Antenna testing, Return loss or VSWR or ??

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RFguy
Posts: 1357
Joined: Wed Dec 21, 2005 6:17 am

Antenna testing, Return loss or VSWR or ??

Post 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.
Karl NVW
Posts: 171
Joined: Wed Sep 03, 2003 7:13 am

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

Post 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.
Karl - WA8NVW AFA5VB
SHARES + NCS
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