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Thread: Red-Headed Step Child that is 900mhz

  1. #1
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    Red-Headed Step Child that is 900mhz

    Hey Guys,

    What happened to 900mhz?

    I'm in my third year of flying FPV with 3 rigs that get used pretty much every weekend in the early mornings (weather and little league schedules permitting). Everything I have is setup for 900mhz. I have cloverleafs on all my planes (and a quad), have a big 900mhz canon...errrr helical on ground station with tracking and an SPW on diversity on the same tracker (more as a failsafe while I'm flying in close).

    Though I have a ton of time with this setup, nothing is perfect and I'm always looking to improve.

    However, all the innovative antennas appear to be on every frequency but 900mhz. Mad Mushroom, Sky Hammer (great name by the way, Alex), Pepperbox, etc. 900mhz has been pretty good to me and the switch from Alex's Vee to one of the first Cloverleafs was nothing short of magical back in the day. The antennas at 900mhz are bigger and relatively easy to assemble (though more difficult to mount on smaller planes). Penetration seems to be nothing short of fantastic when flying low and behind trees and such. And not least of all, it's going to be some bucks and major aggravation to switch everything to a new frequency.

    Is there something I'm missing about 900mhz? Is there some reason why new antennas at that frequency aren't being produced?

    In short, do I need to bite the bullet and switch frequencies before my equipment goes the way of the dinosaurs?

    - Bill

  2. #2
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    I'm running linear 900 on my quad... I think the big issue for most people is antenna size. The CP antennas are prohibitively large, to the point where I don't think it would fit on my quad. On a plane its less of a problem, obviously.

    I actually really like the frequency though, particularly the large fresnel zone and the fact it doesn't lie in a UHF harmonic (unlike 1.3).
    Last edited by CodingTom; 7th February 2013 at 03:46 PM.

  3. #3
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    I still use 900 as well; it works great. I have yet to find the limits of my dipole/patch combo so i've had no reason to upgrade anything.

    I think part of the reason people dont innovate for 910 is antenna sizes and the fact that it is a very crowded ism band. It works great if you find a quiet place to fly, but finding the quiet place can be tricky, especially in urban environments.
    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
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    Working on it... I have been planning a BluBeam Utra set for 910MHz. The problem is that the antenna is so big it needs a big stiff cable to support it. I found one the works, though, so the guy who is going to build it is coming over today to start the first batch.

    I also already drew up the files for the laser cutting of the formers for a 910MHz Crosshair.

    It's coming. Give me some time.

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

    [url]videoaerialsystems.com[/url] - Performance video piloting

  5. #5
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    We fly with 5.8, 1.3 and 900 in our group and 900 works great as an added freq band so we can all fly together! The antenna are big, but the freq is low and penetrates well.
    EchelonFPV - Team Based FPV & Formation Flying
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    TonkaSummit - The Best Ground Vehicle in FPV!

  6. #6
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    The fact that mobile (cell) phone networks use it in Europe might be a factor for companies like IRC not adopting it. I suppose that has a knock on effect, worldwide, for antenna production etc.
    Get out there and give it all you've got, and win just one for the Zipper.

  7. #7
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    Actually, the band is dying. With the need for more data transfer, 900MHz can't hold up and every day it becomes more quiet!

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

    [url]videoaerialsystems.com[/url] - Performance video piloting

  8. #8
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    Alex,

    How big the crosshair will be when compared to the 1.3GHz one. I use 900 MHz but still not that long range yet.
    I have Sircana SPW 900 and that are huge but a piece of art. Do you reckon that bluebeam ultra would bet Sircana SPW on 900 ??
    Thanks.

  9. #9
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    Quote Originally Posted by IBCrazy View Post
    Actually, the band is dying. With the need for more data transfer, 900MHz can't hold up and every day it becomes more quiet!

    -Alex
    Not necessarily.. i'm finding more and more zigbee networks (802.15.4) that use 900, but thankfully most all of those are close range PAN's that are typically indoors. In this area we have a LOT of traffic management systems that use it, mostly for traffic light signaling, and thats why it only works well for me when i'm away from heavily populated roadways.

    It's dying off for long range stuff, thankfully, but the close range stuff seems to be more prevalent. I do think it'd be funny to walk into a major retailer and tell them they need to shut down their zigbee network because it's interfering with my licensed use of the band heh.
    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.

  10. #10
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    I fly 900mhz on my Slow Stick, using a CL and a Helical (both made by IBCrazy). I love it! Very quiet band where I live. The Slow Stick flies so slow, the big CL doesn't really matter to it.
    [FONT=Segoe UI]Regarding "some" peoples thoughts about Trappy and the FAA and "the sky is falling":[/FONT]
    [FONT=Segoe UI][/FONT]
    [FONT=Segoe UI]"Perspective. Time to recognize the root cause and not focus exclusively on a single case."

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