TU8K - A CTCSS tone encoder
OBJECTIVE
The project is designed to be a user friendly CTCSS tone encoder, used in the transmit side of analogue FM radio transceivers, also known as quiet line.
While modern analogue compatible radio transceivers already have the CTCSS encoding option built in, this project addresses the CTCSS encoding requirements of older FM transceivers.
FUNCTIONALITY
The functionality and size is loosely based on the Kenwood TU-8 Encoder, it will retrofit directly into some Kenwood transceivers.
APPLICATIONS
These transceivers can accommodate this unit directly on the TS450S, TS690S, TS140S, TS680S and TS440S (as a TU-8 replacement). With minor tweaks it should fit the TS711A and TS811A, and of course it is flexible enough to be used in nearly all Amateur or Professional mobile FM transceivers built prior to the 1990’s.
OPERATION
Other CTCSS encoders have often used DIP switches to select the tone frequency required. This unit uses a potentiometer to step select one of the 38 tones, the frequency of the chosen tone is displayed on a miniature LCD.
The output level is adjusted to achieve the nominal FM deviation required to trigger the far end receive decoder.
The tone is generated when powered on with a nominal 8v to 12v input.
The cost of modern components is now so low allowing this very user friendly option to be developed. Nominal cost is under 30% of the cheapest encoder currently available.
SCHEMATIC
OPTAINING
We doe have limited number of units available - please look under the Store tab.