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..