Wireless Resources

Local Downloads & Resources

Remote Links

Microwave Propagation

• A Primer for Digital Experimenters

Link Budget Calculation

• Can I reach an SVWUX access point?

You can make an estimate by calculating a link budget in dBm. Sum the dB of the transmit power, antenna gains and cable losses at both ends with path loss. If your result is comfortably above -95 dBm, you have a reasonable hope of sustaining a multimegabit connection. You may fill in the form as follows:

• The SVWUX AP transmits at a net 12 dBm
• Cable loss is 4.4 dB, but net zero on transmit because we have a power amplifier which cancels out cable loss at the antenna feed
• SVWUX antenna gain is 18 dBi (The sum of the above three items will never exceed 30 dB as per Part 15 FCC Regs)
• Enter a distance at 2.8 GHz to calculate path loss
• Your FCC legal antenna gain, such as from one of these (Not an endorsement of this dealer or manufacturer.)
• Your site cable loss
• Your target receive strength for your desired bitrate. Higher bitrates demand stronger signals This Netgear Router has fairly typical receiver sensitivity and its specification sheet can be used as a rough guide to the data rate that can be expected for a given signal strength. Put that dBm value in this field and calculate your result.

Interference from obstacles or other transmitters may demand a greater cushion above the target values above. The greater your margin, the more reliable and faster will be your connection.

Links About 802.11

• Seattle Wireless
• www.openwrt.org OS distros

Software

• Kismet A cross platform, 802.11 layer2 wireless network detector, sniffer, and intrusion detection system

Radio Modulation Schemes

• An in-depth discussion of using OFDM on UHF.
• An overview of the Time Sychronized Mesh Protocol from Dust Networks

Links About APRS

• Xastir APRS map display software: www.xastir.org
• A source for 2006 Tiger/Line maps for Xastir
• APRS callsign map search with APRS World
• Bob Bruninga main site
• APRS Repeaters
• Voice Alert
• California APRS list/group
• KE6AFE Cap Pennel's APRS page
• Local network analysis page
• Winlink messeges via APRS
• APRS Multiline Protocol
• Source for the APRSD daemon for Linux

Links About AX.25

• AX.25 drivers for Windows (and TCP/IP over AX.25): SV2AGW
• Email over AX.25 with the Winlink System

Free Space Optical Technology

• Converting IrDA to use Lasers

Battery Technology

• A discussion of Deep Cycle batteries.

Advanced RF Calculations

• Splat! An RF Signal Propagation, Loss, And Terrain analysis tool for the spectrum between 20 MHz and 20 GHz