Add an antenna to a D-Link DWA-643 ExpressCard?

Nice photo. The connectors are test connectors and are either Hirose u.FL or I.PAX MHF connectors. It's difficult to tell without a better view.

That's a problem. External antennas and MIMO don't work. You can do it if you maintain the approximate spacing and directionality of the original antennas, but that's difficult. However, if you don't care about MIMO and just want more range instead of more speed, just disable MIMO (802.11n) features in the driver settings, attach *ONE* antenna pigtail to an external antenna, and it should work. Deciding which antenna is the "main" and which is the "aux" is a problem. Trial and error (or an oscilloscope on the PIN diode switch) should help.

Another problem is that the original antennas will get in the way. Just plugging an external antenna is not going magically disable the internal antennas. They'll still radiate with some of the RF going to the external antenna, and some of it going to the internal antennas.

Also, the internal connectors are made for production line testing, not user interface. The connectors are good for only a few insertions before falling apart. There's no retaining or locking mechanism. I use hot melt glue.

For good reason. Need a detailed explanation?

Bah. Solder a pigtail to the board with an SMA or bigger on the end.

Thanks for your reply Jeff.

Here is a higher resolution pic:

Speed is not a big issue, all I have is a G router. Do you think this will work: I disable the original antenna by removing the capacitors C51 & C107. Solder the pigtail to end of J4 (or L24) and connect J4 to J6 (or L24). If that doesn't work try connecting separately, test results. How can you determine if you require reverse polarity? I assume if I use an N connector it souldn't matter SMA does?

Thanks again.

It's an MS-156:

Data sheet:

The receptacle is actually a switch. Push on the center "plate" and it disconnects the antenna and makes an RF connection to the jack. The jack does NOT have to be connical shaped for this to work.

Incidentally, this is the offical MS-156 to SMA adapter drawings:

Ok.

Maybe. I don't want to speculate. What I think might be better is to just unsolder both antennas from the board. The solder pads are HUGE and easy to attach a pigtail or connector (with VERY VERY VERY short leads). It kinda looks like the antennas are both PIFA type, which has 3 connections. One is ground, which should be obvious. The 50 ohm feed point is nearest the ground end and goes to the string of small parts that eventually go over to the test jacks. The 3rd end goes nowhere is usually just soldered to a pad for mechanical support. One nice thing about doing it this way is that you don't destroy the board or remove any parts. It's also easily reversable.

Reverse polarity what? The connector? Presumably, you have some connector in mind that's attached to a coax cable or antenna. There's no way for me to guess which antenna you plan to use. However, if you have a coax cable involved, type N is probably best. If you're going directly to an antenna, RP-TNC or RP-SMA. If you're playing with test equipment, have a pile of adapters, or wanna mount it on a bracket, SMA female is probably the easiest. You're choice.

Doesn't matter. The only thing that's important is that the leads are extremely short, with no exposed center conductor.

Note that without a mess of RF test equipment, it's going to be difficult to determine which derrangement or hardware works best.

I have not seen any info as to how these type of units work when they operate in non-n mode. In the case of a 2x2 system do they actually disable one of the radios or do they reduce the throughput through both radios? The operational description on the FCC website is pathetic. "This device is a D-Link DWA-643 Xtreme NTM ExpressCard Notebook Adapter, which operates in the 2.4GHz frequency spectrum with throughput of up to 300Mbps which OFDM technique will be applied. If the signal to noise radio is too poor which could not support 300Mbps, the 11Mbps data rate with DSSS technique will be applied.The transmitter of the EUT is powered by host equipment. The antenna is PIFA antenna without antenna connector." The FCC ID is KA2WA643A1 if you want to look at their photos.

Thanks again Jeff. I'll start destroying and see what I get out of it. BTW I love your Salad-Dish!!!!!!

Ummm... It sorta works, but not very well. The basic idea was to add some gain to junk USB radios and Wi-Spy dongles. The salad bowl is NOT parabolic. When illuminated with a light bulb at the focus, the resultant pattern is a annular ring with a hole in the center. Not exactly an ideal pattern but certainly better than the USB dongle alone. Check the pattern optically before destroying the salad bowl.

Nope. It switched to diversity receive mode, exactly the same as in an ordinary 802.11g adapter. See clues buried in the Ruckus docs at:

"When the SM (spatial mux) mode is not possible, a MIMO system reverts to diversity mode."

Extra credit if you can guess which antenna is "Main" and "Aux" in diversity mode. Sigh...

The description is primarily to satisfy operational requirements and specs detailed in 15.247. I've been told that less detail is best as it doesn't give the FCC anything to complain about.

I don't really like their explanation as all the examples quoted are using diversity techniques, manufacturers seem to like referring to diversity in MIMO as more antennas. "Without doubt,the performance of MIMO systems improves with additional diversity (i.e.,more antennas). In the early examples, from the netgear pdf, they have added an extra Rx to give Rx diversity and in their 2x2 example they are using a diversity combiner. I don't think they will have a "Main" and "Aux" antenna system as it is possible they are using MRC and you get the combined result. "In contrast, switched diversity and Maximum Ratio Combining are diversity techniques that can be implemented on just one side of a communications link; therefore they can benefit all existing