Aircraft Antenna Mod

[beanbubba]

This looks nice. What about thisower Supply Voltage: 3.3-6VDC? What is required to get the voltage from the Mavic/controller lower? How long did shipping take? I just got one of those 8w amps. Gonna try it AC side once I get a connector.

Shipping took a month. Haven't put thought into the power sources yet. Question for you, I just received one of those "8W" amps and they didn't send a power supply and its not listed on the case. Can you share the power supply requirements for this unit?

 

[beanbubba]

Well I couldn't possibly explain it to you, it's just what I heard from a self-proclaimed expert. I'm no antenna expert I'm just a dirtybum that likes to fly silly toys out long distances[emoji41]

And don't forget only in straight lines

 

[mnoutdoors]

Shipping took a month. Haven't put thought into the power sources yet. Question for you, I just received one of those "8W" amps and they didn't send a power supply and its not listed on the case. Can you share the power supply requirements for this unit?

The ones I use are 6-16V

 

[beanbubba]

I have been delayed publishing a new Mavic radio observation video because my spectrum analyzer traffic generator has a peak output of 0 dBm and all the amplifiers we have under test have a minimum input trigger of 3-5 dBm. So I ordered a 20 dBm continuous carrier amp from china that took a month to arrive.

Anyway, the new video version 3.0 is now published and gives great insight that we have not seen before and only previously speculated on the facts. Nothing surprising except for the "8W" amp recently introduced to the forum. It greatly underperformed in TX gain, but was extraordinary with RX gain. This was not expected at all. I triple ran the tests to make sure and this really puts a new wrinkle on overall radio system performance.

I have a couple more significant items to test and will post upcoming videos soon. But the amp comparison video was a long awaited item and I hope you find it insightful and beneficial to your mod's.

@beanbubba


Updates can be found in this thread:

Mavic Radio Mods Primer

 

[beanbubba]

View attachment 34187 View attachment 34188 View attachment 34189 View attachment 34190

Well my calculations were off. Won't fit on the nose. Moved it onto the battery temporarily for testing. Wish me luck!

I hope you can make it work up top, I was never successful and had to move to the side to keep the GPS from being interfered with.

Good luck!

 

[lolo780]

The GPS interference seems to have more to do with antenna position. I think amp up top connected to antenna down below should be alright.

 

[dirtybum]

The GPS interference seems to have more to do with antenna position. I think amp up top connected to antenna down below should be alright.

Yeah like drop it way down, you'll get no interference[emoji41]

 

[beanbubba]

Oh yeah. Also I was hovering it in my office just now and it was interfering with my Bluetooth mouse. I had seen that before when having the Mavic on my desk and turned on somewhat near the mouse but this was with it nowhere near it. Is it just the noise being thrown off by this amp or is it the signal strength? Maybe the noise is messing up the Mavics ability to receive the RC signal at distance?

When I am bench testing, my Mac trackpad goes crazy. It's about 5 feet from my bench. That's normal up close like this.

 

[beanbubba]

Oh yeah. Also I was hovering it in my office just now and it was interfering with my Bluetooth mouse. I had seen that before when having the Mavic on my desk and turned on somewhat near the mouse but this was with it nowhere near it. Is it just the noise being thrown off by this amp or is it the signal strength? Maybe the noise is messing up the Mavics ability to receive the RC signal at distance?

Wait, was your RC close to the mouse?

 

[beanbubba]

Uggg, I recently had a hard landing with this bird and broke the front rotor arm. I repaired it and took it out for a test flight and it went goofy on me and I lost all controls excepts for up/down and maybe 3 mph lateral movement. I managed to set her down on the ground but wondering if anyone sees any pattern in this airdata link for possible repair options:

Airdata UAV - Flight Data Analysis for Drones

 

[mnoutdoors]

One thing that seemed odd was your voltages would go down then up then down then up ( something shorting )

 

[beanbubba]

One thing that seemed odd was your voltages would go down then up then down then up ( something shorting )

Good point, let me go over the bird with a fine tooth comb and see if anything came loose and is shorting after that last crash.

 

[beanbubba]

I finally got around to modding the dragon amp for bird side flight and epoxy'd a heatsink on the radio chips. It's actually a chunk off a mavic bottom plate and works quite well!

 

[beanbubba]

I finished the build for the bird side RX-only port with continuous carrier amp and DC step down converter. Will start testing soon and look forward to seeing what happens.

This is pictured along with the bird side dragon amp on the TX/RX-combo port.

 

[beanbubba]

I have been buying every antenna I could find for possible bird side upgrades. Nothing has proved better than the mavic factory antenna until today.

I stumbled upon this unit and initial tests are strong and out performing the factory antennas.

More testing is needed, but this is the first time ever I found a possible alternative.

 

[mnoutdoors]

Have you tested this one? I have some on the way
4pcs 700-2600Mhz 4G Internal Antenna 5db SMA Male RF Connector cable RG316 10cm | eBay

 

[beanbubba]

Have you tested this one? I have some on the way
4pcs 700-2600Mhz 4G Internal Antenna 5db SMA Male RF Connector cable RG316 10cm | eBay

I have not, but one is on order now! Thx.

 

[fileophile]

What are the best tools to use for terminating these tiny Mavic antenna co-ax cables? I've successfully separated and soldered the shield and line connections to a factory Mavic antenna, but it was a pain trying to strip the insulation back and avoid soldering one big blob. I had to work under magnification. Is there are tool out there that makes this job easier?

 

[fileophile]

Another question: Are you guys sticking with the 2.4GHz Mavic transmission/reception frequency, or are you bumping up to 2.5 or down to 2.3 per the configuration files to try and get to a less-congested space?

 

[beanbubba]

Another question: Are you guys sticking with the 2.4GHz Mavic transmission/reception frequency, or are you bumping up to 2.5 or down to 2.3 per the configuration files to try and get to a less-congested space?

That space is super clean and lightly used. Technically, in the US you must have a HAM license to operate in those bands. I just completed a video yesterday that compares the different mod options including the 2.3/2.5 solution.

EDIT: take note that the RC stays in 2.4 and only the AC will move to 2.3/2.5. And the AC is not boosted. only the RC.

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