36 September 2005

1Notes appear on page 42.

A SimpleDirection-FindingReceiverfor 80 MetersDale Hunt, WB6BYU

KUON HUNT, KB7WRG

Title photo: The author takes abearing on the run with a kit versionof the completed receiver. Hisheadphone is sewn into the bluesweatband, and the blue wires to itrun down his right sleeve. Dale’s mapand compass are in his left hand.

ransmitter hunting is a fun sport,and 80 meters is a good band forbeginners because it is not subjectto the reflections and multipath dis-

tortion of signals that can be confusing onVHF. Amateur Radio Direction Finding(ARDF) international competitions in-clude 80 meter events where competitorsrun through the forest hunting transmitterswith a hand-held receiver.1,2,3 This is anexcellent activity for Scouting ororienteering groups, as well as hams.

Meanwhile, our HF bands are subjectedto an increasing amount of interference fromelectrical equipment, home electronics,touch lamps and other sources. You can usethis hand-held receiver to track interferenceas well as hidden transmitters.

Receivers that cover 80 meters and aresuitable for ARDF have not been easily avail-able in the US, so competitors have usedequipment from Russia, Germany, Austra-lia or China.4 Several good designs have beenpublished in European amateur journals, buthave not been available in English. Some useparts not readily available in NorthAmerica.5,6 The simple receiver described

T here uses common parts and can be modi-fied for other bands as well.

The design goals for this receiver were:• Performance adequate to hear a 1 W sig-

nal from 3 miles away.• Low battery drain.• Easy-to-build using readily available parts.• Lightweight, rugged and easy to

operate.It is worth noting that this is not a high-

performance receiver by conventional stan-dards. The bandwidth is ±10 kHz, and thetuning rate is more than 100 kHz per revolu-tion of the tuning knob. This is a practicalcombination for tuning in CW signals in asparsely populated band while you are run-ning on foot, but finer tuning is recom-mended for SSB signals or for other AmateurRadio use.

Circuit DescriptionThere is nothing new about the basic cir-

cuit (see Figures 1 and 2). It is a direct con-version receiver7,8 using five generic NPNtransistors such as the 2N3904 or 2N2222and two common ICs. A four-turn loopantenna (L1) is tuned to resonance by ca-pacitors C13 and C14, providing the only RFselectivity. The loop alone has a bidirectional

Join the funof the “hunt” withthis easy-to-build

little receiver.It makes an

effectiveinterferencetracker, too.

September 2005 37

pattern. The sense antenna can be switchedin to create a unidirectional (cardioid) pat-tern, as shown in Figure 3. A shielded one-turn coupling loop (L2) feeds the signal tothe cascode RF amplifier9 stage (Q1, Q2).The cascode circuit provides good sensitiv-ity and convenient gain control, and also pro-vides good isolation to reduce thefeedthrough of the oscillator signal to theantenna. A wideband transformer, T1,couples the signal to the mixer.

The balanced mixer uses four common1N4148 switching diodes (D1-D4). D6 andD7 are varactors to tune the VFO. A com-mon-base audio preamp10,11 terminates themixer and drives an LM386 audio ampli-fier. The receiver draws around 10 mA atnormal audio levels, so a 9 V battery willprovide many hours of use.

An LM2931Z-5.0 or other low dropout(LDO) regulator is highly recommended forU2. These units draw less than 1 mA andmaintain output regulation with inputsdown to 5.5 V. A conventional 78L05 regu-lator draws up to 3 mA and loses regula-tion when the battery voltage drops to7.5 V. Much of the rated life of a 9 V bat-tery is below this level, so using an LDOmay give more than double the useful ser-vice from the same battery.

ConstructionFigures 4 and 5 show two versions of

the receiver. A PC board and kit are avail-able, though ugly construction will workas well.12 The circuit can be built in stages,testing each as you go. Touching a fingerto the input of the audio amplifier or themixer diodes should produce a noticeablebuzz in the headphones.

The oscillator operates at the desiredreceive frequency. It can be set by adjust-ing L4 and/or C30 while checking the fre-quency with a counter or by listening forthe signal with an 80 meter receiver. Fre-quencies in the range of 3.5 to 3.6 MHzare generally used for international com-petitions, but you should be able to coverthe whole band by readjusting the coil slug.The TUNING control (R12) should cover a50 to 100 kHz range at any one setting ofL4. D6 and D7 can be varactors or ordi-nary Zener diodes. See the sidebar “Sub-stituting Parts” for more discussion.

