********KITS********

MK484 AM RADIO KIT

This kit provides you with a great place to start for exploring and building kits for reception of AM broadcasts. The parts and instructions supplied with the full kit support reception of the broadcast band, roughly 550 to 1500 kHz. Increasing/decreasing the turns on the ferrite coil shifts reception down to a minimum of 180 kHz/maximum of 3,000 kHz, supported by the MK484.

The heart of the kit features the ubiquitous MK484 IC in a TO-92 transistor package coupled with our old friend, the 386-4 audio amp in an 8-pin DIP. Coupled with an external antenna, FT82-61 ferrite toroid (for tuning coil) and air-variable capacitor, the MK484 AM Radio Kit gets surprising results. The MK484 IC features stable operation and low current drain, while providing a complete RF amplifier chain, AM detection and AGC circuitry. The 4.0 by 2.5 inch PCB houses all of the electronics for the receiver except for external tuning coil, air-variable tuning capacitor, panel and chassis. Parts shipped with our full kit support reception of the standard AM band. Adding a fixed capacitor in series or parallel with the variable tuning capacitor and/or decreasing or adding turns to the ferrite core (or a combination of the two) allows for the reception at 180-550 kHz or above at 1500-3000 kHz.  As with most of our kits, this one can be ordered 2 ways: 1) a Partial Kit based on the PCB and its components and 2) the Full Kit including the Partial Kit along with a laser engraved front panel, chassis, ferrite toroid and 365 uuf air variable capacitor. You must supply your own 8 to 32 ohm headphones or a small 8-ohm speaker, assembly tools, masking tape, 9 volt battery and enthusiasm! The set can be operated without an external antenna and grounding system if you use a ferrite rod or loop antenna (neither provided).

Partial Kit: PCB, PCB Parts & Full Manual: $39.95. Full Kit: PCB, PCB Parts, Ferrite Toroid, Air Variable 365 Capacitor, Laser Engraved Panel, Chassis & Full Manual: $64.95. See the parts page to purchase individual parts.

PARTIAL MK484 AM RADIO KIT
Qty: Price: $39.95

FULL MK484 AM RADIO KIT
Qty: Price: $64.95

GALENA DETECTOR KIT

Step back in time with our galena detector kit and experience the soft detection that comes from minerals. Marconi would be proud of you! Delight in the first broadcast reception using the galena with any of our crystal radio kits or as a replacement for those 1N34 diodes you may have been using.

No soldering required in this simple assembly of mechanical parts. Kit contains 2.5 by 3.4 by 3/4 unstained but predrilled wood base, mounted galena, phospher-bronze cat whisker, 3-inch brass rod, compression spring, and brass parts. Assembly time is about one-half hour. CAT # XSGDK $29.95.

See the parts page to purchase individual parts.

Galena Detector Kit
Qty: Price: $29.95

JFET DETECTOR KIT

Experience some of the operational qualities of a high-impedance DX crystal set by replacing that ordinary germanium diode in your basic set with a junction field effect transistor (JFET) detector circuit. You’ll notice sharper tuning and higher volume due to the high input impedance of the JFET, which preserves the Q of your tuning coil. The 2n5484 JFET is supported by a printed circuit board (PCB), a handful of resistors, capacitors, low-current LED, 9V battery & holder, battery clip with wires, and SPDT switch. You’ll mount the parts on the 2.0 by 1.4 inch PCB, as shown on the picture. All parts required are included except for the 9V battery and any necessary hookup wire.

Manual includes schematic, step-by-step assembly instructions, and suggestions for installing the detector assembly in a crystal set in place of your diode. The power switch, bias pot and LED can be mounted on the board or on your set’s front panel with wires running to the board if desired. The 9V battery clip leads insert at connector 3 (CONN3) at left; earpiece or headphone leads insert at CONN2 at right, and your paralleled coil and tuning cap tank leads insert at CONN1 at bottom left.

XS-JFET DETECTOR KIT
Qty: Price: $19.95

JFET AM CRYSTAL RADIO KIT

This AM crystal set is built around a Junction Field Effect Transistor (JFET) and when coupled with a separate antenna tuner performs a good bit like a Hi-Z DX set. Hi-Z sets generally make use of Litz coils, HI-Z diode, matching transformer, and sound-powered phones. With this set, you experience some of the same results but at less cost and procurement time. Background material on this set can be found in the May and July 2011 newsletters of The Xtal Set Society.

