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Recent content by nadabro

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    Feeding a Antenna without shield of cable

    Hi. This is a basic question, when feeding a waveguide with a coaxial cable, using the inner cable pin to feed the waveguide (without a conector, its feeding directly), but the shield of the cable does not touch the waveguide, will the antenna still work or does affect a lot? Also, is there...
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    Help on getting antenna measurements

    Thanks for the schematic @fiwi. Unfortunately according to a rude simulation i made (cant confirm or not), that schematic will not work well. The formulas that calculators provides maybe not work in a circular waveguide? Anyhow, the schematic on rectangular waveguides is a bit different on...
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    Help on getting antenna measurements

    @fiwi thats for rectangular waveguides , i´m looking for circular waveguides. I tried simulate that measurements in a circular waveguide and it does not work great..
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    Help on getting antenna measurements

    Thanks for the answer. That makes sense, rectangular slotted waveguides have a offset from the center. My big confusion is regarding "half guides´s wavelength" and λ0: Guides wavelenght for a diameter 97.87mm at 2.44Ghz is 181.9, so half guides wavelenght is 181.9/2..? λ0 is wavelenght in...
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    Help on getting antenna measurements

    Hi. Its been a long time i try to design a antenna. I´m trying to build a circular slotted antenna for 2.44Ghz based on the paper "On the Miniaturazation of Cylindrical Omnidirectional Slotted WaveguideAntennas for Wireless Applications" According to a paper: 1) It uses a C22 waveguide...
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    [Moved] Laptop motherboard short circuit?

    Those MOSFET are pretty easy to find, i can replace both. If that is the problem, maybe i can recover the board? Or maybe it damaged something else? I´m getting a little hope here :grin:
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    [Moved] Laptop motherboard short circuit?

    Re: Laptop motherboard short circuit? Thanks for replaying. I did not measure the temperature, but sure its >60º..enough to burn my finger if i keep it there more than a few seconds. Thats the only component that gets hot, the others are cold. After a few seconds it starts to smell overheated...
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    [Moved] Laptop motherboard short circuit?

    Hi. I was using my laptop normally and suddenly it goes off..after that no light in the laptop with adapter or battery (tested with two batteries). When i plug the ac adapter in the Laptop the LED of the ac adapter gets blinking with a on/off buzzing sound...so it looks like a short circuit in...
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    Only positive/negative numbers when using AMP in ADC

    Hi. The first suggestion works great! It allows to enable/disable Vbias, and i can measure voltage (1.76?) from Vbias pin :) But unfortunately did not resolve my issue..i followed the schematic on page 18. But it still gives positive numbers, it stables at -4000 (example) but i only get...
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    Only positive/negative numbers when using AMP in ADC

    I´m testing it in a breadboard, following the datasheet pag18 circuit. But my main issue is to change the code in the microcontroller (Arduino) to activate VBIAS.. The code i use can be found here (https://arduino.cc/forum/index.php/topic,53063.0.html), the part to write to the ADC: void...
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    Only positive/negative numbers when using AMP in ADC

    It makes sense on "converting" the bipolar signal from the amp to match the unipolar signal in the ADC. But before try some of the schematics you gave, i looked in the ADC datasheet and it looks like it has a function (Vbias) that should solve my issue: So using "Vbias" in the ADC should work...
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    Only positive/negative numbers when using AMP in ADC

    Hi. I think this is a very simple issue, but my knowledge is very limited, so here it goes my issue: -I´m using ADC to connected to a sensor, with the sensor connected directly to the ADC inputs, i´ve positive and negative values. -I´ve added a OPA227 OP-AMP to do some tests with the sensor...
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    Is it possible to reduce noise after ADC

    Nice one lol I will try to make that changes tomorrow..once i test i will report here the results. Thanks again for the help.
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    Is it possible to reduce noise after ADC

    Thanks for the advices. What i need to do is cut the line in PIN 3 to redirect to REF, something like this? About the resistor in series, is one 2.7K resistor soldered in the pins of the geophone? Sorry for asking for confirmation, but i had bad examples in the past involving electronic...
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    Is it possible to reduce noise after ADC

    Thanks for fixing the link mtwieg. I measured the resistance on the geophone, from my cheap/non precision multimeter it gave me 374ohm..which is close to the 380ohm from the specifications. About the calculations..i will take some time to do that :) So while this circuit works, the choice of...

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