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Yaesu FTM-350 Low RX Signal Strength

Discussion in 'General Technical Questions and Answers' started by KX5MOT, Aug 3, 2015.

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  1. KX5MOT

    KX5MOT Ham Member QRZ Page

    I have a Yaesu FTM-350R that is used as a backup rig in my radio room and it has been working fine up until the other day when it randomly developed an issue. The receive signal strength on the "Main" band is all of the sudden very low and the receive signal on the "Sub" band is normal. It doesn't matter if I select the right or left side, UHF or VHF, the "Main" band RX is always low compared to the "Sub" band. I have tried different antennas, different coax, and even did a master reset and still get the same results. Looking through the menus I don't see an RF gain of any kind. Anyone else had an issue like this? Suggestions before I send it in?
  2. KX0Z

    KX0Z Ham Member QRZ Page

    I'm going to take a very very very wild shot in the dark. A somewhat common problem with the Yaesu VX7R was one of the IF filters going bad. Perhaps something similar with the FTM350R.
    It would give same symptom, main band fine and sub-band deaf or vice versa. I have a dead sub-band on my VX7R at the moment
  3. VE3IGN

    VE3IGN Ham Member QRZ Page

    Did you ever find out what the problem was?
  4. AI6MS

    AI6MS Ham Member QRZ Page

    Most likely the 450khz IF filter. I've had this happen twice on my mobile rig. See the other posts here and youtube links showing the issue (very common on the FTM-10R as well): Note that FTM-350R uses the LTM450EW not LTM450FW (slightly different 6db bandwidth and impedance) so make sure to buy the right part if you want to match the schematic.

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