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Return loss is a very old term used in the telephone industry for a very long time. There is confusion about the sign, but the negative has been used as long at the term return loss has been in use. Most of us understand the meaning and implications.The 12 dB nonsense came up in a 100% reflection measurement because of losses in the RL bridge, but it's meaningless.The reference for either an open or short is a return loss of zero. The bridge losses should only reduce the dynamic range of a measurement, not the accuracy.However, if you have any transmission loss between the RL measuring device and the 100% reflection, it will give you a better return loss than zero.If a coax has a 3dB loss for instance, it will show (in theory) a 6 dB return loss because the RF will travel twice through a 3dB loss (the coax).
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Stuart K6YAZLos Angeles, USA -----Original Message-----
From: Hans J Albertsson <hans.j.albertsson@...> To: nanovna-users <[email protected]> Sent: Wed, Aug 21, 2019 11:33 am Subject: Re: [nanovna-users] New to group and thoughts on Return Loss and Loss A loss is a negative gain. So, saying a return loss is negative simply means you are expressing that loss as a formal gain. Don't overdo the besserwisserness of your insights. Den ons 21 aug. 2019 20:07Ron Spencer via Groups.Io <ron.spencer= [email protected]> skrev: Interesting topics being discussed. |
