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Using DEMI 2MLDPA LNA at 137 MHz?

Mark K0JM
Mark K0JM Member ✭✭
edited August 2018 in FLEX-6000 Signature Series
I am using a 2M LDPA with a Flex 6700 for amateur satellites in conjunction with the L432-28 transverter. I use the internal LNA on the 2MLDPA for receive. However, I'm also interested in tracking the NOAA weather satellites (receive only) at 137 MHz. These downlinks are fairly strong, so being that far out of band is usually not a problem for VHF antennas and receivers.

However, as soon as I tune below 144.000 MHz the 2MLDPA powers off, the LNA shuts down, and I have no path from the antenna to the 2m receiver port. Thus, I cannot receive out of band.

Is it something that can be modified or reprogrammed? The only setting I can find simply allows selecting 2m or 4m for the LDPA to operate.

Answers

  • KF4HR
    KF4HR Member ✭✭
    edited August 2018
    Unfortunately the DEMI 2MLDPA has no internal bypass circuitry when deactivated, or when tuned outside the 2M band.  To receive NOAA Weather (162.****), marine band, etc, I plan to use a switch to bypass around my 2MLDPA.   
  • Mark K0JM
    Mark K0JM Member ✭✭
    edited August 2018
    Nothing like answering one's own question, but after some playing I found this work-around:

    Open two panadapters. Slice A in one, set for 137 MHz (or 162 or whatever). Slice B in second panadapter tuned to your local 2 meter FM repeater or whatever channel you like in the 2 m band. Second slice holds the LDPA open. Receive only -- both slices have TX turned off.

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