Mystery component on Yun board?

Thanks! Very cool.

['DB]

Be careful. It looks like U.FL but it’s NOT! Actually it’s SWF connector. Unfortunately purpose of this connector is mainly during product testing, so counterpart is far less available than U.FL connector.

Does it mean that the only way to extend wifi is through USB port ?

An other mysterious formation is the four slight diagonal THT holes for header pins on the Wifi side and the six on the Ethernet plug. No labeling, any idea?

Those holes are for mounting a PoE module.

I've just received an answer from the hardware guy: the connector is a MM8430-2610 (see this). You can plug in a MXGS83RK3000/MM126036: once plugged in, the switch connector will turn the internal antenna off and use the probe as an external antenna

Here's an article on how these work:

http://www.murata.com/articles/ta0791.pdf

These are for test...Not intended to be used as a permanent connector for range extension. You may get lucky. It is rated at 100 cycles max. (Remember they probably used a number of these cycles during manufacturing.)

Summary. It is a Microwave Switch Connector. No observable "lip" on connector to hold a connection permanently. It is a N/C connector and passes the signal through to the on-board antenna. When interrupted by the male pin, inserted during test, it re-routes the signal to the contacting pin, disconnecting the on-board antenna.

Digikey has these connectors: http://www.digikey.com/us/en/ph/Murata/SWF_Connector.html But the official male connector is not a latching type, like the U.FL types. The one male plug available is http://www.digikey.com/product-search/en?site=us;lang=en;vendor=490;Keywords=MXHS83QE3000 but is ~US$50 and doesn't appear to have a holding "lip".

They are completely incompatible with the U.FL type.... No amount of forcing, twisting or whining is going to get these to mate.

It COULD BE that someone clever could replace that SMT connector with a pinout-compatible U.FL type, (voiding any warranty, and possibly messing things up,) but some hacker might get lucky and post the results here. We are probably all anxious to be able to find a way to have the Yún in a metal enclosure and yet still have WiFi connectivity.

The reason external antenna is needed is:

  • On board chip antenna has average Gain -0.5 dBi
  • Yun's transmit power is only 17 dBm.
  • Yun is siting at metal case.
  • The distance between Yun and WIFI router is far

Friis Transmission Formula with Propagation Law

  • R = Maximum range for communication link
  • N = Propagation Law (N=2 for line-of-sight, N=4 for urban environments)
  • PT= Transmit power
  • GT= Total antenna gain
  • λ = Wavelength
  • PR= Receiver sensitivity
  • FM= Fading margin

if in urban environments;-

  • Every 12 dBm receiver sensitivity gain will be double the distance.
  • Every 12 dBi antenna gain will be double the distance.
  • Every 12 dBm Transmitter power gain will be double the distance.

in line of sight environments;-

  • Every 6 dBm receiver sensitivity gain will be double the distance.
  • Every 6 dBi antenna gain will be double the distance
  • Every 6 dBm Transmitter power gain will be double the distance.

http://forum.arduino.cc/index.php?topic=175577.msg1304059#msg1304059

An other reason is reduce interference.

The Omni type antenna ( build in chip antenna) has 360 degree field pattern

The pattern below is from a Yagi antenna : From this you can see the Yagi can block all other router signal outside from 60~120 degree.

More Information about transmit power:

Maximum Transmit Output Power in the ISM bands.

http://wisp-router.com/page.php?11

The part 15 of the FCC rules.

Did you ever find a solution for an antenna?

Any high gain 2.4 Ghz antenna will work.

  • Pach Panel Antenna
  • Dish Antenna
  • Dipole Antenna
  • Yagi Antenna
  • Grid Parabolic Antenna

sonnyyu: Any high gain 2.4 Ghz antenna will work.

  • Pach Panel Antenna
  • Dish Antenna
  • Dipole Antenna
  • Yagi Antenna
  • Grid Parabolic Antenna

What about people saying that it woud for after a number of cycles? Would it be a feasible long term solution?

Thanks

mortonc: ... What about people saying that it woud for after a number of cycles? ...

What do you mean?

The connector is designed for semi permanent application. It mean once connect it and leave it.

sonnyyu: ... Friis Transmission Formula with Propagation Law

  • R = Maximum range for communication link
  • N = Propagation Law (N=2 for line-of-sight, N=4 for urban environments)
  • PT= Transmit power
  • GT= Total antenna gain
  • ? = Wavelength
  • PR= Receiver sensitivity
  • FM= Fading margin

...

To complete Friis Transmission Formula;-

  • Increase receiver sensitivity, by change AR9331 with higher receiver sensitivity chip set
  • Add RF power amplifier to increase Transmit power which like a lot of routers
  • Use low frequency, Increase Wavelength

Above is for FYI only.

FYI;-

People make 2 Openwrt base AR9331 with high gain antenna nodes on 1 mile distance wells communications.

Just Give Me Antenna and I'll Show You the World!

Dragino (Yun compatible) MS14 has Antenna plug

http://wiki.dragino.com/index.php?title=MS14_Antenna

16 dbi Antenna

I have managed to successfully attach an external antenna to the Yun, but it is a hack.

I had misread this thread, bought a "SMA Female Plug to IPX U.FL Female Pigtail Cable" ( http://www.ebay.co.uk/itm/231098912466) , connected it to the Yun and saw no improvement.

Under a microscope, I could see that both the socket and plug were female. (see attached photos).

As I had nothing to lose, I thought I would have a go at creating a pin that would bridge the two female connectors. 1/0.6mm solid core wire fitted snugly in both connectors. I guessed at the correct length. Luckily i seemed to judge it about right and the plug is held firmly on the socket.

Amazingly, it worked. The Yun seems to auto sense the stronger signal. With no antenna connected to the SMA connector, the signal strength was about 35%. With the antenna connected, it bumped up to about 80%. I plugged/unplugged it a handful of times to convince myself it was working.

Obviously, with no soldering, this is might not be the most reliable of connections.

I would be interested to know from an RF expert whether I have managed to fluke a solution or whether the RF signal can jump the gap of a "not great" connection.

Let me know if you can reproduce my results.

Pete.

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Custom made connector:

original murata connector, price not working( $80) and height is not. I got customer engineer drawing done. but MOQ is too high. plus Intellectual property?

Case to hold custom made connector.