Decrease range by disabling modulation

[Fredrik]

Hello and thanks everyone for a great forum,

I just got an Asus RT-AC87U currently using Merlin 378.56_2 and everything is running great, in fact even a bit too good.

Using the 2.4GHz band I get connection about 100 meters (~300 ft) from our house. I suppose it's not really a critical issue, but I have a vague memory from working with Cisco-APs that it was possible to block/disable certain modulations to decrease the effective cell size and am wondering if it's possible to to the same here (seems like almost anything is possible with user-scripts even though I haven't got around to them yet). Like I said it's not critical, but it would be nice to clean up the air somewhat for the neighbors, plus that we could keep the SSID a bit more local (not for half the village to find).

The easiest way to go would of course be to lower the Tx power adjustment, but that would likely result in loss of connection in remote places within the house (ie. the basement). Since from what I recall the clients dynamically change the modulation techniques depending on the reception, if I were to block say the DBPSK, DQPSK, CCK and BPSK I would effectively limit the wireless connections to 12Mbit+, thus reducing the cell size considerably, if I'm not completely confused and remember it all wrong.

If it were possible it would be great, and probably even more useful for people in apartments where the air is even more wifi-polluted.

Does anyone have any thoughts?

Thanks

 

[joegreat]

I just got an Asus RT-AC87U currently using Merlin 378.56_2 and everything is running great, in fact even a bit too good.

Using the 2.4GHz band I get connection about 100 meters (~300 ft) from our house.

Hi,

On my two Asus routers (see footer) I can change the "Tx power adjustment" under Wireless / Professional - not sure if the option is still there on the AC87U...

With kind regards
Joe

 

[Fredrik]

Hi,

On my two Asus routers (see footer) I can change the "Tx power adjustment" under Wireless / Professional - not sure if the option is still there on the AC87U...

With kind regards
Joe

Hello, it sure is, but as I mentioned in the original post that would decrease connection in remote places of the house as well. What I'm looking for is more of a cutoff level, to remove the slowest data rates all together.
Thanks for the suggestion though

From the original post: The easiest way to go would of course be to lower the Tx power adjustment, but that would likely result in loss of connection in remote places within the house (ie. the basement).

 

[Etz]

I don`t think you actually can.

Remember, this is SOHO device, not enterprise grade equipment...

AFAIK, you cannot adjust TX power anymore too, Asus has locked it down due to FCC requirements.

 

[Fredrik]

I don`t think you actually can.

Remember, this is SOHO device, not enterprise grade equipment...

AFAIK, you cannot adjust TX power anymore too, Asus has locked it down due to FCC requirements.

Thanks for your reply. I suppose that may well be the case. It's just that I'm amazed with all the new functionality so I though it might be worth to give it a try and ask here.

Strange, I can still change the Tx power at the bottom of my http://router-ip/Advanced_WAdvanced_Content.asp
I suppose it could be that 100% equals 20 dBm EIRP and it's only possible to lower it, or that the FCC regulations does not apply in the EU?
(downloaded the most recent firmware last week so unless it happened just now I should be affected).

 

[Etz]

Strange, I can still change the Tx power at the bottom of my http://router-ip/Advanced_WAdvanced_Content.asp
I suppose it could be that 100% equals 20 dBm EIRP and it's only possible to lower it, or that the FCC regulations does not apply in the EU?
(downloaded the most recent firmware last week so unless it happened just now I should be affected).

Slider is still there, but have you actually measured signal strength after adjusting it?
Not sure about actually decreasing TX power, but I can try it right away.

About FCC, I believe they locked it down in CFE level and it is pretty much unified.

EDIT: Set my 2.4Ghz TX power to 10% from 100% on my RT-AC68U, no measurable change according to Acrylic Wifi. Still RSSI shows as -35dB.
Also Wifi Analyzer on my 1+2 Phone did not show any decrease in signal strength...

 

[Deleted member 22229]

EDIT: Set my 2.4Ghz TX power to 10% on my RT-AC68U, no measurable change according to Acrylic Wifi. Still RSSI shows as -35dB.

Be advised i have read that after changing TX power you must reboot the router for the changes to take affect.

 

[Fredrik]

Slider is still there, but have you actually measured signal strength after adjusting it?
Not sure about actually decreasing TX power, but I can try it right away.

