Quality English communications products hand-crafted to order

Proprietor;- Antony Nailer HNC BA G4CFY. 


Tel: UK 01305 262250 International 0044 1305 262250.  Email:


26 May 2024

You can pay by card or to via Paypal, or direct to my bank Santander, Spectrum Communications, sort code 09-01-29, account 67273308. For multiple quantities or multiple items, please email for a quote or for a Paypal money request.  You can also obtain many of my products from my Ebay shop


Understanding Radio Book 1 is a re-write of the Technical for the Terrified Book 1 published by Practical Wireless and compiled from 27 articles of that name previously published in PW Magazine between February 2005 and October 2008. The first chapter is a short revision for everyone who has not used algebra since leaving secondary or grammar school.  It should also be useful to youngsters still at school and trying to get to grips with it.  The articles have been reworked into chapters so there is now a natural progression of information through the book.  All the circuits have been redone and a lot of wasted space and unnecessary comments removed.  It runs to 112 pages, which is 10 less than the T4T Book 1 but there is a lot more in it.  The writing style is aimed to be easy to read and should be of great value to readers of all technical levels.   Subjects include; Algebra; Resistors & Ohm's Law; Diodes and Rectification; Transistors - FETs & Valves; Transistor biasing; Amplifier Classes of Operation; Reactance & Resonance; Parallel Tuned Circuits; Bandpass Coupled Pairs; Small Signal Bipolar RF/IF Amplifiers; Small signal FET & Mosfet RF/IF Amplifiers; Oscillators; Mixers; Decibels; Modulation Modes; TRF & Superhet; Filtering in HF & VHF Receivers; Modes & Demodulation; Choosing RF - IF & LO; Phase Locked Loop; PLL in CB & 10M rigs; Antennas & Feeders.  

Understanding Radio Book 2 is a re-write of Technical for the Terrified Book 2 including all the articles 28-49 published in PW between October 2008 and April 2013 plus article 51 published in August 2013.  The articles have been condensed into chapters and unnecessary duplication of information has been trimmed back and then the subjects further expanded.   It runs to 114 pages and the subjects include Passive components, old and new; Equivalent circuits; Variable Frequency Oscillators; Crystal Controlled Oscillators; Feedback & Amplifier Stability; Singly Balanced Mixers; Analogue Low Pass Filters; Laying out Printed Circuit Boards; Measurements and Test Jigs; Receiving 100kHz - 30Mhz; Superhet Receivers; AGC of RF & IF Stages; Superhet with Tuneable IF; Coax & Twin Feeder; SWR/PWR Meters & the Noise Bridge; Aerial Impedance - Bandwidth & Gain; Aerials for Receive & Transmit; ATU's for Receive & Transmit.

To buy an individual book will cost £18.60 including P&P.

To buy both books will cost £32.10 including P&P.


SSB IF Filter 6-Pole, 9 or 10.7MHz Regen Receiver, single band
RX 9MHz IF Amplifier with AGC Regen Receiver, four band
SSB Detector & CIO 9 or 10.7MHz Super Sudden by G3TEX & G4CFY
SSB Detector & CIO 455kHz Kaytone KT2000



Ladder filters using 6 crystals for 9MHz or 10.7MHz. Bandwidth at -6dB 2300HZ . Bandwidth at -60dB 6000Hz. Shape factor 2.6:1. Insertion loss 2dB. Termination 820 Ohms or 50 Ohms, you choose, and less than 5pF. PCB size 60 x 27 x 15mm. Choose 9MHz or 10.7MHz.

Built £26.60 UK, £33.25 EU, £35.60 World. Prices include P&P.



This circuit uses a single FET plus two AGC controlled MOSFET amplifiers to achieve a gain of 90dB and an AGC range of over 100dB. The supply rail is derived from a low drop out regulator providing stable 9.4V from a supply input of 10-13.5V.  The AGC level is presetable for meter set zero and there is another trimpot for fsd or S9 scale calibration.  It is designed to work with a 100uA meter movement. The input to the first FET includes a resistor to match the crystal filter, either 820 Ohms for the Spectrum 9 MHz filter or 560 Ohms for the usual commercial 9MHz filters.

