How much power on psk31 - Digital Forum at eHam.net

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eHam.net Forum : Digital : How much power on psk31

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How much power on psk31	Reply
by ON8WW on November 1, 2008	Mail this to a friend!
Hi All I'am wondering how much power they using on digital mode like bpsk31? Much says 30% of max power power is best enough for working dx. Anyone has more info about max power on psk31 or yours power here in the forum? 73's Dave ON8WW

RE: How much power on psk31	Reply
by AA4PB on November 1, 2008	Mail this to a friend!
The important thing on PSK31 is to run a very clean (low IMD) signal. With most radios it is best to keep the power output between 1/2 and 1/3 of the radio's maximum rating in order to accomplish that. Never let the ALC meter show any reading. On FSK modes like RTTY the important thing is not to overheat the transmitter. On some radios you can run a full 100W all day without a problem. Others need to keep the power down to 50% to keep from overheating. Of course you also need to check the capability of the power supply to handle 100% full duty cycle power. The difference is that PSK signals contain amplitude variations that require linear operation. FSK signals have only frequency changes.

RE: How much power on psk31	Reply
by N4HRA on November 1, 2008	Mail this to a friend!
I have been running PSK for severial years, my max power out is 20 Watts. What I do is set the power level for 20 watts, and adjust the audio input until the ALC justs starts to move, then back it off just a little. I have maintain a IMD around -28 this way Just my 2 cents Lew N4HRA

RE: How much power on psk31	Reply
by AA4PB on November 1, 2008	Mail this to a friend!
You should do better if you set the power control full open and then back the audio down until you get the desired 20W output. That'll keep you well below any ALC action. All setting the power control down low does is make you operate closer to ALC activity. The power control is designed for modes (like SSB) where you want the ALC to limit your power output.

RE: How much power on psk31	Reply
by KL7IPV on November 4, 2008	Mail this to a friend!
I always back my power output to 20 watts or less. It works great and if I can read them I can work them. Sometimes I have read them without even seeing the chain in the waterfall. THAT is astounding! Frank

RE: How much power on psk31	Reply
by VA3XQ on November 5, 2008	Mail this to a friend!
I run 30-50 watts depending conditions and how much print I am getting from the other station

RE: How much power on psk31	Reply
by K5MBV on November 5, 2008	Mail this to a friend!
AA4PB is correct. The actual amount of power has NOTHING to do with the IMD. It's how much audio you push it with. 20 or 30% of the mamimum output should yield a clean signal whether this is 20 or 30 Watts or 200 to 300 Watts. Set for max power then reduce the output using the audio gain control. Ken K5MBV

RE: How much power on psk31	Reply
by N5YPJ on November 5, 2008	Mail this to a friend!
No more than 20 to 25 watts. I've worked plenty of DX with 20 watts. More power only wrecks the band for others and doesn't give you any QRO advantage like it would in RTTY.

RE: How much power on psk31	Reply
by N5YPJ on November 5, 2008	Mail this to a friend!
No more than 20 to 25 watts. I've worked plenty of DX with 20 watts. More power only wrecks the band for others and doesn't give you any QRO advantage like it would in RTTY.

RE: How much power on psk31	Reply
by K5MBV on November 5, 2008	Mail this to a friend!
Not correct. "Wrecking the band for others" is a function of bandwidth. The wider signal will of course take up more spectrum. The width is what "Wrecks" the band for others and IMD from overdriving amplifiers is the cause, not power. . Ken

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