[SMCARA] PSK-31 Signal

[Clarke, Tom AIR4.0P NATOPS]

Hi Allen,

Typically if you overdrive the audio into a SSB transmitter creating the PSK31 signal, you wind up with all those nasty sidebands. Adjusting the audio level into the transmitter so that there is no, or minimal, ALC indicating on the rig, will help keep it clean.  If you are really into PSK, there is a nifty little gizmo called PSK-Meter that will monitor your RF output and "ride herd" on the gain of the system via a signal sent to the sound card gain circuit. Also make sure you have the audio processing turned off. A mis-tuned linear amplifier (i.e., not running it "linear") will do this, but amps are not normally used on PSK, since 30-50 watts is all that is needed.

Many hams subscribe to the "all knobs turned full right" theory of tuning up!  This also creates havoc on an SSB voice transmission.  We have all heard the "ESSB" boys and the guys with too much processing on the bands creating nasty sounding signals.  All those racks of audio processing equipment are fine if you are running a rock station, where distortion is considered an "enhancement", but not on the ham bands where intelligibility (note ,I didn't say intelligence!) is the goal!

73 Tom/W4OKW

Tom Clarke
Wyle, Inc  Aeronautics
P3 Product Lead, PEO(A)
USN/USMC National Airworthiness Office
Naval Air Systems Command, AIR-4.0P
(301) 995-3793/DSN 995-3793
Fax: (301) 342-3776
Cell (301) 904-2053
frederic.clarke at navy.mil

"A good Navy is not a provocation to war. 
It is the surest guaranty of peace."
President Theodore Roosevelt


-----Original Message-----
From: smcara-bounces at mailman.qth.net [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Allen Landmann
Sent: Saturday, September 07, 2013 2:44 PM
To: club
Subject: [SMCARA] PSK-31 Signal

I thought people might like to know what a bad signal looks like on the air. So here are a few pics of a guy in Ohio cluttering up the air waves at night on 40M, I was unable to reach him but another helpful ham was able to render assistance.
 I'm curious what caused this, was it transmitter overload or a ground loop problem, the ham that helped him said that it could be the bands? It seems to me that no matter what the conditions are, a radio should not radiate harmonics by itself like that. 
The first screen shot is of a PSK-63 signal, the second is a PSK-31 both from the same guy. The red arrows show where the harmonics are. Any help in relation to why this would happen would be appreciated. Maybe we should have a test-your-radio-on-the-air night or activity and do our part to keep our bands free of bad signals.

Allen,
KB3WEY