[Amps] Power metering in linears

[Michael Tope]

Yes that's it, Marv, except that I think you meant to say
that the single "turn" primary of the first transformer is
connected between "ports 1 & 2" instead "1 & 4".

See figure 2 of the following document:

http://directional-coupler.notlong.com

73 de Mike, W4EF....................................................

>
> Hi Mike & Tom,
>    Perhaps...
>
>    Visualizing the thing as a 4 port device.
>
>     Port 1 is the RF input
>     Port 2 is the RF output
>     Port 3 is the Forward sample
>     Port 4 is the Reverse sample
>
>    Two identical transformers with 32 turn secondaries (for -30 db
> coupling) are employed.
>
>    The single "turn" primary of the first transformer is connected
> between Ports 1 & 4.
>    The secondary of the first transformer is connected between ground &
> Port 3.
>    The single "turn" primary of the second transformer is connected
> between Ports 3 & 4.
>    The secondary of the second transformer is connected between ground &
> Port 2.
>    Phasing of the windings is consistent with the connection order
> detailed above.
>
>    For cable TV use, I suppose the reverse port is terminated (w/ 75
> ohms?) to make a 3 port critter.
>
>    For 50 ohm power measurement, the sample ports need to be terminated
> in 50 ohms non-inductive of suitable power rating.  A rectification of
> this sample may be used to drive a meter or other indicator.
>
> 73 & Good afternoon,
>    Marv  WC6W