Limiting to 100W more accurately?

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My 6600M seems to be all over the place with output power. It depends on antenna, temperature, and else... My external W2 watt meter gives me readings of anywhere between 97 and 110 W. I have set the rig to 100W. Is it possible that the output can be monitored and more accurately be controlled?  110W is a little high if I run LP in a contest.

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Andy - KU7T

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Posted 2 years ago

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Photo of Roger,  W6VZV

Roger, W6VZV

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I would say that this is pretty normal (I will defer to the Flex crew, but I notice variance in output based on how much transmitting I do with my 6400M; nothing to be concerned about IMO); variance no doubt based on temperature.  In our area Edison plays with the voltage some of the time and this could also be a factor.
de Roger W6VZV 
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Bill -VA3WTB

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If you set you power slider to a level you want then the radio will transmit at that setting. But you can save a profile with the power setting of your choice and recall the profile anytime.
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Burt Fisher

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Where are profiles saved? On a computer?
Also my 6400M crashes anytime I key it up on CW over 75 watts (even on a dummy load) unless I hit the ATU first. SWR is not an issue. Tim gave many good suggestions, none worked. So I will live with it because is addressed easily by hitting the ATU. I mention it in case someone else has the same issue. It is not a big deal.
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Jon, EA2OT

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What about a unit without ATU installed? I hope it ́s not happening as well!
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Mack McCormick, Elmer

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Of course you understand you're talking about a 0.5 db difference between 97 and 110W. Very trivial.

Alpha Team
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HCampbell WB4IVF

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Don’t take the meter readings too literally.  Even very good wattmeters have error margins,  from +/-  3 to 5% and often higher (and don’t forget that also applies to the rig’s power settings).    The impedance presented by the loads can also affect the readings, as can meter placement.   I agree with Roger and Mack, you’re right in the ballpark.


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N5LB - Lionel B

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I have experienced similar with my 6400; SSDR wattmeter and external WM reading high and very different under certain conditions  and rig crashing on the first "dit". 

Initially, I thought it was RFI on my ethernet cable/computer, though this was possible it really more broadly issue #1 below.

I found two issues.

1. Common mode RF getting into outboard tuner WM (the tuner also would get flakey at times) , and also affecting the SSDR WM reading.  This I fixed by carefully following best practices for bonding and grounding of equipment (52 years-what the heck!).   Also, the real issue was from an antenna problem (and feed).  This had to be corrected.  A new homebrew current balun helped.  The root cause of CM is often the antenna system.

1.a. I had the crash problem with the dummy load also.  This was a bad connector install on some old RG8X.  I replaced all of the in shack jumper cables with LMR-400 and carefully installed connectors.

1.b. LMR-400 is well shielded, better than 8X, 213 etc.   I guess LMR-240 is as good. 

1.c.  Lots of ferrite cores, #31.

2.  The arc plug (for a 100w rated plug) in my Alpha Delta was firing under certain conditions of my multiband, open wire fed dipole.   This would appear as a short to the 6400, and protecting itself from my mistake, instant shutdown-crash.  Not pretty.

So, this seems to have been multiple causes.  Good luck. More sanity than I could afford to lose was lost in the episode.