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Need Help w Spectrum Analyser for P3

Discussion in 'Pro/Adv Discussion' started by DCP700, Apr 16, 2016.

  1. DCP700

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    I have the RPAS exam coming up and there seems to be 'strong advice' to own a spectrum analyser.
    So having bought it... could someone pls advise if we have to alter it or set it up to monitor for the P3.
    The 48 page manual does not really cover specifics...
    Thx in advance for any pointers.
     
  2. alokbhargava

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    What do you want to analyze? Which model did you buy?
     
  3. DCP700

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    I have RF Explorer Hand Held Spectrum Analyser - I was told we had to have one for the RPAS exam to monitor activity to ensure no conflict of users in the area
    "We will use a 2.4GHz RF Frequency Spectrum Analyser as part of a pre flight check. "
    Do they have shares in these...
     
  4. alokbhargava

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    RF analyzer will measure noise in DB at different frequency levels around 2.4 GHz. These are called channels. You can check the signal pattern on Go App. Your analyzer should give a similar pattern. Only caution is that RF is directional. You will see peaks varying if you turn your analyzer.

    Your task would be to check the frequency pattern with RC off and with RC on and to check noise levels around your RC signal.
     
  5. WetDog

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    Are they REALLY suggesting that you do that? Totally weird and basically unnecessary as the GO app does exactly this thing and can route around congestion issues automatically. (As alok stated.)

    I'd just show them the screen on the GO app. Tell them it's a signal analyzer - which it is. If it's good enough for the manufacturer, it should be good enough for the government. You can buy Wifi signal strength analyzers for network analysis. Decent ones are fairly expensive, cheap ones are junk. You can build one (look up 2.4 Ghz signal analyzer circuit) - braindead simple except for finding the proper UHF signal diode.
     
  6. DCP700

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    Yep they made a point of it on my manual exam.
    I just want to turn this thing on and know if its set up right and that it will indicate what I need... I'm not a techie like you I'm afraid.
     
  7. DCP700

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    Thanks yes
    I just want to know if I tamper with this little device in set up or if it is good to go out of the box. Its just numbers to me...
     
  8. alokbhargava

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    You can keep on selecting different channels on the App. That varies the transmission frequency. You can watch the results on the spectrum analyzer then.
     
  9. WetDog

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    I think he is unclear what he's supposed to do with the spectrum analyzer once he gets it so he can impress the guy giving him the test. If it were me I'd rent or borrow a $10,000 Aligent professional spectrum analyzer with the vector display and press some buttons to get the most confusing display - then I'd nod occasionally, twiddle a knob or two, frown once or twice and turn the machine off.

    But the OP is unlikely to think this appropriate or amusing. Typically the cheaper analyzers meant for computer WiFi installations have some sort of display, typically an LED bar graph. There should be a way to change the channel. So run through the channels and make sure that you don't peak the bar graph. If you do, turn 90 degrees and try it again. You should be able to find a direction that has less signal. Not that this means anything. But it should look impressive. If you are red lined everywhere you probably should find another place to fly. Or possibly unplug the antenna.

    And as I pointed out, the GO app has a perfectly cromulent analyzer. It even will automagically switch to the least congested channel. I'm wondering if the testers are less than familiar with the DJI system and don't realize that this capability is indeed built in. When I get around to it, I'm going put together a kit from Down East Microwave that seems pretty advanced for the price. I want it to play with antenna output measurements. But that's probably overkill for the OP's use.

    I've not heard other British pilots complain about this particular issue though.
     
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