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#11
September 29th 15, 08:01 PM
posted to rec.radio.amateur.antenna
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Parallel coax
"John S" wrote in message ... On 9/29/2015 10:32 AM, rickman wrote: On 9/29/2015 9:22 AM, Jerry Stuckle wrote: On 9/29/2015 12:55 AM, rickman wrote: On 9/28/2015 8:56 PM, Jerry Stuckle wrote: On 9/28/2015 8:09 PM, rickman wrote: On 9/28/2015 7:55 PM, Jerry Stuckle wrote: On 9/28/2015 5:18 PM, rickman wrote: On 9/28/2015 4:34 PM, Jerry Stuckle wrote: I'm not interested. I know what it says. Guess I should have kept up my IEEE membership, but it just wasn't worth it. So share with the rest of us. What does it say? Exactly what your table showed. But you mentioned the resource, not me. You pay for it or you've just once again you're full of it. You said you *know* what the IEEE article says. Why not share with us? You want it - you pay for it. Or once again you prove you're full of it. No, I have not read the article. But I understand the physics and math behind it - unlike you. Someone who thinks magnitude without vector (direction) is valid! ROFLMAO! Ok, so you mispoke when you said, "I know what it says." No, I didn't. I didn't say I read it. I said I know what it says. And I do from other IEEE peer-reviewed articles. I don't need to read it to find out it agrees with other documentation. And if it didn't, it wouldn't have gotten published. You have said repeatedly that the return loss should be calculated by using the power in as the reference and the reflected power as the thing being measured which results in a negative log. I am pretty sure the paper says this is not the correct way to calculate it and many people are making a mistake doing it this way. So you've read other IEEE documentation which supports what you say? I'll see if I can get my hands on the paper. I'm not going to pay for it. If I thought it would get you to admit you were mistaken, I'd pay the $100. But I'm sure you will find a way to berate the authors or twist their logic and I'm not will to pay $100 for that. So stand by. Someone may be getting it for me. I really don't give a damn. You would argue the sun rises in the west. I have a copy of the paper. Trevor Bird Editor-in-ehief,Engineering IEEE Transactions on Antennas and Propagation CSIRO leT Centre, PO Box 76 Epping, NSW 1710, Australia Tel: +61 2 9372 4289 Fax: +61 2 9372 4446 E-mail: Definition and Misuse of Return Loss Trevor S. Bird Here is the equation from the article Pin RL = 10 log,10 ( ---- ) dB, (1) Pref The author explicitly states the resulting value will be positive when Pin is greater than Pref. He goes on to say, "That is, return loss is the negative of the reflection coefficient expressed in decibels." Since the reflection coefficient is never greater than 1, its value is negative. It follows that the return loss is positive. He goes on to quote from the "IEEE Standard Dictionary of Electrical and Electronic Terms, Fourth Edition". (1 ) (data transmission) (A) At a discontinuity in a transmission system the difference between the power incident upon the discontinuity. (B) The ratio in deci- bels of the power incident upon the discontinuity to the power reflected from the discontinuity. Note: This ratio is also the square of the reciprocal to the magnitude of the reflection coefficient. (C) More broadly, the return loss is a measure of the dissimilarity between two impedances, being equal to the number of decibels that corresponds to the scalar value of the reciprocal of the reflection coefficient, and hence being expressed by the following formula: |Z1 + Z2| 20 log,10 |-------| decibel |Z1 - Z2| where Z1 and Z2 = the two impedances. (2) (or gain) (waveguide). The ratio of incident to reflected power at a reference plane of a network. So is this what you "knew" the paper said? Seems to be the opposite of what you have been promoting. Anyone feel this paper is incorrect? # Good find Rick. That should put it to bed. .....LOL  |
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