With the parts values specified for theVFO components, capacitor C30 usuallywill not be necessary. However, it allowsfor an additional fixed or trimmer capaci-tor if needed because of parts variations.

T1 is most easily wound on an FT-37-43 core, though other sizes can be used.See Figure 6 for detailed winding instruc-tions. Once you have the receiver work-ing, the core should be secured so itdoesn’t vibrate and break the leads. A spotof glue, a thin tie-wrap or a piece of string

tied through the holes on the circuit boardwill do the trick.

The mechanical construction is rugged,but requires no special tools. The antennaloop is formed from an 18 inch length of3/8 or 1/2 inch diameter plastic tubing, bentinto a circle and glued to the case. (Themilky-white “poly” tubing works well.)

To make the loop housing, drill a holein opposing sides of the case the same sizeas the plastic tubing. Form the tubing intoa loop, insert one end in each hole, andsecure with hot-melt glue or epoxy. Thencut five pieces of insulated wire severalinches longer than the tubing. Tape thesewires to a length of RG-174 miniature co-axial cable and work the whole bundle intoone end of the tube and out the other end.The shield of the RG-174 is grounded onlyat the end that connects to C1. The centerconductor is grounded at the other end, butthe shield is insulated with a piece of tapeor heatshrink tubing. Figure 7 shows thedetailed connections of the loop wires. Theactual loop size is not critical as long asC13 plus C14 can tune it to resonance.

The inductance of the tuned loop an-tenna varies depending on how it ismounted. The wire type may also make adifference. The most common problem isthat when the ends of the tubing are tooclose together, the inductance is too low andtuning capacitance provided by the combi-nation of C13 and C14 isn’t enough. In theprototypes shown in Figures 4 and 5, theloop ends are about 1.75 and 2.5 inchesapart. The kit version, shown in Figure 8,uses a clever mounting system for the loopantenna but places the ends closer together.If you can’t get the loop to tune, try mov-ing the loop ends farther apart if you can,or increasing C13 to 240 or 270 pF.

A metal case is recommended, but plas-tic will work. Look for something easy tohold in your hand. The circuit board fits ina RadioShack 270-238 aluminum box(51/4×3×21/8 inches). For smaller hands, a

Figure 1—Block diagram of the simple direct-conversion 80 meter DF receiver.

wooden handle can be added to the bottomof the case as shown in the photos. Thehand-wired (“ugly construction”) prototypeshown in the photos uses the Radio Shack270-1804 plastic case (1×2×6 inches) whichis a perfect size to hold. However, it is atight squeeze—even with small potentiom-eters—if you want to put the battery insidethe case. Otherwise the battery can be tapedto the back. If you are going to use the re-ceiver with a compass, the case should havea minimum of ferrous metal.

The RF GAIN control gets the most use,so it should be convenient to operate withone of your fingers holding the case (or yourother hand). The knob should have a pointerso you can tell how strong the signal is—this helps to judge the distance to the trans-mitter. The SENSE ANTENNA switch, S1, canbe put where your index finger can workit easily (like a trigger). The VFO knobshould have a fairly large diameter for easytuning, but should be relatively flat againstthe case to make it harder to bump the re-ceiver off frequency accidentally.

AlignmentFirst, adjust L4 to put the VFO in the

desired frequency range. The loop can betuned close to resonance with a dip meter.Final adjustment is by peaking C14 formaximum received signal at the desired fre-quency. You should be able to hear the back-ground noise peak when the loop is tunedto resonance. Sensitivity should be adequateat ±50 kHz. Tuning across the band in theevening, you should be able to copy QSOs.

The only additional adjustment is thesense antenna. A 6 inch whip or piece ofwire strung from the case to the far side ofthe loop housing provides plenty of sig-nal. I’ve also used a flexible wire hangingout the bottom of the case. (The circuit ac-commodates a wide range of sense antennalengths.) R23 is used to set the senseantenna signal level. To work properly,R23 must be adjusted so that the signal

38 September 2005

September 2005 39

Figure 2—Schematic diagram and partslist for the 80 m DF receiver. Mostcomponents are stocked by distributorssuch as DigiKey (www.digikey.com),Mouser (www.mouser.com),RadioShack (www.radioshack.com)and Dan’s Small Parts(www.danssmallpartsandkits.com).Resistors can be 1/4 or 1/8 W, standard20% values unless otherwise noted.C1-C4, C6, C8, C28, C29—0.01 µF

capacitor.C5—220 µF, 16 V electrolytic capacitor.C7, C26, C27—4.7µF, 16 V electrolytic.C9, C10, C24—100 pF capacitor.C11, C12—470 pF mica, NP0 or

polystyrene capacitor. A differentvalue may be needed depending onthe inductor used for L4. See text andTable 1.

