• Hi all,

    Not sure if this is the right place to post this, please let me know otherwise.

    I am setting up a small testbed and I am looking for an 11n USB dongle with output power configurable through GUI or commands. Preferably with SMA for antenna connection.

    Does anyone have any recommendation?

    Thanks and kind regards, 

  • It's been sometime since I worked with Wi-Fi Dongles that have antenna connectors, but I know MonoPrice had both g and n versions.   I don't know if you could adjust the power levels.

    Ubiquiti may have one.

    Oftentimes, one companies drivers will work for another device if they use the same chipset.  Though some manufacturers "fix" their drivers so this won't work.

    It is also possible to replace/add external antenna connectors if you are careful.  At least one Zyxel dongle had a U.FL connector on the inside that could be accessed if you opened the case.

  • Thanks a lot Howard, I am going to have a look at these manufacturers and see if I can find something.

    I've actually seen a 2SS USB 11n adapter with antenna connectors in MonoPrice's site, although it's gonna be tricky to find out if I can configure the output power.

    Thanks again!

  • You're not going to be able to get more power than whatever the maximum power it puts out, but some manufacturers driver will probably allow you to lower the level, at least in steps.

    I work at a desk most of the time now, so I can use fixed inline attenuators without too much hassle.  Both Pasternak and Mini-Circuits sell them.   You'll still need an SMA to RP-SMA adapter of course.   You can find all of these on-line and at Ham Radio Swapmeets.  Usually $3 at the latter.   I have 1, 3, 6, 9, and 20 db versions of the attenuators.  

    For single stream, and if you have more $'s to spend, then a Trilithic variable attenuator works GREAT.   Mine goes from 0 to 99  in 1 dB steps, up to 6GHz, and handles up to 2 Watts (33 dBm).  

    Be careful with used step attenuators.   Many only go to 1 GHz, and most you'll find have burned out sections.   Often good units rated lower than 1 GHz  will still work (somewhat) in the 2.4 GHz range.  The calibration will be off though, probably by several dB.

    I have seen several articles in Ham radio magazines for building DIY switched units - some look better than others.   I would suggest finding one used for Amateur Satellite.

    Hopefully you'll find a GUI controlled dongle and not have to fuss with any more hardware.

    Please let us know what you find out, even if you don't find THE answer.

  • Hi Howard, 

    Thanks a lot for all the info. I found that Realtek Wireless Diagnostic SW allows the user to change the output power. Unfortunately, both Realtek cards I've got are miniPCI. I will see if there is any dongle available compatible with that SW.

    I've got some attenuators (3 dB, 6dB and higher) so that should give me some options. 

    I searched for the model of the 1 dB step variable attenuator you mentioned, is it the RSA-6510?


  • By Howard - edited: February 11, 2015

    Here is a link to a picture for my Bench-top version - model BMA-3511BMA-R.   I love it.

    I believe their RSA (Rotary Step Attenuator) models are what they put inside this one, but I know you can buy those separately too.  If you only needed one, or were building you own instrument cluster, that would definitely be easier on the pocket book.

    As long as it was for my employer, and is perfect for my application (and probably yours too), it is the one I went for.

    Buy yourself one or two good quality 5/16" Ignition wrenchs for tightening SMA-xx connectors with either attenuator type you go with, i.e. rotary or fixed.   They should only cost you a couple bucks each.   To make consistent measurements, you need to firmly tighten the connectors.   One rule of thumb it to tighten them finger tight, and then a tiny bit more.  If you can un-tighten them by hand, without the wrench, they are too loose.   With a little practice you can get very consistent results, which is what you should be aiming for.  You should be aiming for between 3 and 5 INCH pounds of torque on the connectors.

    I have laboratory quality test gear at work, and torquing the connectors definitely makes a measurable difference.   I have a miniature snap-type torque wrench ($$), but I sometimes fall back to my "calibrated" fingers  with an ignition wrench.

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