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Range extenders

Discussion in 'Pro/Adv Discussion' started by neslex, Jun 9, 2015.

  1. neslex

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    I've noticed there hasn't been a great deal of discussion concerning range extenders, as the stock antennas do a pretty **** good job with range. However some people like to push the limits, and I've noticed the likes of DBSmods creating a third party solution that was capable of producing a 4mile (6.4km) distance (video) - I know stock antennas have done similar ranges, however I am more interested in boosting my signal from a suburban/residential perspective.

    Has anybody done any experimenting with such solutions? Dbsmods should be releasing their version next week @$100 and I am considering it - Currently lucky to get more than 1/2 mile in resedential areas.
     
  2. Charmande

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  3. Dome

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    Using Phantom in a context of a big city is very diffcult anyway. You can boost signals in term of dbm (power) to achieve better range. Keep in mind that antennas that are too much directional in a city are not winners. Concrete reflects and splits signals making the digital trasmission a nightmere. To this add that 2.4G band is really jam packed now in a city. On my 3rd floor apartment I get, with a stock antenna, 23 different wi-fi from ch 1 to 14, and also on ch 15-20 there are so strong signals that the DJI DSSS lightbridge system is really stressed by error correction. Now I'm using 5ghz wifi band for home, 2.4g is at saturation and it sports no more than 10Mbs bandwidth.
    It would be interesting to test 800-900mhz band where same power can triple your range with wire antennas and it's a pity that this bands haven't a free legal bandwith for video relay.
     
  4. aburkefl

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    Nice to see frequency comments from someone who obviously knows something about it! Can you imagine what it's going to be like when commercial quads start filling the air? In the RC plane arena, flying a bunch of planes in the same general vicinity is not a serious problem. Of course, most of what I see in that arena - they are out of town and not in the middle of a WiFi quagmire!

    Frequency spectrum is getting more and more rare and more and more expensive. The frequencies where a lot of the old VHF TV used to be sold for fortunes. There are still some stations there - many HD signals set up camp where there used to be two or three TV channels. Obviously, if there isn't another HD TV broadcasting anywhere near you, that frequency can be reused. But, if I remember correctly, most of those VHF freqs were auctioned off during the Clinton administration.

    We need somebody to come up with something like multiplexing spread spectrum and generate another "new" batch of frequencies. There's a moderately tall building (relatively speaking - I live in a small town!) in the downtown area. I thought one day it would be neat to live there. I could put a small tower on top of the building and get my antennas way up into the air. But, from an RF perspective, being in the middle of a ten-block town, it's incredibly noisy. I wouldn't dream of trying to fly my Phantom down there!
     
  5. Dome

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    @aburkefl I think that next future of remote video streaming in drone industry will be similar to digital television a sort odfm systems with QAM modulation.. In just 8mhz bandwidth you get full hd at 30fps. Interesting experiments are in place in 1.2ghz band
     
    #5 Dome, Jun 9, 2015
    Last edited: Jun 9, 2015
  6. aburkefl

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    Absolutely - probably on all counts! When we first started laying fiber optic cable, there was a belief that a few cables would provide hundreds of thousands of "links" for the tele-savvy public. Boy were we wrong!There's obviously something like Moore's Law that applies to bandwidth. If you build it, not only will they come - they'll bring their friends, neighbors, their laptops.....

    There were a couple of huge advances early on in fiber optics - like wave division multiplexing for one - that saved our bacon. It sometimes disappoints me that the U.S. seems to be getting further and further behind in some tech areas. There are many countries in the world where internet bandwidth is far wider and far cheaper than what we're being offered.

    Better get off my stump! Again, nice comments and I think you're spot on.
     
  7. Atom1234

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    Do u have a link for DBS moods
     
  8. zaphodbeeb

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    Umm, not quite correct in several aspects.

    It was not during the Clinton administration unless you meant the Hilary Clinton Secretary of State administration as the analog TV shutdown occurred in the US on June 12, 2009. However lower powered stations were allowed to continue to operate until 2012. You were right that the law was originally passed during the Clinton years in 1996 which called for the shutdown in 2006 but the date was pushed back several times.

    And it wasn't VHF spectrum that was sold off, it was UHF spectrum of channels 52-69.

    And digital TV allows channels to be packed closer together and you can get sub-channels. If you use an OTA tuner you may see that you may have channels like 7-1,7-2, 7-3. That is three channels packed into the frequency that used to hold one channel. And I also believe that with with digital you can use adjacent channels as there isn't as much interference - it used to be that if you used channel 4 for analog TV in a city then you couldn't use channels 3 or 5 as it would cause interference.
     
  9. aburkefl

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    I could be all wet, but I think you have it backwards. Yes, I agree, the "plans" to auction off a bunch of former TV frequencies was hatched during Bill's tenure - yes it was pushed way back.

    Show me I'm wrong, but just because Channel 7-1, and 7-2 are listed, they are (a) NOT on the same channel (b) they're not all broadcasting HD and (c) the majority of HDTV stations today are camped on UHF frequencies, not VHF frequencies. If a station wants to use the frequency that used to be Channel 4 and there's no other station within many miles trying to broadcast on Channel 3 or Channel 5 (just to pick a couple of examples), *then* the station can stay on Channel 4. The frequency separation in the UHF range is far greater (the frequencies are not all contiguous) than it ever was in the VHF spectrum - and there's a lot more of it : 2 - 13 vs 14 - 88. Convince me I'm wrong, but the last time I looked at a chart showing frequency spectrum utilization, that's what I remember seeing. I *was* surprised to find how many stations were still broadcasting using a VHF frequency, but they're not all HD - that's too much bandwidth. Remember, the "old" stations were in a "window" that was essentially 6 MHz wide, so they could comfortably support a 4 MHz wide signal - including stereo audio. With HDTV that's no longer true.

    If the channels were auctioned off, as you state: 52 thru 60, that would have left 14 thru 51 and 61 thru 88 - still a huge chunk of spectrum to handle all the HDTV - and probably many of the soon-to-be 4KTV stations we'll see in the next 10 years.