Speed lost in repeater mode

"SLO" hath wroth:

Which hardware version DWL900AP+ ? I'll guess C1.

Increases how far? What distance? What obstacles? Numbers please.

Are you using the stock antennas or something better? If not look into adding reflectors to boost the signal:

That's really slow. It could be due to interference or weak signal. Is this indoors (going through several walls) or outdoors (susceptible to interference)?

Also note that your speed through a repeater will be half (or less) of the speed going direct.

Repeaters suck. Compatibility and timing problems like this are all too common.

No, it's probably a timing problem in the repeater. The DWL900AP+ has a short list of "compatible" products. |

take 3 boxes to play repeater. I know that two are DWL-900AP+ boxes. What's the third box?

Some things to try:

1. Verify you have the latest firmware: |
   formatting link
2. Disarm the 4x mode. See: |
   formatting link

Thanks for your answer.

Jeff Liebermann wrote: .

rev C2 for both DWL 900AP+

The AP is located at the second floor of a French coutry style house, under the roof (made of tiles). So the only obstacle is the roof since the repeater uses an external outdoor antenna. The distance between the AP and the repeater's outdoor antenna is 10 meters (30 feet).

I have first made tests placing the AP and repeater at 6 meters (20 feet) from eachother and without any obstacle (direct view). In these conditions everything worked fine.

The AP uses his omnidirectionnal stock antenna and as I have already written, the repeater uses an outdoor high gain (15 dB) helico=EFdal antenna coupled to an omnidirectional indoor antenna to distribute signal inside a second building. The repeater is connected to those to antennas using an antenna coupler.

This is half indoor and outdoor as described. I have already been thinking to use an outdoor directionnal antenna for the first AP, but it would be difficult to install this antenna on the first building an to install the wire to feed it. In fact it would be as difficult as installing an ethernet cable between the 2 buildings...

In the first building there is a DSL modem. To share the DSL internet connection, a DLink DI 524 wifi router is connected to the DSL modem through ethernet. Since the DI 524 is not compatible to the DWL 900 AP+ in repeater mode, i have connected a DWL 900AP+ to the DI 524's ethernet switch and configured it as an Access Point. In a second building, where i want to distribute the internet connection, is located the second DWL 900AP+ configured as a repeater for the DWL 900AP+ Access Point. And finally i use my laptop Acer computer with built in wifi to connect to the repeater.

I 'm using the last firmware.

"SLO" hath wroth:

Well, I was close. The A1 and B1 versions do not have the repeater feature.

Roof tiles are a substantial obstacle. 2.4GHz will go through roof tiles but not without some loss. Unfortuantely, I don't have any numbers for the attenuation.

OK. That means that the radios and such are working.

Antenna coupler? Is that a power splitter or power combiner? I'm not sure, but it appears that you have two transmitters connected to the same antenna. That's a rather bad idea. When one transmitter goes on the air, the other receiver is sure to be overloaded and desensitized. The power splitter will offer perhaps 20-30dB of isolation, but that's not enough to prevent overload. Even if the radios are on different channels, there will still be some receiver overload (i.e. blocking). There's also the possibility of the transmitters mixing and produceing intermodulation products. You won't hear these, but other services will see the interference. Is this what you're doing or am I reading your description incorrectly?

Well, if it is interference, it should come and go with time of day. Very few sources of wireless intereference are on the air 24 hours per day. If it's a problem all the time, it's probably NOT interference.

Well, given the choice, running wire (or fiber) is always better than wireless. If the outdoor antenna can position the line of sight over the obstructing tile roof, the problem will probably be solved.

Is the DWL900AP+ on the same RF channel (1, 6, or 11) as the DI-524? It should NOT be.

Looks like the DI-524 radio section isn't really necessary for testing the repeater link. Try turning OFF the wireless part of the DI-524 and see if the DWL900AP+ performance improves.

Except for my comments on the sharing of an antenna, this seems to be a workable system. The DWL900AP+ should certainly be compatible with another DWL900AP+. That leaves the attenuation caused by the tile roof. I don't know of any way to eliminate the loss, other than repositioning the antennas for line of sight.

Thanks again for your answer.

