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CB Radio History from its early days
CB Radio Repairers in the UK
Spectrum communications have been going for quite a long time now and one of their areas of expertise is the design and build of
boards for CB radio's UK and FCC. Eprom boards, roger bleeps and various other boards as listed below. These are very keenly priced
and come with complete fitting instructions. You can fit the components to the board yourself or for a few more pounds the kit comes
ready assembled.  To visit their website click
HERE.
12 WEATHERBURY WAY, DORCHESTER, DORSET, DT1 2EF, ENGLAND
SP1000E SPEECH PROCESSOR

to increase the sideband power and hence communications
effectiveness of SSB and AM transmissions. The unit has a
frequency response which enhances the higher voice tones
which carry most of the intelligibility. The peak to mean ratio of
the transmission is improved by 10dB which has the same effect
as increasing the transmit power by 10 times.
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.
KT2000 KAYTONE Bleep

(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
TT2000 TUNETONE Bleep

Musical end of message signal with nine individually selectable
notes. Adjustable pitch, level, and speed. With relay switching to
make it suitable for all commonly available rigs
HG2000 HYGAIN BLEEP  

A board designed to mimic the sound made by the bleep unit in
the Hy Gain 5 multimode rig. Adjustable speed and level.  With
relay switching to make it suitable for all commonly available rigs
NS1000 NOISE SQUELCH

A really effective cure for all the annoying background noise
produced by FM receivers. Allows reception of weak signals
without loss of any except those which would have been
unreadable anyway. Particularly useful for homebase use where
its performance like that of AM is less annoying
SF10.7 SPECTRA FILTER 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
FM455 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
SP059 SPEECH PROCESSOR

For Cybernet multimode rigs. Specially designed to overcome
poor quality audio on PTBM059 & PTBM121 chassis. The board
picks up the audio drive to the VCO processes it and then feeds
an add-on varicap board. PCB size 40x20x15mm
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
useVCO28

VCO48 VCO BLOCK.
Replacement for silver block in Cybernet multimode rigs using
PTBM048AOX chassis
   
SC26L SYNTHESISER CONVERSION

to add EU band to UK rigs which use the LC7137 PLL IC
SC26A SYNTHESISER CONVERSION

to add EU to UK Amstrad rigs which use the LC7136 or LC7137
PLL IC
SC27L SYNTHESISER CONVERSION

to add UK to EU rigs which use the LC7132 PLL IC
SYNTHESIZER CONVERSION CB to 10FM

suitable for UK CB rigs with LC7136/7 or TC9119P PLL IC’s. Puts
the rig onto 29.31-29.70 MHz. State rig type when ordering. PCB
size 64 x 40 x 17mm. Type SC29
SC02A SYNTHESIZER CONVERSION

eprom board for adding UK81 to Cybernet multimode rigs. PCB
size 40x30x10mm
SC02B SYNTHESIZER CONVERSION

adds UK81 and 40 below the existing low band to Cybernet
multimode rigs. To achieve this spread of channels a
replacement VCO block VCO27 will probably be required. PCB
size 40x30x10mm
SC02C SYNTHESIZER CONVERSION

adds  UK81 to Cybernet AM/FM rigs. PCB size 40x30x10mm
SC106 SYNTHESIZER CONVERSION

adds UK81 to Uniden multimode rigs, Stalker 9, Cobra 148GTL
DX, Superstar 360, Maddison, Jackson, State rig type when
ordering. PCB size 40x30x10mm
SC3900 SYNTHESIZER CONVERSION

adds UK81 to Superstar 3900 and Galaxy Pluto rigs. PCB size
50x40x10mm
 
EU and UK add-on boards for FM and Multimode radios
Contact Details:

Tel: 01305 262250
Orders & quote requests to  
jean@spectrumcomms.co.uk

Technical queries to  
tony@spectrumcomms.co.uk
VCO Blocks
Please email or phone for a quote or to place an order by credit/debit card or for a Paypal money request. Purchase of
several items is likely to make a saving on postage.  Tel: 01305 262250
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