About FCC, I believe they locked it down in CFE level and it is pretty much unified.

EDIT: Set my 2.4Ghz TX power to 10% on my RT-AC68U, no measurable change according to Acrylic Wifi. Still RSSI shows as -35dB.

Ah so it's just there for the show. I hadn't tried it at all. Thanks for your effort to try it!

I am thinking about the Multicast Rate(Mbps) on the same page. In the drop-box there are different types of modulations.
I have no idea what it does as of now, but as soon as the rest of the family has disconnected I will try to change it to see if it could affect the cell size.
I guess that I could get a higher multicast rate and maybe that would block the lower data rates all together.

Does anyone know what this setting does?

EDIT: I think it would set the base transfer-speed in which the router sends multicasts, resulting in devices connecting with lower speed not being able to send traffic. Not sure how it's implemented though. Or if I'm confusing things all together.

 

[Etz]

Be advised i have read that after changing TX power you must reboot the router for the changes to take affect.

Seems to have done the trick, I just made my 2.4Ghz Wireless dissapear...
Sure enough, it restarted both radios before, but apparently it was not enough.

 

[Etz]

I am thinking about the Multicast Rate(Mbps) on the same page. In the drop-box there are different types of modulations.
I have no idea what it does as of now, but as soon as the rest of the family has disconnected I will try to change it to see if it could affect the cell size.
I guess that I could get a higher multicast rate and maybe that would block the lower data rates all together.

Does anyone know what this setting does?

EDIT: I think it would set the base transfer-speed in which the router sends multicasts, resulting in devices connecting with lower speed not being able to send traffic. Not sure how it's implemented though. Or if I'm confusing things all together.

Multicast is completely different thing, it is for TV streams etc, to limit those.
Multicast is nasty in wireless, it basically would fill all the bandwith and kill all other networking.

http://routerguide.net/optimizing-multicast-rate-for-home-use/

 

[Fredrik]

Multicast is completely different thing, it is for TV streams etc, to limit those.
Multicast is nasty in wireless, it basically would fill all the bandwith and kill all other networking.

http://routerguide.net/optimizing-multicast-rate-for-home-use/

Thanks! I'll definitely keep my hands of the multicast settings then.
I mixed it up with the mandatory data rates. That does what I intended, but on the other hand it can't be changed in the GUI (or elsewhere either I think!?).

 

[Etz]

I mixed it up with the mandatory data rates. That does what I intended, but on the other hand it can't be changed in the GUI (or elsewhere either I think!?).

I don`t think you can change those, besides standard b/g/n settings, even via CLI.

 

[sfx2000]

Multicast Rates can impact range - higher rates there will keep lower speed connections off the AP - e.g. if you set Multicast to 11Mbps, then that's the minimum speed allowed for the client to connect... so it effectively shortens the range of the AP...

Use this, along with IGMP Snooping, if you're stuck with an IPTV solution (or multiple STB's)..

In a multiple AP/Radio config, this can help out a lot with Client Roaming decisions.

 

[PolarBear]

Using the 2.4GHz band I get connection about 100 meters (~300 ft) from our house.
[....]
it would be nice to clean up the air somewhat for the neighbors, plus that we could keep the SSID a bit more local (not for half the village to find).
[....]
The easiest way to go would of course be to lower the Tx power adjustment, but that would likely result in loss of connection in remote places within the house (ie. the basement).

Elsewhere on the forum is a discussion of how the radio coverage area changes shape based on the alignment of the antennas.

If they are aligned vertically, the horizontal range is increased, at the expense of vertical coverage. Aligning them at 45 degrees increases the height and depth of coverage, at the expense of horizontal range.

Might this be a solution to what you are trying to achieve ?

 

[Fredrik]

Multicast Rates can impact range - higher rates there will keep lower speed connections off the AP - e.g. if you set Multicast to 11Mbps, then that's the minimum speed allowed for the client to connect... so it effectively shortens the range of the AP...

Use this, along with IGMP Snooping, if you're stuck with an IPTV solution (or multiple STB's)..

In a multiple AP/Radio config, this can help out a lot with Client Roaming decisions.

Interesting. I'm still not entirely sure if it's good with Multicast rates (I haven't got IPTV), but it might be interesting to try to meddle with, if nothing else to learn how it works

The multiple AP-part is along the lines of what I was originaly thinking about with the mandatory/unsupported data-rates, sounds like something to investigate further. Thank you!

