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lyonodyne
lyonodyne crystal set

Builder and Operator Mike Tuggle


The "Lyonodyne-17" is an advanced DX crystal set evolving over the years. It was a first place winner of the DX "Open Class"contest two years in a row in 2000 and 2001. Mike placed second in 2003 after handicapping himself by using a rock (lead telluride) as the detectors. The radio incorporates the "Tuggle" front end (which will be shown later), and very high quality parts. 


Note:
This is not intended as a "How To" article for a beginner. The following is supplied as information only. Some of the techniques used in the construction of this radio are very advanced and not recommended for a beginner or even an intermediate builder.


The following is from Mike Tuggle

Lyonodyne Version 17 Crystal Set

Summary

The "Lyonodyne-17" is a much-advanced version in a series of DX crystal sets evolving from circa 1974.  I've been particularly interested in crystal sets since 1959, when I first discovered you could actually DX with them.  It's a completely passive set -- no amps, no bias on the detector.  The circuit is double-tuned and uses super-high quality components:  silver-plated variable capacitors and high-Q litz wire basket-wound coils. Isolated coil Qs are in the 700s across the BCB and over 1000 for much of the BCB.  In-set Qs are less, of course.  Phones are high quality, surplus sound powered ("balanced armature") units, matched to the high-Z secondary tank/detector by a high quality line transformer.  Detector is a single 12101 3RT, sold by Radio Shack as a "1N34 Type."  It's the best I've found so far.  With traps and all, it takes up the better part of a desk top.

Description

After several abject experimental failures, I concluded that the magical "high L-to-C ratio" for tuned circuits is a crock -- in spite of what theory might suggest.  That, and the high Qs obtained in 200/44 litz  wire (now, 660/46) coils got me to re-thinking my set's design and construction. This led to a completely rebuilt crystal set -- same circuit, but redesigned components per the following principles: 

 (1)  design for the lowest L/C ratio as practical

 (2)  use highest quality variable capacitors available

 (3)  if necessary, pad the variable capacitors with high-quality air trimmers to get to lowest frequency and spread out top-end tuning

 (4)  choose coil design which peaks in Q in the central BCB range -- operating near the self-resonant frequency is self-defeating

Superior quality tuning capacitors (silver plated with ceramic standoffs) were used in the present version.  The two prime tuning capacitor candidates I had were a 500 pF and a dual, 470 pF per gang, both silver-plate, ceramic insulated.  (Typical parallel leakage resistance measurements on these were 20 megohms, by the Boonton 260-A.)  Accordingly, the set was designed about them.

I credit Bill Bowers of Oklahoma with exposing me to the virtues of finer-strand litz for medium frequencies, the use of larger coil diameter-to-length ratios (ca. 5-to-1) than theory suggests, and for going back to 'over-1, under-1' winding pattern. They are not as pretty and have lower L's than the same-sized 'over-2, under-1's', which I used for many years, but they do have substantially higher Q's.

And credit to Al Klase for preaching the virtues of sound-powered phones long enough and loud enough that I finally had to listen -- despite my being firmly convinced nothing could ever surpass Brush crystal phones.  The sound-powered's are a real ear-opener, literally, and an order-of-magnitude improvement.

Antenna has been, for some time, a 50-foot, 4-wire flat top (wires spaced 1 ft. apart), maybe 25 feet high.  At my previous location, I used to have a 105-ft. long-wire, but high winds took out the tree at the other end.   The shorter flat top worked so well I brought it here to Hawaii, where real estate for long antennas is at a premium.  It's about all I can fit gracefully onto this lot.  Ground is tapped directly into the city water system.

Circuit Details

The antenna-ground system is tuned by the primary, L1-C1, and is coupled to the secondary, L2-C2, via loose L1 - L2 coupling (physical distance 3 to 4").  L1 and L2 are positioned radially (side-to-side), while the coils of two QRM traps (high-Q, parallel L-C ckts.) are coupled axially to L2.  L1 has virtually no effect on L2-C2 tuning and Q, but the QRM traps do affect tuning, especially near the QRM frequencies.  So, their coupling is kept to the minimum which will still allow reception of the stations of interest. The set is capable of receiving stations on frequencies adjacent to murderous locals.  The low-Z sound-powered phones are impedance-matched to the secondary tank , L2-C2, and detector with a UTC A-27 100 k-ohm-to-200 ohm input transformer.  The single12101 diode detector is estimated to present about 200 k-ohm resistance in the forward direction.  These impedances, in series, allow you to place the detector-phones directly across the tuned circuit without undue loading.  Taps, used in the past, are a mess -- especially with litz wire.  Further, they kill a coil's Q, and are to be avoided if at all possible.
 


 

lyonodyne crystal radio


 


Lyonodyne-17 Parts (as of 2/5/01)


C1 two gang, 15-470 pF per gang, variable capacitor, high parallel leakage
resistance, Rp.

C2 R/C (or TRW) 15-497 pF straight line frequency variable capacitor, Rp on the order of 20 megohms.  No. 107-C-522; FSN 5910-546-9239.  Fair Radio Sales cat. no. C123/URM125

C3 same as C2.

C4 same as  C2.

C5 0.02 uF polystyrene.

D1 selected (by listening) Radio Shack 12101 3RT germanium diode.

L1 51 turns 100/44 litz on 5/8" dia. x 1-3/16" long ferrite rod, u(eff) = 10.33; 
length = 1-35/64"; L = 146.6 uH; Co = 4.54 pF; Q @ 0.5 MHz = 649

L2 36 turns 660/46 litz, basket-wound over-1, under-1 on 5" dia. 13-point form;
 length = 1.9375"; L = 185.6 uH; Co = 7.40 pF; Q @ 0.8 MHz = 1134

L3 36 turns 660/46 litz, basket-wound over-1, under-1 on 5" dia. 13-point form;
 length = 1.9375"; L = 185.7 uH; Co = 7.40 pF; Q @ 0.8 MHz = 1060

L4 42 turns 660/46 litz, basket-wound over-1, under-1 on 4-1/4" dia. 13-point form; length = 2.25".  L= 186.7 uH; Co = 6.45 pF; Q @ 0.8 MHz = 1082

R1 500 k-ohm pot.

S1 DPDT miniature toggle

T1 UTC A-27: input transformer --100 k-ohm primary; secondary taps, 50 to 600 ohms -- around 200 ohms seems best with the RCA phones below.

PHONES: RCA MI-2045 sound powered phones, known as "Big Cans" in the trade.
 

All variable capacitors have vernier drive dials.
 


Lyonodyne 17

lyonodyne crystal set 2
 

The "Tuggle" Front End
 

tuggle front end

C1 is a two gang air variable



Special Thanks to

Mike Tuggle
of Hawaii (lucky dog!)

for the use of the above information.
And taking the time to write the above article.






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