayward (I wonder if there is any relation to Wes and Roger -- all three are from Oregon and all three are technical geniuses.)
 
I found this very nice web site about Roger Hayward: http://scarc.library.oregonstate.edu/omeka/exhibits/show/hayward/introduction/introduction/
There are great illustrations in many places.  For the Scientific American drawings go to the 1960s section.

And check out this one:


From: http://scarc.library.oregonstate.edu/omeka/items/show/4456

 
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, December 5, 2013

W4OP -- Earth-Moon-Earth and Another Barebones Superhet


Years ago I bought a Barebones Superhet from Dale Parfitt on E-bay.  Several years after that, having forgotten who I bought it from, I was asking questions about how to get it working on 17 meters.  Dale jumped in with some very helpful e-mails.  It took us both a while to realize that I was working on the receiver that he had built.  Dale is active in a really wide range of ham radio activities, everything from QRP to EME.  Check out his homebrew projects here (I really like his Solid State Drake 2-B!) http://www.parelectronics.com/par-homebrew-projects.php 
And his vintage projects here: http://www.parelectronics.com/vintage-radio-restoration.php
And here's what Dale has been doing with the Moon (that's his 15 foot dish in the picture): 
 
Hi Bill,
 
I thought of you today when I won a Bare Bones Barbados RX on eBay for $5. I am going to team it with a DDS VFO and a matching TX.Some parts are apparently missing, but i have a huge junk box and also know how to order from Mouser should the junk box fail me.
 
 
Right now I am putting my solid state 650W 1296MHz EME amp , Power Supply, meters etc. in its waterproof cabinet so I can mount it right at the dish and not incur any feedline losses.
 
1296 is probably the best EME band. Power is getting easier and easier to acquire (although solid state is around $5/watt), dishes are fairly easy to acquire or build and  perhaps most importantly, we all use circular polarity feeds with no relays/hybrids. Activity weekend can sound like 20M, with a number of stations just ragchewing on CW and SSB.
 
73,
Dale W4OP
for PAR Electronics, Inc.
http://www.parelectronics.com


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, December 4, 2013

Thermitron (Tube, Valve) Op-Amps


It is kind of appealing.  I like it better than the 741.  This one you can take apart and see how it works.   Thanks Rogier!

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, December 2, 2013

On the suffering of Geeks. Indeed, we suffer...

M I a Geek :D

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, December 1, 2013

11 MHz IF for new BITX 20/40 Dual Bander? Also: Cabinetry and Socketry

I am gathering parts and ideas for a BITX dual bander (20 and 40 meters).  I know Farhan used a 10 MHz filter for his "Simple SSB Transceiver."  But I was thinking of going a bit higher, to 11 MHz. This would allow me to run the VFO from 3.175 to 3.355 for 20 meters, and 3.695 to 3.875 for 40 meters. I'm hoping that I can do this with one single VFO (Farhan used two VFOs), perhaps with a reed relay switching in some additional capacitance for the other band. I'll also follow Farhan's lead and switch the Low-Pass and Band-Pass filters with DPDT relays.

I set up a simple spread sheet and looked at the VFO harmonics to see if any fell within the desired tuning ranges.  That looks OK. I have not looked at mixing products between VFO and BFO.  What do you folks think?   Would the 11 MHz IF for these bands work?  Or are there evil birdies lurking in my future?

I've gone ahead and bought another wood box for the new rig (I didn't even have to suffer through a second visit to the crafts store -- they are available on Amazon).  I also got a roll of copper sheeting at Home Depot.  This time I will prepare the box first, lining the inside with copper and preparing all the "socketry" (George Dobbs' word) before putting the PC board in.
 
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Friday, November 29, 2013

First Pictures of the Far Side of the Moon (1959!)


On October 7, 1959, the Soviets sent an "automatic interplanetary station" to the moon.  This, in itself, was an amazing achievement.  Even more amazing is how they managed -- using 1950s technology -- to photograph the far side of the moon and get the images back to the earth. 

The Soviet document on the Harvard site (below) says that the transmitter put out "a few watts" and used semiconductors.  There appears, however, to have been at least one vacuum tube aboard (the cathode ray tube used to scan the chemically developed photo negatives).  Frequency modulated analog video similar to FAX) was used to send the data.

http://articles.adsabs.harvard.edu//full/1962IAUS...14....7L/0000007.000.html

From Wikipedia:

Luna-3 was the first successful three-axis stabilized spacecraft. During most of the mission, the spacecraft was spin stabilized, but for photography of the Moon, the spacecraft oriented one axis toward the Sun and then a photocell was used to detect the Moon and orient the cameras towards it. Detection of the Moon signaled the camera cover to open and the photography sequence to start automatically. The images alternated between both cameras during the sequence. After photography was complete, the film was moved to an on-board processor where it was developed, fixed, and dried. Commands from the Earth were then given to move the film into a scanner where a spot produced by a cathode ray tube was projected through the film onto a photoelectric multiplier. The spot was scanned across the film and the photomultiplier converted the intensity of the light passing through the film into an electric signal which was transmitted to the Earth (via frequency-modulated analog video, similar to a facsimile). A frame could be scanned with a resolution of 1000 (horizontal) lines and the transmission could be done at a slow-scan television rate at large distances from the Earth and a faster rate at closer ranges.
The camera took 29 pictures over 40 minutes on 7 October 1959, from 03:30 UT to 04:10 UT at distances ranging from 63,500 km to 66,700 km above the surface, covering 70% of the lunar far side. Seventeen (some say twelve) of these frames were successfully transmitted back to the Earth, and six were published (frames numbered 26, 28, 29, 31, 32, and 35). They were mankind's first views of the far hemisphere of the Moon.

More info: http://www.svengrahn.pp.se/trackind/luna3/Luna3story.html#Film



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