PSK ALC Question

Discussion in 'Working Different Modes' started by N9SOX, Mar 18, 2012.

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  1. N9SOX

    N9SOX Ham Member

    Hi everyone,

    I recently picked up a Kenwood TS-480SAT and have it interfaced (for PSK operation) to my PC using a Rigblaster NoMic. I noticed while adjusting my transmitter drive via the PC Volume Control, I can run my radio all the way up to 100W out (into a Dummy Load of course) and never see any reading on the Radio's ALC meter.

    I can't figure out why this is occuring. I don't think I should be able to drive the transmitter that high without seeing the ALC jump off the scale. I've got to be missing a setting somewhere and I've looked through the 480's Manual and haven't come up with anything.

    All my testing has been done into a Dummy Load and metered via my tuner so I know I'm getting on the air. I just don't want to transmit with no indication on my ALC.

    Any ideas? Thanks in advance for the help. I'm not new to PSK, I've been using my Yaesu FT-847 for months without any issues using the same setup. I've leterally just taken out the 847 and connected up the Kenwood. :confused:
     
  2. KD8DEY

    KD8DEY Subscriber

    Maybe you need to adjust the little white knob on the nomic? Not enough audio in to drive the radio? difference in gain at the mic input of the kenwood vs the Yaesu??
    You did change the jumpers inside for the different radio and made sure they had good connections inside??
     
    Last edited: Mar 18, 2012
  3. KA9JLM

    KA9JLM Platinum Subscriber

    Did you adj the ALC ?

    If it is not indicating, maybe it is set wide open.
     
  4. KA5S

    KA5S Subscriber

    You should be able to run full peak power without ALC indications, though a lot of rigs won't or can't. ALC was originally intended to prevent the onset of nonlinearity (usually by detecting grid current) when used with a linear amplifier, and it is a good thing when a rig is linear enough to run normal power without ALC. Many rigs are still linear enough to operate PSK even when their ALC indicators, meters or LEDs say ALC has been applied. If in doubt, have someone watch the waterfall with one of the popular SC programs and monitor your IMD as you turn the power up and then increase the audio drive.

    Turning the power up with audio and DOWN with the power level setting is doing things backwards, by the way; FAR better to set the power level to 100 W peak and then reduce SC mode output with the SC audio controls.

    Cortland
    KA5S
     
  5. KA9JLM

    KA9JLM Platinum Subscriber

    I think that is correct Cortland.

    It looks like that radio is made to limit the power while operating PSK using the power level setting and ALC is not even used. Unless it is connected to a amplifier. As far as I can tell.

    It may be operating normal.
    .
     
    Last edited: Mar 18, 2012
  6. N9SOX

    N9SOX Ham Member

    Thanks everyone for your replies. I got myself straightened out.

    KD8DEY - Thanks for reminding me of that little white knob on the NoMic, I double checked it and it was turned all they way up. The NoMic's jumpers were in the correct position as well (I had reset them for the Kenwood).

    I did the following:

    1) If I set the Radio to 100W and run the audio drive all the way up, I do not see any ALC indication on the Radio.

    2) If I set the Radio to a lower power level (say 25W or 50W) and then increase the audio drive past a certain point, I can see the ALC indication moving up the scale.

    I've done some other reading out on the net (and watched K7AGE's video again) and believe the radio is working just fine and I'll just leave it set to 100W as it should be. I only run up to about 30 watts when using PSK.

    Thanks again guys for the help. When setting up the new radio, I got myself confused somewhere along the line.
     
  7. KD8DEY

    KD8DEY Subscriber

    Weird coincidence.

    Tried to do PSK on the 897 yesterday,
    Meter indicated Modulation, but no Power or ALC indication on any mode except AM/FM.

    Hadn't made any changes.
    Apparently RF caused the problem since it took a HARD Reset of the radio to get everything back working properly

    Darn processor based radios.....
     
  8. G0GQK

    G0GQK Ham Member

    PSK requires that you have no ALC evident for a clean undistorted signal and there is no requirement to use more than 30 watts maximum indicated on a power meter when operating PSK. You will be able to make contacts all around the world using 15 watts with a clean sharp transmitted signal. Use a 100 watts and you will be "blacking out" the waterfall and de-sensitizing all the nearby users, and will not be popular ! Remember that what your power metre indicator shows is doubled, so 25 watts is actually 50 watts and 100 watts is 200 watts
     
  9. WC5B

    WC5B Ham Member

    In the past I remember adjusting for alc and then kicking back a bit, but when I got back into it I experience the same thing you do. I would say everything is fine. I have had many many qso's since and the alc never moves, regardless of how hard I drive it. Only thing I can come up with is it is something that has changed in the software itself lately on the quality of signal being generated, because everything else seems just fine. This is the same on two radios btw.
     
  10. KF5FEI

    KF5FEI Ham Member

    I typically set the radio for full power and adjust the audio drive to shoot for about 1/4-1/3 of max output. Never had any complaints of a dirty signal.
     
  11. N5MDT

    N5MDT Premium Subscriber

    And I have set the power to 100w and set digital gain so that it only outputs 85w and have been sent photos of a nice clean psk signal from me. It is all about not over driving the audio.
     
  12. N2ADV

    N2ADV Premium Subscriber

    Having recently purchased a 480, my experience is the same: little or no ALC. I've made dozens of contacts via PSK and everyone says I have a very clean signal. The 480 appears to just be very PSK friendly.

    I you're worried about getting out or how your signal is, pick a time and frequency (10, 15, or 20 meters is where I'm limited right now) and I'll tell you how you're looking. :)
     
  13. K7JBQ

    K7JBQ Moderator

    Say what?

    73,
    Bill
     
  14. N5MDT

    N5MDT Premium Subscriber

    You know...SSB. Half of an AM signal is half the power, right?
     
  15. WS2L

    WS2L Guest

    K9SOX,

    I am running the exact set-up that you are, Kenwood TS-480SAT with a with a Rigblaster Nomic and I have never experienced the problem you are explaining. Normally I run 50 Watts but often tomes run 75 and even 100 watts without any kind of troubles. I have all of my computer audio settings set to 100% and I use the adjustment knob on the RigBlaster to help adjust for the proper audio out. Any fine tuning I may have to do is done with the mic gain control in order to bring the ALC into proper alignment.

    Hope that helps.
    Dave

    PS: If you continue to have problems you can email me at:
    ws2l@qrz.com
    Or send me a Private Message through the bulletin.
     
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