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Thread: Noise floor and the RF Explorer

  1. #1
    RTFM aeryck's Avatar
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    Noise floor and the RF Explorer

    I finally got my RF Explorer (240-960MHz model) and I have to say, this thing works great.

    I was curious so I tried running the explorer at a couple sites I've flown at - One site I was able to hit 3.3 miles with no signs of video degradation (turned around due to battery life), and another site I couldn't make it 1 mile before the video started getting fuzzy.

    See if you can figure out which scans of the RF explorer came from what flying sites? =] Both were set up for the same parameters: Centered on 910.000MHz, range -40 thru -120dbm, using a magnet mount antenna somewhat tuned at 910MHz (my calculations may have been slightly off). In both cases, I was running the unit in Max-Hold mode, letting it scan for about 5 minutes to see if there were any errant spikes in the spectrum range.

    Of course, these scans were taken without my video tx running (didn't even have the plane with me), so it's just a sweep of the noise floor, not counting how my video signal competes with it.

    This little device is invaluable for figuring out whether I should even bother trying to fly at a particular site; just checking various places around town shows just how saturated the 902-928MHz ISM band really is.
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    Far better is it to dare mighty things, even though checkered by failure; than to take rank with those who neither enjoy much or suffer much, because they live in the gray twilight that knows not victory nor defeat.

  2. #2
    Let your perspective soar
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    Nice... gotta get me one of 'em soon.

  3. #3
    RTFM aeryck's Avatar
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    Quote Originally Posted by jimmaplesong View Post
    Nice... gotta get me one of 'em soon.
    I've only had mine a few days and I love it.

    The only drawback is that as of right now, the only video bands it's capable of analyzing are 900MHz (with the 240-960 model or module) and 2.4GHz. Currently there is nothing that can analyze 1.2GHz or 5.8Ghz, however I did hear that Ariel is working on a wideband model that can cover from 15MHz - 2700MHz, and a downconverter for analyzing 5.8GHz. Details in this post, however the timeframe and final price is still TBA.
    Far better is it to dare mighty things, even though checkered by failure; than to take rank with those who neither enjoy much or suffer much, because they live in the gray twilight that knows not victory nor defeat.

  4. #4
    The field located in the second (flat) image is less than a mile away from a tower broadcasting 400 watts on 928.2MHz.

    When the explorer's span is enlarged, 910MHz appears as a perfectly flat valley safely nestled between the mountains of GSM around 870 and the towering spires of the local power company's telemetry systems starting at 928.

  5. #5
    Engineer for Jesus Christ IBCrazy's Avatar
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    Another trick is to screw your directional VRX antenna into the RFExplorer and do a scan of the area pointing it in various directions. You will notice the noise floor changes. This way you can determine which direction is best to fly from your location.

    -Alex
    If it is broken, fix it. if it isn't broken, I'll soon fix that.

    videoaerialsystems.com - Performance video piloting

  6. #6
    RTFM aeryck's Avatar
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    Quote Originally Posted by IBCrazy View Post
    Another trick is to screw your directional VRX antenna into the RFExplorer and do a scan of the area pointing it in various directions. You will notice the noise floor changes. This way you can determine which direction is best to fly from your location.

    -Alex
    Yep, was going to do that too until I realized I forgot to grab the 900MHz patch antenna off my ground station before I headed out, heh.

    I also like the client software; much easier to adjust sweep settings and also the data logging is a big plus.
    Far better is it to dare mighty things, even though checkered by failure; than to take rank with those who neither enjoy much or suffer much, because they live in the gray twilight that knows not victory nor defeat.

  7. #7
    I love peanut butter Pen's Avatar
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    Quote Originally Posted by Airborne View Post
    The field located in the second (flat) image is less than a mile away from a tower broadcasting 400 watts on 928.2MHz.

    When the explorer's span is enlarged, 910MHz appears as a perfectly flat valley safely nestled between the mountains of GSM around 870 and the towering spires of the local power company's telemetry systems starting at 928.
    Are you saying that RFExplorer is unreliable because it is showing low noise floor at 910 when there is really a high noise floor that will knock down your range?

    ... or are you saying that you can be less than a mile away from a huge noise floor source on 928 and still fly clean on 910?

    ... and how do you know where aeryck took those readings, are you flying buddies or are you just being facetious?

    I just received my RFExplorer in the mail at Sentry's recommendation and not sure of the best way to utilize it yet.

    Is aeryck doing something wrong?
    Last edited by Pen; 13th February 2012 at 02:16 PM.

  8. #8
    No, just the opposite. The RF explorer works perfectly. It will be an invaluable addition to your toolkit. We spent the better part of the day yesterday driving and scouting our flying locations looking for noise sources.

    At our field, there are huge noise sources (up to -40 dbm) around 870MHz and also at 928MHz, however the part we care about (902 - 928) is completely noise free as shown in his screenshot, even though the source is less than a mile away.

    What I was getting at is that even though there are high powered signals relatively close to 910, they do not 'bleed over' into our band, and are not a huge concern. He gets a perfect picture for miles from here.

    If he had taken the screenshot while RF explorer was showing a wider span (say 850 - 950), you would see huge "mountains" of noise on either side of 910.

    If you're looking for a way to put it to use, tune it to show your video band, set it in 'max hold' mode and watch it for a few minutes. You want to see a flat line like screenshot #2. If you see "mountains" like screenshot #1, pack up and move because you aren't going to get a very good picture there.
    Last edited by Airborne; 13th February 2012 at 02:45 PM.

  9. #9
    I love peanut butter Pen's Avatar
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    Quote Originally Posted by Airborne View Post
    No, just the opposite...
    Awesome! Thx for the clarification. I have a flying spot where I got 6 miles with perfect video on 910 and another spot where I couldn't get a mile, so I plan to do a sweep on each to confirm that I will get similar RFExplorer results as you guys did.

  10. #10
    You'll love it. Hook your patch to the input and it's real easy to figure out where the noise is coming from. 900MHz is a wasteland of baby monitors, cordless phones, older or long range wifi networks, etc. Even some of the traffic lights around here use a 900MHz network to communicate. These are all things you can't "see" by watching your RX with the TX switched off, however they show right up on the explorer.

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