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Old Sep 22, 2012, 09:37 PM
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my rangelink receiver turns off after about 5 minutes everytme I try and turn it on to test it . Me and a friend both bought rangelinks and we tried binding both receivers to the same transmitter separately and my one turns off after 5 minutes everytime even after walking away 2 blocks with the transmitter turned on and getting good signal then a few feet away when I returned the receiver turned off ( red light goes out and no movement on servo ) . The other receiver binded to the same transmitter never turns off and seems to be getting good range. My o ne seems to get OK range when its on but it shuts off and I dont know what to do or whats wrong
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Old Sep 22, 2012, 09:46 PM
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Lakewood, Colorado
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Quote:
Originally Posted by CN I Dawg View Post
Just a cautionary note, if you test for an intermittent connection, be sure to use micro mode, as did Ian. Otherwise, you may damage your Power Amp. Probably the visual inspection would be the first choice detection method.
Steven
While I certainly agree in principle and recommend that one should never remove the Tx
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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Old Sep 22, 2012, 09:47 PM
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Quote:
Originally Posted by Steve34 View Post
my rangelink receiver turns off after about 5 minutes everytme I try and turn it on to test it . Me and a friend both bought rangelinks and we tried binding both receivers to the same transmitter separately and my one turns off after 5 minutes everytime even after walking away 2 blocks with the transmitter turned on and getting good signal then a few feet away when I returned the receiver turned off ( red light goes out and no movement on servo ) . The other receiver binded to the same transmitter never turns off and seems to be getting good range. My o ne seems to get OK range when its on but it shuts off and I dont know what to do or whats wrong
Not to put too fine a point on it, but it sounds defective.
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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Old Sep 22, 2012, 10:16 PM
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Quote:
Originally Posted by Daemon View Post
Not to put too fine a point on it, but it sounds defective.
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
yup we used the same battery for the test on both

I guess need to send it back . I must be cursed or something . I had to send my fatshark goggles back when I bought those too because they were defective aswell . Seems cant seem to get stuff that works the first time. Im cursed !
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Old Sep 22, 2012, 10:19 PM
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It is a dipole, yes. You should have the antenna pointing straight up, and make sure to put the ground element down, the active element up, when mounting the RX dipole on the plane.
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Old Sep 23, 2012, 08:40 AM
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Quote:
Originally Posted by Daemon View Post
While I certainly agree in principle and recommend that one should never remove the Tx
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
I haven't opened my Tx yet to completely relate to what you guys are talking about but would a replacement like this work for a more robust solution? http://www.mouser.com/Search/Product...ocN43sQQ%3D%3D From your description, the fix is a bit dicey. Sid did mention a connector change on new Tx's maybe this is part of the reason. http://www.rcgroups.com/forums/showp...postcount=1074

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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Old Sep 23, 2012, 11:40 AM
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Quote:
Originally Posted by CN I Dawg View Post
I haven't opened my Tx yet to completely relate to what you guys are talking about but would a replacement like this work for a more robust solution? http://www.mouser.com/Search/Product...ocN43sQQ%3D%3D From your description, the fix is a bit dicey. Sid did mention a connector change on new Tx's maybe this is part of the reason. http://www.rcgroups.com/forums/showp...postcount=1074

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
we should be able to buy this connector from sid ?
http://www.rcgroups.com/forums/showp...postcount=1074
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Old Sep 23, 2012, 12:33 PM
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Maybe so. It should resolve the issue. Is probably why he switched.

ian
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Old Sep 23, 2012, 02:09 PM
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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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Old Sep 23, 2012, 03:17 PM
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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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Old Sep 23, 2012, 03:31 PM
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Sometimes you just
have to isolate those components through micro-power range tests


what is that?
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Old Sep 23, 2012, 03:53 PM
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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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Old Sep 23, 2012, 04:43 PM
Chris R
United Kingdom
Joined Dec 2009
713 Posts
Flown with Rangelink @ 200mw

4832m 15853ft Very high altitude with RC Plane FPV (9 min 44 sec)
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Old Sep 23, 2012, 08:13 PM
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Quote:
Originally Posted by snelan View Post
It is a dipole, yes. You should have the antenna pointing straight up, and make sure to put the ground element down, the active element up, when mounting the RX dipole on the plane.
This may sound like a dumb question but how can I tell the difference between the two ends ?
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Old Sep 23, 2012, 09:15 PM
Opt
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New Zealand, Auckland
Joined Oct 2010
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Without cutting off the heashrink - use a multimeter to see which element is connected to what on the sma connector
i.e. outside of sma connector is ground
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