My home-made antenna coupler is intended to connect 2 antennas on the same repeater. It's a kind of "splitter". I have one cable connected to the repeater antenna socket onone side and to the "coupler" (or splitter) on the other side. And the coupler is connected to my outdoor helicoidal antenna on one side, and to an indoor omnidirectionnal antenna on the otherside. The antenna coupler is a kind of "T". Here is a link where you kind see what it looks like :

If i didn't use this coupler and only the outdoor antenna, my repeater would receive signal from AP but my laptop computer wouldn't be able to receive repeater signal. And if i only used the omnidirectionnal antenna on the repeater, my laptop computer would receive signal from repeater but the repeater wouldn't be able to connect to AP. So I had to use one directionnal outdoor antenna to connect the repeater to the AP, and also an indoor omnidirectional antenna to connect the repeater to my laptop computer. Since I had to use 2 antennas, I had to use an antenna coupler (or signal splitter).

The bitrate loss occurs 24 hours per day.

I think that's what i am going to try next. Maybe i could first use an indoor directionnal antenna connected to AP and oriented in direction of repeater through roof. If the problem is still present I could put this antenna outdoor.

DI-524 is on channel 6 and the two DWL900AP+ are on channel 10.

What I don't understand is that my repeater seems to be more sensitive to signal attenuation, or obstacles than any laptop computer or wifi adapter. Indeed if i stand with my laptop computer outdoor and connect directly to AP the bitrate is very good. But if i use my DWL 900AP+ in the same location, as a repeater, or even as a wireless client connected to my laptop through an ethernet cable, bitrate collapses...

Thanks again for your answer.

My home-made antenna coupler is intended to connect 2 antennas on the same repeater. It's a kind of "splitter". I have one cable connected to the repeater antenna socket onone side and to the "coupler" (or splitter) on the other side. And the coupler is connected to my outdoor helicoidal antenna on one side, and to an indoor omnidirectionnal antenna on the otherside. The antenna coupler is a kind of "T". Here is a link where you kind see what it looks like :

If i didn't use this coupler and only the outdoor antenna, my repeater would receive signal from AP but my laptop computer wouldn't be able to receive repeater signal. And if i only used the omnidirectionnal antenna on the repeater, my laptop computer would receive signal from repeater but the repeater wouldn't be able to connect to AP. So I had to use one directionnal outdoor antenna to connect the repeater to the AP, and also an indoor omnidirectional antenna to connect the repeater to my laptop computer. Since I had to use 2 antennas, I had to use an antenna coupler (or signal splitter).

The bitrate loss occurs 24 hours per day.

I think that's what i am going to try next. Maybe i could first use an indoor directionnal antenna connected to AP and oriented in direction of repeater through roof. If the problem is still present I could put this antenna outdoor.

DI-524 is on channel 6 and the two DWL900AP+ are on channel 10.

What I don't understand is that my repeater seems to be more sensitive to signal attenuation, or obstacles than any laptop computer or wifi adapter. Indeed if i stand with my laptop computer outdoor and connect directly to AP the bitrate is very good. But if i use my DWL 900AP+ in the same location, as a repeater, or even as a wireless client connected to my laptop through an ethernet cable, bitrate collapses...

That will work (with 35 ohm line) sorta. It has almost no isolation between ports. The more complex Wilkinson divider/splitter/combiner, has about 20-30dB of isolation between ports. |

sharing two antennas on a single, the isolation requirement is minimal. All you need to do is make sure that the antennas do NOT see each other. If they do, you will have nulls and peaks, with the accompanying weird antenna patterns.

For sharing 2 antennas, you can probably get away with using just a T-connector, and a 35 ohm coax cable that's an odd multiple of 1/4 wavelengths from the xmitter to the t-connector junction. You only need the splitter if you have a high power xmitter, where the VSWR might cause it to shut down, or blow up.

Oh, I see. Well, that's a good reason to use one.

Then, it's probably not interference. There are a few RF sources that are on the air continuously. See if any of these are possible:

best guess is that the attenuation of the roof tiles is the problem.

Well, there is a slight bit of overlap between 6 and 10. Try 6 and 11 or better yet, try 1 and 11.

Well, if the DWL900AP+ had some form of signal level meter, it would be easy to determine the relative effects. However, without numbers, we're just doing guesswork. If you have an attenuator, you might try locating the radios close together and putting the attenuation in series with the antenna lead. Then you can tell how much attenuation the system can handle, which should give you an idea of what range to expect.

Your laptop apparently just has a better receiver than the DWL900AP+. Most 802.11g radios are generally better quality designs than 802.11b only radios, such as the DWL900AP+.