This set uses a 3.5-inch PVC formed 250 microhenry (uH) coil, consisting of 61 turns of # 24 plastic coated wire. Our standard 365 uufd air variable capacitor is placed in parallel with the coil to resonant it at the desired AM band frequency. A 2 by 1.4 inch printed circuit board (PCB) is provided for the detector. The source-follower output of the detector can drive a crystal ear piece or old-style high impedance headphones, such as a Baldwin pair. The high impedance of the “gate” input of the detector helps to preserve the Q of the input coil, thus preserving selectivity that would otherwise be reduced by the load of a simple 1N34 and phones. The “source” output voltage maintains most of the signal level presented by the tuned circuit too, thus providing a bigger signal to the phones than with a diode detector. The result is generally better selectivity and volume than with a simple low-cost set.  For weak signal reception, best results are obtained when using a good antenna and an antenna tuner that is lightly coupling to your crystal set.

JFET AM CRYSTAL RADIO KIT
Qty: Price: $64.95

AM BAND ANTENNA TUNER KIT

This AM Band Tuner will work with most any crystal radio set. Tuners are attached to the antenna and inductively couple the signal captured into your crystal radio set. By adding the tuner to your station, selectivity and volume can generally be improved.
The backside of the tuner is shown at right. A dual-gang 365 pf capacitor is used to resonate the tuner coil and the antenna system as a whole. The result is an increase in the signal gleaned from the antenna and coupled to the set magnetically. The tuner uses a 6 by 5 inch front panel and a 6 by 8 in chassis. Two switches are used to configure the tuner. In addition, a nylon shaft is added to the tuning capacitor to reduce “hand capacity” while tuning. Kit time is less than one hour experienced builder and should add performance to your crystal radio station.

AM ANTENNA TUNER KIT
Qty: Price: $64.95

XS-402 The Little Wonder Crystal Radio Kit

Our “Little Wonder” is a super starter kit for kids and beginning adult builders! It tunes the entire broadcast band. The extra large solder pads make it easy for beginning builders to have a successful first radio. There are only a few solder joints, and the pads are spread out making it clean and simple to assemble. The “Little Wonder” was designed especially for the XSS by our founder, Grampa Phil, WØXI. We tried to combine everything we’ve learned about building radios with beginners and kids to create a radio that everyone can build the first time. There is no coil to wind, a high resonant frequency molded choke have been used in place of the coil. A nice photo diagram is included showing all the parts and their placement on the printed circuit board (PCB) . This radio is perfect for parents and grandparents to build with kids. It is also priced right for classroom use, and can be used to teach basic radio theory, soldering, and handling of electronic parts and PCB’s. Kit includes a high impedance crystal earplug. A super performer and a great little kit; you’ve got to have one! XS402 $18.95.

XS-402 The Litte Wonder Crystal Radio Kit
Qty: Price: $19.95

XS-500 Basic Crystal Radio

The XS-500 Basic Crystal Radio is a tapped-coil crystal set, designed for those who wish to wind their own coil and for solder or non-solder assembly. Set tunes the AM broadcast band and requires, as usual, an antenna and grounding (antenna wire not included). One-hundred foot wire spools are available via mail order or our web site. We like the assembly flexibility of this set: a bit of a challenge in winding the coil and the alternative for non-solder assembly. This basic kit includes a pre-drilled wood base, pre-drilled PVC coil form, 50 feet of enamel wire, 1N34 detector diode, ear piece, capacitors and a resistor, alligator clips, Fahnestock clips, 6-32 mounting hardware, and manual. Cat # XS500 $19.95.

XS-500 Basic Crystal Radio
Qty: Price: $19.95

XSS-MM   My Marconi Radio Kit

The My-Marconi 2106 Crystal Radio Kit is described in some detail in the May issue of the Xtal Set Society Newsletter. It’s a double-tuned set using toroid-wound coils and includes an antenna tuner. These pictures present a quick snapshot.

The kit tunes the AM band. The primary and secondary LC “tank” circuits each utilize a 365 pf air variable capacitor with a 250 uH coil wound on an FT82-61 ferrite toroid core. A third air variable cap is used for antenna matching. The tank caps and coils mount on a 10 x 7 x 1/8th inch hardboard chassis. The antenna cap and ¼-inch phone jack mount on the 10 x 6.625 by 1/8th inch hardboard front panel. Nylon shaft extenders connect the tuning caps to the front panel knobs. The kit includes: chassis, front panel with lexan graphic, side rails, metal and nylon hardware, pointer knobs, 3- 365 air variable capacitors, 2 FT82-61 toroids, hookup wire, two earplugs, and composite manual, including kit instructions, circuit detail, and operating instructions.

The 10 mil thick Lexan Panel plastic sheet, with screened graphics and (3M) peel-off adhesive matches up with the front panel. The textured surface includes white and black graphics screened on the back side.

If you wish to wrap a case around the bottom, sides and top, plans are included with the radio kit. Case dimensions are: Top: 8.25 x 7 x 0.75 pine, Two Case Sides: 7 x 5.875 x 0.75 pine, and Beveled Case Bottom: 11 x 8.5 x 0.75 pine. See your local home supply store for the wood.

