FPVLR VS. DBS
- Thread starter Sammynels
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On a separate note...
Has anyone tried a combination of Patch/Linear and RHP antennas?
Aka, half Itelite & half FPVLR?
One radio channel on each?
Has anyone tried a combination of Patch/Linear and RHP antennas?
Aka, half Itelite & half FPVLR?
One radio channel on each?
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i would place the amps away from your antenna I'd say your getting cross channel talk check on healthydrones if your getting lots of signal errors and that will be the culrpit.
Personally, it doesn't really look that great to me, but I'm far from an RF expert.
If anything, it looks like the amps are touching the ground plane of the antenna and possibly touching each other via that same ground plane.
The amps themselves are very close to the antenna and it looks like your output cables from the amp to the antenna could easily get bent every time you put the controller down.
Bends in RF cables are bad.
Also, it looks like you're not attenuating the signal from the controller into the amps.
Double check the specifications from your exact model amps, but I bet you're feeding more input power into them then they are designed to handle. Even if the controller uses variable power output (which, given my own signal analysis, I don't think it does), it will still drive up the output power as signal quality decreases. Aka, you're probably pushing >20 dBm into the amps, while I bet their recommended input power is 0-20 dBm. Yes.... on the DJI website it states the controller output power as exactly 20 dBm, but I have a suspicion it's actually quite a bit more.
If you push more power in than the amps want, prepare for poor signal quality.
Think of two people talking in a crowded room. More RF power means talking "louder". RF signal quality is how much "annunciation" each person is using.
Yelling at someone while slurring your words ain't likely to help the other person understand.
I'll post my setup pics later, but I mounted my amps to the back of the tablet holder and tried to keep each channel as isolate as possible, from my wiring within the controller, to the amps, to the antenna itself.
Good luck!
I'm curious if you ever flew the same flight route with a WindSurfer antenna prior to the setup you are using now? And if so, what altitude were you flying at, and what was the distance achieved with the WindSurfer antenna?David W's WindSufer I took off around 90% battery and flew to the point the warning box appeared saying to be safe it would RTH in X number of seconds. When this appeared I still had full bar reception on both WiFi and HD.
Guys,
I thought I'd offer some feedback based on my personal experiences using these three popular P3 antenna mods. I own and have flown all three antennas in Silicon Valley in an area with a high and concentrated RF noise floor. As always, YMMV:
The Windsurfer from David W (dwet6162 on eBay) $30
DBS Mods' ITELITE antenna $109
FPVLR Advanced v2 antenna with amplifiers $299
David's Windsurfer is the best bang for the buck for solid range of 2 miles. No physical mods required to your controller. I like the "two piece" version which fits easily in my Chinese cheapo P3 backpack.
A group of us started flying with David's antenna and we all got into the 12K' club pretty easily. There are a bunch if Chinese versions of this antenna. From what I've seen David's production values are still the best.
The DBS Mods ITELITE antenna has a very clever quick on / off mounting system that is very well engineered and constructed.
My distance limit with this antenna seems to be just at 3 miles.
The controller mod is easier than it looks and the new shorter cables make the "over the gimbal" wire routing a snap. The quick on / off mount allows me to disassemble the antenna from the mount and pack everything away in my P3 backpack.
I consider the FPVLR advanced kit with the v2 antenna the best long range system for my personal flying environment. I can fly past 3 miles without any loss of signal on either the controller link or the video link. As others have stated, with this system the practical limiting factor is the battery capacity of the P3.
About 17,600' is my practical outbound limit if you want to get home with 8-10% battery remaining. Maybe 18K' in absolutely ideal conditions. The FPVLR advanced antenna kit is not really an easy on / off mod as there is just more stuff involved. For me, this is not a big deal, though it is a consideration.
I have not tested the FPVLR v2 antenna without the amps, but I would expect that it would compare to the DBS Mods antenna.
The internal wiring mod for the FPVLR antenna is identical to what is required for use with the DBS Mods antenna, so if you have the wiring mod completed you can switch from one antenna to another.
All the vendors I have mentioned are US based and stand behind their products so you can buy with confidence.
If you are just experimenting with long range FPV flying with your P3 then start with a Windsurfer and go from there.
A word of caution...long distance FPV flying is thrilling. Know your aircraft's limitations and you personal limitations and stay within each. Safety first - Always.
:harry
I thought I'd offer some feedback based on my personal experiences using these three popular P3 antenna mods. I own and have flown all three antennas in Silicon Valley in an area with a high and concentrated RF noise floor. As always, YMMV:
The Windsurfer from David W (dwet6162 on eBay) $30
DBS Mods' ITELITE antenna $109
FPVLR Advanced v2 antenna with amplifiers $299
David's Windsurfer is the best bang for the buck for solid range of 2 miles. No physical mods required to your controller. I like the "two piece" version which fits easily in my Chinese cheapo P3 backpack.
A group of us started flying with David's antenna and we all got into the 12K' club pretty easily. There are a bunch if Chinese versions of this antenna. From what I've seen David's production values are still the best.
The DBS Mods ITELITE antenna has a very clever quick on / off mounting system that is very well engineered and constructed.
My distance limit with this antenna seems to be just at 3 miles.
