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Adjacent Channel Rejection Test
🕑 Added 2017-05-04 01:35:36 +0000 UTC Today I did a test of the ability of True-D and LaForge to reject signal from an adjacent channel. I set both modules on 5740 MHz, then I set a copter transmitting at 5740 MHz down, 200' away. Then I powered up a copter transmitting at 5760 MHz, and I walked towards the receivers to find the distance where interference became visible. As I walked closer, interference got worse, and I was able to compare which module handled the interference better.This is raw video from the test. Here is a write-up of the test, with time stamps to relevant parts.
Setup: both copters @ 25 mW. X-Air 10 dBi crosshair and TBS Triumph on both modules. One copter on 5740 MHz, one on 5760 MHz.
LaForge on left screen, True-D on right screen.
4:37 - Set 5740 MHz down at 250'. Because the copter is on the ground and because of the lay of the land, signal is slightly breaking up at this distance.
5:37 - Set 5740 MHz down at 200'. Signal is solid to both RX.
6:06 - Power up 5760 MHz. Begin walking towards RX, watching for the beginnings of breakup to occur.
7:01 - First sign of interference begins to occur on both modules.
7:28 - Stop and stand at a distance of 40', which is where clear interference was definitely visible on both modules.
8:07 - Walk to a distance of 30' and stand.
8:22 - Hold the transmitting copter higher in the air to make it more visible to the RX.
8:39 - Walk to a distance of 20' and stand.
9:18 - Set 5760 MHz down on the ground and walk to the RX to swap antennas. When the TX is on the ground, interference mostly goes away on both RX modules.
10:11 - Swap antennas between modules to rule out the antennas as a causal factor.
11:24 - Pick up 5760 MHz from the ground.
11:50 - I say, "The right hand one is still worse. The LaForge is still worse." This is a mistake. I mis-spoke in the moment. The right-hand one is definitely True-D, not LaForge.
12:01 - I walk away, looking for the farthest-away point where any interference is observed. This is determined to be 120'.
Comments
Joshua Bardwell
True-D is running a 5808 as far as I know. But given Furious's history with hardware engineering, I'm surprised they haven't developed their own module yet.
But which one is better? J/k. If nothing else they hav different software which can be a huge differentiator.
We interviewed Bruce and Shea a little while ago on FPV Life. I believe the guys said that the RX module is built from the ground up .. and isn't just a 5808 module that you can buy from bang good. I am not sure what True-D is running though.
Joshua Bardwell
Try this. <a href="https://1drv.ms/v/s!Al4b3QGPtgasl-UZf1XuK_-oT9ovrg" rel="nofollow noopener" target="_blank">https://1drv.ms/v/s!Al4b3QGPtgasl-UZf1XuK_-oT9ovrg</a>
Very interesting...looks like Laforge has something else under the hood.
I can't get the video to work