My Marconi Kit With Lexan Front
Qty: Price: $79.95

XSS-MMSW   My Marconi Shortwave Radio Kit

(Out of Stock).

The My Marconi Shortwave Crystal Set Kit is an offshoot of the popular “My Marconi 2106” AM band Kit. This shortwave set is described in some detail in the September 2009 issue of the Xtal Set Society Newsletter. It features a single-tuned front end followed by a two-transistor audio amplifier, and accepts a dual-earphone assembly or high-Z headphones. The set is reasonably selective for having only one tuned circuit. The set covers the 49 meter band, with selected tuning from 4.8 to 6.5 MHz and from 5.9 to 7.5 MHz. Reception is primarily at night, when the ionosphere provides signals of a sufficient power level to be heard on a crystal set. Cutting a vertical end-fed wire antenna to roughly 38 feet and providing a good ground via a copper rod enhances performance. The antenna is not provided with this kit. The LC “tank” circuit utilizes a 365 pf air variable capacitor and a fixed capacitance network with a 7 uH cylindrical coil wound on a 1.95-inch form as the tuner. A small secondary coil, wound on the same form is used for antenna pickup. A 10 mil thick Lexan plastic sheet, with screened black and white graphics and peel-off adhesive on the back dresses up the front panel.

The kit includes: chassis, front panel with lexan and graphics, side rails, metal and nylon hardware, power switch and ¼-inch phone jack, large pointer knob, a 365 air variable capacitor, two earphones, necessary resistors capacitors and transistors, wire, audio amplifier printed circuit board, and 20 page manual (including step-by-step assembly instructions). Assembly time is less than 2-hours for the frequent builder.

If you wish to wrap a case around the bottom, sides and top, plans are included with the radio kit. Case dimensions are: Top: 8.25 x 7 x 0.75 pine, Two Case Sides: 7 x 5.875 x 0.75 pine, and Beveled Case Bottom: 11 x 8.5 x 0.75 pine. See your local home supply store for the wood.

Out of Stock.

CW REGEN FILTER, (Alias: The Scrubber)

This kit was inspired by the inhibiting galactic noise encountered when listening to HF CW. Many proficient CW operators turn the AF gain full on and manage the audio signal and noise with internal rig filters and the RF gain knob. Even with these techniques band-limited cosmic static is present along with some man-made noise. There isn’t much one can do to copy CW notes that are simply too weak; but, one can scrub away a portion of the static that makes its way into our consciousness with an audio regenerative filter. (See the feature article on the CW Scrubber in November, 2012 CQ Magazine.)

For example, when tuned to a quiet spot on 30-meters, regen’s output shows a reduction in noise compared to the signal at the phone jack of the receiver. In bypass mode one simply listens to what the rig has to offer. In scrubber mode, the multiple-op-amp filters and regen work together to remove a majority of the remaining white noise. The processed signal sounds clean with a slight echo-chamber quality. For most this is an improvement, reducing stress and improving copy.

For experienced kit makers, assembly and alignment is about two hours. You can use a meter or scope to align the filters and the audio delay line. If you have neither of these you can align the filter by ear. Download tuning by ear instructions by clicking on this link. Download those instructiions by clicking here. If you don't have a signal generator, you can use CW from your rig, a code oscillator or download 600, 700, and/or 800 Hz wavefiles from our "downloads" webpage. In addition, you’ll supply the connectors and cabling for your specific radio and the following tools and supplies: pliers, cutters, knife or wire stripper, soldering iron & solder, masking tape and your enthusiasm! The filter can be supplied with a well regulated and grounded +12VDC supply or 9V battery. A well grounded station is necessary when external high gain audio-based accessories are added to prevent or substantially reduce any “ground loop” interference. The populated PCB fits in a plastic case that is W 3.700, H 1.450, and L 6.100 inches.

CW REGEN FILTER KIT, PCB & MANUAL ONLY
Qty: Price: $29.95

CW REGEN FILTER KIT, NO CASE
Qty: Price: $49.95

CW REGEN FILTER KIT WITH CASE
Qty: Price: $69.95

1/4-WATT 4-STEP ATTENUATOR Kit

A step attenuator is a very useful tool and good addition to your radio bench. We were motivated to develop this kit since commercial units for audio and HF use are expensive. It’s also useful in isolating or buffering between circuits and reducing effects of circuit mismatches during tests. A bypass switch and separate 50-ohm load are included, not usual features. As pictured four DPDT switches are included, each enabling the connection or bypassing of one pi-network resistive pad. Pads included are: 20, 6, 3, and 1 dB respectively, based on a 50-ohm system. As such insertion losses (reduction in voltage) from 0 to 30 dBV are available for measurements. BNC connectors provide input/output. Chose from the 1/4-watt or 3-watt package. The Kit is available with PCB, parts, case and manual or as PCB with manual only. Manual includes templates to be taped to case top to assist in drilling holes. Formulas are included in the appendix for those who wish to convert the attenuator pads to other attenuation values.

