From amfone :;wap2
John K5PRO:
Before the days of plastic antenna analyzers, you either used a GR bridge or a slotted line (for VHF), or just knew the SWR from a cheap wattmeter or Bird, or if you were lucky, a Delta OIB-2. This is the cousin of the famous OIB-1 and OIB-3 used by by broadcast engineers. Freq range is 2-30 MHz, 1 kW thru-power. Reads +/- 500 ohms resistive and up to +/- 800 ohms of reactance, and includes the meter amplifier for precise null
And the modern version using a Hp8753C with a DIY directional coupler , 2 Attenuators , and RF amplifier:
Newbie as I am on NanoVna , it will be beneficial if some can suggest how to use the NanoVna to achieve OIB measurements like the ones mentioned on the paper
