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Re: Digi mode power

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  • nealedave
    Jon Many thanks for a really useful and comprehensive reply. Sure agree about the conflicting advice in the thread! I think the problem lies in the
    Message 1 of 11 , Apr 21, 2013
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      Jon

      Many thanks for a really useful and comprehensive reply. Sure agree about the conflicting advice in the thread! I think the problem lies in the p.c.soundcard and will go down the SignalLink route and isolate the pc soundcard.
      Many thanks
      Dave de G7DHW

      --- In FT897@yahoogroups.com, "JP" <jon.perelstein@...> wrote:
      >
      > Dave,
      >
      > You've been given some good advice in this thread and some miserable advice in this thread. Most of the manufacturers (especially Yaesu, Kenwood, and Icom) have explained time and again how to run digital and their recommendations are:
      >
      > 1. Put the rig in DIG mode (for SSB soundcard) or PKT mode (for FM soundcard). If you don't, various things may not work right when you do digital -- depending on the software revision level in your radio. For example, in many FT-897s, the radio will not transmit if you're using the DATA jack and also using the CAT/Linear jack and have the radio in USB or FM mode. Others have found that the rig won't transmit at all if they're using the DATA jack with USB or FM mode. KB1TCD continues to tell people to use USB or FM mode even though he's been told time and time again that it causes problems for most users.
      >
      > 2. For SSB soundcard operations, you do not want to run the rig at more than about 1/3rd rated power. Since it's a 100 watt rig, that means that you don't want to run it at more than about 35 watts (yes, technically 33 watts). Various people in this group have communicated with Yaesu about this issue and we have very specific recommendations from Yaesu telling us to not run the rig at more than 1/3rd power. That comes about because the rig is designed for typical SSB operations, which on average run the rig at 1/3rd power even when you have the power set at 100 watts (that's just the way human voice works). Running higher than that will shorten the life of your finals, perhaps drastically.
      >
      > 3. For FM, you should run at no more than about 50% of rated power. That comes about because the manufacturer designed the radio with an expectation of voice transmissions being no more than a minute or so at a time. Digital transmissions are often many minutes at a time. Again, operating above this will shorten the life of your finals. For 2 meters that's about 25 watts, for 440 that's about 20 watts.
      >
      > 4. The Big 3 manufacturers (Yaesu, Kenwood, Icom) all recommend that for SSB soundcard you set your rig to a fairly high RF power setting (menu item 75), and then use the input gain to limit your digital signal to the recommended power level. You can use the playback gain in your computer, the TX gain on the Signalink, and the digital input gain on the FT-897 to adjust the input gain to get the 1/3rd power. It's best to try to adjust all three so that you're not at the extreme end of any one control (which can add some distortion). That doesn't work with FM, so for FM soundcard you have to lower your RF power setting.
      >
      > 5. You want little or no ALC. You do not want 1/4 ALC. ALC on your signal means that your signal is distorting. That means (a) other stations may not be able to copy your signal, and (b) you will be splattering, which interferes with everyone else on the band.
      >
      > 6. It is considered polite to limit your PSK transmissions to no more than 30 watts because to transmit at higher power causes your signal to drown out all the adjacent signals on the band.
      >
      > If you are not getting a power reading on your FT-897 when you transmit digital, there are a couple of possible problems:
      >
      > a. You do not have your Signalink jumpers installed properly
      >
      > b. You are plugged into the CAT port and not the data port
      >
      > c. You did not set the Signalink as your receive and playback device (in the digital software).
      >
      > d. You have the computer's playback gain set too low (the playback gain for the Signalink device, not the playback gain for your soundcard).
      >
      > e. You have the Signalink's TX gain set too low
      >
      > f. You have the FT-897's digital gain set too low
      >
      > *****
      >
      > We may now sit back and watch the flaming begin as people tell you all about how they do it some other way which does not follow the manufacturer's recommended way of operating the rig in digital and how it's worked for them so far. Which it probably has, even though they are shortening the life of their finals and/or splattering all over the bands.
      >
      > 73s
      > Jon, WB2RYV
      >
      > p.s. For those running Elecraft radios, the manufacturer's recommendation is to set the output power control at the desired transmit power - but that's because Elecraft does things differently.
      >
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