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Mike Tuggle's Lyonodyne 17 Crystal DX Tuner

The use of integrated circuits can be interesting in that one IC can be used to build a full superhet. The use of an IC means that the set will not qualify for the 1AD nor for the 2AD bonus points."

The challenge was too hard to resist for many and the contest was popular for several years running. Some of the inventive entries for individual years may be seen here. The contest logbooks  also make for interesting reading and demonstrate the capability of some of these simple radios.

Although the contest has not been run for the past few years, there is still much interest and discussion of "1AD" radios on Dave Schmarder's "RadioBoard" forum.

Mike's LF tuner is a prime example as he uses it daily and continues to post some amazing DX to the Yahoo "ndblist" Group. His furthest ndb catch in North America with the regen has been "YY" in Mont Joli, Quebec.
Now, "YY" is a good catch for me, from B.C., but Mike is listening from Kaneohe, Hawaii !

You can read about Mike's original design here, while his latest version shown below, incorporates a dedicated LF antenna tuner.

LF Regen (Courtesy Mike Tuggle)



LF Regen Schematic (courtesy Mike Tuggle)

A recent posting to the ndb list by Roelof Bakker(PAØRDT) of mini-whip prominence, described his recent construction of his own LF regen, based largely on Mike's design but with a few interesting changes.

Courtesy: Roelof Bakker, PAØRDT

Roelof has also published a nice write-up describing the project which sparked a lot of "must build" discussion within the group.....even enough to make Mike get out his soldering iron and build the European-version!

As old and as simple as they are, regenerative receivers still hold much fascination amongst radio builders and dollar-for-dollar are amazingly good performers, especially on LF.

Courtesy: http://www.alaskacooling.com

This past weekend saw another of the monthly "Co-ordinated Listening Event" (CLE) activities sponsored by the Yahoo ndblist Group and organized by Brian Keyte, G3SIA. This is a group of dedicated low frequency NDB DXers that enjoy hunting down new catches as well as keeping track of NDB activity in general. These low powered beacons make excellent propagation indicators and are always a good measure of one's LF receive capability.
As often happens, the monthly events seem to coincide with poor propagation periods for some unexplainable reason, as was the case once again. As well as the generally poor propagation, North America was plagued with high levels of lightning activity making any weak signals very difficult to hear through the steady din of QRN.

In spite of the poor conditions, two nice catches from Alaska (ELF and TNC) heralded the fast receding midnight-sun in the 49th state and the start of another Alaskan NDB DX season!

The NDB at Cold Bay is 'ELF' and transmits on 341kHz. Cold Bay is located on the Alaskan Peninsula, at the top of the Aleutian chain.

Courtesy: http://pics3.city-data.com

Built as a military airfield in WWII, Cold Bay's traffic is now mostly cargo and its long runway serves as an emergency 'alternate' for flights in the north Pacific.

A search of Google Maps shows the NDB itself is located several miles north of the airport and appears to use a large vertical and an extensive ground system. With the transmitter power listed as 1000W, ELF makes an excellent target for DXers looking for their first Alaskan NDB.

Source: https://maps.google.ca

The NDB at Tin City is 'TNC' and transmits on 347kHz. Tin City is located in northwest Alaska next to the Bering Strait and, unlike most places in Alaska, you really can 'see Russia from here!' The airfield is not open to the public but is owned and operated by the USAF and used to support their long-range NORAD radar facility northwest of Nome.

Source: https://maps.google.ca

TNC is located right at the airfield, west of the gravel runway. Although the power is not indicated, I suspect it is running more than the typical 25 watts as its signal is often fairly good copy, as heard here early one morning.

Like 'ELF', the antenna appears to be a vertical but possibly of smaller size.

Source: https://maps.google.ca

If you are listening for these targets, remember to tune with your receiver in the narrow-filter CW mode and listen for either the upper or lower sideband keyed modulation tone.

For ELF, listen on 342.030kHz or 339.968kHz. The carrier will be on 341.0kHz.

For TNC, listen on 348.034kHz or 345.968kHz. The carrier will be on 347.0kHz.

For a list of all active NDB's in Alaska, complete with accurate frequency-spotting information, visit the beacon-reporting RNA website. Put 'AK' in the 'States' window and pick 'All Results' in the 'Show' window. There are presently at least 60 or more NDBs known to be operational in Alaska.

As mentioned before, please exercise caution should you decide to jump-in...chasing NDBs can quickly become addictive as anyone in the 'ndblist' Yahoo Group will tell you.

On the other hand...Alaska is waiting!

WC - 332KHz White Rock, B.C.

The recent three-night NDB listening event (covering 320-335KHz) was dominated with very high noise levels from the numerous thunderstorms across North America. Although propagation was good, all participants struggled with the lightning noise, as is usually the case when listening on LF during the summer monhts.

source:http://www.spc.noaa.gov

One of the beacons in my log this weekend is pictured above - 'WC' in White Rock, B.C. The beacon is located in a residential neighborhood, with homes on both sides...not a typical NDB location.

Here is my short log, all captured using Perseus:


If you are planning a 630m station, listening for NDB's is a good way to test your system's receive capability as there are hundreds of signals to be heard, many of them very close to our new 472KHz band.

An informative Introduction To Beacon DXing by Alan Gale may be found here. To find the location of any NDB's that have been heard in North America, check the always accurate RNA database by Martin Francis.