SPECTRUM COMMUNICATIONS

Quality English products hand-crafted to order

CB RADIO BOARDS - 26 May 2024

Proprietor;- Antony Nailer HNC BA G4CFY.

12 WEATHERBURY WAY, DORCHESTER, DORSET, DT1 2EF, ENGLAND

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

You can pay by card or to g4cfy@talktalk.net 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 https://ebay.co.uk/str/Spectrum-Comms

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.

CONTENTS

Piptone (Roger Bleep), Kaytone	Frequency mod-demod, FMD455
Spectra bleedover filter, SF10.7	UK add-on for multimode rigs
Noise Squelch	VCO27 block for Cybernet 059 & 121
Improved FM for Cybernet Multimodes, SP059	VCO48 block for Cybernet 048

Bleep Boards

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PT1000S PIPTONE. Roger Bleep. The unit provides 50mV across a 600 ohm microphone. Tone frequency and amplitude are pre-settable. A relay is included for loudspeaker and PTT switching. PCB size 44 x 25 x 17mm.

PCB Kit £11.10.PCB Built £14.35. Prices include UK P&P.

KT2000 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.

PCB Kit £17.85 UK. PCB Built £24.60. Prices include UK P&P.

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FM NS1000 NOISE SQUELCH. A really effective cure for all the annoying background noise produced by FM receivers and the gun shot noise after releasing the microphone key. It allows reception of weak signals without loss of any except those which would have been unreadable anyway.

PCB Kit £18.35 UK. PCB built £24.35 UK. Prices include UK P&P.

SF10.7 SPECTRA FILTER. An active filter incorporating a 2 pole crystal filter to replace the 10.7MHz ceramic first IF filter in early CB radios. The effect is to reduce bleed-over by about 90% and by being active does not cause loss of sensitivity of the rig. PCB size 36x20x17mm.

PCB Kit £12.65 UK. PCB built £14.75. Prices include UK P&P.

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FMD455 FREQUENCY MOD-DEMOD. Adds very good quality FM transmission and reception to AM only CB rigs. Receive side connects to the last IF amplifier before the AM detector. The transmit side connects directly to the microphone input and provides processed audio to the varicap diode in the PLL circuit. PCB size 44x39x16mm.

PCB kit £16.00 UK. PCB built £21.10. Prices include UK P&P.

FM IMPROVEMENT PCB SP059.Speech clipper and amplifier to overcome the woolley soft FM on Cybernet PTBM059COX and PTBM121D4X rigs. The board picks up the audio drive to the VCO processes it and then feeds an add-on varicap board. PCB size 40x20x15mm.

PCB kit £13.10 UK. PCB built £15.60 UK. Prices include UK P&P.

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VCO BLOCKS

VCO27 VCO BLOCK. Replacement for green block in Cybernet multimode rigs PTBM059COX and PTBM121D4X, also allows the rig to accommodate extra channels such as UK81 band. Type VCO27 for CB bands, for conversion of rigs to the 10 metre band use VCO28. Built £7.00 each, plus £3.60 P&P UK. plus £10.50 EU, plus £12.85 World.

VCO48 VCO BLOCK.Replacement for silver block in Cybernet multimode rigs using PTBM048AOX chassis. Built £10.00, plus £3.60 P&P UK, plus £10.50 EU, plus £12.85 World.

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EPROM BOARDS

UK Band add-on boards for multimode rigs

SC02A SYNTHESIZER CONVERSION. Eprom board for adding UK81 to Cybernet multimode rigs. PCB size 40x30x10mm. It can also be configured to add 40channels below the lowest USA block on Cybernet multimode rigs. To achieve this spread of channels might require a replacement VCO block VCO27. PCB size 40x30x10mm.

SC106 SYNTHESIZER CONVERSION. Adds UK81 to Uniden multimode rigs, Stalker 9, Cobra 148GTL DX, Superstar 360, Madison, Jackson, State rig type when ordering. PCB size 40x30x10mm.

PCB kit £13.75 UK. PCB built £16.25 UK. UK P&P £3.10.

SC02 board sm.jpg

SC3900 SYNTHESIZER CONVERSION. Adds UK81 to Superstar 3900 and Galaxy Pluto rigs. PCB size 50x40x10mm.

SC3900F SYNTHESIZER CONVERSION. Adds UK81 to Galaxy Saturn homebase and relatives with frequency readout.

PCB kit £17.25. PCB built £20.75. UK P&P £3.60.

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