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

SolderSmoke Podcast #162: Part II with Pete Juliano, N6QW

 

SolderSmoke 162 is now available at  http://soldersmoke.com/soldersmoke162.mp3
 
June 21, 2014
Part II of our interview with Pete Juliano, N6QW
 
-- Bill's Moxon Monstrosity
-- Amplifiers and Exorcisms (See slideshow link below)
-- Varactor tuning
-- Polivaricon capacitors
-- The challenge of building small rigs
-- Heat, layout, components and VFO stability
-- "No frills" as a building philosophy
-- The future of Bill's Heathkit HW-101    
 
We still have a lot more to talk about.  Stay tuned for Part III!

Slideshow of Pete's RF Amplifiers: 
https://onedrive.live.com/?cid=4f1e8c71e0d4f1dc&id=4F1E8C71E0D4F1DC%212640&Bsrc=Photomail&Bpub=SDX.Photos&sff=1&authkey=!AGq3hc4UajARH1s




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

Bert WF7I Finishes BITX, WORKS ITALY

 

That, my friends, is the look of exhausted contentment that comes after you have FINALLY gotten your new homebrew rig to work, and were rewarded by crossing the mighty Atlantic on your first call.    Congrats Bert!   Details here:

 

http://wf7ihomebrew.wordpress.com/2014/06/18/bitx20a-on-the-air/



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

Confucian Wisdom from VU2BK in Hyderabad

I'm not a big collector of QSL cards, but this one has been kicking around in boxes and on various hamshack walls for more than 20 years.  I like the bit of Confucian wisdom that arrived in Santo Domingo all the way from Hyderabad.  I was running my trusty HT-37 and Drake 2-B.  Anyone know OM Kab, VU2BK?

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 5 Watter Makes the Trip to Tokyo

The solar flux index was only 151 this morning, but grey line conditions to Japan were very good.  Yoshi, JA1OJJ, was booming in on 17 meters.   We had a nice chat.  He said I was 55.  His 5 element quad helped a lot!   

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

F6FEO's BITX 20 (and DSB Rig)

This morning I was looking at F6FEO's wonderful web site (Frank, KM4AXA is building the 28 Mhz DSB rig from Michel's site) .  The drawings have a nice JF1OZL feel to them.

Check out Michel's site.  Just hit the translate button if you have trouble with the French language:
http://f6feo.homebuilder.free.fr/index.html

Merci Michel! 



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

MOXON Antenna Project -- Need Rotator Advice

 

 

I've been put together a fishing pole MOXON antenna for 17 meters.  It will be used with my 5 Watt BITX rig.  I need something to spin it around.   I know that many of the cheap TV rotators don't hold up very well.  I had one die quickly out in the Azores.  There seems to be several brands out there, but the rotators and the control boxes look suspiciously similar. 

 

Is there any brand out there that is more robust and reliable than rest? 

I came up with a pretty cool way of affixing the corners of the antenna elements to the fishing poles.  That coil-like thing is the wire part of a bungee cord.  It fits nicely into the end of the fiberglass pole. You have to be sure to get the pole length and the element dimensions properly proportioned, with a sufficient amount of bend in the poles.

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

Fireballs Emitting RF at HF!

Yea, and that damn gamma ray bust static has been totally messing up the 12 meter band! Someone should complain to the FCC!

https://medium.com/the-physics-arxiv-blog/1382596c320d

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 DX That You Can Never Work. Never.

There is some amazing info in this site. It is worth reading.

https://medium.com/starts-with-a-bang/the-disappearing-universe-d7447467c63a

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