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Cecil Moore wrote:
wrote: It was stipulated in the original post that the swr was being measured at the source end for the 50 ohm line. If all one changes is the impedance of a 1/2 electrical wavelength line, and nothing else, the answer is 1:1. Nope, not if a 72 ohm SWR meter is being used. An SWR meter calibrated for the transmission line Z0 of 72 ohms will read 1.44:1 even if the 50 ohm transmitter is happy with the 50+j0 ohm virtual impedance being presented to it. I have SWR meters calibrated for 50, 75, 300, 450, and 600 ohms - doesn't everybody? Please note that it was ***NOT*** stipulated in the original post that the SWR meter was calibrated for 50 ohms. "What is the SWR?" was the question. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#2
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Cecil Moore wrote: Cecil Moore wrote: wrote: It was stipulated in the original post that the swr was being measured at the source end for the 50 ohm line. If all one changes is the impedance of a 1/2 electrical wavelength line, and nothing else, the answer is 1:1. Nope, not if a 72 ohm SWR meter is being used. An SWR meter calibrated for the transmission line Z0 of 72 ohms will read 1.44:1 even if the 50 ohm transmitter is happy with the 50+j0 ohm virtual impedance being presented to it. I have SWR meters calibrated for 50, 75, 300, 450, and 600 ohms - doesn't everybody? Please note that it was ***NOT*** stipulated in the original post that the SWR meter was calibrated for 50 ohms. "What is the SWR?" was the question. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- SWR meter reads 1:1 at the source with 50 ohm line, that will tell you that the swr bridge Z and the antenna Z are the same initially (1/2 wave line). Changing to 72 ohm line will still be 1:1. Gary N4AST |
#3
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wrote:
SWR meter reads 1:1 at the source with 50 ohm line, that will tell you that the swr bridge Z and the antenna Z are the same initially (1/2 wave line). Changing to 72 ohm line will still be 1:1. Here is the original question again: "What would the SWR be if I substituted the 50 Ohm feedline with a 1/2 wavelength of 72 Ohm feedline?" Did he ask what would a 50 ohm SWR meter read? NO! He asked "WHAT WOULD THE SWR BE ..." The SWR would be 72/50=1.44:1 on the 72 ohm feedline. That answers the original question. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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