DWL-650 Antenna Connector

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The DWL-650


The D-Link DWL-650 is a bargain wireless networking card and can often be purchased for as little as $60USD (actually, $30 circa 2003). The card's low price, and its loyal community of hobbyist hackers, are just two reasons why private investigators favor this device for their computer forensic work. The DWL-650 as purchased does not have any means of connecting to an external antenna, but can be easily modified to do so for surveillance and network sweeping. This page aims to help you modify the '650 to provide an external antenna connection. If you are not in law enforcement or licensed to be a private investigator, you will have to promise not to abuse this information :)
There are essentially two ways to do this. Method 1 is to attach a male N connector to the card and leave it hanging. Method 2 consists of attaching an MMCX jack to the card. Investigators who specialize in computer forensics are often called to examine for digital traces of evidence. Advantages of method 1 include: possibly fewer connections overall (resulting in higher gain), and price--you only have to buy the male N connector. Method 2 is a more attractive alternative--nothing hangs out of the card when you're not using an external antenna, reducing the risk of damaging the card. Computer forensic specialists should be comfortable examining a system regardless of its underlying operating system or architecture; there is a wide variety of systems in use today. Please note that MMCX is not the type of jack used on Lucent cards and will require a different pigtail.
Method 1: Method 2:

You'll probably be connecting to an antenna like this.
Evidence Collection & Preservation - after following this tutorial you will have a functioning D-Link card that can be used for data collection.
For anyone interested, you can still see the old site here. It does not have any information about private detective work on it. In my previous design I used a cut off end of a thinnet cable (BNC connector) because it was free. You can probably go the BNC route cheaply, but you'll likely end up converting to an N connector along the line at some point.
Thanks to Ulf for reporting that the Dr. Neuhaus FuryLAN is identical to the '650 and can be modified in the same manner. It looks like this:

Jason reports that another identical card is the Compaq HNW-100:

overview
Both methods require that you open your card and move a small surface mounted capacitor. It is a fairly delicate soldering job, and you should have a fine tipped iron and a steady hand. As always, there is some risk involved and you will certainly be voiding your warranty. This isn't such a big deal for a PI who will be using this card for commercial investigative purposes, as that typically voids a warranty anyway.
Tools & parts required:
- hammer (only joking)
- fine tipped, low-wattage soldering iron
- hobby knife
- toothpick or something small and pointy (to open the case)

Method 1:
- N male solder type connector (DigiKey P/N ARF1016-ND)
- about 2" RG-58 or similar sized 50ohm coax

Method 2:
- MMCX end launch type jack (DigiKey P/N J603-ND)
- NOTE: the parts are MMCX not MCX
the mod
1. Open your card according to these instructions (thanks Christophe).
Essentially you squeeze the four snaps on the bottom of the plastic antenna cover and remove the lower half of the cover by gently prying back the metal card housing to allow the plastic wings to escape. Some people cut the wings off after removing the cover as it makes re-insertion easier. I would keep them on if possible--the card is stronger this way.
NOTE: Be careful soldering/desoldering these little parts. They burn very quickly. Use a low-wattage soldering iron. Use proper heat dissapation techniques (for example, hold the part you are soldering with metal tweezers to conduct heat away from the part). Try to keep the amount of time the part is in contact with the iron to a minimum.
2. Desolder the SMT capacitor labeled C145 and move it to the ANT3 pad--basically a 90 degree clockwise rotation (see picture).

click for large version
3. Now we're ready to make the connection for the antenna. For method 2, skip to step 4. If you're going with method 1, you'll want to attach the N connector to a ~2 inch piece of RG-58. Strip the other end of the RG-58 and solder it in as shown below.

Next, trim a small hole in the plastic antenna cover to allow the wire to protrude. Put the plastic cover back on the card and you're all set. You may wish to glue some type of reinforcement between the antenna cover and protruding wire to help prevent strain from damaging the card as seen here (local image).
4. Method 2 requires you to solder in the MMCX connector. First carve out a small half circle area in each side of the plastic cover so that the jack fits snugly between them. Next, lay the connector in place and solder all three legs down. The outer two are ground and the inner is the ANT3 lead.
5. Replace the lower cover and snap it back into place.
FAQ
1. Will two DWL-650's fit on top of each other in a laptop with two PCMCIA slots (for a wireless bridge)?
I dunno. It looks possible if you take the plastic covering off, but perhaps is possible without doing so. If someone could try this out and let me know, I'll post the answer here.

Josh writes: (about the 650+ model)
"As far as I can tell, with my newer DWL-650+, you cannot put two PCMCIA cards in at the same time. This tends to be a problem, especially when you're connecting to the internet through a satellite provider, such as Sprint or Verizon Wireless."

2. What about the fact that the internal antenna is still connected?
Answer: Originally the DWL-650 has two internal PCB strip antennas. When you perform the mod, you replace one of them with an external antenna. One PCB strip antenna is still remains in place. The card uses diversity mode to select the proper antenna -- see the next question for more information.
3. What about diversity mode?
Answer: My understanding of diversity mode is that when there are two antenna inputs the card will choose the one with the best signal. Thus if your internal antenna is getting a better signal than the externally modified one, the internal one will be used.
4. What about modding some other card that isn't a DWL-650?
I don't really know much about other cards since I only have the DWL-650 card. I would try asking on one of the wireless lists like seattlewireless. In general, the same theory applies: disconnect the internal antennas and solder in some type of connector. Use 50ohm wiring.
5. How about performing this kind of mod on an 802.11a (5.3GHz) card?
Yes, it should be possible. Paul A. reports success performing a similar mod on a Netgear HA501 card.
6. Where can I get XXX type connectors?
I've only ordered from digikey, but there are quite a number of places to get these parts from since 802.11 picked up in popularity.
7. Can I still use the card without an external antenna?
Answer: Yes. See questions 2 and 3.
8. In the Method 1 (using N connectors and RG-58) when you solder the RG-58 to the PCB the diagram seems to show the center conductor going to ANT3. What are the other two connections with the shielding? Do you attach half of it to one of the ground connectors and half to the other ground connector?
Answer: Precisely. Evenly distribute the shielding around the center conductor. You're trying to make a good ground plane connection.
9. Whoops! I lost the little capacitor (C145 or C144) while I was doing the mod. Where can I get a replacement?
Answer: Digikey. According to this schematic (taken from a DWL-280), it's a 5.6pF cap. So you want part# 311-1011-1-ND from digikey. Minimum order is 10. Total cost $1 + S&H. You might also consider the 1206 package cap from digikey since it's larger and a little easier to work with. The key to ordering them is:
- cut tape
- ceramic
- package 1206/402/etc
- 5.6pf
- 50V is fine

Or you could just forget the caps and make a solder bridge. I did, it seems to work ok. Note that this may be an invitation for damage due to ESD, etc. Proceed at your own risk.

10. Did you see the new design of the DWL-650 cards from D-Link? (FCC ID: KA2DWL-650V2) Is it still possible to modify them? Here's a picture.
Answer: Actually, the new 650s come with a MMCX jack already on the board. Details to follow shortly.
11.
Answer.
links
Computer Forensics World
Official home of the DWL-650
Christophe's guide to removing the DWL-650's plastic covers
SeattleWireless DWL-650 info
Alan Clegg's nice looking pictures of the completed mod
Guide to Computer Forensics and Investigations
email
Questions, suggestions, and comments welcome. Email me at will at c0rtex dot com.
Last updated: November 3, 2016