 

[Fredrik]

Elsewhere on the forum is a discussion of how the radio coverage area changes shape based on the alignment of the antennas.

If they are aligned vertically, the horizontal range is increased, at the expense of vertical coverage. Aligning them at 45 degrees increases the height and depth of coverage, at the expense of horizontal range.

Might this be a solution to what you are trying to achieve ?

Thank you for your suggestion. I will try it out! I imagine that the coverage of the antennas is a bit doughnut-shaped (from what I've read they are dipole dual-band antennas?!), the question is if it will lessen the signal strength within the house too much as well. I assume it would have similar effect as to lower the Tx-power, but with added coverage in the otherwise hard to reach-places (like opposite side of the house one floor down). Might definitly be something to try. Would be interesting to see a diagram of the radiation pattern, but I suppose thats hard to come by with the stock-antennas

 

[Etz]

Would be interesting to see a diagram of the radiation pattern, but I suppose thats hard to come by with the stock-antennas

They are omnidirectional...
So doughnut shape applies on both bands...

 

[Fredrik]

They are omnidirectional...

True, but I figure no antenna-design is perfectly round. Most of the omnidirectional I've come across has variations i.e. in the middle of the "doughnut". On the other hand that might be more out of curiosity. In reality the difference is probably smaller than I'd ever notice though, plus the furniture and walls in the house would probably distort the radiation pattern either way.
Thanks for you comment!

EDIT to Etz edit:
I though almost all home equipment Wifi-antennas were (omnidirectional) dipole or 1/2 dipole or something like that.

(From the review of the AC87U http://www.smallnetbuilder.com/wire...less-ac2400-gigabit-router-first-look?start=1 )

 

[Etz]

True, but I figure no antenna-design is perfectly round.

Yes and thats why it is always doughnut, not sphere...

Most of the omnidirectional I've come across has variations i.e. in the middle of the "doughnut". On the other hand that might be more out of curiosity. In reality the difference is probably smaller than I'd ever notice though, plus the furniture and walls in the house would probably distort the radiation pattern either way.
Thanks for you comment!

Well, indeed there may be differencies due to used materials, wavelengths, etc...
Still, does not change general characteristics of radiating pattern.

EDIT to Etz edit:
I though almost all home equipment Wifi-antennas were (omnidirectional) dipole or 1/2 dipole or something like that.

(From the review of the AC87U http://www.smallnetbuilder.com/wire...less-ac2400-gigabit-router-first-look?start=1 )

Omnidirectional antennas are mostly dipoles.
But not all wireless antennas in general are omnidirectional.
Indeed most home equipment uses omndidirectional ones for best all-around performance and coverage.

2,4Ghz wavelength is 0.125 meters = 4.92 inches, now divide it by two to get half dipole length.
You will get around 6,4 cm = 2,54 inches, now measuring those antennas in size, my guess is that they are actually half empty...or are double in actual wavelength...
Which makes me wonder, maybe they actually are full dipoles.

EDIT: Sorry for hell of a lot of edits, but english is not my native language and I do suck in grammar

 

[Fredrik]

Yes and thats why it is always doughnut, not sphere...

Touché
But I was thinking more along the lines of something like this:
http://www.cisco.com/c/dam/en/us/pr...00aecd806a1a3e_null_null_null_08_07_07-05.jpg
(the pointy things in the middle of the doughnut).

Well, indeed there may be differencies due to used materials, wavelengths, etc...
Still, does not change general characteristics of radiating pattern.

No thats very true, but I would assume it would affect the effective radius in different directions, I might have been unclear (english is not my native language either).

2,4Ghz wavelength is 0.125 meters = 4.92 inches, now divide it by two to get half dipole length.
You will get around 6,4 cm = 2,54 inches, now measuring those antennas in size, my guess is that they are actually half empty...or are double in actual wavelength...
Which makes me wonder, maybe they actually are full dipoles.

Hm, interesting question. I tend to think more like the first alternative, they have to look cool and powerful to sell

EDIT: Sorry for hell of a lot of edits, but english is not my native language and I do suck in grammar

This is s a very interesting subject, we are however quite a lot of topic right now, I don't know about the stick-to-the-topic rules here, hope it's alright.

I do however suppose this might be classified as an alternative solution to the original problem (hopefully).