The K9AY is terminated loop. It consists of a wire loop of any convenient shape (diamond, delta, etc), hung from a single support and with a ground rod at the bottom. A 9:1 impedance-matching transformer is connected from one end of the loop to the ground and terminating resistor is connected the other end of the loop to the ground. This antenna is directional. Favoring signals are arriving from the feed...
This page describes an FSK/CW PC interface that will allow a PC to key your transmitter producing either a pure FSK or CW signal. The interface is fully optically isolated and RF filtered. Interface board kits or fully assembled and tested boards are available from W3YY. The cost of the kit version, including the PC board, all parts for the board, mounting hardware, and assembly instructions, is $29.00...
The Oak Hills Research OHR 100A single band CW transceiver kit is offered in 80, 40, 30, 20, and 15 Meter versions. Each can be aligned to cover 70-80Khz in a fairly wide band, but here are the defaults for which detailed specification is provided in the manual:
15M 21.000 - 21.070
20M 14.000 - 14.070
30M 10.100 - 10.170
40M 7.000 - 7.070
80M 3.500 - 3.570
... or other 70-80KHz...
Build your very own superheterodyne radio. Simple to follow instructions with schematics and wiring diagrams! You get a manual, all the parts including silk screened printed circuit board, 4 tubes, sockets, tuning capacitor, Aerial, Oscillator and IF coils, 4 inch speaker, resistors, capacitors, wire, nuts and bolts etc.
“Toothpick” Audio CW Filter Kit
Variable bandpass helps peak desired signal
Audio amplifier will drive speaker to room filling volume
In / out switch
Use with phones or speaker
Will work with other qrp rigs and older receivers
Measured peak bandpass 700 to 1000 Hertz
The “toothpick” is a simple variable bandpass audio filter designed to compliment the “Splinter”...
EA3GCY ILER 40 / 4-5W QRP SSB Monoband Transceiver KIT.
Frequency Coverage: VXO tuning 20 a 100KHz segment in 40M band (60-70KHz for better stability). Bandwidth range is selected according L6 value in the VXO circuit.
Frequency Control: high stability VXO oscillator.
Option A: two 12.031MHz. crystals (upper limit aprox. 7.105MHz)
Opción B: one 12.098MHz. crystal...
The Microcode kit assembles into a versatile Morse Code reader capable of decoding and displaying audio Morse code signals from speeds of 10 words per minute (wpm) to over 40wpm. A sensitive integral microphone combined with a tunable bandpass active filter allow the Microcode to operate effectively by being placed near to a receiver's loudspeaker. Alternatively, a line input allows direct connection...
The ‘Retro-75’ 75/80 Meter AM Transceiver board kit & The ‘Retro-40’ 40 Meter AM Transceiver board kit
This project is a frankly nostalgic look back at our hobby of 50 years ago. It’s now been updated using all modern components.
Board size 3.5” x 5.27”
Tunable Receiver- 50 kHz, selectable, varicap-tuned
4 kHz receiver crystal filter