Amps
[Top] [All Lists]

[Amps] Sampling RF at input and output of an amplifier

To: <amps@contesting.com>
Subject: [Amps] Sampling RF at input and output of an amplifier
From: "Karin Anne Johnson" <karinann@tampabay.rr.com>
Date: Thu, 16 Jan 2014 11:25:29 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Here's a really simple sampler/signal pick off device.
1 - Use a UHF TEE connector. Shown below.
 
                    =================
                    |               |
            Female  >---------------<  Female
                    |       |       |
                    ======  |  ======
                         |  |  |
                         |  |  |
                         |  \/ |
                           Male
2 - Remove the center male pin by unscrewing it from the connector.
    Not all center pins will be able to be removed by simply unscrewing
    the center pin.  Find one that will. The remaining female to female
    center pin will be floating free in the connector dielectric.
3 - Use a UHF Female to Female barrel connector, and screw it into 
    the Male port you just removed the center pin from.
4 - Connect your amplifier or rig output to one of the Female ports and
    the other Female port to a dummy load.
5 - Connect the "Tap Point"(the Male port on the Tee which now has a 
    Female barrel screwed into it) to your measuring device(ie: scope).
6 - As measured on an HP8753C VNA, the tap port is better than 90 dB down
    from the main line at 28 MHz with a 50 dummy load connected to the 
    thru line.
7 - The stray coupling capacitance between the main line and the center pin
    on the inserted female to female barrel provides a capacitive pick off
    point for connection to a measuring instrument.  The signal is not 
    calibrated relative tot he main line but can be used for monitoring
    at reduced mainline amplitudes.  

        Karin K3UU

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>