Proper Grounding in an Apartment

[09d08]

Hi all,

I'm building my first SSTC and I couldn't figure out how I'm supposed to ground the thing. Every guide I found online mention an RF ground that is separated from main ground but that I don't know how I'm supposed to do that in an apartment. Even if I stick a metal rod in the ground and run a 3 meter cable through the window (first floor) the inductance of the cable would probably be too high to be effective. Should I just lay a sheet of aluminium foil under the coil and connect it so the base of the secondary winding?

I will use an AC line filter but I still don't feel comfortable just connecting the base of the secondary to mains ground through the filter, killing other devices wouldn't be nice. What is the safest way to ground a coil in an apartment?

The coil itself is nothing too big, the secondary is around 24cm long and has a diameter of roughly 7cm which should give me a resonance frequency between 150 and 200 kHz.

Thanks in advance

[johnf]

for your own safety you must be connected to your power ground
As you have already worked out an RF filter to connect your local ground to power ground is recommended.
the filter needs to use the higher permeability powdered iron torroids or air core inductors, the use of ferrites except in common mode chokes is not recommended due to saturation problems. Most of your rf energy is in the first 10 harmonics up from your primary drive frequency so any filter needs to attenuate these by a large amount. Most commercial filters do not work well in the area as there is little to protect from. commercial filters are there primarily to protect the AM broadcast band from interference

[09d08]

Thank you, I will use a line filter and mains ground to ground the base of the secondary. Is there a need to lay foil under the coil or is grounding the bottom end of the secondary enough?

I was initially going to use a filter + IEC socket combo I salvaged from an old PSU but building my own filter seems much more suitable as it is probably not intended for RF as you said. I have some yellow/white toroidal iron powder cores intended for LF filters and chokes (Material 26 in this list http://www.qrz.lt/ly1gp/amidon.html). The resonance frequency is in the LF range so it should work, right? Is a filter like Circuit 4 in the image suitable for something like this?



Thanks in advance

[ritaismyconscience]

You want the extra resistor so you don't get shocked when unplugging it