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Antenna testing, Return loss or VSWR or ??

Posted: Fri Nov 22, 2019 9:15 pm
by RFguy
We had a discussion at work the other day and this subject came up. I've always used Return Loss in dB when sweeping an antenna. Someone else suggested using VSWR.

I've never found VSWR very useful as I can't easily related it to anything of adjust for things like feedline loss.

For example, if I have a return loss of 20 dB and it changes to 17 dB, I know I have twice the reflected power than I did. Also if I know I have 2 dB feedline loss, I know I need to allow for 4 dB (there and back) in my return loss measurement. Instead of setting a 14 dB return loss as a pass/fail, I'll set it to 18 dB as the fail point.

I'm I missing something for not considering VSWR for antenna testing?

Thansk in advance for any comments/insight.

Re: Antenna testing, Return loss or VSWR or ??

Posted: Sun Nov 24, 2019 7:59 pm
by Karl NVW
Two different ways to express the same amount of impedance mismatch. Some folks like to measure reflected power in absolute watts, others like you prefer the easier add and subtract when looking at the more complex system view. To-may-to, to-mah-to, it's all sauce.