This is a short review of the Feelworld FPV-720 monitor with dual diversity receiver. I’m mostly comparing it to the popular Flysight Black Pearl, which is the same size and about the same price. After reading a favorable review (in German) of the FPV-718, which concluded that the FPV-718 beats the Black Pearl, I was curious to see how the FPV-720 would compare.
The FPV-720 is a new 7″ monitor that, at least on paper, looks to be an improvement over the FPV-718:
|Viewing Angle||75° left/right/down, 70° up||85° left/right/up/down|
I ordered mine from Feelworld Germany, which is the only distributor in Germany at the moment (October 2015). It came in a box apparently designed for the FPV-718. The foam doesn’t quite fit the antenna ports of the FPV-720, which seems a bit unprofessional.
The box contains:
- The monitor.
- Two long (17cm) linear antennas.
- An AC power supply.
- A sunshade consisting of two parts: A small frame that is attached to the monitor, and the actual cover that is velcroed on the frame (the velcro is already in place).
- A 2S 2200mAh LiPo battery that must be installed by unscrewing a cover on the back.
- No manual, not even on the website.
The battery is about 98x99x4 mm in size.
There are only two wires so it won’t be balance charged. It is shipped unprotected and mine had an imprint of its connector on one side.
The monitor uses RP-SMA connectors (i.e. pin on the monitor, hole on the antenna) and weighs 555g with the sunshade, 493g without.
The menu is very basic and allows to set the following parameters:
- Display ratio (16:9 or 4:3)
- Video system: NTSC M, PAL M, NTSC BG, PAL N, NTSC DK, PAL DK, PAL I, SECAM BG („PAL I“ is what turned out to work with the PAL setting on my Möbius)
- OSD transparancy, timeout and position
The monitor can be powered from an external source, but you’ll have to buy or build the required cable yourself since none is supplied.
Inputs can be selected using the back arrow key (hey, I figured that out without a manual), holding CH enters channel selection mode where the BAND key selects the band. Short press on CH or BAND adjusts the audio volume.
Pressing the magnifying glass key starts a channel scan. I’m not sure this feature is useful; I’d be concerned that it finds an adjacent channel that, at close proximity, has good reception but will degrade once the model gets away. Also, the scan can take a little while. Setting the channel manually is safer and often faster.
There is no indication of RSSI or, more importantly, which of the two receivers is currently active. You might have a defective antenna or receiver and not notice that the monitor always uses the other antenna/receiver. Or you might be using an omnidirectional and a directional (patch/helix) antenna, in which case you’ll want to realign the directional antenna towards the model when the monitor switches to the other receiver. But this is not possible since you never know which receiver is active. This is a major drawback.
For this test I used an ImmersionRC 25mW transmitter and a Möbius C2 camera (firmware 2.41). The Möbius needs to be set to 4:3 for the image to fit the 16:9 screen. When it’s actually set to 16:9 there are black bars at the top and bottom. This is the same with my Black Pearl monitor, so presumably it’s a bug in the Möbius.
Image quality is somewhat disappointing. With the standard settings the image is overexposed and slightly blurry. The colors are way too strong. Tuning saturation and brightness helps a bit, but to me the image always seemed either too pale or too reddish. I found no way to fix the blurriness.
Here’s a comparison with the Black Pearl (photos taken with identical camera settings).
I like the Black Pearl better because the colors are more natural and sharpness is better. Compare e.g. the bubble foil in the lower left corner or the bar code on the nVision box to the right of it. The Black Pearl also has more settings to tweak the image to your preferences (such as sharpening, color temperature and noise reduction).
I didn’t notice any differences in viewing angle. Both screens perform well in this regard.
Brightness is specified at 600cd, but to my eye it’s pretty much the same as the Black Pearl, which has 300cd according to specs. It is certainly not “twice as bright” (photos taken with identical camera settings):
This is 100% brightness on the FPV-720, but around 80% on the Black Pearl since at 100% its image is almost entirely white. The FPV-720 has a slightly “whiter” image, but at the expense of contrast and details.
At one point the FPV-720 was showing some ghosting (look at the head of the white astronaut, or the USB cable plugged into the screen):
The Black Pearl receiving the same signal at the same time, placed right next to it, shows no ghosting:
The ghosting disappeared after power cycling, but it did nothing to improve my confidence in the FPV-720 since the problem was clearly in the monitor.
I tested reception quality indoors through some walls and a ceiling, using the provided linear antennas. It is pretty much the same as the Black Pearl.
In direct comparison, which seems fair given that both screens are about the same price, the Black Pearl wins:
- Indicates active receiver.
- Better image quality.
- More image parameters to be set.
- Easily exchangeable battery (mine came with two batteries).
- Better sunshade, folds flat to protect the screen.
- Slightly better build quality.
- More accessories in the box.
The FPV-720 does have two advantages:
- Can be charged on 12V (the Black Pearl needs a bit over 12.6V for its 3S battery, but is shipped with a 12V power supply that actually can’t fully charge it).
- Four bands (A/B/E/F; the version of the Black Pearl sold in Germany only supports the F band).
I like the Black Pearl a lot better. Although it’s silly that it cannot be charged with its own power supply, at home I have a 15V power supply and at the field I can use the second battery and don’t have to charge at all. A/B/E bands would have been nice, but almost all transmitters support the F band anyway, so this would only be an issue when flying with many people at the same time, all in the F band.
These are just minor drawbacks (at least for me), whereas the advantages the Black Pearl has over the FPV-720 are significant, and in case of the active receiver indication even essential.