C13—220 pF capacitor as needed toresonate loop.

C14—100 pF trimmer capacitor asneeded to resonate loop.

C15, C21, C25—0.1 µF capacitor.C16, C17, C20, C22—47 µF, 16 V

electrolytic capacitor.C18, C19, C23—10 µF, 16 V electrolytic

capacitor.C30—Fixed or trimmer capacitor as

needed, see text.D1-D4—1N4148 diode.D5—Part number not used.D6, D7—Varactor diode (MV209, MV2109,

BB104) or Zener diode (1N759, 1N963,1N5240B, 1N5242B). See text.

L1—4 turns, 6 inches diam. inside18 inch length of poly tubing(see text and Figure 7).

L2—1 shielded turn wound with L1 (seetext and Figure 7).

L3—1 turn wound with L1 (see text andFigure 7).

L4—PC-board mount adjustable coil inthe 6-10 µH range. See text and Table1.

Q1-Q5—Small signal NPN transistor,2N3904, 2N2222 or equiv.

R1, R2, R17—10 kΩΩΩΩΩ.R3, R9, R10, R15—22 kΩΩΩΩΩ.R4—47 kΩΩΩΩΩ linear taper potentiometer.R5, R18—100 ΩΩΩΩΩ.R6—470 ΩΩΩΩΩ.R8—47 kΩΩΩΩΩ.R11, R16, R22—100 kΩΩΩΩΩ.R12—100 kΩΩΩΩΩ linear taper potentiometer.R13, R24—1 kΩΩΩΩΩ.R14—2.2 kΩΩΩΩΩ.R19—470 ΩΩΩΩΩ (higher value may be needed;

see text).R20, R21—10 ΩΩΩΩΩ.R23—10 kΩΩΩΩΩ trimmer potentiometer.R7, R24-R31—Part numbers not used.R32—47 ΩΩΩΩΩ.S1—Normally open pushbutton switch.T1—Primary: 16t #26 or #28 enameled

wire on FT-37-43 ferrite core.Secondary: 4t bifilar. See text andFigure 6.

U1—LM386 audio amplifier.U2—Low dropout 5 V, 100 mA voltage

regulator, LM2931Z-5.0 or equiv. 78L05can be substituted (see text).

The parts used in this receiverare generally not critical, and can befreely substituted based on thecontent of your junkbox. For D6 andD7, look for varactors with a listedcapacitance around 20-40 pF. TheMV209 or MV2109 from Dan’sSmall Parts and other sources willwork just fine, as will the BB104 (adual-package that will require somework to fit the PC board). Othersuitable alternatives include the1N5144, 1N5470, MV2107, MV2108or BB605.

Ordinary Zener diodes can alsobe pressed into service as varactorsfor D6 and D7. For example, a1N961 10 V Zener diode will tuneabout 35 to 55 pF with a 1 V to 5 Vtuning voltage, similar to anMV2109. Higher voltage Zenersgenerally have less capacitance (a36 V Zener measured 18 to 28 pF).Look for Zeners in the 10-15 Vrange, such as the 1N759, 1N963,1N5240B or 1N5242B. The older1N759 and 1N963 tend to offermore capacitance swing, and thus awider tuning range. You can also tryusing two Zeners in parallel formore tuning range. Keep in mindthat capacitance of Zener diodesmay vary depending on manufac-turer. A 1N4742A (12 V, 1 W) Zenerfrom one manufacturer came in at180-300 pF.

The VFO coil (L4) is probably theleast common part. The receiverwas originally designed aroundvariable inductors in 10 mm cans,such as the TK1416-ND (6.8 µH) orTK1206-ND (8.2 µH) from Digi-Key.These inductors are falling victim tothe shift away from leaded compo-nents and are now more difficult tofind.

