> Can you clarify a few things....... > > When you say "hardware" do you mean Tx-Rx, Ants, RF Coax, etc.? > Can you explain further "Recommendations for Topology"? (are you trenching?) > What do you mean by "incidental radiation with a highly directional antenna."
1) hardware as in will a brace of off-the-shelf APs do what I want, or would peaseas with wireless NICs be a better choice, or even something like a Soekris Net4521 at each node. Probably I'll need a directional antenna for some of the links, but the first one might be able to squeak by with a good omni at each endpoint. I'm mainly looking for the link part here, as a gateway will be taking care of encryption at each node. 2) topology as in point-to-point everywhere, or mesh network, or ? I'll be starting with two nodes, but expect to have 6-7 before I'm done-- all located within a less-than-one-mile radius and various minor obstructions in between. I could probably grade them into primary, secondary, and tertiary depending on expected traffic volume. Internet connections are currently individual broadband or dialup links, I'd like to consolidate them into one or two. Intranet traffic will probably account for less than 10% of network traffic overall. (I'm hoping to accurately map the endpoints and any intervening obstructions Real Soon Now, but my Copious Spare Time, isn't...) > > Incidental radiation is generated by a device that radiates radio frequency > energy during the course of its operation although the device is not > intentionally designed to generate radio frequency energy, antennas are usually > not considered incidental radiators. Well, I tried to talk the talk, but I guess I don't know as much as I thought I did. I'm concerned about RF energy ending up where it's not supposed to be. I understand from lurking that with high-gain antennae even low-power transmitters can be dangerous, as well as illegal. I may not be overly fond of the guy across the street, but there's no reason for me to carelessly irradiate him. Several prospective endpoints are rather low to the ground and somewhat concealed by trees, but a tall mast would not be my first choice. As my budget consists of unspent lunch money anything I can build myself is a plus, and making my own directional antennae _seems_ like a win, but perhaps I just don't have enough information to make a good decision. > > *In-tunnel coverage is difficult, at best, to predict with certainty. Some Ah, I see one of my problems here-- when I said tunnel, I meant a secure encrypted data path from point A to point B, not a physical tunnel. Sorry for the mis-communication. > Some of the important ant specs to look for are ........ > > Front to Back Ratio- > Beamwidths- > Gain- > VSWR- > Polarization- > Antenna Gain Patterns- > > > Average Signal Loss for Radio Paths Obstructed by Common Building Materials > > > Material Type / Loss (decibels) > > Wall constructed of metal plate 26 > > Aluminum siding 20.4 > > Foil insulation 3.9 > > 2.7 x 2.7 square reinforced concrete pillar 12-14 > > Concrete block wall 13 > > Sheetrock (3/8 in) 2 sheets 2 > Very useful, thank you. I wish I had been a little more clear originally. :/ Bob -- NYCwireless - http://www.nycwireless.net/ Un/Subscribe: http://lists.nycwireless.net/mailman/listinfo/nycwireless/ Archives: http://lists.nycwireless.net/pipermail/nycwireless/
