Digital mode conflicts between waterfalls--what do you trust?

Discussion in 'Working Different Modes' started by K3RW, Sep 11, 2016.

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  1. K3RW

    K3RW Ham Member QRZ Page

    If you have a computer software showing a waterfall, and you have a rig that also shows a waterfall, which would you trust for adjusting the squelch? Are they all supposed to be 'about the same'?

    I've run into this issue with waterfalls on both Fldigi and JT modes, and between these waterfalls and a rig waterfall as well (on my 'Elmer's rig, not mine). Normally I adjust the squelch in Fldigi while tuned on the JT segment (7.076 for example) then open a JT program, not adjusting this program's squelch. If I get a clean Fldigi waterfall, just opening up the JT one, I notice it doesn't look as clean. Procedurally I just ignore the JT one.

    Does the waterfall on the program you're using for RX need to be the one you are adjusting the noise level for?

    It is always possible this newbie is doing something wrong. Maybe it shouldn't even be different, or I've got a setting off.

    My 'Elmer has a rig waterfall and also runs digital modes. So which waterfall should he adjust the noise levels for? I would think with weak-signal modes even a small difference could be significant. But for SSB/CW, he/I wouldn't use a computer, so there wouldn't be a conflict. We'd just use the rig one.
  2. W8JX

    W8JX Ham Member QRZ Page

    It is going to be based on software decoding it waterfall. I would not worry and which one is right as the only one really relevant is one decoding it. I would focus on computer screen not rig here.
  3. K3DCW

    K3DCW QRZ Lifetime Member #212 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    The waterfalls are simply visual representations of the spectrum and have no real effect on the decoding of the signals. Each program uses different FFT display algorithms (there are a variety) so they're not calibrated in relation to each other. In fact, you can turn the waterfall off and it won't affect decoding but it does make it a bit harder for you to tune or find new signals. Basically, if you can see the signal (or in the case of the JT modes, even if you can't), the software will decode it as it hears the doesn't "read" the waterfall.

    Now, if you have local noise, or you want to make adjustments in the rig to turn on/off preamps/attenuation/AGC, then the waterfall can be a very useful guide. And of course, as mentioned earlier, it sure makes tuning a lot easier.
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    You need to calibrate most software to match the hardware that you are using.
  5. K3UJ

    K3UJ Ham Member QRZ Page

    Adjusting the squelch in Fldigi only affects Fldigi. That program does not interact with JT65. If you are trying to make a JT65 contact, shut down Fldigi. It's not doing anything.

    Personally, I don't even care about squelch in digital.
  6. K3RW

    K3RW Ham Member QRZ Page

    Oh snap!

    How should I use the program waterfalls? So using the waterfall as a visual aid for cleaning up the noise level with the squelch isnt the right way to go?

    I wonder if I've been squelching out weak (but decodable) signals on JT all this time... I figured I had since I never saw anything below -20dB, and supposedly it can decode up to -27.

    Good to know that one waterfall has no impact on the other. I suspected as much.

    <beats head against the wall>
  7. KF5FEI

    KF5FEI Ham Member QRZ Page

    Just so we're clear, we're talking about the squelch slider on FLDigi, and not the knob on the radio, right? The squelch adjustment on FLDigi just limits how weak a signal it will try to decode -- usually you just pick an unused part of the waterfall, and adjust squelch until the program quits spitting out random characters. It may need to be bumped up a tad more in some situations, but usually it s pretty low.
  8. K3RW

    K3RW Ham Member QRZ Page

    Good point. I meant the rig squelch.

    On Fldigi I notice depending on mode, worse than -2.5 gets a bit garbled on decode. I usually leave this around -2.5 and then adjust the noise on the waterfall with the rig squelch. In other modes its a different value, but PSK is the one I use most in Fldigi.

    In JT modes I drop the squelch entirely on the software (slider all the way down) and keep the rig squelch in the same position as before.

    But its been my suspicion that looking at the Fldidi waterfall and adjusting the rig squelch, is not the right procedure if I just switch to JT and move nothing--or maybe since I dropped the JT mode slider all the time, that it makes no difference.

    But between a rig waterfall and Fldigi, etc., I am guessing the rig one is for SSB and CW. I'm guessing digital operators don't use it instead of the Fldigi one... but that is just a guess.
  9. K3UJ

    K3UJ Ham Member QRZ Page

    That's pretty much it. Use program squelch to keep from decoding noise. Too high and you miss the weak signals.
  10. K3RW

    K3RW Ham Member QRZ Page

    Where should I position the rig squelch?

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