SLIM-MXR-2 rev B
Mixer with Diplexer
Updated
6-13-08. Updated to reflect Revision B
SLIM-MXR-2,
Mixer, size-A
Use your mouse's "right click" and "Save Link" to download:
a. SKSLIM-MXR-2
rev B,
Schematic, in ExpressPCB software.
b. LAYSLIM-MXR-2
rev B,
Layout, in ExpressPCB software.
Use this drawing to locate
the parts on the SLIM Board.
c. PLSLIM-MXR-2 rev C,
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-2 is configured with the
Minicircuits,
ADE-11X.
This mixer was originally designed to be used as the second mixer in
the
MSA.
Minicircuits specifies the conversion
loss at -7.5
dB. I measured the conversion loss at -6.5 dB.
C25 is a low value capacitor to allow
only high frequencies to pass. 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: Added a 2 pF chip capacitor to the mixer pin 6
junction to ground (C9 position). This helps match the mixer to
the 50 ohm drive on J1.
Revision B:
1. Deleted the Rev A modification. Remove the 2 pf
capacitor, C9. The next mod (2.) makes the capacitor, unnecessary.
2. 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, which, improves 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.