Recent content by cyclone24

Thank you. SE = shielding effectiveness calculation. I was curious to know if shielding effectiveness is calculated separately if the EM source is very close to the aperture or very far from it.

anyone? thanks

Hi, When you are dealing with apertures and performing theoretical SE calculations, would you consider a near-field or a far-field condition? Or both? i.e. do we have to take into account about the RF or EM wave proximity to the aperture, apart from the aperture dimensions?? Thanks.

Just a thought, Can I do an analogy that RF tight = water tight = light tight? I have a diode inside the RF shield. Can I say vaguely that if the Faraday cage shield is so good that even light cannot penetrate through the shield? But if there is a light leak in the shield that means RF may...

I have a question. The RF in microwave is continuous and over a period of seconds to minutes? For RF used in a MRI study it is pulsed. Things don't cook up inside MRI because of the pulse duration in milliseconds? So is pulse duration a factor here? The MRI scanners are rated for 3kW - 4kW...

That was dumb. Thanks!

vk6kro and waht, thank you for that explanation. It is now clear. Just curious, Vrms is usually = Vpk/(sqrt(2)). Why did you divide by another 2 in the equation? The RF here is a sinc wave. Thanks

Thank you. I already did that. So how do I convert the voltage value (in mV) in watts? Or how do I define the RF power here? guess I am putting it in a crude way...

Hello I have a basic question about the decibel -voltage - watt conversion. I am calculating pulsed RF power on the scope. The setup involved an RF transmitter connected to one end of an attenuator. The other end is connected to the scope. Sure I used 100 dB attenuator first and decreased...

marcusl Thank you for your inputs for all the queries. The mechanics of my setup doesn't allow me to shield the RF source. However, I agree with your explanation. RF transition times and edges do matter. In summary, I wanted to understand how a second layer worked. Is it the thickness or the...

I appreciate your responses. lambda/20 is a standard. I had the question of whether this standard is true for PCBs too compared to wires. 1. Thanks for making it clear. Holes or slits of that dimension is not the problem then. Got it! 2. You are suggesting that shielding my DC circuit...

Sure... 1. I have a high freq. (DC) PCB inside a faraday shield covered with copper. An RF source generating 400 MHz freq. is placed near the shield as close as 3 mm. Now the faraday cage has multiple screw holes where plastic screws go in. The diameter of the screws is 3 mm. In this...

Well the leads are well shielded as they go in or come out of the faraday cage. I have circular holes that are 3 mm in diameter on the faraday cage and I have 400 MHz source near it. Now are you saying RF can leak through those holes? I am still stuck at this fundamental question. "Is it the...

RF tight = water tight No drips allowed. Can anyone please elaborate the above statement? Can RF still penetrate into seams and holes even at wavelengths less than 1/4 or 1/100 etc. Thanks

Thanks for the reply. In other words, because of large inductance on the wire, the wire creates reactive fields. These reactive fields when in close proximity of other wires, transfer the RF energy and hence result in emissions. Is this explanation correct? Is this true even in the case of DC...