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Thread: TBS CROSSFIRE with 1.2GHz Video

  1. #11
    Thanks Perna, standing by..

  2. #12
    Navigator Lenin's Avatar
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    I'm reading about the problems with these digital receivers. But, anyone tried with lawmate receivers? I didn't see nothing about this receiver with crossfire...
    Have a nice day!!!

  3. #13
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    Looking at the video at around 0:57, after the notch filter was applied...you can still see interference lines.
    So it seems the notch cuts a lot of the noise, but there's still a repeating pattern.

    Does that really solve the issue, when the Crossfire is still clearly showing interference.
    It would probably be the same result if you removed the notch, and just cut the CF output power a bit during the same test.

    The real world test, would be to add the notch filter and test it out to 1-2miles.
    See how bad those interference lines still affect the VTX.
    I bet the farther you go, the worst it will get. Just like people are currently seeing.

    To really, really, really prove that the notch solution, is The Solution.
    You need to run it in a side-by-side comparison in distance with another radio system either on 2.4 or UHF.

    VTX Test1 - max distance
    -CF on 2W and 1.2Ghx VTX

    VTX Test2 - max distance
    -UHF on 2W and 1.2 VTX

    Sure UHF has more penetration power...but doesn't matter.
    Were looking for close quarters. Same power output would probably be best fair test.

    Anyway...that's my 2 cents.
    I don't have a CF yet. So I can't confirm any of this.
    But I'm watching closely to a solution here, which will determine if I buy one.

  4. #14
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    Quote Originally Posted by Perna View Post
    They specify a range from 900 to 1500MHz. Not sure if this receiver will solve the problem out of the box. Some other people did some tests with this receiver but I don't know the exact results.
    It's quite expensive tho so I would try the filter first.
    I have a YellowJacket and a Crossfire.
    Using a Moxon on the Crossfire (up to 500mw) and a Mad Mushroom on the YellowJacket, I found zero (nadda, nothing) interference when holding the two antennas less than an inch apart. To be honest, when I moved the two antennas close together, I saw a very short (1ms maybe) "flick" in the video, but after that absolutely nothing more.
    I am currently unable to do any real in-air testing to confirm this but I expect similar results. The YellowJacket is a very high quality vRX as many here know and I would expect nothing less than excellent filtering in it by Iftron, the maker.
    Have an extra YellowJacket laying around, if anyone wants, PM me.

  5. #15
    Quote Originally Posted by daBKLYNdoorman View Post
    I have a YellowJacket and a Crossfire.
    Using a Moxon on the Crossfire (up to 500mw) and a Mad Mushroom on the YellowJacket, I found zero (nadda, nothing) interference when holding the two antennas less than an inch apart. To be honest, when I moved the two antennas close together, I saw a very short (1ms maybe) "flick" in the video, but after that absolutely nothing more.
    I am currently unable to do any real in-air testing to confirm this but I expect similar results. The YellowJacket is a very high quality vRX as many here know and I would expect nothing less than excellent filtering in it by Iftron, the maker.
    Have an extra YellowJacket laying around, if anyone wants, PM me.
    You'll have to put some distance between your plane and the video rx. The problem only appears once the vtx signal strength falls, then the xfire transmissions start appearing. I'm currently considering buying your rx anyway - - I love the other features. Just trying to convince myself to throw more money at the problem :/

  6. #16
    Quote Originally Posted by N-Z-N View Post
    Looking at the video at around 0:57, after the notch filter was applied...you can still see interference lines.
    So it seems the notch cuts a lot of the noise, but there's still a repeating pattern.

    Does that really solve the issue, when the Crossfire is still clearly showing interference.
    It would probably be the same result if you removed the notch, and just cut the CF output power a bit during the same test.

    The real world test, would be to add the notch filter and test it out to 1-2miles.
    See how bad those interference lines still affect the VTX.
    I bet the farther you go, the worst it will get. Just like people are currently seeing.

    To really, really, really prove that the notch solution, is The Solution.
    You need to run it in a side-by-side comparison in distance with another radio system either on 2.4 or UHF.

    VTX Test1 - max distance
    -CF on 2W and 1.2Ghx VTX

    VTX Test2 - max distance
    -UHF on 2W and 1.2 VTX

    Sure UHF has more penetration power...but doesn't matter.
    Were looking for close quarters. Same power output would probably be best fair test.

    Anyway...that's my 2 cents.
    I don't have a CF yet. So I can't confirm any of this.
    But I'm watching closely to a solution here, which will determine if I buy one.
    I'm not sure if you really got our test. We put the video link to the range limit ( way further than 1-2miles ). So the receiver was actually seeing a a really weak ( -80 to -90dBm ) signal. The sensitivity of the receiver was before and our testing receiver could receive a video down to -90dBm.
    This notch filter will increase your video range a lot and it's a very simple and cheap fix. I think it will solve the issue quite well. I agree with you there is still some noise - at video range limit, 2W on the Crossfire TX, in very close proximity to the VRx. The test is supposed to simulate extreme conditions, under normal operating conditions the issue is solved. The filter can't do magic so the more you separate or the less TX power you use the less problem you will have. In our test we got rid of all the noise with a separation of 2m. If you go really close you can still see it a little but it can't be compared how the receiver perform without. It will be also different depending on what antenna you put on your video receiver. You can also run two of them in serial. This will give you about -60dBm attenuation and increase the blocking bandwidth, but it will also increase the insertion loss a little.

    Anyway for the power/range rate, we have people flying 20km on 10mW and I bet if you will get one system yourself, you will never give it back
    Last edited by Perna; 16th January 2016 at 07:33 AM.

  7. #17
    Navigator stocki's Avatar
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    Is there an timetable when the notch filter will be available?

  8. #18
    We are getting the parts to build a few on monday. we'll send it to the "usual suspects" here in the forum who are experiencing problems. After that we will make it available immediately.

  9. #19
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    So, I actually was on the right track... #2063

    I guess it's also good to know that my Kaltman spectrum analyzer maybe isn't junk after all... However it still makes me an idiot for not knowing how to use it.


    How much narrower does the receivers bandwidth need to be? I ordered the parts to try to get my receivers bandwidth narrower down to 14-17MHz. Will I need to go any tighter than that from your findings?

    Nevermind; I believe I just found my answer here
    Last edited by Clouseau; 16th January 2016 at 12:11 PM.
    "If it ain't broke, fix it until it is because obviously it doesn't have enough bells and whistles as it is...

  10. #20
    Navigator Killerbean's Avatar
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    Perna and Trappy,

    Really hope this will be the solution, also for the FS nexwave 1.3 receiver i use for short/mid range flight.
    The crossfire is just awesome, the support is amazing.
    Just this little bump to take and you have a winner !

    Hoping that i can test one soon :-)

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