[FADCA] Mitrek filters

[Chuck Hast]

On 6/13/05, bud thompson <budt at cfl.rr.com> wrote:
> >One item that we have done in the past is to change the filters to filters
> >which are more data friendly and have much steeper skirts in many cases
> >this will make a world of difference in BER.
> 
> We change out four IF filters for 'wider' filters from Dig-Key.  (if the fifth filter is in the radio it is removed and a jumper put in place.)
> 
> While these are not specifically 'data' filters, they are wider than the stock narrow voice filters in the Mitreks.  When this mod was invented there were no data-specific filters avaialble.
> 
> We purchased 100 of these so need to use them up until we run out - then we may want to see if there are 'data' filters that could be used.  If you know specific filters for this purpose, I might purchase enough for two Mitreks and see if there is much improvement over what we are doing.
> 

If they are the wide ones they are OK. Particularly if you do keep all tuned to
filter center. The data filters are much steeper skirted and so pass data in
less bw than the voice devices. This is because you have to have wider
skirts on the voice filters in order to get the data through the area
in the filter
where you have the lowest group delay.




-- 
Chuck Hast 
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."