Several points: 1. The Pringles can antenna is a directional antenna with about 40 to 60 degrees of coverage, it is not an omni. The gain on the antenna on the card is probably 0 dBi or even shudder - 3 dBi. The can antennas are probably between 6 and 9 dBi. 2. Because these devices are unlicensed ISM band (2.4 GHz) the connectors if there are any, are proprietary - this means they only work with the manufacturers antenna. Because the device is an un-licensed consumer product, the FCC requires that the product design be tested and certified by an RF lab as meeting the Part 15 requirements in the FCC code. To meet these standards, the device is limited in terms of its transmission power - typically 1 Watt or 30 dBm or less. So even if the card had a connector, you would have to change it to an SMA type to connect a standard RF coax cable to the unit and to a high gain antenna. 3. Yes people hack the 802.11 b cards. If you do this, you need to be good with a soldering iron and having one that is electrically isolated and has temperature regulation is recommended. You also need to have one who knows how to connect up the cable to the antenna harness correctly. These are small copper traces and can be damaged or bridged with too much solder. Poor workmanship can destroy the benefits of the hack. 4. The length of cable is a function of (a) the insertion loss of the cable (expressed as so many dB per foot), (b) the gain of the antenna and (c) how much of an effective gain in the transmission power and receiver resolution you wish to obtain. 5. You will also have to use an xacto knife to open the plastic radome on the end of the card to access the antenna traces and may have to cut away part of the metal/plastic near the end of the card. Great care has to be taken to avoid making the card fatter than the permissible limits. 6. There are sites that have photos of hacked cards. Good luck. Cordially C. bolton -----Original Message----- From: Matthew Bohnsack [mailto:] Sent: Saturday, September 07, 2002 10:27 AM To:
Subject: 802.11b CF with external antenna Does anyone have any experience with a Compact Flash 802.11b card and an external antenna?... I want to use better and possibly directional antennas like those found at http://www.hdcom.com/bundles.html or the homemade Pringles-can waveguide variety. I see this model seems to support external antennas: http://www.symbol.com/products/wireless/la4137.html Anyone done something like this? What kind of cable length is possible? -Matt -- Matt Bohnsack <
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