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antenna unless it's in micro-power mode, given the nature of the problem I discovered, it means I have several times had the Tx powered up at full power, with no center connection to the antenna at all. Seems to have held up ok so far. BTW, was trying to repair one of my Rx antennas last night, and twice snapped off the center conductor immediately after re-soldering it. It's really thin fragile coax, and it's the same stuff used inside the Tx, who's center conductor has to support the center receptacle of the female SMA connector. ian |
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Latest blog entry: My 2012 FPV year in Review
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Did you try powering your buddy's Rx with the same power source you're using for yours, and power yours from his? If so, then it's broken, send it back. ian |
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Latest blog entry: My 2012 FPV year in Review
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The reflected power due to impedance mismatch (antenna disconnect) doesn't necessarily cause catastrophic failure. In fact, most often it is graceful degradation, unless you let it cook for an extended period. Steven |
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http://www.rcgroups.com/forums/showp...postcount=1074 |
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Maybe so. It should resolve the issue. Is probably why he switched.
ian |
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Latest blog entry: My 2012 FPV year in Review
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....what is the difference between RangeLink and DragonLink?sorry to ask because I'm looking for a new UHF system.... I'm sick of my ImmersionRC EzUHF going into failsafe without me understanding why.... I want something reliable and simple to hookup. My friend has DragonLink v.2 so I pretty much know the basics of his.... I'm using 1.2ghz for video, so I hope RL has a filter built in..... Please convince me to buy RL ($185 vs $270)..... thank you for your experiences'
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DLv2 pretty much adopted all the features RL already had (power switch, micro power mode,
indicator light on the Rx, headtracker port, plug-n-play with trainer port, firmware upgradeable, etc). I can't think of really any significant difference now. RL has multi-master mode (two Tx can control one Rx), and I don't know if DL has that yet. RL has decent filtering, although DL has been at it a bit longer, so they likely have same or better. Something to consider though, is that no matter what UHF system you choose, there are still components that can spew so much UHF noise that they'll render them unusable. Sometimes you can resolve it with increased separation. Sometimes you just have to isolate those components through micro-power range tests, and then eliminate them from your platform. ian |
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Latest blog entry: My 2012 FPV year in Review
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ezUHF, DLv2, and RL all have some sort of micro power mode, which causes
the transmitter to output somewhere between 1-20mW. It's used for comparative range testing. You first put the Tx into micro-power mode (refer to appropriate manual), and then power up the Rx alone with just a 4-5cell NiMh or a trusted low noise BEC (like Turnigy 3-5A model). Attach a servo to the Rx, and set the failsafe position to something other than center. Set the Tx on something at about the height you'd hold it, and then walk away with the Rx until the servo jumps to failsafe position. Try different antenna orientations and such to establish the near and far end of your failsafe range. Most UHF Rxs have some sort of link status light these days so you can also watch that to get some indication of the quality of the signal. The light will usually start indicating loss of packets before it jumps to full failsafe. If your Tx has the option to cycle all the channels, then put it in that mode, and watch the servo. When it stops moving smoothly, you know you're dropping packets. That establishes your baseline range. Now put the Rx in your aircraft, and start powering up other components progressively (just ESC and servos first.. then FPV video Tx, then video camera, GoPro or other HD camera.. etc) For each new thing you power up, perform the range test again. If you've got an Rf noisy component you should see your range drop fairly dramatically. If in the end with everything powered up, you've cut your micro-power range down by more than about 20-25%, you should really isolate or eliminate the noisy component. The worst offenders will cut your range by more than 50%. Over the years, I've personally had Rf noise issues with various flight cameras, some switching voltage regulators, a popular brand current sensor (same one you may have), the GoPro, and a video Tx. Others have reported issues with certain multi-rotor flight controllers and so forth. You have to treat *every* component on the plane as a potential source of UHF noise and test accordingly. Any time you add something new, test the micro-power range again. Note: ezUHF's micro-power mode is 20mW which may be too much power to walk to the edge of range. May have to drive. Alternately you can add a -20dB attenuator on the Tx side to cut the radiated power down to the level you can drive. Another trick is simply to place the whole radio and Tx inside a microwave oven. It'll cut even full power down to walking range. ian |
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Latest blog entry: My 2012 FPV year in Review
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