Updated 6-13-08.  Updated to reflect Revision A
SLIM-MXR-4, Mixer, size-A
Use your mouse's "right click" and "Save Link" to download:
a.  SKSLIM-MXR-4 rev A , Schematic, in ExpressPCB software.
b.  LAYSLIM-MXR-4 rev A, Layout, in ExpressPCB software.  Use this drawing to locate the parts on the SLIM Board.
c.  PLSLIM-MXR-4 rev B, Parts List in text format.
d.  PWB-MXR-ADE, Base artwork for PWB, in ExpressPCB software.  Use this drawing to order the pwb from Express.
This SLIM is constructed on a common printed wiring board, the PWB-MXR-ADE.  Click to get full information on this Mixer PWB.

    The SLIM-MXR-4 is configured with the Minicircuits, ADE-11X.  This mixer was originally designed to be used as the mixer addition, when expanding the MSA/TG into the VNA.
    Minicircuits specifies the conversion loss at -7.5 dB.  I measured the conversion loss at -6.5 dB.
    The strange looking circuit in the I port path is a diplexer.  Wide band frequencies (and noise) exiting the mixer at the I port "see" a dual path at the junction of L15, C16.  Frequencies higher than 33 MHz follow C16 and get absorbed by the 50 ohm load at R17.  Frequencies lower than 33 MHz follow L15 and are launched at J2.  This gives the mixer a constant 50 ohm load over a very wide frequency range, making it very "happy".  The diplexer could be re-designed for any frequency crossover point.
  I continue to recommend this mixer, only because of it's very low cost.

Revision A:
1.  Added a 2.5 dB attenuator network in the L port path to the mixer.  This provides a better impedance match between the LO input connector -  J1, and the mixer.
2.  Added a 14 dB attenuator network in the R port path to the mixer.  This provides a better impedance match between the R input connector -  J31, and the mixer.
These modifications greatly improve the mixer isolation.  This makes it necessary for the LO Drive to be approximately +10 dBm.  To use this module as a mid-drive (+7dBm), the attenuator must be removed.