PCB Kit £31.70 UK, £38.35 EU, £40.70 World. Includes P&P.


SSB DETECTOR & CIO 9 or 10.7MHz. The board includes two carrier insertion oscillators (CIO) connected at the transistor collectors like Siamese twins.  This allows each to be selected by switching the base bias to the transistors.  This avoids the usual pulling effect of one oscillator tuning on the other.

The SSB signal is demodulated using an a singly balanced product detector followed by a low pass filter to remove any residual 9 or 10.7MHz IF or carrier signal.  Choose 9MHz or 10.7MHz.

PCB Kit £30.35 UK, £33.00 EU, £39.35 World.  Including P&P.

PCB Built and aligned £41.70 UK, £48.35 EU, £350.70 World. Includes tracked carriage.


SSB DETECTOR & CIO 455kHz. The board includes two Carrier Insertion Oscillators (CIO) connected at the transistor collectors like Siamese twins.  This allows each to be selected by switching the base bias to the transistors.  This avoids the usual pulling effect of one oscillator tuning on the other.

The SSB signal is demodulated using a a singly balanced product detector followed by a low pass filter to remove any residual 455kHz IF or carrier signal.

PCB Kit £21.70 UK, £28.35 EU, £30.70 World, including P&P.

PCB Built and aligned £31.85 UK, £38.50 EU, £40.85 World, including P&P.



>REGEN Photo small.jpg

REGENERATIVE RECEIVER G3RJV-G4CFY  This is my development of the circuit described by George Dobbs G3RJV in April 2013 PW.  It comprises an FET infinite impedance detector and a conduction controlled Q multiplier or oscillator to enhance AM reception or receive and decode SSB signals.  It also includes an IC audio amplifier to drive a loudspeaker.  

Coil: Version A 1.8-3.8MHz uses 45uH, version B 3.5-7.5MHz uses 11uL,              version C 7.0-15.0MHz uses 2u6L, & version D 11.0-23.0MHz uses 1u2L. 

PCB kit and pots & polyvaricon £28.00 UK,  £32.55 EU, £34.90 World.

Coil pack kit for 4 Band Receiver £15.20 UK, £21.85 EU, £24.20 World.

Knobs and phono socket NOT included.


G4CFY 4 Band Regen Receiver  This is a further development of the single band G3RJV/G4CFY Regen Receiver with optimization of the oscillator section of the receiver to cover the bands carrying the maximum number of SW broadcast and Amateur Radio traffic.  These are 1.8-3.35MHz, 3.35-6.5MHz, 5.85-11.4MHz, and 10.5-20.5MHz.  This is achieved by removing the coil from the receiver board and using an additional coil pack board.  To achieve the best operation over this total range it was necessary to also change the values of C3 and C5 of the single band version. 4 Band Kit excluding the knob PCB kit and pots and polyvaricon £39.20 UK,£43.75 EU, £46.10 World.  



  SUPER SUDDEN RECEIVER As featured in SPRAT Magazine from the   G-QRP Club design by Tex Swan G3TEX, PCB by G4CFY.

PCB (on its own) with data £12.60 including UK P&P.

Complete kit of parts with data, and includes the special pulse transformer, £33.35 UK, £40.00 EU, £42.35 World. Including P&P.


KAYTONE. A name coined by Spectrum, this unit is the successor to the original Kaytone sold in 1979. End of message Morse K particularly useful for weak signal situations. Adjustable pitch, speed, and level. A relay is included for TX and RX switching making it suitable for all rigs. PCB size 58 x 39 x 15mm. Type KT2000.

PCB Kit £17.85 UK, £25.50 EU, £26.85 World.  PCB Built £24.60 UK, £31.25 EU, £33.60 World. Including tracked carriage.

KT2000 sm.jpg