Frequently Asked Questions

---

The following Frequently Asked Questions, answered by the authors of this book, are designed to both measure your understanding of the concepts presented in this chapter and to assist you with real-life implementation of these concepts. To have your questions about this chapter answered by the author, browse to www.syngress.com/solutions and click on the “Ask the Author” form. You will also gain access to thousands of other FAQs at ITFAQnet.com.

1.	Since store-bought wireless NICs don’t have external antenna connectors, where can I purchase cards that have them?
2.	What is the difference between using the NMEA standard when WarDriving and the Garmin proprietary standard?
3.	Why can’t I find an 802.11a PCMCIA NIC with an external antenna connection?
4.	What are the frequencies used by of each of the 2.4 GHz channels?
5.	Both 802.11a and 802.11g networks support speeds of up to 54 Mbps. What is the difference between the two standards?
6.	Are there any good online information resources that WarDrivers should check out?

Answers

1. 

Both Wireless Central (www.wirelesscentral.net) and Fleeman, Anderson, and Bird Corporation (www.fab-corp.com) sell cards with external antenna connectors. They also sell pigtails, antennas, and other wireless accessories.

2. 

The NMEA standard reports its signal to your WarDriving software every two seconds. The Garmin standard reports its signal once each second. The Garmin standard can provide a more accurate location for each access point found while WarDriving.

3. 

Because 802.11a cards that are sold today use both UNII1 and UNII2. The FCC has ruled that any UNII1 devices may not be connected to an external antenna. These restrictions obviously apply only in the United States.

4. 

There are 11 channels used in the United States and Canada and 13 channels in Europe on the 2.4 GHz spectrum starting with Channel 1 at 2.412 GHz and incremented by 0.005 GHz for each channel. See Table 1.2 for additional details.

Table 1.2: Frequency Assignments for 2.4 GHz Band

Channel	GHz
Channel 1	2.412
Channel 2	2.417
Channel 3	2.422
Channel 4	2.427
Channel 5	2.432
Channel 6	2.437
Channel 7	2.442
Channel 8	2.447
Channel 9	2.452
Channel 10	2.457
Channel 11	2.462
Channel 12	2.467
Channel 13	2.472

5. 

There are many differences between the two standards. Two primary ones are that 802.11a operates in the 5.0 GHz spectrum while 802.11g operates in the 2.4 GHz spectrum. Because of the frequency spectrum they’re associated with, 802.11g networks support greater distances than 802.11a networks.

6. 

User-supported forums are an excellent place to both learn and exchange information with other WarDrivers. Two of the best are the NetStumbler Forums (http://forums.netstumbler.com) and the Kismet forums (www.kismetwireless.net/forum.php). Topics ranging from specific hardware issues to ethics to topical news discussions can be found at both sites.

---