Other inductor values from atleast 4 µH to 20 µH can be substi-tuted with suitable changes to C11,C12 and C30. For example, a ver-sion with a 12-20 µH inductor from

Dan’s Small Parts at L4 requiredchanging C11 and C12 to 180 pF.Rewinding a 455 kHz IF transformerwith 20 turns of wire provided a7-14 µH coil for one prototype, andan unknown 10.7 MHz IF trans-former was used in another.

The PC board is designed for a10 mm can, but you can use 7 mmcans with a little creativity. Snip offall the leads except the two for thecoil and bend the shield tabs hori-zontal. Then, with a bit of bending ofthe leads, the coil will fit into twoadjacent holes on the board. Thisputs one of the 7mm coil leads intothe middle hole of the 10 mm lay-out, rather than the two ends. Thispad is not wired to the circuit, so anextra solder bridge is needed on thebottom. Short ground wires sol-dered to the case will help securethe can. As of this writing, Digi-Keyhas a better selection of 7 mm cansthan 10 mm cans. See Table 1 foroptions.

Although an adjustable coil isstrongly recommended because itmakes it easier to set the oscillatoron frequency, a fixed 10 µH coil canbe used instead. For example, youcould use 45 turns of #26 wire on aT-50-2 core, 270 pF capacitors atC11/C12, and a 50 pF trimmer atC30. Another possibility is a 10 µHRF choke.

If the coil has a high-permeabilityferrite core (as might be found in anRF choke or a 455 kHz trans-former), it may be susceptible toexternal magnetic fields. With onecoil, the VFO shifted up to 100 Hzwhen the receiver was rotated be-cause of the influence of the Earth’smagnetic field on the core perme-ability.14 If this is a problem, mountthe coil with its axis vertical.

L4 can be replaced with a crystalfor fixed-frequency use. This isconvenient for beginners, or if youalways hunt on the same frequency.

Table 1VFO Component Values

L4 Type Part Number Source C11/C12 C3010 mm, 4.7 µH TK1415-ND Digi-Key 470 pF 100 pF7 mm, 6.6 µH TK3115-ND Digi-Key 470 pF7 mm, 10.7 µH TK2428-ND Digi-Key 270 pF7 mm, 10.9 µH TK2430-ND Digi-Key 220 pF7 mm, 11.8 µH TK2429-ND Digi-Key 220 pF10 mm, 12-20 µH Dan’s Sm. Parts 180 pFFixed, 10 µH See text. 270 pF 50 pF

Substituting Parts

40 September 2005

picked up on the sense antenna is the samelevel as the signal picked up on the loop.When so adjusted, the signals will add inone direction and cancel in the other, giv-ing a single null in one of the directionswhere the loop had a peak. This null is notas sharp as those of the loop alone, so thesense antenna is generally used just toidentify which of the two nulls on the looppoints to the signal source.

A good distance for tuning a senseantenna is about one wavelength from thesignal source, giving a reasonable com-promise between far-field and near-fieldperformance. Also, sense antenna per-formance will depend on height aboveground, so make the adjustments at the

Figure 4—This early prototypeof the 80-meter DF receiveruses a Radio Shack 270-1804plastic case and “uglyconstruction.” The RF gaincontrol can be operated withthe thumb and the senseantenna switch with the indexfinger. The sense antennacircuit (Q5) is at the top, the RFamp (Q1 and Q2) is under theloop wiring and C14. T1 issecured with a drop of hot meltglue just left of R4. L4 is in therectangular metal can justbelow S1, with Q3 just below it.U1 is on the left side just abovethe tuning control, R12. Theheadphone jack is beside thebattery, and the plastic tubingfor the loop antenna is glued tothe case. The yellow wire for thesense antenna protrudes fromthe top.

Figure 3—Patterns of theloop (A) andsense (B)antennas. Theloop antenna isbidirectional, butwhen combinedwith the senseantenna, theresult is aunidirectionalcardioid pattern(C).

height where you will generally be hold-ing the receiver while using it.

Set up a signal source about 250 to 300feet away with a vertical antenna. Senseantenna adjustment should be done out-doors, away from the influence of powerwires. If the receiver case is metal, the ad-justment should be made with the caseclosed, so R23 should be accessiblethrough a hole in the case.

