Scrap wood, some wire, four fishing poles and an old tripod: Moxon Update

 

It is not up on the roof yet, but we are getting close.   Above you can see he center "hub" -- just some scrap plywood and 8 u bolts.



 

Here is how I handled the corners.  The coil thing is from the end of a bungee cord. It makes for easy disassembly. 

 

 

 

Here is how the mast connects to the hub.  I had some 1x1 scrap wood. The 1x1 will be U-bolted into the rotator.  



 

 

 

Made of wire and fishing poles, Moxons are not very photogenic.  But I think mine looks great.  The 17 meter version is quite small. 

 



 

A bit of a balun.  Just to keep RF currents off the outside of the braid.

 



 

That tripod was last aloft in the Dominican Republic (1992-1996!).  Two spray cans of flat black paint have been applied.  Stealth!  

 

Four 16 foot "crappie" telescoping fiberglass poles purchased from Amazon.   



 

The only thing holding me up at this point is a safety concern.  The roof has a somewhat steep pitch, and I am not at agile as I used to be.   So before I install this magnificent sky hook I'm getting one of those roof safety harness systems that roof workers are supposed to use (but rarely do).  This sill also benefit the poor fellow who comes to clean our gutters.  



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

Crazy Joe May Have THE KNACK

http://www.crazyjoe.org/studio.html

Check out Joe's VERY long-running audio studio project.  It appears to be mostly appliance/commercial gear, but look closer and you will discover that most of it is homebrew.


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

Thomas's Magnificent Minima

Wow, Thomas's page makes me really want to build a Minima.  Note the Manhattan style with Rex Harper's Me-Pads.  Excellent.   Thomas provides a really great stage-by-stage description of the project with the kind of candid descriptions of mistakes that SolderSmoke listeners are so fond of!  

http://www.sarfata.org/ham/minima/

Thomas himself has an interesting "international brotherhood"  personal history:

http://www.sarfata.org/about.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

ISEE-3 Recovery Hiccup

Now that's a McDonald's that you would want to work in!  That's the headquarters for the ISEE-3 recovery effort. (Is it also the place where they recovered the long-lost moon photos from the 1960s?) 

This week the ISEE-3 effort hit a bump in the road.  Getting old gear to work properly is never easy.   Be patient fellows! 

http://www.nytimes.com/2014/07/09/us/in-effort-to-shift-abandoned-nasa-craft-a-hiccup-or-burp.html?action=click&contentCollection=Science&region=Footer&module=MoreInSection&pgtype=article

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

Finally! Dis-Intergrated Circuits! Discrete Component Op Amps!

That, my friends, is a discrete component version of the 741 op amp chip.  I like it!  No more mysterious miniature black boxes -- here's a "chip" that you can understand, troubleshoot, and modify.   Seven Forty Fun!

https://www.kickstarter.com/projects/1208645775/open-analog

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

Jason's WBR Regenerative Receiver

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

Alan Wolke Explains Varactor Diodes

As always, a very illuminating presentation by Alan.  I wish my oscillators were that stable!
And I couldn't help thinking how much simpler this circuit is in comparison to the DDS devices we've been talking about. 

Homebrew Radio Rock Video! By N6QW

Watch out MTV!   There's a new music channel in town! 
Music and rigs all by Pete Juliano, under the direction of the famed Italian producer/director Giovanni Manzoni.

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 Wrote Another Book

This one is not about radio or electronics, but over the years many SolderSmoke listeners have written in saying that they liked the opening "travelogue" portion of the podcast.   This book may appeal to them.  It might also be of interest to spouses who've been hearing about these "soldersmoke people."  This would be, I think, a good "beach book." 

The title is:  "Us and Them -- An American Family Spends Ten Years with Foreigners"

 Here's the description:

What happens if you take an American family and send them to Europe for ten years? In the summer of 2000, Bill and Elisa Meara, accompanied by 2 year-old Billy and 4 month-old Maria, left their home in the suburbs of Washington, D.C. and moved to the Azores. There they experienced the highs and lows of diplomatic life on a small distant island. After three years in the Azores, they spent four years London and three years in Rome. Overseas they lived in two houses and two apartments, went to five schools, used four different health care systems, experienced one earthquake, 9-11, the terrorist attack on London, tea with the Queen, the election of Barack Obama… and all the ordinary things that families go through. They lived mostly with the locals, learned Portuguese, Italian, and a bit of Cockney, and made many friends (foreign friends!) They returned to the United States in 2010 with a changed view of the world. This is their story.

In print form is available from Amazon and from Lulu:

AMAZON:  http://www.amazon.com/Us-Them-American-Family-Foreigners/dp/1499286287/ref=sr_1_2?s=books&ie=UTF8&qid=1403693380&sr=1-2&keywords=meara+us+and+them

LULU: http://www.lulu.com/shop/bill-meara/us-and-them-an-american-family/paperback/product-21687240.html

And it is available in e-book form from
AMAZON KINDLE:
http://www.amazon.com/Us-Them-American-Family-FOREIGNERS-ebook/dp/B00L8DR4RK/ref=sr_1_2?s=digital-text&ie=UTF8&qid=1403653620&sr=1-2&keywords=us+and+them

If you know anyone who might like this book, please use the little MAIL icon (below) to forward this post to them.  Thanks.


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

A New Look at BITX Carrier Suppression; N6QW IN EMRFD!

Bert, WF7I, was recently struggling to get his BITX 20 going and he asked some good questions about carrier suppression.  I realized that I hadn't really paid much attention to this.  Perhaps as a result of my long experience with DSB, I was happy as long as I was able to null out MOST of the carrier. 

I fired up the scope and took a look at the output from the BITX 2040 on 40 meters.  Here's the test setup:  Coax from the antenna terminal to a 50 ohm resistive load at the Rigol O'scope probe.  Just keying the transmitter (no mic connected),  carrier was at 980 millivolts rms or about 19 milliwatts.  I then connected an AF sig generator into the mic in connector and pumped in some 1000 Hz sine wave. Peak output was 20.7 volts rms, or about 8.6 watts.   That puts the carrier about 27 db down.  I felt I should be doing better. 

I took a look at the shape of my crystal filter and the frequency placement of my carrier oscillator.  I noticed that the carrier oscillator freq was fairly close to the bandpass portion of the crystal filter -- fairly high up the skirt, only about 9 db below the passband level.   I figured that if I just moved that carrier oscillator up around 300 Hz, I would get around 10 db of additional carrier suppression. 

Sure enough,  with the carrier moved a mere 300 Hz further away from the passband,  the residual carrier dropped to 346 millivolts rms, or about 2.4 milliwatts.    Now peak output was 20.9 volts rms, or 8.7 watts.  36 db of carrier suppression. 

I guess I could do better if I moved the carrier up another little bit, but I like the sound of it now.  I may have been able to better if I'd fiddled with the balanced modulator diodes a bit more.  But what do you guys think?  Should I worry about 2 milliwatts of residual carrier?  Heck I once ran a CW rig (W1VD' VXO 6 watter) that kept the oscillator running on key up, producing about 15 mw of "backwave." No damage was done, few noticed, no one complained.

Oh yea, is this the way to measure carrier suppression? 

----

While doing all this, I pulled out my trusty copy of EMRFD.  The index led me to the balanced modulator section on page 6.56.  There I spotted a familiar call:  W6JFR!!!  That's Pete Juliano, N6QW!  Pete is credited with a mod to the SBL-1 mixer that adds a balance control pot to the device.   Wow, actually being IN EMRFD fully confirms Pete's homebrew guru status.


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