Goal is to learn needed details of the capabilities and limitations of using LA-1K on MARS/CAP HF frequencies prior to purchase.??
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It is well known to use a contiguous set of low-pass filters (sometimes even band-pass filters) in the output of HF amplifiers and transceivers to ensure suppression of harmonically related or undesired emissions.? Pictures of the inside of the LA-1K suggest the use of five filters to cover HF - the minimum number of less-than-octave lowpass filters.
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It is expected that the frequency sensing capabilities of the LA-1K are used to select the use of a particular output filter depending on the detected frequency.? Thus a set of frequencies probably exist in the amplifier’s memory such that above each such frequency in the set a certain filter is selected.? Call these frequencies the change-filter-frequencies (CFF).
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As an example, selecting “160 meters” must result in the amplifier’s use of at least a low-pass-filter that attenuates above something like 3 MHz.? So one might guess that 3 MHz is a CFF and thus below 3 MHz the “160 meter" filter is used and immediately above 3 MHz the “80 meter” filter is used.
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Comments on the Internet note that use of the LA-1K has been effected on MARS and CAP frequencies, but without providing specificity.? An additional issue could be frequency spans that are too close to a low-pas filter’s so-called cutoff-frequency.
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Specifically, what are the CCF used by the latest control software?? If any exist, what HF frequency spans are to be avoided (other than 26 to 28 MHz)?? Thanks for filling in needed information.? ?73? ?Mac? N8TT?
