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Re: Measured Low Voltage Drop Out? - General Comments

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  • Howard Long
    ... You know, until I d seen these threads on Low voltage Dropout and Min Rx Current Draw I thought I must be the only guy in the world who d taken an FT-847,
    Message 1 of 4 , Oct 1, 2002
      --- In FT897@y..., "Woodrick, Ed" <Mail-Lists.FT-817@e...> wrote:
      >
      >
      > Rx Drop out is about 8 V
      > Tx Drop out is about 9.2V the power starts rolling off.
      >
      > 15A full power Tx (SSB)
      > 8A 20W Tx
      > 4A 5W Tx

      You know, until I'd seen these threads on Low voltage Dropout and Min
      Rx Current Draw I thought I must be the only guy in the world who'd
      taken an FT-847, IC-706 or an FT-100 in the field with a 7Ah gel cel!

      Great info.

      Anyone like to tell me what the TX power is on 70cm with an external
      11 or 12V is?

      I was very disappointed when I read they the internal battery will
      only allow 10W on 70cm. Not really enough for a decent AO-40 natter.

      BTW had a nice long play with an FT-897 a few days ago at a hamfest
      here in the UK and the radio is much bigger than I thought. Not much
      smaller than the FT-847 which was parked next to it.

      73 Howard G6LVB
    • Brian Badger
      ... HFPack is an absurdly large group, now. You are not alone... BTW, current draw is also relevant for those of us looking at the FT897 as a possible mobile
      Message 2 of 4 , Oct 1, 2002
        --- In FT897@y..., "Howard Long" <hlong@b...> wrote:
        > You know, until I'd seen these threads on Low voltage Dropout and Min
        > Rx Current Draw I thought I must be the only guy in the world who'd
        > taken an FT-847, IC-706 or an FT-100 in the field with a 7Ah gel cel!

        HFPack is an absurdly large group, now. You are not alone...

        BTW, current draw is also relevant for those of us looking at the
        FT897 as a possible mobile rig -- power consumption does matter when
        you need your car battery to start in a blizzard. There is no doubt
        about it, the FT897 would be much kinder to the battery than an IC-706.

        --
        Brian N0KZ
      • Alan Barrow
        ... Min ... cel! Nope, there are more of us than most realize. The FT-817 does seem to dominate the discussion on many groups though. I had quite good luck
        Message 3 of 4 , Oct 1, 2002
          Howard writes:

          > You know, until I'd seen these threads on Low voltage Dropout and
          Min
          > Rx Current Draw I thought I must be the only guy in the world who'd
          > taken an FT-847, IC-706 or an FT-100 in the field with a 7Ah gel
          cel!

          Nope, there are more of us than most realize. The FT-817 does seem to
          dominate the discussion on many groups though. I had quite good luck
          with a DX-70 and 7 & 17 Ah gel cells.

          The Alinco would drop out starting at 11v or so, and that appears to
          be a fairly common number for the mobile rigs. In examining the DX-70
          schematics, it appears that the 8v regulator is the suspect.... it's
          a common 7808. If I had kept the DX-70 I would have replaced it with
          a low dropout version to see if I could improve the low voltage
          operation.



          But now that's not an issue, as I traded for an FT-897 yesterday. 24
          hours observation: This is a very nice radio! Forget bells and
          whistles, it has the features I have been looking for. Some are not
          obvious, but show Yaesu was really thinking about it's intended use.

          An example: The dial light is configued to stay on when connected to
          external 12vdc, but goes into an auto mode when running off internal
          batteries. Of course, this is configurable. This is a common sense
          feature that was a nuisance when using mobile rigs. I was always
          having to enable/disable the dial light for portable use.

          There are many features that show the radio was well thought out for
          small battery use. It also looks like Yaesu did well on the TX bias
          issue everyone was concerned about. There has to be more to the
          subject, as even the Alinco had lower TX idle current drain on 10w
          than on 100. The 897 figures posted earlier are quite reasonable to
          me given the DSP, etc. Definitely lower than using traditional HF
          mobile.

          For what it is worth with 24 hours of ownership, unlike most rigs
          I've owned, I have not found a "wish they had done XYZ" on the 897
          yet. (beyond the obvious ones like price, battery capacity, etc)

          Actually, there might be one. Though the rig is quite substantial,
          far sturdier than most, I really wish it was weatherproof. I'm not
          even that concerned about water as much as all the holes for dust,
          dirt and mud to enter.

          I also wish the AT was not coaxial, or at least had a top mounted
          threaded mount for portable use like some of the military manpacks.
          (And possibly the VX-12xx?)

          > BTW had a nice long play with an FT-897 a few days ago at a hamfest
          > here in the UK and the radio is much bigger than I thought. Not
          much
          > smaller than the FT-847 which was parked next to it.

          It is larger than you think initially. Certainly larger than my DX-
          70. But when you compare it to the size of a DX-70 and a 7AH Gell
          cell, then it's quite reasonable. You have to remember that the stock
          FT-897 is almost half empty with the slots for battery packs or
          internal supply.

          My issue with the separate radio/battery/tuner was the form factor.
          They all made quite thick packages, and you had to pad them or use
          some form of enclosure to keep from damaging them in portable ops.
          The 897 form factor is close to ideal, as wide but thin is far easier
          to backpack than thick but narrower. (They are all about the same
          depth)

          I'm curious to see if the battery connection uses any form of
          standard connector which would allow the use of external batteries
          while triggering the "battery" mode of the radio.

          Also will have to give some thought on charging the NiMh batteries
          with solar without the losses the charger provides. (IE: is there a
          safe attended "trickle" charge for the NiMh without the controller)

          OK, I'll report more later! But so far, I'm quite pleased.

          Have fun!

          Alan Barrow
          km4ba
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