I just got a nanovna. It has a SWR function that I got for testing antennas. It seems to work ok for only being 50 dollars. I'd recommend it for anyone looking to see if their antenna is tuned correctly.
you have to normalize the trace "after" you connect the coupler before connecting the antenna. It does not matter how flat is the coupling with frequency, you normalize that out and then what you measure after you connect the antenna is directly the return loss of the antenna (well assuming the directivity of the bridge is good) also the chaotic looking trace @16:54 is because you have a long coax with non perfectly matched load (antenna). That's the classic shape of return loss for such a combination, in a twisted way it corresponds to the having standing waves (maxes and mins) on the line
Hello Bill. Thank you for the video on this return loss bridge. A project that I really must undertake. I have a few questions. When taking a bandwidth reading of your own built bridge, you enevitably used the 'Normalize' function which seams to feature on the Rigol and Siglent SAs, probably others from the far east as well. I'd be interested in what the BW display might be with an uncorrected generated signal. As my SA is somewhat old school. Kind regards Mike.
Hello, I'm watching a lot of your videos, very interesting. I'm in the learning phase and have recreated your return loss bridge for the spectrum analyzer but something is wrong. The drawing of the toroit confuses me a little, could you tell me exactly how the windings to which pin must be connected. I made measurements on a 70cm antenna which according to VNA is correct at 434 MHz, then the return loss on the spectrum analyzer should be lowest at the frequency 434 MHz or am I wrong about that. I hope you can help me further.73 de massi
Hi Bill, I think that the output port on bridge should be terminated with 50R load while making measurements. In your setup generator was not terminated with 50R, so you measured worse performance than it really is.
Hello Sir Can you please make Video on "Tesla Coil" just example How is work and what frequency it work is enough for me I watch lot for video but they not verywell example and watch your example well so
Bill, I am confused. On the schematic, you show all 50 Ω resistors, but on the photograph, you have 100 Ω from BNC to BNC, what appears to be 2 100 Ω in parallel from what I believe would be the input side BNC to a lead on the toroid and to one side of a 100 Ω resistor to ground. In other words, your schematic and the photo don't seem to match. Can you help me understand? Also, something that will probably give you a good laugh at me, I have Tinnitus which makes understanding what I hear quite difficult. In the first few videos of yours when you said "it's me Bill" I thought you were saying "it's Maybelle!"
Wayne, no problem. Two 100 ohm resistors in parallel will have a combined resistance of 50ohms. I had 47ohm single resistors, however using pairs of 100ohm gets me much close to the stated 50ohm. How much difference it will make, I don't know! Cheers Maybelle!
