Newbie question: I've an Android TV stick (Rikomagic MK802 III) and I'm having wifi signal problems. I've opened the device, and this is what I've found: shield connected

Both the wire and the shield are connected to the antenna, is this normal? The connection to the board is identical, wire and shield.

Here is another photo so you can see the entire antenna: enter image description here

  • \$\begingroup\$ I can't really tell from the picture, but are they both connected to the same metal strip on the antenna? If you have a multimeter you can do a connectivity test between the shield and the wire. \$\endgroup\$ – NickHalden Feb 25 '13 at 21:19
  • \$\begingroup\$ yes, they are both soldered. \$\endgroup\$ – Salvatorelab Feb 25 '13 at 21:57
  • 1
    \$\begingroup\$ I'll leave the thorough explanation to RF guys (if we have any), but this looks quite normal to me. The antenna's shape itself would form a needed impedance at the emission frequency, even if there's a short at DC. \$\endgroup\$ – AndrejaKo Feb 25 '13 at 21:57

Yes, this is normal. Note that the shield and the center conductor are not connected at the same place. The current path between the two points is a significant fraction of the wavelength, so this is perfectly plausible for a antenna.

When trying to understand antennas, you can't think in DC or viewing them as lumped systems. Two points 1/4 wavelength apart, even if shorted DC-wise, are very different connection points.


protected by W5VO Feb 26 '13 at 2:22

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