Quality English communications products hand-crafted to order

Proprietor;- Antony Nailer HNC BA G4CFY. 


Tel: UK 01305 262250 International 0044 1305 262250.  Email: g4cfy@talktalk.net 

26 May 2024

Jean Nailer, my wife for 51 years and business partner in Spectrum for 40 years passed away from a brain haemorrhage on 29 november 2021.

Product Update

The Spectrum CFJ455K5 ceramic filter is now available and also modules to fit in the Kokusai Filter used in the KW2000 transceiver and related products. Send me an email for a quote or for a card or Paypal money request.  

I have a limited stock of BLW60C transistors that are yielding 50W output for 6-8W drive on 4m. So the 50W & 100W amplifiers are available to order again.  I may be able to get further stocks of the BLW60 to continue production. 

Please email or phone for a quote or for a Paypal money request. Payment can be by credit/debit card to g4cfy@talktalk.net via Paypal. Otherwise direct to my bank, Santander, Spectrum Communications, sort code 09-01-29, account 67273308.  Orders with address and card details can be taken by phone. You can also obtain products from my Ebay shop https://ebay.co.uk/str/Spectrum-Comms


Coax cables Balun 1-42MHz Air cored (RX & TX) Active Wire Aerial HF (RX)
Noise Cancelling 95 Ohm Twin Feeder Balun, 20m 95R feeder, & centrepiece Nomad VHF/UHF (RX)
G4CFY Traps, 80m, 60m, 40m, or 20m  Slim-G 2m, 4m, Air, & Marine (RX & TX) Active Nomad VHF/UHF (RX)
G4CFY HF Trap dipoles (RX& TX) Flexi-whips 2m, 4m, Air, & Marine (RX & TX) Compact Coil HF Active Aerial (RX)
Inverted-L HF (RX & TX )  Mobile Whip Aerials VHF/UHF (RX/TX) Long Wire HF portable Aerial (RX)


Piptone, Kaytone, & Hy-Gain Bleep Improved FM for Cybernet multimodes, SP059
Spectra bleedover filter, SF10.7 VCO27 block for Cybernet 059 & 121
Noise Squelch for FM VCO48 block for Cybernet 048
UK band add-on for multimode rigs Piptone Roger Bleep PT1000S
FM RX/TX add-on for AM rigs, FM455  


PTFE Feedthroughs Ferrite Binocular core Field Effect Transistors, junction type
Polyvaricon Tuning Capacitors Ceramic 2 pole 5 way Switch Dual Gate Mosfets, 3N201, 3SK45
Spectrum 10mm Coil (TOKO replacements) Power Relay IF Filters, crystal, ceramic, & ladder
Capacitors, fixed and trimcap Resistors, fixed and trimpot Crystals, HC49U
Dust Iron Toroidal Cores Diodes, signal, varicap, zener, rectifier Integrated Circuit, Op Amps, & RF/IF, etc
Ferrite Toroidal Cores Transistors, small signal, AF, IF, RF power Valves, B7G, B9A, & Octal


RX L-TYPE ATU 110-400MHz Scanner Preamp Mains
RX SPC ATU Station Preamps RF Switched, 2m & 4m, 13.5VDC
QRP TX SPC ATU Masthead Preamps RF Switched, 2m & 4m, with station box, 13.5VDC
HF Tuneable Preamp 1.8-30MHz 13.5VDC Masthead RX Preamp 137MHz, with station box, 13.5VDC
HF Switched Preamp 1.8-30MHz 13.5VDC Transverters from 10m to 2m, 4m, & 6m, 13.5V
110-400MHz Scanner Preamp 13.5VDC Transmit Amplifiers, 25 & 50W, 4m & 6m, 13.5V


Stable Colpitts VFO, 5.0-5.5MHz, or 80m, or 40m, or 20m Audio 500mW Amplifier
SSB IF Filter 6-Pole, 9 or 10.7MHz 50R or 820R Regen Receiver, single band
 9 or 10.7MHz IF Amplifier with AGC Regen Receiver, four band, 1.8-20.5MHz
SSB Detector & CIO 9 or 10.7MHz Super Sudden RX by G3TEX & G4CFY
SSB Detector & CIO 455kHz Kaytone KT2000


High Pass TVI Filter 175MHz Capacitance Meter, 1pF to 10uF
High Pass TVI Filters 450 & 550MHz HF Wide Range Power Meter
Coax Cable Tester BNC Switch boxes, 2Way, 3Way, or 4Way
Two Tone Tester, for transmitter alignment Morse Oscillator


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.

Spectrum Communications was established as a part-time business by me in October 1978.  In August 1981 following the legalization of CB in the UK there was sufficient work and CB sales for me and my wife Jean for full time employment.  CB popularity declined steadily to a very low level by about 2000 and for the following 4 years sales were almost at unsustainable levels.  Following becoming an author with PW in 2004 and developing new projects for the Doing It By Design series, sales have risen back to make us busier than ever. I became author of another PW series In 2005 titled Technical For The Terrified. I ceased being an author in 2017 following the change of ownership of PW.

G2DYM Aerials was purchased from Richard Benham-Holman G2DYM on 30 October 2006.   Garex Electronics was purchased from Peter Longhurst G3ZVI on 1 December 2011.

In August 2016 I slipped on a grassy bank and tore the rotator cuff on my left shoulder.  Following surgery for rotaty cuff repair, I created my Ebay page and sales took off keeping Jean and myself busy full time all week and often either a Saturday or Sunday as well.  Following the death of Jean in 2021 I have found it almost impossible to reign beck Ebay sales, so I am now going to update the website and remove built products from Ebay.  It is my hope that sales will reduce to a steady level and I can reduce my working hours.