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08-09-2009, 06:03 AM
imported_RaderCad

Quote:

Originally Posted by Citruspers

Nice post, it got me thinking:

You say reception/quality varies by multiple factors, including different frequencies. Could it be that a certain frequency has better reception? (IE using a different channel, say 1 instead of 11). I'm not talking big frequency shifts here like from 2.4 to 5 GHZ, just the channel freqs.

The best channels in the 2,400MHz band are 1 and 6 they have the least amount of bleed over from the other channels. LOL the other channels get bled over from them.

For a good look at the rules go read my first post here put the link back together.
08-09-2009, 03:24 PM
Barry

Quote:

Originally Posted by RaderCad

The best channels in the 2,400MHz band are 1 and 6 they have the least amount of bleed over from the other channels. LOL the other channels get bled over from them.

For a good look at the rules go read my first post here put the link back together.

1, 6, 11 don't bleed over to each other. This "rule" only applies for multiple channels within range of each other. Now if you live in an apartment complex, or a densely populated neighborhood, the best channel to use would either be the one no one else is using, or the one not as many are using.
08-09-2009, 09:03 PM
Thorn

Quote:

Originally Posted by RaderCad

The FCC rules allow for stronger rigs at the Antenna than 36 dBm.

If you have a 30dBm amplifier then you can only have a 6dBi antenna. However! For every 1dBm amplifier drop you can have 3dBi of antenna gain.

For example, if an installation reduced power at the transmitter to 29dBm, it could use an antenna having a gain of 9dBi. Or in the case of the ALFA 27dBm + 15dBi for the maximum transmitter and antenna combination.

That is why our 40.2dBm rig is legal in the USA. Europe is way more restrictive.

Here is a good site with the conversion table and the rules. Oops! I am a newbi so I had to take it apart.

http : // www . cpcstech.com / dbm-to-watt-conversion-information . htm to Watt Conversion Table

That is incorrect and misleading.

FCC Rules Part 15 Section 247 limits Effective Isotropic Radiated Power (EIRP) with an omnidirectional antenna to 36dBm. Period. You can combine a 30dBm transmitter to a 6dBi antenna, or a 18dBm transmitter to a 18dBi antenna, but you cannot exceed 36dBm EIRP when using an omnidirectional antenna.

There is an allowance for a 1dBm amplifier reduction with a 3dBi of antenna gain only when using a directional antenna, in a point-to-point configuration.. In that case the maximum allowed is a 22dBm (160 mW) transmitter used in conjunction with a 30dBi directional antenna for an EIRP of 160.0W.
08-13-2009, 04:18 AM
imported_RaderCad

Quote:

Originally Posted by Thorn

That is incorrect and misleading.

FCC Rules Part 15 Section 247 limits Effective Isotropic Radiated Power (EIRP) with an omnidirectional antenna to 36dBm. Period. You can combine a 30dBm transmitter to a 6dBi antenna, or a 18dBm transmitter to a 18dBi antenna, but you cannot exceed 36dBm EIRP when using an omnidirectional antenna.

There is an allowance for a 1dBm amplifier with a 3dBi of antenna gain only when using a directional antenna, in a point-to-point configuration.. In that case the maximum allowed is a 22dBm (160 mW) transmitter used in conjunction with a 30dBi directional antenna for an EIRP of 160.0W.

:eek:

Thanks for the clarification on the rules, the cute dBm to watt conversion table did not have an exact reading and never mentioned a directional antenna. So I am 4.2 dB over allowable maximum for a one to one with an omni directional antenna. It is a good thing I am not in the USA to face the ire of the FCC. Also since our transmitter is in a boat we are at times more than 1/2 mile away from any AP's. Anyway, I am not apologizing for solving my own problems with distance on a constantly moving object.

:cool:
08-13-2009, 05:39 AM
Thorn

Quote:

Originally Posted by RaderCad

:eek:

Thanks for the clarification on the rules,

You're welcome.

Quote:

Originally Posted by RaderCad

:eek:

the cute dBm to watt conversion table did not have an exact reading and never mentioned a directional antenna.

I am shocked -shocked!- that some unofficial information on the Internet is incomplete and incorrect. ;)

Seriously, it just proves you have to read the source information. In this case the FCC rules are all available online.

Quote:

Originally Posted by RaderCad

So I am 4.2 dB over allowable maximum for a one to one with an omni directional antenna. It is a good thing I am not in the USA to face the ire of the FCC. Also since our transmitter is in a boat we are at times more than 1/2 mile away from any AP's. Anyway, I am not apologizing for solving my own problems with distance on a constantly moving object.

:cool:

Just be careful. In some places, it's no big deal, while in other countries, the regulatory bodies and rules make the FCC look very mild. For example, some of the French and Israeli rules are extremely restrictive.
08-13-2009, 08:50 AM
imported_RaderCad

Quote:

Originally Posted by Thorn

Just be careful. In some places, it's no big deal, while in other countries, the regulatory bodies and rules make the FCC look very mild. For example, some of the French and Israeli rules are extremely restrictive.

Wrong continent. :D We are in a place that is a little more third worldly. Kind of WAY WAY south of central USA. ;) Where people think WEP is the best protection. And never read instructions or even know how to set the passwords on their AP's.
10-12-2009, 02:11 PM
Trokij

Hi guys, I need help to choose an antenna.
At first I tried with the home made-mc giver staff but with really bad results, so I choose to buy a ready made antenna but don't know which one choose!
Don't think I really need too much distance but seeing those models with impressive distance range makes me desire them!
So now I'm stacked and can't choose which one between those

2.4GHz PANEL 20 dBi Antenna

5.8G GRID 27dBi+Lightning Protector-RTNCP-400-15m

Or this one:

+30dBm NextG USB-Yagi High Power WiFi Antenna

This looks great, better performance than the others, easy to use, a cheaper price but I don't like the integrated dongle, I like the idea of using any pci card I want with the other.
So any opinion?

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