MFJ MFJ-8504, Инструкция по эксплуатации

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The filters are plugged into FL1, FL2, or both depending on the filtering desired. The orientation of the
filters is not critical and can be placed in either direction. If no filters are used then only ANTENNA 1
is available for input.
Place the filters in the MFJ-8504 and set the jumpers according to the Filter Jumper chart to properly
connect the filters up.
Filter Usage
No Filter
This is the default setting where all signals presented to the ANTENNA 1 port are distributed to the
Receiver ports.
One Filter
A single filter can be installed in either FL1 or FL2 for any of the filtering functions such as the
Broadcast Band Notch filter to remove AM Broadcast band signals to eliminate overload from local
stations. The 1.7MHz High Pass filter can be used for the same thing if signals below the AM BCB
are not monitored. The 30MHz Low Pass filter is used for reducing unwanted TV, FM, and Paging
interference. The 30MHz High Pass filter is used to remove HF signals that can overload the
Multicoupler if HF monitoring is not desired.
Two Separate Filters
Two filters can be installed and by setting the jumpers for FL1 and 2 the two inputs can be used for
two different frequency ranges. The filter outputs will be connected together to feed the amplifier
stage. For example setting the 30MHz Low Pass filter in FL1 and the 30MHz High Pass filter in FL2
an HF antenna can be connected to ANTENNA 1 and a VHF antenna on ANTENNA 2.
Two Filters in Series
Two filters can be set in series to tailor the desired pass band. For example a Low Pass and a High
Pass filter can be placed in series to either pass a specific frequency range or block a specific
frequency range. To pass a single band such as 20 meters a custom High Pass filter set to 13.5Mhz
and a custom Low Pass filter set to 15MHz can be made and used to pass between 13.5 and 15MHz.
Similarly if a band needs to be reduced such as the FM Broadcast band then a Low Pass filter below
the rejected range around 87MHz and a High Pass filter above the rejected range around 109MHz in
series will reduce the FM signals.
Two Filters in Parallel
Two filters can also be placed in parallel to tailor the desired pass band. For example a custom Band
Pass filter can be made to pass a specific range of frequencies and a High Pass filter above the Band
Pass filter to pass everything above the High Pass filter cutoff.
Optional filters are available.
MFJ-8504-NC 8-pole Standard Broadcast Band reject filter.
MFJ-8504-HP 5-pole 1.7 MHz High Pass.
MFJ-8504-HP 5-pole 30 MHz High Pass.
MFJ-8504-LP 5-pole 30 MHz Low Pass.
MFJ-8504-BP 10-pole Custom Band Pass Filter. This filter is a board without inductors or capacitors
for setting up custom band pass ranges.