The controller mod is easier than it looks and the new shorter cables make the "over the gimbal" wire routing a snap. The quick on / off mount allows me to disassemble the antenna from the mount and pack everything away in my P3 backpack.
I consider the FPVLR advanced kit with the v2 antenna the best long range system for my personal flying environment. I can fly past 3 miles without any loss of signal on either the controller link or the video link. As others have stated, with this system the practical limiting factor is the battery capacity of the P3.
About 17,600' is my practical outbound limit if you want to get home with 8-10% battery remaining. Maybe 18K' in absolutely ideal conditions. The FPVLR advanced antenna kit is not really an easy on / off mod as there is just more stuff involved. For me, this is not a big deal, though it is a consideration.
I have not tested the FPVLR v2 antenna without the amps, but I would expect that it would compare to the DBS Mods antenna.
The internal wiring mod for the FPVLR antenna is identical to what is required for use with the DBS Mods antenna, so if you have the wiring mod completed you can switch from one antenna to another.
All the vendors I have mentioned are US based and stand behind their products so you can buy with confidence.
If you are just experimenting with long range FPV flying with your P3 then start with a Windsurfer and go from there.
A word of caution...long distance FPV flying is thrilling. Know your aircraft's limitations and you personal limitations and stay within each. Safety first - Always.
:harry
Last edited:
Harry, were you able to get the 2-3 mile range with the Windsurfer/DBS in any direction from where you flew?
I can get 3 miles with both the Windsurfer/DBS but only in a certain direction (NE of my location). All other directions and the signal craps out 1-2 miles out.
I hear all this talk about these amps to boost penetration performance, will these only work on the FPVLR antennas or can I get them for the DBS?
Not really a good comparison. You can't compare one antenna with amps such as the fpvlr advanced with an unboosted dbs itelite antenna. For comparison value you should take the amps off if the fpvlr antenna and test it and then put amps on the dbs itelite antenna and test it.
I have had similar experiences...as I fly more long distance flights I find that it's easy to encounter environmental factors that contribute to signal break up and loss. Spurious RF, physical objects reflecting your signal, etc. These can be anywhere, though I find that these "interference anomalies" tend to persist over time.
There is a specific spot on one of my favorite routes where video break up is pretty common on most, but not all weekend days. At this particular spot we have learned that you can fly through the break up and keep going for a pretty fair distance. The decision to fly through interference needs to be made carefully. Be sure your RTH is set up correctly just in case the signal loss is protracted and the RTH feature is triggered.
Fly safe.
:harry
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Thanks for the response. I'm not to worried about the output 20dBm from the controller. The FPVLR version of the amps are rated the same and they don't use a power reducer (I have not read any comments about failed boosters). I will try taking the boosters off the antenna and mounting them away from the antenna. I didn't get great range with the stock antennas either. With the same flight and with the stock antennas I was getting about 2500ft, so the DBS Mod did increase the distance to 7500ft.
Thanks for the response.
So, technically speaking, why shouldn't one use a mix of antenna types? Aka, half linear half circular polarized?
N017RW
Premium Pilot
Polarization has to do with the way the signal is transmitted.
Below is an excerpt from this page:
Antenna Polarization Vertical Horizontal Circular Polarization | ASTRON WIRELESS
Polarization is an important design consideration. The polarization of each antenna in a system should be properly aligned. Maximum signal strength between stations occurs when both stations are using identical polarization.
When choosing an antenna, it is an important consideration as to whether the polarization is linear or elliptical. If the polarization is linear, is it vertical or horizontal? If circular, is it RHC or LHC?
On line-of-sight (LOS) paths, it is most important that the polarization of the antennas at both ends of the path use the same polarization. In a linearly polarized system, a misalignment of polarization of 45 degrees will degrade the signal up to 3 dB and if misaligned 90 degrees the attenuation can be 20 dB or more. Likewise, in a circular polarized system, both antennas must have the same sense. If not, an additional loss of 20 dB or more will be incurred.
Also note that linearly polarized antennas will work with circularly polarized antennas and vice versa. However, there will be up to a 3 dB loss in signal strength. In weak signal situations, this loss of signal may impair communications.
Below is an excerpt from this page:
Antenna Polarization Vertical Horizontal Circular Polarization | ASTRON WIRELESS
Polarization is an important design consideration. The polarization of each antenna in a system should be properly aligned. Maximum signal strength between stations occurs when both stations are using identical polarization.
When choosing an antenna, it is an important consideration as to whether the polarization is linear or elliptical. If the polarization is linear, is it vertical or horizontal? If circular, is it RHC or LHC?
On line-of-sight (LOS) paths, it is most important that the polarization of the antennas at both ends of the path use the same polarization. In a linearly polarized system, a misalignment of polarization of 45 degrees will degrade the signal up to 3 dB and if misaligned 90 degrees the attenuation can be 20 dB or more. Likewise, in a circular polarized system, both antennas must have the same sense. If not, an additional loss of 20 dB or more will be incurred.
Also note that linearly polarized antennas will work with circularly polarized antennas and vice versa. However, there will be up to a 3 dB loss in signal strength. In weak signal situations, this loss of signal may impair communications.
