ICOM 718 low power output

[W8JX]

I cannot remember last time I even had my rigs in shack set to 100 watts. Most I run barefoot is about 50 watts. I use 50 watts when I drive amp so I rarely exceed that barefoot to I never have to turn it down to use amp. Only rig I have set for 100 watts out in one in car.

[KE3LB]

Well I changed the power supply back to normal but when I was changing the power supply I noticed the positive terminal connection was loose but just relaced the power supply with my other astron 20amp everyting is back to normal wondering if the loose connection would cause the problem or I will have to switch it back and see ok thanks for all the responses at least the problem is solved thanks very much 73

[W8JX]

Well I changed the power supply back to normal but when I was changing the power supply I noticed the positive terminal connection was loose but just relaced the power supply with my other astron 20amp everyting is back to normal wondering if the loose connection would cause the problem or I will have to switch it back and see ok thanks for all the responses at least the problem is solved thanks very much 73

If it was loose and loosing connection it would have been hot and would have effected output. Did you ever check voltage under load at rig when there was a problem?
 

[KE3LB]

No, I didnt check it under load yet just put my back up ps in place  which is much newer than the one I had there the one I had there I picked up used I usually dont buy used stuff but the price was right at the time but like I said before it was working 100% for about 6 months  maybe that slightly loose terminal might have caused the low power out put on radio but now with my other supply everthing is fine, going to ck it  out when I have time for further checking thanks.

[N4CR]

This is not the proper way because your "clean signal" is in effect under modulated. You set proper AF drive level you can adjust power to any output you want from 5 watts to 100 and not need to readjust audio. If this is a popular practice this is the first i ever heard anyone doing it. It would be interesting to test signal developed both ways for cleanliness and modulation/loudness. I normally run 20 watts but when I need more or less I change power level control and not audio drive.  I set my audio levels and forget them.

Yes, this IS the proper way to run digital modes. TX power fully max, limit power output by reducing audio drive levels.

For any digital mode, ALC is distortion. Running the rig at full capability and then not going there with the drive levels guarantees that your ALC circuit never has any reading and is not introducing distortion into your digital stream.

It is standard operation for digital modes.

from http://kc.flexradio.com/KnowledgebaseArticle50363.aspx

"Procedure for Adjust RF Power Output for Best IMD when Operating Digital Modes

Step 1. Set the PA Gain to 100.
Set your PA drive at 100. When you keep the audio input levels below -1dB, this will produce a signal that has the most optimal IMD figure with the maximum RF output."

From http://www.mymorninglight.org/ham/psk.htm

"Set your rigs' RF OUT to MAX, then set the MIC GAIN to MIN. "

From http://www.westmountainradio.com/content.php?page=supportduo

"Your radio should be set to your normal mic. gain setting for you and your mic. The speech compressor should set on or off depending on the mode you are running, see the software help files. Set your radio's RF Power (drive control) at maximum and the radio in USB, even for sound card operation with RTTY AFSK"

[W8JX]

I do find it funny that you try to use Flex radio as a reference here when they rigs and software is a cluster fart at times and not the standard by any means. Also what is fixation with using mic input here? I use data jack on back and menu in rig to set audio levels in and out via this jack and control output with pwr level control and NEVER have any ALC issues. The max power method with maybe work best with old hybrid or tube rigs that use mic input and have no power control but with a modern rig it is counter productive and not very accurate at all.

[AD7VB]

If you feed the 718 thru the 13 pin socket the mic will be hot all the time when you transmit unless
you turn down the mic gain to zero.

Rigblaster M-8's are cheap at hamfests and work very well with this radio thru the mic socket.

Menu setting for power at 100 and adjust power with the audio signal level.
Shut off the compression and it makes a fine digital radio.
Now if I only had the rtty filter for contests

Some other radio may be different.....

Todd
AD7VB

[KE5ZZN]

I think it's because the 718 uses the alc circuit to limit the power when you change it in the menu.
Things worked much better for me when I left the power at 100 percent and just adjusted the audio
to control power. Don't know how other radios work as the 718 is my first and only HF radio.

Todd
AD7VB

Yes, that is correct. I tried playing around with the power on the radio at first to keep the ALC down, but it was an uphill battle if you ever wanted to change anything. I've run a LOT of PSK with the radio power at 100w and controlling the output via the audio level to 5-10w. I always get great reports and never have to worry about being all over the waterfall because ALC kicked in and distorted the signal.

[N4CR]

The max power method with maybe work best with old hybrid or tube rigs that use mic input and have no power control but with a modern rig it is counter productive and not very accurate at all.

Just curious.

When you turn the power up to 100% on your rig in either data or ssb mode and give the radio no input, how much power is it putting out? If you supply low levels of audio, is your rig output non-linear?

If the answers are anything but "0" and "No" then there's something wrong with your rig.

Power at 100% for digital modes is normal, not strange. And most definitely not counter productive. If you have one of the rare rigs where the power control is a drive control and not an ALC limiter such as the FT-1000 series then it's not counter productive, it just works a different way.

An input signal that makes ALC kick in makes your digital signal non-linear. The cure is to turn up the power control until the ALC doesn't indicate. Turning it up even more than that causes no issue, so the standard is to turn it all the way up.

Why do you think this is a problem when the entire idea of turning the power control to 100% is to insure that your ALC circuit doesn't kick in?

[KC4YT]

Did you turn speech processor back on when you switched back to SSB?
Richard KC4YT