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Re: Return Loss


Dr. David Kirkby from Kirkby Microwave Ltd
 

Yes, I am G8WRB.

The problem is return loss is *often* used as a negative number in
professional academic publications. This one from an IEEE, has a
particularly amusing title;

Low-Return-Loss Printed Log-Periodic Dipole Antenna

Published in
IEEE Antennas and Wireless Propagation Letters
<>
( Volume: 13 )
Page(s)
503 - 506
ISSN Information
INSPEC Accession Number
14195004
DOI
10.1109/LAWP.2014.2310057 <>
Publisher:
IEEE
Sponsored by
IEEE Antennas and Propagation Society <>




and another, not published by the IEEE,


and another



As such, whilst I will continue to use a positive for all passive and most
active components, I really have no appetite for changing the mind of
others.



On Fri, 4 Oct 2019 at 20:26, Reinier Gerritsen <r.gerritsen@...>
wrote:

return loss is (almost always) a positive number. If one insists on
negative numbers, just call it s11 (or s22). In essence the same
property, but negative.

Op 4-10-2019 om 17:20 schreef Ron Spencer via Groups.Io:
I read a recent post that said that, among hams, its become the
consensus that return loss is a negative number. I respectfully disagree.



Regarding return loss, I understand some think its a negative number,
some a positive. I am in the later camp. Why? When I was a young engineer I
had the great fortune, in the early 1980s, to work for HP. Arguably the
premier test and measurement company of its time. And equally arguably a
leading if not THE leading microwave and rf company.



As new sales people, we were sent to 3, 3 week training sessions to
learn the technology and the products so we might interact with our
engineering customers in a technically sound way.



One thing HP taught, as I've said in a much earlier post, was that
return loss was always a positive number. As someone on this list pointed
out, negative loss is gain. And we KNOW that no return loss measurement, of
a passive device, can exhibit gain.



With respect, there is no gray area here. Return loss, is always a
positive (or, perhaps better said, a non- signed) number.


Even if you are at a hobby level of involvement, why not use the proper,
and correct, terminology? If you're a private pilot, you are expected/
required to use the proper terminology. Same if you are an amateur road
racer. Or "fill in your favorite" hobby.













Sent using





--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

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