"Your signal is overdriven" - Digital Forum at eHam.net

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eHam.net Forum : Digital : "Your signal is overdriven"

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"Your signal is overdriven"	Reply
by AC4RD on August 9, 2009	Mail this to a friend!
I have 20 meters on, taking a look to see what's coming in this morning. I just saw a trace on the waterfall that was saying "... your signal is too wide and exhibits splatter, and appears to be overdriven." I switched away to look at another trace and when I came back it was saying ".. please look into this. Your friends on the bands, some concerned hams." I've left the pointer there but haven't seen a reply from the "overdriven" signal's owner. I've been bothered by overdriven signals myself, and think it's a nice idea to very politely suggest that the offending stations check their drive levels ... though I didn't ever see the complaining station identify, which strikes me as a very bad idea indeed, both legally and ethically. (If you want to complain to someone about his signal, IMO, you still need to identify yourself!) Anyway, this is one I've never seen before.

RE: "Your signal is overdriven"	Reply
by G0GQK on August 9, 2009	Mail this to a friend!
The biggest cause of the problem is when there is ALC showing. There should be no ALC, some suggest a little is OK, it isn't. When you are transmitting PSK every item not needed should be switched off, like the processor. Its a good idea to let a station know that his transmission is poor, and its poor practice for people to answer a poor transmission knowing that the transmission is "dirty" and doing nothing about it. If you saw a car being driven in an erratic manner, would you report it, or wait until you read in the paper the driver had mounted the kerb and injured or killed some poor soul ? G0GQK

RE: "Your signal is overdriven"	Reply
by W1ZI on August 9, 2009	Mail this to a friend!
Night after night I see PSK31 signals that are up to 500 Hz wide with sidebands. Over-driving the audio is a discourtesy to all those neat and narrow PSK31 or PSK63 signals that are trying to share the spectrum space, as well as a terribly wasteful and inefficient habit on a wonderful mode. Perhaps in some cases a polite and private reminder using the email published in QRZ.COM would be appropriate? Or, perhaps an SWL card? I realize that it is very difficult to call out someone like this without seeming to want to declare war on them, but some sort of helpful notice would be useful. How about "The Order of the All-Gold Waterfall?" [an elective society...]

RE: "Your signal is overdriven"	Reply
by KG6MZS on August 10, 2009	Mail this to a friend!
>>>The biggest cause of the problem is when there is ALC showing. There should be no ALC, some suggest a little is OK, it isn't.<<< Surprisingly this depends on the radio. Elecraft's K3 is at optimum drive level with 4 bars of ALC showing because Elecraft has a different approach to their ALC metering. Inversely, some radios will show no ALC and the sound card can still be over-driven, Short of outboard IMD metering, It is best to ask different stations what they see and perhaps even send you a screen shot. 73 de Eric, KG6MZS

RE: "Your signal is overdriven"	Reply
by KE4DRN on August 10, 2009	Mail this to a friend!
hi, if the signal was that bad you could mail or email a screen print of the qso in progress along with the waterfall showing the poor signal. if they read it and take action that is another story. 73 james

RE: "Your signal is overdriven"	Reply
by W5RKL on August 11, 2009	Mail this to a friend!
KG6MZS said: "some radios will show no ALC and the sound card can still be over-driven" Eric, I'm not sure what you meant by your comment? In PSK transmit, the radio does not over drive the sound card. I wonder if you meant to say, "some radios will show no ALC but the radio can still be over-driven by the sound card" That would make more sense. Mike W5RKL

RE: "Your signal is overdriven"	Reply
by AA4PB on August 11, 2009	Mail this to a friend!
You should also note that distortion anywhere in the signal chain, including the receiver, can cause PSK31 signals to be wide and display poor IMD numbers. If most everyone appears wide or all the stronger signals appear wide then you might want to check your receive setup before lodging complaints. I've done some testing here and find that signals over about S5 can appear wide when the AGC is set to fast (Icom). Switching to slow AGC can improve the IMD on all those signals by up to 10dB!

RE: "Your signal is overdriven"	Reply
by KG6MZS on August 11, 2009	Mail this to a friend!
>>>Eric, I'm not sure what you meant by your comment? In PSK transmit, the radio does not over drive the sound card. <<<< The computer can over-drive the sound card. If the wave level controls in the computer are maxed and the mic gain in the radio is reduced accordingly, no ALC might show, but the audio can still be distorted. AA4PB said it better - distortion can occur anywhere in the signal chain. Even in the RX. I actually see surprisingly few over-driven signals in the waterfall. I do see some very strong signals fairly often.

RE: "Your signal is overdriven"	Reply
by AC4RD on August 11, 2009	Mail this to a friend!
G0GQK said: "If you saw a car being driven in an erratic manner, would you report it, or ..." Friend, it is obvious to me that you have never visited Raleigh, North Carolina. Here, we take notice if we see a car that is NOT being driven in an erratic and dangerous manner. Three of every four drivers on the local main highway, I joke not, have cellphones to their heads. On my morning commute, I routinely see drivers reading newspapers, eating breakfast, or applying makeup, all at 75mph on the highway. A couple of weeks ago I watched a man--passing me in the high-speed lane--typing away with one hand on a laptop computer perched on his dashboard. Your figure of speech would probably make perfect sense in a rational, civilized place. But in Raleigh, not so much. :-(

RE: "Your signal is overdriven"	Reply
by KF6IIU on August 12, 2009	Mail this to a friend!
Make sure receiver intermod from nearby loud signals is not influencing your view of a signal. Kick in the attenuator for a second and see what happens. My IC706mk2g does this from time to time, to a greater extent than my previous rig, a Yaesu FT-101E. If the signal is still 100khz wide with attenuation, don't be afraid to give them a 550 signal report.

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