Icom: IC-718 Possible Power Output Problem

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enduser56

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I recently fired up my IC-718 that had been in storage and connected it to a MFJ Versa Tuner 962D and end fed antenna length of 42 feet. The system tunes ok on 80 and 40 at 15 watts out with acceptable swr. However, when I put the 718 back to 100 watts and key down, the peak audio only swings to about 50 watts on the 962D tuner meter. Is that normal, or should the needle land around the 90-100 range on the audio peaks? I fear I may have somehow accidentally damaged the finals over the years. Any comment or opinion is appreciated.

Thanks and '73
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jwt873

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The Versa Tuner needle can't move fast enough to measure peaks on SSB. Also, with SSB, the power out depends on how loudly you talk. It's not a good method of checking the output power of the finals.

To check the actual output you need to use a continuous signal. The way I do it is to put the radio in CW mode and press down on my key. If you don't have a key, I think you can get away by setting the mode to RTTY and pressing the PTT on the mic.
 

cmdrwill

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Even with one of the really good wattmeters, you will only see about one half power on voice peaks in SSB Mode. So 50 watts is probably right on.
 

enduser56

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jwt873,
Thanks so much for bringing me out of the darkness on this! And you're also correct, when I output 100w on RTTY the needle behaves accordingly and sits at 100w. I was generally aware that the volume of the audio was the large factor in what you would see on the needle but had know idea you were only going to see about half the output displayed on SSB, very interesting. Again, appreciate yours and others very helpful replies!
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enduser56

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I've struggled hard to not fall into the "whistler" group over the years but was close to it this time :) Thanks again for yours and everyone's helpful comments. I'm sure I'll have other questions as I climb back on the air after 2 years offline.
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kc0nzm
 

KE5MC

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I've struggled hard to not fall into the "whistler" group over the years but was close to it this time :) Thanks again for yours and everyone's helpful comments. I'm sure I'll have other questions as I climb back on the air after 2 years offline.
enduser 56
kc0nzm

Being a whistler into a dummy load is never a problem. :D

You do have a dummy load... Right?:p

Seriously a dummy load is an important tool to remove the antenna from you overall setup to determine your baseline functionality.

Mike
 
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