Test setup

knightmoves
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Re: Test setup

Post by knightmoves »

You probably don't want it on the back of the backplane, because you don't want it to disturb the test environment, and I suppose you might possibly get reflections off the router body or something. But I'd be surprised if it made very much difference at all.

To me, it seems like mounting the router somewhere is more work than just setting it on the floor / a chair / whatever.
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RasmitDevkota
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Re: Test setup

Post by RasmitDevkota »

Just a heads-up, I would look at this one instead, since it's updated for this season. Also much clearer than the 2017 version!
knightmoves wrote: October 21st, 2021, 9:07 pm What are people getting for the reference signal level for the 3.1cm reference paperclip at 3m distance? Mine comes in at about -60 dBm.
To answer, I've been getting around -80 dBm but it obviously depends on a lot of factors, I would instead compare it to the dBm for the detachable antennas and the dBm for the bare SMA connector to get a feel for the different ranges of values if you want to decide whether your antenna is doing well or not.
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SusanV (December 16th, 2021, 10:36 pm)
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Re: Test setup

Post by knightmoves »

RasmitDevkota wrote: November 20th, 2021, 3:56 pm To answer, I've been getting around -80 dBm but it obviously depends on a lot of factors, I would instead compare it to the dBm for the detachable antennas and the dBm for the bare SMA connector to get a feel for the different ranges of values if you want to decide whether your antenna is doing well or not.
That's a good idea. My paperclip is about 10 dB better than the SMA by itself. My router is the Asus rt-n12 that was recommended, and the cable between the router and the SMA should be worth about 1.5 dB of attenuation (I don't have measurement equipment, but can read the spec sheet!). The paperclip seems a bit variable, though - like it doesn't always make a great electrical connection.
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Re: Test setup

Post by alkotz »

I finally received a Wifi router for this event - the ASUS RT-N12D1 was what I could readily get. Unfortunately, when I started poking around, I found that the transmit power setting GUI has been removed, so I can't set the transmit power. From what I could gather from other posts on transmit power, it looks like ASUS removed the transmit power GUI in response to an FCC requirement that users not be able to turn their transmit power up. However, that leaves us with no way to turn it down either.

Has anyone else encountered this? If so, have you found a work around or a different model? The 2mW transmit power requirement spelled out in the rules is pretty low compared to what appears to be the factory default of 200mW for the RT-N12 HP model that had the power adjustment GUI.
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Re: Test setup

Post by szelazny »

I'm having a heck of a time finding a paper clip that can fit inside the female bulkhead connector. Instead using a length of copper wire right now.....

We are getting about -58 dBsm at 3 meters.

The rules say an average of the signal will be taken over 10 seconds but the software package recommended doesn't seem to offer this as an option so we are instead recording 5 measurements by hand and taking the average.

Am I missing an option of the software to automate this?
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Re: Test setup

Post by SusanV »

We are getting -57 as our lowest connection with the paper clip pushed directly into the SMA connector. What would be the expected reading for a commercial antenna?

Edit: We used the smallest size standard paperclip. That worked in the SMA connector listed in the testing station construction instructions.
Last edited by SusanV on December 16th, 2021, 5:50 pm, edited 1 time in total.
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Re: Test setup

Post by RasmitDevkota »

SusanV wrote: December 16th, 2021, 5:48 pm We are getting -57 as our lowest connection with the paper clip pushed directly into the SMA connector. What would be the expected reading for a commercial antenna?

Edit: We used the smallest size standard paperclip. That worked in the SMA connector listed in the testing station construction instructions.
There's not really an expected reading, other teams I've talked to at least have given numbers between -40 and -80. It would probably be better to compare it to your antenna and the router's proper setup (if you got the ASUS one recommended in the rules that would be comparing your monopole readings to the two detachable antennas that come with the router). It's also going to vary a lot anyways since we all test in very different environments. As long as your antenna is connecting successfully at good distances then you should be fine, it's all relative for a reason.
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Re: Test setup

Post by knightmoves »

szelazny wrote: December 3rd, 2021, 12:29 pm I'm having a heck of a time finding a paper clip that can fit inside the female bulkhead connector. Instead using a length of copper wire right now.....
A regular paperclip (the small size) fits. Larger ones don't.

The center pin of an SMA connector is 0.9mm. A standard small paperclip is 0.8mm.

Note that small paperclips don't have a 3.1 cm straight section - you have to straighten it out first.
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Re: Test setup

Post by andrewwski »

alkotz wrote: December 1st, 2021, 7:22 pm I finally received a Wifi router for this event - the ASUS RT-N12D1 was what I could readily get. Unfortunately, when I started poking around, I found that the transmit power setting GUI has been removed, so I can't set the transmit power. From what I could gather from other posts on transmit power, it looks like ASUS removed the transmit power GUI in response to an FCC requirement that users not be able to turn their transmit power up. However, that leaves us with no way to turn it down either.

Has anyone else encountered this? If so, have you found a work around or a different model? The 2mW transmit power requirement spelled out in the rules is pretty low compared to what appears to be the factory default of 200mW for the RT-N12 HP model that had the power adjustment GUI.
That router supports third-party firmware such as DD-WRT or Tomato, which allows you to configure the transmit power. See here for DD-WRT installation instructions, for example:

https://wiki.dd-wrt.com/wiki/index.php/Asus_RT-N12

The RT-N12D1 has a "recovery" mode so it's fairly hard to brick.
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