Tune in the signal and rotate the re-ceiver for peak signal from the loop. Withthe sense antenna off, adjust the loop tun-ing for maximum signal. Check that thereare two nulls in the loop pattern, and thatthey are 180° apart. These nulls will bedeepest when the plane of the loop is per-

pendicular to the line to the transmitter,so you look through the loop at the signalsource. Position the receiver to null thereceived signal, then enable the senseantenna switch. With R23 at minimum re-sistance, the pattern should not change.Slowly turn up R23 until the received sig-nal is about as strong as it was at the peakof the loop pattern.

Now, with the sense enabled, rotate thereceiver and you should find the signal offone end of the loop much weaker than thatoff the other side. Final adjustment is to pointthe end of the loop with the weaker signal atthe transmitter and adjust R23 for the bestnull. (The important thing is to have enoughdifference between the two directions to tellwhich is stronger.) Be sure to mark whichdirection is weaker and which is strongerwith the sense antenna activated.

You can change the direction of the nullto point the other way by reversing theconnections to L3. Be sure to recheck thesense antenna when readjusting C14.

Possible Construction ProblemsRick Campbell, KK7B, has an excellent

description of common problems with directconversion receivers in Experimental Meth-ods in RF Design.13 There are two generaltypes that may be encountered building thisreceiver: audio instability and microphonics.Audio instability is caused by the high au-dio gain in the receiver. The gain of theLM386 stage can be lowered by increasingR19. Try going from 470 Ω to 1 kΩ if youhave a problem.

Eliminating common impedances in thedc and audio circuits also helps. The head-phone jack should not be grounded to thecase, but connected to ground only on theboard near the junction of R19/R20. Simi-larly, connecting the positive battery leaddirectly to the hot end of R21 will reduceinteraction in the dc line. Ordinary carbon-

September 2005 41

zinc batteries were found to be much moreprone to audio feedback problems than al-kaline or NiCd batteries because of the in-ternal impedance.

Microphonics are one symptom of oscil-lator radiation reaching the antenna. A metalcase is a big help. Mounting L4 with its axisat right angles to that of the loop antennaand dressing the loop wires away from theVFO section of the circuit board are alsogood ideas. Winding L4 on a toroid corewould help, but it makes alignment more dif-ficult.

Two other problems may arise whenusing a plastic case. A strong transmitter

Figure 5—This version of the receiver uses the FAR Circuits PC board and aRadioShack 270-238 aluminum box. Because the box is a bit wide for most hands, thisversion is easier to use when mounted on a wooden handle. The SENSE switch is adoorbell button easily operatedwith the index finger, and theRF GAIN and TUNING controls areeasily reached with the other hand.(Left-handed ARDFers wouldprobably want to move thecontrols to the other side ofthe box.) Note the orange tapeon the loop, indicating thesense antenna null as describedin the text.

Figure 6—Construction details for T1, which is wound on an FT-37-43 with #26 or #28 enameled wire. First, wind the primary—16turns of wire, spaced evenly to cover most of the core (A). Then cut two pieces of wire about 4 inches long for the secondary. Stripthe insulation from the ends of one wire so you can tell them apart, and wind them together (B). Then wind the secondary, 4 turns,over top of the primary, beginning and ending at the opposite side of the core from the ends of the primary winding (C). Unwind thetwo strands from the secondary. Connect the stripped wire from one end of the secondary with the unstripped wire from the otherend—this becomes the center tap. The remaining ends of the secondary go to the diodes in the mixer.

signal can be picked up directly into themixer wiring (bypassing the RF GAIN con-trol), and the oscillator radiation may beheard in nearby receivers. Adding someshielding inside the case (aluminum foilor metal window screen) should help.

OperationOperation is straightforward. Plug in the

headphones and turn on the radio. Adjust theRF gain to max, and tune in the desired sig-nal. Rotate the receiver to find the null inthe pattern, where the signal strength isweakest. If the signal is too loud, turn downthe RF gain. The signal source should be ina line perpendicular to the loop. To resolvewhich direction (ahead or behind you), turnthe receiver 90° in either direction, switchin the sense antenna, and check the signalstrength. Then rotate the loop 180° and com-pare. One end should be much stronger than

the other, and hopefully you marked whichwas which during calibration.

The loop will give the best DF resultson vertically polarized ground wave sig-nals. It will receive skywave signals, butmay not be able to get a good null. Also,the sense antenna will start to work differ-ently as you get within 100 feet or so ofthe transmitter antenna (the signal from thesense antenna will be stronger than thatfrom the loop). There probably will stillbe some front-to-back ratio using the senseantenna, but it will not be as distinct as itis at longer distances.

