Experiments with a 0.5 to 20 GHz Directional Coupler from Werbel Microwave, Antenna SWR Measurement

[@thedmutz]

Excellent 👌

[@mechmania8450]

Hi Kerry I have been looking at cheaply available directional couplers on ebay to enable accurate power measurement on a 436 power meter. The coupler can be calibrated at a lower level with the same power meter. It is of course true that outside the range of these couplers they still work but the coupling factor will be lower at a lower frequency. I wonder if you have ever done experiments with this. Knowing the coupling factor at any particular frequency allows one to calculate the true power typically 30db is watts to mw on the 436.

[@paulklasmann1218]

Nice demo of the coupler. Have you got or do you use any of the old Marconi Instruments test equipment? The 6500 Amplitude analyzer or Radio Test Sets? I'm looking for detectors that are specified to 26.5GHz.

[@KerryWongBlog]

The only Marconi I have is a 2305 modulation meter.

[@paulklasmann1218]

@@KerryWongBlog They're claimed to be very good for the time. I was going to buy one but the Radio Test 2955 came up first so I went with that and that contains a modulation meter. Then I got a little bit addicted to buying old test equipment to fix.

[@joesmith-je3tq]

Ouch, only 11dB directivity. Even 17 typical, not real useful for me anyway.

[@KerryWongBlog]

Something didn't quite add up. If you take a look at the datasheet, on page 3 you will see the average directivity is much higher. The lowest occurs at around 16 GHz, but the average is a lot higher.