Wireless

[monty]

Does anybody know how the legal status is of wireless equipment in Thailand?

I thought to have read that their law is based on the European regulations, wich for example states a maximum radiated power of 20dbm.

Now when i see at the website of Bangkokwireless that they started to market outdoor antennas with a gain of 24dbi. This would mean that even on the lowest powersetting of my AP (Lynksys wap11) I would be illegal!

I also thought that outdoor use was prohibited.

I do also think it'll be very hard to find illegal stations, at least I hope so since I have a 4km wireless bridge up and running

I see the Bangkokwireless guys have a 3.2 km link somewhere ( not very hard using two 19dbi antennas I use two 17dbi patches, lot more discreet and still get 11mbps even during heavy rain! (microwaves really don't like humidity)

Any feedback welcome

Maybe the siamwifi guys???

Monty

[PlanetMan]

Does anybody know how the legal status is of wireless equipment in Thailand?

I thought to have read that their law is based on the European regulations, wich for example states  a maximum radiated power of 20dbm.

Now when i see at the website of Bangkokwireless that they started to market outdoor antennas with a gain of 24dbi. This would mean that even on the lowest powersetting of my AP (Lynksys wap11) I would be illegal!

I also thought that outdoor use was prohibited.

I do also think it'll be very hard to find illegal stations, at least I hope so since I have a 4km wireless bridge up and running

I see the Bangkokwireless guys have a 3.2 km link somewhere ( not very hard using two 19dbi antennas   I use two 17dbi patches, lot more discreet and still get 11mbps even during heavy rain! (microwaves really don't like humidity)

Any feedback welcome

Maybe the siamwifi guys???

Monty

Hey Monty,

Like most laws in Thailand, what they be depends on who you ask The folks at bangkokwireless.net tell me that, technically, all wireless devices in LOS need type approval. Some of the 802.11 kit has gotten such approval, but most not. This requirement isn't commonly enforced, which always scares me a bit. (Well is it a law, or not?)

Most of the kit at Pantip et al is 802.11b, although some g is appearing. 802.11a is personna non grata in LOS; no 5 GHz spectrum available here. 30 mW cards are most common, although a shop on Lad Phrao sells the Senao 200mW cards (you might have to ask for it specifically.)

Net net, I think you'll be OK to do what you want, but be a good wireless citizen, no more power than you need, use good antennas and cables, and if you are farang, keep a low profile.

The folks at bangkokwireless.net are great. Think they are in Samui right now unwiring a resort. PM me if you want a contact there. Also, I'm interested in the distance link you have. Is it a hop across Bangkok, or upcountry?

Cheers

[JJDinsay]

You know, never really realized about rules differing. What about the available channels? Can we use up to 11 out here? I didn't even realize that there was a law against the maximum power outage for an AP? Can someone explain to me why this even matters? I'm about to hook up a bunch of AP's throughout my condo for a communite wireless network like dey have out in California, Seattle and NYC

[phazey]

JJDinsay:

I suggest you look at the excellent "MeshBox" project at www.locustworld.com - this may suit your needs for shared wireless network, with ample control for users. The units themselves (you can make one and install the ISO image) are controled from a dedicated portal system, www.wiana.org - it's pretty cool.

I've started development of outdoor units and client side equipment, with the ODU's coming in at around 430 each dependant on antenna. The Senao cards mentioned above are also quite good, even they are rated at 200mw, they can be pushed up.

I have many links for design examples, going right down to building your own hi gain antenna's to cut costs. I'm sure if you don't do it yourself the labour costs will be low.

Hope this helps, and feel free to get in touch.

As far as power output regulations, wifi *does* cause interferance at higher levels, expecially with satallite TV - be careful.

./P

[monty]

JJDinsey,

The main reason of limiting radiated power is to give everybody a fair chance to use a wireless system. If you happen to have a neighbour using poweramplifiers on their transmitter, combined with a high gain omnidirectional antenna, you're not going to do anything wireless at all at your place (in the same frequency range anyway)

For this reason you're allowed a higher output power if you're using directional antenna's (as in a point to point bridge) because you would only interfere with somebody right between your two antenna's. As far as I know it's like that in the states, in Europe you're only allowed a limited power, regardless of of antenna!

[Guest IT Manager]

I recently learned of a plan to project a high speed internet connection across 6 km, using 802.11b.

Gain is around 34-44 dbm for the antennae. In my opinion, that will equate to about 15km reach.

Any views?

[monty]

15 km on 30mW and 30 dbm antenae is theoretical very good possible...

Only on a 15 km link you'll have a pretty big fresnel zone. You need at least 60% of this zone unobstructed to have a reasonable propagation of your radiowaves...

As well on these distances you need to take in account the curvature of the earth.

Check out this page on the basics of long distance links, what a fresnel zone is and why these longe distance links most often don't perform as expected!

http://www.wireless.navigator.co.uk/radio_link.php

[monty]

Itman,

did a quick calculation on a 15 Km link:

Earths curvature will be 14.2m (meaning the ground will be 14.2 m higher exactly halfway)

60% of the fresnel zone is 12.8m

This results that both antennae need to be 27m above the ground, IF the area between them is perfectly flat, like a desert or a lake. Any obstructions between will need higher placed antennae or you'll very quickly have reduced quality...

As well, up until now I haven't seen an antenna with a 34dbi gain in the 2.4Ghz range. A 1.2 parabolic will give you around 24-26dbi, and they're not easy to aline over long distances since they have a pretty narrow beam...

If you know anything more about that project I would be very gratefull to learn more about it (just love the stuff)...

Cheers,

Monty

[SeaVisionBurma]

A little off-topic, but I don't want to pass up an opportunity to ask for some info from you boffins who seem to be in the know.....

Can you please direct me to websites/contact numbers for electronic/wireless/gadget type stores in Bangkok? I am starting a project to construct wireless cameras which will upload images remotely.

I need, among other things, radio modems, antennas, tandy-type electronic parts, etc etc.

Any help would be much appreciated

I'm also looking to set up a workshop/office and am looking for some techno-gadget-whiz to assemble the units. Info on that please PM me.

Best!

SVB

[PlanetMan]

JJDinsay:

The Senao cards mentioned above are also quite good, even they are rated at 200mw, they can be pushed up.

./P

phazey,

The Senao cards are excellent, although I think it would be unadvisable to use them in a condo residential environment. The problem is that at such high power the clients might step on each other. Depends on how many clients are expected and usage patterns, but regardless this would be less of a problem at lower power.

Better to increase the number of (relatively low power) Access Points and assign channels to reduce interference. Managing the channel assignments will be one of the more difficult aspects to get right. Good luck.

Cheers

[phazey]

Planetman: understood, but with a dual radio system (as the one i'm testing) the high power links are more for the backbone meshing rather than the client hotspots.

I see your avatar says "Siam wifi" - your business ?

./P

[PlanetMan]

Planetman: understood, but with a dual radio system (as the one i'm testing) the high power links are more for the backbone meshing rather than the client hotspots.

If that is how it has to be done, it is possible, but it does complicate the frequency plan a bit. You can probably find a good discussion about having dual WiFi cards in a AP Seattle Wireless; worth a read if you plan to go down that path.

If there is any way to cable 'em together it will make the overall system more robust and it will have better overall throughput (until it gets to CAT . But if it isn't possible, too bad.

I see your avatar says "Siam wifi" - your business ?

./P

Yup. PM me if your retail establishment is interested to host a HotSpot. Or kindly read Hosting a Siam WiFi HotSpot.

Cheers