kenwood 480sat atu within

Discussion in 'General Technical Questions and Answers' started by 2E0OKC, Jul 31, 2019.

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  1. 2E0OKC

    2E0OKC Ham Member QRZ Page

    hello all ,
    i have a strange thing going on even though the radio is working ok as far as I can tell,
    and as I have a resonant antenna up and the SWR on that is fine,

    so anyway i didn't need my internal atu so i have turned it off but the rx signals keep dropping off over time
    and as soon as i use the internal atu they come back again and then i can turn off the atu again and the signals stay until it all happens again ofc over time,

    my coax run is one length plug on each end all new stuff, its just over past few days I'm sitting here doing other things and having the radio on in the background i was thinking wow man these bands are quite even the noise floor lol till hit the atu and ow there it is, bit like night and day,

    i was just seeing if anyone else has had the same problem with the said radio kind regards there andy
  2. KU3X

    KU3X Ham Member QRZ Page

    It sounds to me like something is breaking down. Maybe heating up from power? Some end fed antennas, the unun gets hot and as it heats up, the SWR goes up. When your power goes down, have you taken a close look at the SWR to see if it's going up? Maybe a loose connection somewhere?

    Barry, KU3X
  3. WC5P

    WC5P Platinum Subscriber Platinum Subscriber QRZ Page

    For whatever it’s worth, there is a menu setting where the ATU can be de-selected during receive. I don’t have the manual handy at the moment, so I don’t recall the menu number, but it is easily found in the book. Don’t forget that there are 2 sets of menus in the 480, so you might want to change both of them, depending on how you operate.
  4. K7TRF

    K7TRF Premium Subscriber QRZ Page

    I'd suspect dirty relay contacts in the relay that bypasses the internal tuner or something along those lines. IOW, if the antenna is well matched it probably isn't the tuner actually doing its job that helps you but when the tuner is deselected you have a problem that increases over time till you reactivate the tuner. Dirty relay contacts would fit that bill.

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