MuTek_SLNA-145SB_user_YU7WL

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Now remove the four countersunk screw securing the back panel of the transceiver (two on each side) and very carefully ease it a way from the area of main work. By putting just enough low-noise gain ahead of the receiver to set the overall sensitivity to a level where external noise is the limiting factor an optimum ( for the system) is reached. Now locate transformer T101 (T01 in some manuals). Now adjust the attenuator on the SLNA 145sb with the trimming tool provided until the slightest degradation in signal to noise ratio is noticed. CIRCUIT DESCRIPTION A low noise relay provides the antenna changeover function. This is shiny can next to the C101 which you should already have removed. Solder the screens of the red and blue-coded cables to the earth tag on the tag strip by the PA compartment. SLNA 145sb installation instruction Thank you for buying muTek limited’s SLNA 145sb transceiver-optimized preamplifier. There are usually two reasons for the less than adequate sensitivity of current transceivers. If you are at all unsure of your abilities muTek strongly recommends that you find a competent technician to perform the installation: we can not accept responsibility for any damage however caused. The installation notes below refer to the FT290: we regret that we have no detailed information available regarding installation of the unit in other transceivers. Lower noise figures are easily obtainable with modern devices, but they won’t let you hear any more! However there is distinct advantage in using a very low noise preamplifier to improve the sensitivity of transceiver – if has been properly designed. Solder the white-coded cable to the areas shown – the centre to the pad at the input of T101, and the screen to the adjacent ground area. Installation is complete! muTek limited rf technology Retyped by YU7WL . Now look at this area on the track side of the board – you should recognize the diagram below. Keep this component – in the unlikely event of the SLNA 145sb having to be returned for service, the FT290 can fairly easily be returned to its unmodified state if the removed components are retained (almost any sub-min plate ceramic capacitor of around 1nF would be suitable for the C101 in this eventuality). Remove both top and bottom cover of the transceiver. This is probably best done by crushing the component with a pair a long-noised pliers and cutting clear remaining debris – it may sound crude, but it’s better than wrecking the reverse side of board – easily done! 4. Firstly, the receiver designer’s brief includes a dynamic range specification which leads him to balance large signal handling with sensitivity. Following the output matching a variable attenuator provides the gain control without compromising the dynamic performance, which would be case if the usual amateur practice of providing gain control by varying the bias on G2 of the FET was followed