UR5FFR

Радиолюбительские конструкции и программы
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PostPosted: 17 Jul 2019, 19:21 
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Вот человек собрал и все перемерял у себя в хозяйстве (много фото) http://www.diygoodies.org.ua/?p=1907


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PostPosted: 26 Sep 2020, 20:36 
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Печатка под SMD https://easyeda.com/IgrikXD/Antenna-analyzer-SMD


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PostPosted: 16 Mar 2021, 10:41 
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Hello. I have built this swr mouse and it works very well on the pc. I added the e-ink display control to the code, but I do not know how to calibrate the SWR value. The first measurement with an open port, the second with a 100 ohm resistor, how to correctly calculate the SWR from these values. Can you give me a hint? Can you put a mathematical formula for this calculation, or a piece of code?


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PostPosted: 16 Mar 2021, 12:25 
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Hi
You can find algorithm description and code sample here viewtopic.php?p=1213#p1213


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PostPosted: 18 Mar 2021, 18:07 
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Thank You for Link.
After 2 days of thinking, I understand something, but I can't understand how to convert Vadc to gamma to use the formulas you provided.


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PostPosted: 18 Mar 2021, 19:05 
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SWR measured without and with extra 50oHm and used in algorithm for calculate Z.
SWR = (1+Gamma) / (1-Gamma)
Gamma = 10 ^ (ReturnLoss / 20)
ReturnLoss in db = (ADC - ZeroLevel)*Slope

In circuit AD8307 out to ADC return loss value. ZeroLevel and Slope - calibration constant. ZeroLevel depended from frequency. I'm store it for each 1MHz freq change. ZeroLevel measured as ADC value without RF load.
Slope measured on single frequency 1MHz. Connect 100Ohm resistor to RF port and measure
Slope = 9.542 * (ZeroLevel[1MHz] - ADC)


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