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Sunday, July 31, 2016

W9ZN's CW Warm-up: "Ben's Best Bent Feet"



I happened to come across this fellow's signal on 40 a week or so ago.  His warm up routine really had me scratching my head.   I've been on the air for a long time, much of it on CW, and I never heard anything like this.   Listen to the video (!) and you will see what I mean. Harmless fun I guess, and there does seem to be a connection to radio history. 

Saturday, July 30, 2016

Pilgrim's Progress: A Peregrino Rig Concealed in a Book


On the G-QRP list guys have been talking about the Peregrino.  This is a nice little homebrew rig out of Spain.  Peregrino = Pilgrim and usually refers to people who are hiking along the Trail of Santiago that runs through the North of Spain to Santiago de Compostela.

I'm normally averse to chips, but this little rig uses two very understandable NE602s and an equally understandable LM386.  It has a homebrew crystal filter.  I like it.

GM4WZG came up with a really wonderful enclosure for his rig.  This reminded me of the time I put a QRSS transmitter inside a copy of "The DaVinci Code."

The Spanish guys have a nice site that describes the rig.  Google Translate should help, but even without it you can get most of the info you need from the schematic, chart, and foto gallery.  Check it out: http://ea3ghs.qrp.cat/peregrino.html

Enhorabuena!

Thursday, July 28, 2016

Juliano Blues


Pete swears the rigs work better with this color. 

We are adding Sherwin Williams "Juliano Blue" paint to our investment mutual fund: Drake 2Bs, copies of SSDRA, QF-1 Q Multipliers and now, Juliano Blue! We'll all be RICH!  

Tuesday, July 26, 2016

Which way does current REALLY flow?

I've talked on the podcast about launching a worldwide campaign to require the reversal of ALL those little arrows on the symbols for transistors and diodes.   You see, they are saying that electricity flows from the positive to the negative.  Engineers apparently got that idea from Ben Franklin, and they are sticking with it.  It is time for a change!   Reverse the arrows!  Down with CCF!  Viva Electron Flow!  Let's tell the truth!

This morning Bob Crane W8SX sent me this very interesting article on this topic from Nuts and Volts:

http://www.nutsvolts.com/magazine/article/which-way-does-current-really-flow?utm_source=Newsletter+%2332&utm_campaign=Newsletter+%2332&utm_medium=email

The article describes very well the origins of this controversy. (There were one or two scary moments in which I thought the author was getting ready to tell us that positive ions can move through wires and transistors (NO!) but he pulled back from the brink and clarified that he was talking about ion flow in electro-chemical batteries.  Whew, that was scary!)

But here's a question for the philosophers and historians of electronics:  When physicists decided to label the electron as "negative" this was an arbitrary choice, right?   They could have just as easily decided to call it "positive" with the protons being called "negative" right?  In this case all the arrows in our diagrams would not be in need of reversal, right? 

Monday, July 25, 2016

Shotwell had the Knack (Car Knack), and so does Jay Leno



I've joked about homebrew cars -- we have a bumper sticker on Café Press that says "My Other Car Was Homebrewed From Junkbox Parts."  Well, in this video Jay Leno shows us a true homebrew car, this one built by a 17 year-old in 1931.  In the video you will hear some interesting comments from Jay on the kind of technical and mechanical skills that were expected of young men in the 1920s and 30s.  At the end of the video, watch Jay suffer the consequences of replacing a 20 amp fuse with an 8 amp fuse.  Who among us have not done something similar?   

Sunday, July 24, 2016

Cool, Blue, and Homebrew! Pete Juliano's Tiny SSB Rig


Blue is the new Black!  I think some smart paint manufacturer should put a trademark on "Juliano Blue."

Check out Pete's latest efforts:
http://n6qw.blogspot.com/2016/07/small-radio-big-signal.html





Saturday, July 23, 2016

Building LC Oscillators



Yesterday I came across this very nice video -- I thought you guys would like it.  2E0VIR obviously has The Knack!

I'm building a very simple LC VFO today. This is for the HRO Dial Receiver that I've been slowly working on. Mine is a Hartley, from Chapter 3 Figure 7 of SSDRA.   Stay tuned!

Wednesday, July 20, 2016

CBLA Dallas Division: Multiple Mighty Mites in the Lonestar State


Bill:

Just thought you would like to know that I am a new member of the color
burst army.  I am also a member of the Dallas Makerspace and our Amateur
Radio Special Interest Group is planning on offering classes (open to
HAMS and non-HAMS) where we build these Mighty Mites for the colorburst
frequency.

The class version will have a resistive dummy load instead of antenna,
to allow the project to be built by non-HAMS.  The idea is to get our
HAMS who just use commercial radios interested in building radios.  It
is also to get our general members (who like making things) into HAM radio.


Walter

Tuesday, July 19, 2016

In Search of the Elusive Imperial Whitworth



This beautiful old variable capacitor came out of a 1930's British regen receiver that I picked up years ago at the Kempton Park rally near London.  When I rebuilt that receiver, I found that the cap was thoroughly stuck.  No amount of solvents could loosen it.  I put it in the junk box and used a more modern cap in its place.

When planning for my current BIG VFO project (see yesterday's post) I re-read Frank Harris's chapter on VFOs.  Frank recommended a non-linear cap -- actually a cap that maintains a constant percentage change in capacitance as it goes through its tuning range.  My old British cap seemed to fill the bill.  Also, it appears to be brass or bronze which is said to have better temperature stability.  So I pulled the Brit cap out of the junk box.  It was still stuck, but as I tugged on it a bit, it suddenly loosened up.  Wow!  TRGHS.

When I tried to mount the capacitor in the QF-1 box, I discovered another problem:  the nut for the main mounting screw was missing.   And guess what:  None of the nuts in my "big box of screws and nuts" (I know you guys all have one of these boxes) was the right size.  Or, as Pete put it, all were of two sizes: a bit too big, or a bit too small.

Dex ZL2DEX informed me that the needed nut was likely an "Imperial Whitworth" (Don't you love British names?).  I started to think about how to get such an elusive part.... I thought about walking into Home Depot and asking them where they keep their Imperial Whitworths.  This wouldn't have been productive.

Then I started to wonder where the original nut went.  It would have stood out in my junk box because it is brass-colored.  I looked again in the junkbox.  No luck.  Then I realized that I might have used it to mount that replacement cap in my rebuild of the old British regen.  I pulled that old beast (wooden chassis!) off the shelf.  There it was, the needed brass nut.  Cap and nut were reunited, problem solved.   

It is kind of fun to include an old part like this in the new project.

Thanks Dex.  And thanks again to Frank Harris for the great book.
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column