Counterpoise? Need help!

[antoine_z_h]

Hi Guys.,

So I have SSTC2 now, working and operational, and I get feedback thru a current transformer, but unfortunately I don't have any Good Ground so sometimes my secondary feedback wire spark inside the CT, my friend Chris advised me about counterpoise, which would help grounding my coil ..


Any idea how to make that at home ? Can I use aluminum foil sheet ? or reflective car sunscreen?


Sunscreen

[Hydron]

Aluminium foil would work. The car windscreen thing probably has a very thin layer of aluminium - maybe too thin to be useful, and tricky to get a good connection.

I think most people use "chicken wire" mesh or similar as it is more durable and easier to deal with than big bits of foil. Note that the holes are _not_ a problem for this use.

[antoine_z_h]

Okay so I may use chicken wire , or a mesh with tighter holes, would both work ?




Also please could you tell me, how to apply that to my device ? I mean do you want me to spread a sheet of the mesh under my coil (lets say 1M X 1M ) and connect the secondary ground to it ?

thanks,

[profdc9]

Either will work.  Even if the counterpoise was a loop of wire on the floor with spokes from a center point, the capacitance would be a good fraction of a fully filled mesh because the charge tends to be concentrated on the edge of the counterpoise.  However, it is still worth using chicken wire rather than a loop of wire as its cheap and still given you more capacitance.

Dan

[antoine_z_h]

can you tell me how to apply that in real life ?

I mean do you want me to spread a sheet of the mesh under my coil (lets say 1M X 1M ) and connect the secondary ground to it ?

[Mads Barnkob]

can you tell me how to apply that in real life ?

I mean do you want me to spread a sheet of the mesh under my coil (lets say 1M X 1M ) and connect the secondary ground to it ?

Yes, think of it as an artificial ground plane. The idea of the ground is to have a much bigger capacitance than your topload, so there is a ratio between its size and how effective it will be. It is recommended to have roughly 10 times capacitance in the ground plane compared to the topload, that is is almost always not practically possible.

You should read this huge article I wrote: http://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/grounding-circuit-protection-and-emi/