1/4-WATT 4-STEP ATTENUATOR Kit
Qty: Price: $39.95

3-WATT 4-STEP ATTENUATOR Kit
Qty: Price: $49.95

4-STEP ATTENUATOR (PCB & Manual Only)
Qty: Price: $24.95

QRP 5W Step Attenuator and Dummy Load Kit. "Can You Copy Me Now?" This kit allows you to reduce your 5W QRP power level to your antenna in 12 steps to as low at 2.5 mW. How low can you go and maintain contact? Order three ways: full kit, kit without case, or simply PCB only with full kit manual.

This kit was inspired by our enthusiasm for low-power communication. With this power step-attenuator in-line between your transceiver and antenna, you can reduce the output power to your antenna in steps and ask the station in contact, “Can you copy now?” or “QCN”. You’ll be able to see how low in power you can go and still maintain contact. In order to continue to hear the other station as power is attenuated, a bypass switch is provided for reception and/or full power operation. Two -12, one -6 dB and one -3 dB power attenuator pads are provided, allowing you to reduce 5-watts in 12 half-power steps to as low as 2.5 mW. A 5-Watt dummy load is included that may be engaged instead of the antenna load for bench work or comparison with antenna. An LED power indicator is included too that emits light at 5 W, or QRP Max. The full kit includes parts shown and case. The tools you’ll supply are pliers, screw drivers, solder, soldering iron, masking tape, drill, and 9/32, 5/32, and 1/8-inch drill bits.

Manual includes templates to be taped to case top or front/back panels to assist in drilling holes. Formulas are included in the appendix for those who wish to convert the attenuator pads to other attenuation values. A power in / expected power out table is included too, for any combination of attn pad switches.

QRP SADL Kit
Qty: Price: $49.95

QRP SADL (No Case)
Qty: Price: $41.95

QRP SADL (PCB & Manual Only)
Qty: Price: $24.95

XS-W Crystal Set

This is our smallest crystal set yet, measuring 1.5 by 2 by 0.5 inches. It’s small enough to wear on your wrist, and includes jacks for plugging in an antenna and ear piece. Set is tuned by selecting a set of capacitors wired in parallel with the miniature molded coil. Kit is constructed by soldering the parts onto the printed circuit board provided. Plugs to match the jacks, along with an ear-piece are provided. As with all sets, it requires an antenna, not provided. Cat # XS-W,
$ 18.95.

XS-W Crystal Set
Qty: Price: $19.95

 

XS-DE Dual Ear Kit

This kit features binaural listening by interconnecting two traditional crystal ear pieces. By utilizing both of your ears, a signal heard will sound as if it is inside your head, less "brassy," and you'll hear less background noise! The kit may be used with crystal sets or other radios or audio devices with 8-ohm or "phone" outputs, thus giving you inexpensive headphone listening. The kit features a 2 by 2-inch printed circuit board, three 3.5 mono-jacks, a toggle switch, back-to-back 1N914 diodes, and a thumb potentiometer. The DPDT-switch enables a series or parallel connection of the ear pieces. The pot and diodes are used to limit volume; and the pot has some effect on the "timber" of voices heard. The kit includes two crystal ear-pieces and three mono-plugs but does not include cable and connectors for your crystal set or radio. Assembly time is roughly 25-minutes. Cat # XS-DE, $ 19.95.

XS-DE Dual Ear Kit
Qty: Price: $19.95

XS-TGK Test Generator Kit

(Out of stock, on redesign schedule)

 

This test generator kit (TGK) produces an AM test signal and tunes the 550-1600 kHz AM BC Band with a thump pot on the PCB. The audio is a fixed at 1 kHz; ideal for checking out your crystal set or kit. The signal is low-level and must be clipped to the insulation of the set coil. Parts assemble on PCB; manual included; 9-V battery not included. Assembly time is about 45 minutes. Cat# XS-TGK $19.95

 

 

XS-SDLK (Self Powered) Smart Dummary Load- 10 Watts.

For QRP Amateur Radio use. This kit and our passive CW filter kit were inspired by our enthusiasm for non-powered - no batteries - electronics. The “smart” dummy load, assembled on a 1-1/4 by 4-1/2 inch PCB, features a 10-watt dummy load with power levels acheived denoted by four LEDs. The circuit includes six 3-watt metal film resistors, four detector diodes, four zeners, four LEDs, and bias resistors. The four LED circuits denote power achieved: 1, 2, 5, or 10-watts. The signal measured supplies the power. No batteries Mom! Assembly time is about 25 minutes. Coax with PL-259 connector not included. Kit Price, $19.95.

XS-SDLK Smart Dummary Load
Qty: Price: $19.95