RF shielding enclosures are a technology all of their own. I worked for a
major manufacturer of communications equipment for 37 years, and we had
many of these, including enclosures that you could work in ("screen
booths"). The trick is in the door - you must keep the contact periodicity
in the seal to be a small fraction of the wavelength of the radiation that
you are sealing against - preferably soldering if you really want to keep
it out. Most box mfgrs. use a fingered copper gasket that insures near
continuous contact. The problem is that if you have a contact gap that is
near a half wave of the frequency of interest, it becomes a slot antenna,
that will re-radiate the RF inside the box. The bandwidth of the slot will
be determined by its area and can be quite wide.
Proper Faraday cage boxes are constructed with copper, and are certainly
copper, silver, or gold in the contact area and gasket. Copper oxide is
conductive while aluminum oxide is not - so you cannot use aluminum
reliably for this purpose.
With a perfect seal, there will be some leakage due to the resistance of
the metal; however, the amount that leaks in directly through the metal is
small compared to the amount that leaks in due to a bad gasket/door seal.
On Tue, Jan 26, 2016 at 12:17 PM, Jones Beene <[email protected]> wrote:
> Bob,
>
>
>
> Well – I looked this up online, specifically wrt Wi-Fi which is primarily
> the RF of interest for recharging since the end use is cell phones. This
> frequency will be around 2-3 GHz. In the video below - it was 2.4 GHz.
>
>
>
> As this video shows, a single Faraday cage reduces the RF signal - but
> only by half !... and grounding the cage does not improve that. I am
> shocked (so to speak) to see that the effect of a metal cage is so small
> for this frequency.
>
>
>
> Of course, a signal which is reduced by half is still able to recharge an
> Orbo. This is Steorn’s gimmick, apparently. They assume that their audience
> believes that a single Farraday cage allows no signal, when in fact, it
> reduces the signal by half. Adding a second Wi-Fi router would presumably
> bring the signal back to an uncaged level!
>
>
>
> To do this right, Steorn (or the customer) would need at least 3 and
> probably four nested Faraday cages and also to turn off all Wi-Fi. That way
> it should be possible to do an accurate test.
>
>
>
> https://www.youtube.com/watch?v=9eUCyR7jesk
>
>
>
> Jones
>
>
>
> *From:* Bob Higgins
>
>
>
> Jones,
>
> A Faraday cage requires no ground. It just requires a continuous metal
> box enclosure. The Orbo test would be simple. Put the Orbo and the phone
> inside the box with its charging cable connected totally within the box.
> No cables enter or exit from the box. Close the box for XX hours and see
> if the phone is charged when it is removed. Then close the box and keep
> the Orbo entirely within the box. Then do it again - over and over.
>
> If you want to eliminate the possibility of energy gain from the outside,
> just don't let any cables go in or out of the box. Strictly speaking, you
> would also want to have a magnetic mu-metal shield around the Faraday box.
>
> On Tue, Jan 26, 2016 at 9:40 AM, Jones Beene <[email protected]> wrote:
>
> Observers should overlook the Steorn claim of Faraday cage testing as
> essentially meaningless… with a history. Steorn was saying the exact same
> thing about the other Orbo incarnations, going back 8 years. Look it up -
> it’s still online - same old BS then, as now.
>
> Even if they “got religion” and are honest this time around, consider
> what they are really saying. The problem with the claimed Faraday testing
> is that you cannot accurately test any device containing a large capacity
> battery unless you leave it there for months, knowing for sure that the
> cage is actually “earthed”. Steorn has in the past used a ground which
> could actually have functioned as an antenna ! (and probably did)
>
> At best, a Faraday cage would eliminate a possible source of battery
> recharging
> from RF. But Steorn did not show proper grounding… so we are back to the
> question of basic honesty.
>
> Side note: As moderator Bill B sez: the word "ground" can mean several
> things, several of which can actually be used to implement fraud – or it
> can be inadvertent, in the case of neon lights in the pub wiring… Ho, Ho
> Three more quarks for Muster Mac!
>
> 1-4 below are not proper earth grounds since they are easily tampered with.
>
> 1) A direct connection to the house or factory power supply via a
> negative terminal.
>
> 2) A “common” or negative connection of uncertain status based on
> having a third, or ground prong.
>
> 3) A connection to the inside of a shielded metal fuse box.
>
> 4) A connection to a metal mass which is much larger than the
> circuit (e.g. car chassis or “chassis ground”)
>
> …or
>
> 5) A direct electrical connection to a conductor purposely driven
> into the earth or to a copper water pipe which extends out of the house
> or factory (or pub) and into earth.
>
> Only 5 is a useful as a Faraday cage ground which is difficult to trick.
>
>
>