For hunting interference in buildings, thepower wiring will affect the properties of theloop. The receiver may work normally if theinterference is radiating from a vertical wire,but if the wire is overhead the maximum sig-nal will generally be when the loop is paral-lel to the direction of the wire carrying the

42 September 2005

Figure 9—Two ways to use a stereoheadphone jack to switch power. Theversion shown at (A) uses a 1/8 inch monoplug wired to the headphone in thenormal manner. This method is simple,but momentarily applies power across theheadphone as it is plugged in. Theversion shown at (B) avoids applyingpower across the headphone but requiresa specially wired 1/8-inch stereo plug.(Wire the plug so the headphoneconnects between ring and sleeve andshort the tip contact to the sleeve.)

noise (caused by inductive coupling). Usingthe receiver to sniff for the strongest signallevel may be the best approach in some cases.

Probably the most common cause ofdead batteries is having the receiver switchon accidentally during transport. To pre-vent this, the receiver can be wired sopower is only applied to the circuit whenthe headphone plug is inserted, as shownin Figure 9. The receiver turns off whenthe headphones are unplugged.

Does it work? Prototypes have identifieda noisy fluorescent light fixture, tracked aninterfering carrier on 3510 kHz, and foundnoise “hot spots” on power lines. And threehams have won medals in the national ARDFchampionships using versions of this re-ceiver. ARDF is a fun and challenging ac-tivity. If you’re interested in giving it a try,see the Region 2 ARDF Web site atwww.ardf-r2.org for more information,links, equipment notes, calendar and so on.

Figure 7—Wiring details of the loop antenna.

Notes1R. Baldwin, “Amateur Radio Direction Finding

in China,” QST, Mar 1994, pp 22-24.2D. Hunt, “Amateur Radio Direction Finding: The

1998 IARU World Championships,” QST, May1999, pp 28-31.

3J. Moell, “Amateur Radio Direction Finding: USAHolds Its First National Championships,” QST,May 2001, pp 57-60.

4J. Moell, “80-Meter ARDF Comes to America,”73 Amateur Radio Today, Nov 2000.

5B. Lenander, “M92—miniatyrmottagare för3,5 MHz CW/SSB,” QTC, Apr 1992.

6G. Hoffschildt, “80-m-Minipeiler,” cq-DL, Sep1979.

7R. Floesser, “Junior 80,” cq-DL, Dec 1996.8B. Lenander, “RX 91—en liten rävsax,” QTC,

Nov 1991.9K. Taddey, “fuchsjagd—Peilempfanger Junior

C,” cq-DL, Jan 1977. 10R. Lewallen, “An Optimized QRP Transceiver,”QST, Aug 1980, pp 14-19.

11R. Campbell, “High-Performance Direct-Con-version Receivers,” QST, Aug 1992, pp 19-28.

12The circuit board is available from FAR Cir-cuits, 18N640 Field Ct, Dundee, IL 60118. Forordering information, see the FAR CircuitsWeb site at www.farcircuits.net and ask forthe WB6BYU 80 m DF receiver board. For fulland partial kits and prices, contact MarvinJohnston, KE6HTS, 408 Grove Ln, SantaBarbara, CA 93105, e-mail marvin@rain.org,or visit www.rain.org/~marvin/.

13W. Hayward, R. Campbell and B. Larkin, Ex-perimental Methods in RF Design (Newington:2003), section 8.3. Available from your localdealer, or from the ARRL Bookstore, ARRLorder no. 8799. Telephone toll-free in the US888-277-5289, or 860-594-0355, fax 860-594-0303; www.arrl.org/shop/; pubsales@arrl.org.

14Private correspondence with Bryan Ackerly,VK3YNG.

Dale Hunt was first licensed as WN6BYU in1969 and holds an Amateur Extra class li-cense. He has been participating in interna-tional ARDF events since 1996, and cur-rently is the ARDF Coordinator for IARURegion 2. When not hunting transmitters ordesigning receivers, Dale works as a soft-ware engineer. He lives in Yamhill, Oregon,with his wife Kuon, KB7WRG, who is alsoan ARDF competitor. Dale can be reachedat PO Box 108, Carlton, OR 97111 orwb6byu@arrl.net.

Figure 8—Here’s acompleted kit versionof the receiveravailable from MarvinJohnston, KE6HTS(see Note 12).