Direction Coupler for SWR measurements


This Direction coupler can be used from 5 to 500 Mhz. I have not tested it above 500 Mhz
This design and PCB is not my own invention, but an old project from my local EDR club.
It can be used with the Digital Wattmeter that has a special measurement screen that displays the difference between two signals
This difference is displayed both in dB and SWR !!

Measurements:
Freq Input Forwd. Refe. F-R= SWR 500Mhz +10dBm -4.1 -18.2 14.1 1.49 400Mhz +10dBm -5.8 -20.1 14.3 1.49 300Mhz +10dBm -6.8 -21.4 14.6 1.49 200Mhz +10dBm -9.7 -24.2 14.5 1.49 100Mhz +10dBm -15.6 -30.1 14.5 1.49 50Mhz +10dBm -21.2 -35.8 14.6 1.49 20Mhz +10dBm -28.9 -43.5 14.6 1.49 10Mhz +10dBm -35.1 -49.5 14.4 1.49 5Mhz +10dBm -40.8 -52.5 11.7 1.78
The loss at 450 Mhz is about 0.2 dB, tested on the PCB as shown on the picture..
See the table, the directivity is only about 14dB, this is not good !!
I am working on a better construction, more about this later..