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Cowboy_bob
Junior Member
Username: Cowboy_bob

Post Number: 29
Registered: 12-2004
Posted on Saturday, January 14, 2006 - 8:10 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Scenario: 4 watt radio...5 pill linear inline with power off...swr 1:1 flatline...NOW, linear power on..I recalibrate swr and get 1.5:1 which is great even though it may be a false reading.... HERES THE QUESTION. When I deadkey with the linear on its @ 1.5:1...when I talk the swr needle swings down to flatline...WHY?
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Sonny
Member
Username: Sonny

Post Number: 80
Registered: 5-2004
Posted on Saturday, January 14, 2006 - 8:26 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Cowboy bob, I'm not sure but could be reflective power driving it down !
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 1019
Registered: 9-2004
Posted on Saturday, January 14, 2006 - 9:01 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

an SWR meter will always show a downward swing when modulation is applied.
im not sure why, but its not meant to read modulation.
it doesnt mean anything is wrong with the radio or meter; it actually sounds like everything is working fine.
i always turn my mic gain down when setting SWR so i dont get a false reading.
later,
matt
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Alsworld
Advanced Member
Username: Alsworld

Post Number: 965
Registered: 1-2002
Posted on Saturday, January 14, 2006 - 9:31 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Take the SWR on a dead key (carrier) only. That gives you the actual SWR. I would not worry about any reading when you add modulation if your meter is set to the SWR mode.

If your power Avg or PEP power also goes backwards when you modulate with amp on, that usually indicates too high of a dead key. In SWR mode, I would not sweat it.

But, to be honest I cannot answer your question as to 'why'?

Alsworld
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Cowboy_bob
Junior Member
Username: Cowboy_bob

Post Number: 32
Registered: 12-2004
Posted on Sunday, January 15, 2006 - 9:15 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

OH YEAH....everything works great...dk 400w....swings 1100w peak, but still curious why?....LOL
Thank you all, especially Tech808
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Therealporkchop
Advanced Member
Username: Therealporkchop

Post Number: 535
Registered: 11-2002


Posted on Sunday, January 15, 2006 - 6:24 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Not all meters swing backwards, some will go forward.

I believe it's been answered before cause I ask the same thing. Experienced the same situation.

I believe it was best put that it's because the meter is calibrated to one power and you are modulating to another. The meter can't reference cause the source has changed.

Maybe you should try with a self-calibrating meter?

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