[Boatanchors] Kilowatt Matchbox w/directional coupler- SWR

[Gary Peterson]

I am pretty sure you have a problem in your directional coupler.  If connected correctly, it reads the VSWR on the coax between the transceiver or transmitter and the input of the Matchbox tuner.  It should not indicate the VSWR on the output of the tuner.  A good test would be to connect the transceiver or transmitter to the input of the E.F. Johnson directional coupler and the output of the directional coupler to a known good 50 ohm dummy load.  If the VSWR reading is much above 1:1, I would measure the values of the resistors in the directional coupler and compare them with the schematic or manual.  I think the bridge resistors are the most likely source of any error.  Keep us posted on what you find.

Gary, KzeroCX    

In SWR mode the meter dips like it should, but reads 3:1 when actual is close to 1:1
Anyone have experience with these?? Wondering if the problem is within the directional coupler or the .01 mfd ceramic caps which are across both the meter and the 2k pot which adjusts the meter for full deflection before switching to SWR mode.  Did they intend for the indicated SWR to be accurate on a random wire??
--Brad? W1BCC