Callsign
Page 2 of 2 FirstFirst 1 2
Results 11 to 17 of 17

Thread: MicroMatch MM-2

ad: L-HROutlet
ad: l-assoc
ad: l-gcopper
ad: l-WarrenG
ad: l-innov
ad: l-Waters
ad: l-rl
ad: l-tentec
  1. #11

    Default

    Quote Originally Posted by KB1ZEJ View Post
    Attachment 130871OK, Thanks. Here is what I have. Shield is one end of pot. white wire is other end of pot. Shield goes to one side of meter as well, not marked for polarity. Middle (wiper) of pot goes to other side of meter, also unmarked. Picture included.

    If you think that this can be reversed, then this is not the garden variety meter movement, e.g. x no. of dc microamps.

    Again, thanks for help and insight.
    That connection doesn't allow for a "switch," as it's obviously not bring both "forward" and "reflected" current data from the coupler to the meter housing. So, looks like you're stuck with swapping the coax connections around if you want to know what reflected power or SWR is.

    The MicroMatch couplers I've had have three wires coming from the coupler to the meter box: A forward wire, a reflected wire, and a common (shield). Using a switch on the meter housing, it swaps what drives the meter from "F" to "R."

    Although the meter may not be marked for DC microamps, it is. Probably 0-50 or 0-100 uA. Wouldn't be difficult to measure it and see.
    What if soy milk is just regular milk introducing itself in Spanish?

  2. #12

    Default

    OK. Any way to figure out how to get current from the "other" direction?

    Thanks again.

  3. #13

    Post

    Quote Originally Posted by KB1ZEJ
    OK. Any way to figure out how to get current from the "other" direction?
    Thanks again.
    The MAGIC happens in the coupler for the meter with the Germanium or Schottky diodes.

    Here is the NA0TC tutorial, scroll down to Dual Directional Coupler.
    http://www.na0tc.org/Homebrew%20SWR%20Meter.pdf

    Almost every ARRL Handbook covers this, plus DIY Build project.
    Nullius in verba

  4. #14

    Default

    I am unfamiliar with that particular coupler, so I don't know if it even has separate "forward" and "reflected" circuits. It might, but it might not.

    If not, without rebuilding the coupler there would be nothing you could do to actually measure SWR by virtue of F/R indications.

    Why not take the coupler apart and see what's in there?
    What if soy milk is just regular milk introducing itself in Spanish?

  5. #15

    Default

    Quote Originally Posted by WB2WIK
    Why not take the coupler apart and see what's in there?
    That will be required to understand (reverse engineer, draw schematic) current coupler design.
    Some form of Directional Coupler.
    I have never seen a diagram or the sensor M.C. Jones used in this model.

    A FWD and REV might be possible with simple additions/modification,
    BUT without current schematic -- that is conjecture.

    Tandem Match Coupler can be found in 2010 Antenna Handbook (ARRL).
    Last edited by W9GB; 04-26-2013 at 01:55 AM.
    Nullius in verba

  6. #16

    Default

    Thanks to all. I have my work cut out.

  7. #17

    Default

    Quote Originally Posted by KB1ZEJ View Post
    Thanks to all. I have my work cut out.

    It's not much work. Open up the coupler and see what's in there. Either it has two diode detectors on opposite ends of a coupling system, or it doesn't. This should take about 60 seconds to resolve.
    What if soy milk is just regular milk introducing itself in Spanish?

Page 2 of 2 FirstFirst 1 2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •