More feedback on the innovative 'Joule Thief'

Above, three views of the craftsmanship of W7RDP in his version of the "Joule Thief" mini-LED trail-friendly light featured in the February edition of the Trail-Friendly Radio column in WorldRadio Online magazine.

Click here for the link to the 'Joule Thief' by Big Clive, which inspired the YouTube video by Bre Pettis and Wendell H. Oskay.

Click here for links to how the "Joule Thief" does its magic.
Explanation 1
Explanation 2

Click here for the EDN Magazine article that inspired Doug Phillips, W7RDP's version of the "Joule Thief."

Click here for a link to Dan's Small Parts and Kits, one source for the FT50-61 toroid used in the "Joule Thief."


An inside look at AD7GR's version of the "Joule Thief."

(For an enlarged view, click on the images.)

Open mind, open spaces and the W3EDP

As featured in the April 2009 Trail-Friendly Radio column in WorldRadio Online magazine by Richard Fisher, KI6SN, the W3EDP end-fed wire antenna is a great, versatile performer when you're out and about in the field. Spreaders, made of specially cut PVC pipe material, provide lightweight spacing for the antenna and accompanying matching section.

The 84-foot antenna, 17-foot matching section, spreaders and an antenna tuning unit don't add much weight or take up much space in your radio tote bag.

A test set-up in Southern California a few years ago (pictured below) put the W3EDP through its paces on 40- and 20-meter CW during an on-air competition. The antenna is easy to put up and take down, and under field conditions can be used with only one support - a great advantage when you're operating above the tree line.

Here are links to sites with information related to the W3EDP antenna:

THE FFD ANTENNA: A Field-Friendly Doublet, With Notes on Related Designs, by Charles Lofgren, W6JJZ

KB6NU's HAM RADIO BLOG: The W3EDP Antenna, by Dan Romanchik, KB6NU

DXERS UNLIMITED: Item 3 - The W3EDP Antenna, by Arnie Coro, CO2KK

Field-Deployable Antennas, by William Eric McFadden, WD8RIF

For enlarged views, click on the images.

The Sudden Storm receiver goes to the field

N6GA's TFR transceiver in the 1990s was the inspiration for many trail-friendly radios of today - including the renowned Elecraft KX-1.


As featured in KI6SN's Trail-Friendly Radio column in the March 2009 edition of WorldRadio Online magazine, the QRPme Sudden Storm Receiver kit, designed to fit on top of an empty tuna-fish can with components exposed, is hardly a piece of gear that could withstand the rigors of the trail. But with a few modifications, the homebrewer can easily package this direct-conversion receiver into a unit that is great for listening in the outdoors.

Click on the links here to find several Internet references cited in the March column.

Cam Hartford, N6GA's, winning entry in the Adventure Radio Society's Trail-Friendly Radio competition (pictured above). For an enlarged view, click on the image.

"Anywhere, Anytime HF," the story of the Elecraft KX-1 transceiver, by Wayne Burdick, N6KR

The KX-1 from Elecraft Radio

Hendricks QRP Kits

The Sudden Storm Receiver kit from QRPme For an enlarged view, click on the images.

The KI6SN Trail-Friendly Joule Thief

As featured in Trail-Friendly Radio in the February 2009 edition of WorldRadio on-line magazine, the Joule Thief is a handy LED-based device that can be used to illuminate your field operating position while getting the most out of AA and AAA batteries that have been pronounced "dead" by other electronic devices - such as digital cameras.

A hay-wired version of the Thief shows the simplicity of construction and the handful of parts needed to put it together.

(For a larger view, click on the photograph.)

The drawing below shows the Manhattan-style layout used to build the KI6SN Trail-Friendly Joule Thief.

(For a larger view, click on the drawing.)

Click here to see a Bre Pettis You Tube video showing how the circuit is assembled, including detailed instructions on how to wind the toroidal inductor.