Hi Tom,

If the noise bridge is between the TS-590 and the amp, you shouldn't 
have to worry about running too much power into it.  It's only when 
the bridge follows the amp that you would have to make sure the switch is off.

73,

Dave, W7OQ

At 10:43 AM 1/1/2014, you wrote:
>Lloyd:
>
>I think Howard and Lowell have answered this question, if I'm interpreting
>their posts correctly.
>
>Apparently, if the switch on the noise bridge is off, one can use the
>amplifier without any risk to the device.
>
>Tom Behler: KB8TYJ
>
>
>-----Original Message-----
>From: For blind ham radio operators [mailto:[log in to unmask]]
>On Behalf Of Lloyd Rasmussen
>Sent: Wednesday, January 01, 2014 12:12 PM
>To: [log in to unmask]
>Subject: Re: Using MFJ Noise Bridge To Determine Antenna Resonant Frequency
>
>I would put the noise bridge in the line between the transceiver and the
>amplifier.  This would prevent it from seeing your 600 watts.  I don't know
>about the on-off switch.
>
>
>
>Lloyd Rasmussen, Kensington, MD
>http://lras.home.sprynet.com
>-----Original Message-----
>From: Tom Behler
>Sent: Wednesday, January 01, 2014 11:40 AM
>To: [log in to unmask]
>Subject: Re: Using MFJ Noise Bridge To Determine Antenna Resonant Frequency
>
>Bob:
>
>Ok on not using both the manual and internal tuners together. ... This is
>what I suspected.
>
>Ok also on confirming Howard's procedure for determining the resonant
>frequency of an antenna using the MFJ noise bridge.
>
>Now, I have one more question:
>
>Here in the home shack, am I correct in saying that I'm ok with keeping the
>noise bridge in the circuit at all times, as long as I am absolutely 100%
>sure to turn the noise bridge off before transmitting with 100 watts, and
>especially before tuning and then using my AL811H amplifier?  The amp puts
>out about 600 watts, and I know the Noise Bridge only handles 300 watts.  I
>realize that the noise bridge has a protective circuit, but I have learned
>over the years not to totally trust those protective circuits.
>
>Tom Behler: KB8TYJ
>
>
>-----Original Message-----
>From: For blind ham radio operators [mailto:[log in to unmask]]
>On Behalf Of Bob, K8LR
>Sent: Wednesday, January 01, 2014 11:20 AM
>To: [log in to unmask]
>Subject: Re: Using MFJ Noise Bridge To Determine Antenna Resonant Frequency
>
>Tom,
>
>The noise bridge works very well in getting your SWR down to 1-1.  The
>really nice thing about the MFJ212 and the VEC512 is that you can transmit
>with the noise bridge in line with a power of up to 300 watts.
>
>I would not use your 480 internal tuner if your running an external tuner.
>That combination could cause some really high voltages at the antenna
>connector that could pop some components.
>
>Howard has got it right on how to find a resonant frequency with the noise
>bridge.
>
>Bob, K8LR, [log in to unmask]
>
>----- Original Message -----
>From: "Tom Behler" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Wednesday, January 01, 2014 9:49 AM
>Subject: Using MFJ Noise Bridge To Determine Antenna Resonant Frequency
>
>
>Hi, again, everyone.
>
>
>
>Sometime late last Summer, someone on the list suggested that an MFJ 212
>Noise Bridge might be useful for determining the resonant frequency of an
>antenna, even one that might be resonant outside the ham bands.
>
>
>
>Is this possible, and, if so, how exactly might that be done?
>
>
>
>Tom Behler: KB8TYJ