Hi,

The VEC512 and the new MFJ212 are fixed at 50 ohms.  If you search for a 
null by tuning your receiver, it will only work if the impedance gets close 
to 50 ohms.  There are other noise bridges where you can adjust the 
resistance and reactance for a null, but you can't keep those bridges in 
line and transmit through them.

Bob, K8LR, [log in to unmask]

----- Original Message ----- 
From: "Steve Forst" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, August 30, 2013 8:05 AM
Subject: Re: Fw: MFJ Noise Bridge General Quiry


So I guess the null isn't so sharp that it is going to give an actual
resonant frequency,  but maybe  enough to give a general idea of the
resonant point.

73, Steve KW3A

On 8/29/2013 10:27 PM, Lloyd Rasmussen wrote:
> You could make an educated guess.  At resonance, the impedance is not
> necessarily 50 ohms, although it is likely to be somewhere between 25 and
> 100 ohms.  Thus I would guess that the null might not be very sharp.  It
> would still be worth trying.
> 73 -- W3IUU, in Ocean City, NJ
>
> -----Original Message-----
> From: Steve Forst
> Sent: Thursday, August 29, 2013 6:09 PM
> To: [log in to unmask]
> Subject: Re: MFJ Noise Bridge General Quiry
>
> I know the current thread on  using a noise bridge deals with adjusting
> an antenna tuner, but  couldn't it also be used to find the resonant
> spot on an antenna that is resonant out of band?
>
>
> 73, Steve KW3A
>
>
>