# Tag Info

22

Short answer: Yes, this is very much true. The VTX sends out radio-frequency (RF) energy through the antenna connector and pigtail, and if nothing (or the wrong thing) is connected at the other end, all the energy gets reflected back and could damage your VTX (or just heat it up). Long answer: At high frequencies a thing called "impedance matching" becomes ...

9

Your VTX is a high-power RF transmitter. When operating with an antenna, the RF power of the transmitter is radiated out through the antenna. When the antenna is missing, the RF power is reflected from an unterminated antenna port back into the transmitter. This reflected RF energy will be dissipated as heat (best case scenario), or damage/destroy your ...

8

No, you do not require an Amateur licence to use this equipment. Most RC equipment that operates at 5.8GHz (or 2.4GHz) makes use of what is known as an ISM band, a series of frequencies made available for anyone to use (historically for Industrial, Scientific and Medical purposes) subject to certain restrictions - such as transmitter power. These ...

7

You have a few options. One is to switch to a digital video system such as the fat shark bytefrost and do something like this to convert the video to a format compatible with your laptop. Essentially the above link documents how to convert a digital FPV feed into your laptop for doing low latency video calling, but you don't have to do the video calling part....

7

I'm going to give you the answer first: Yes, it is worth calculating the approximate range if you're building a (very) long-range aircraft. However, theoretical calculations will usually be such a crude approximation of reality that you can't rely on them, and the actual maximum range will depend on a myriad of factors besides what you can consider in the ...

6

This sounds like a loose video wire from your camera to your flight controller. Since you still see OSD, but a gray screen, it indicates that the connection from the flight controller to the VTX is good (that's why you are seeing OSD), but the gray indicates that something is wrong on the camera end. A warm camera is a little alarming. A warm VTX is ...

6

tl; dr: Analog is: Cheaper; Lower resolution; Has a noisier, more staticky picture that breaks up gradually when the signal gets weaker. Analog image breakup, while unpleasant to the eye, is generally easier to see through. Has a constant low latency; Is an entirely open standard, with anyone free to produce compatible equipment Digital is: Currently ...

6

The distance is dependent on the wavelength of the lowest frequency. You can calculate the wavelength $\lambda$ (m) from $\lambda = c \div f$, where $c$ is the speed of light in a vacuum (ms-1) and $f$ is the frequency (Hz.) Taking the centre frequencies of the ISM bands we get: 2.4 GHz: $$\frac{299 792 458 }{ 2 450 000 000 } ≈ 0.12 = 12 cm$$ 5.8 GHz: \...

5

Are the rules different around the world? Is a technicians class amateur radio license sufficient? What about the requirement to transmit your call sign every 10 minutes? Is that necessary in this use case and if so, how do you comply? Addressing this specifically, just in case you decide to get your ticket for the purpose of flying (and many people do!). ...

5

The rule of thumb here is the further away from each other the better. The problem is, that receiver is operating on different band and so it has some input filtering to not receive "out-of-band" signals, but no filtering is perfect and some receivers are better than others. What happens is, that some energy gets through and adds to background ...

5

A "mushroom" is just a clover-leaf antenna. Generally they have a plastic cover that makes them look like a mushroom, hence the name.

4

There’s a lot to unpack here, so I’m going to give a general kind of advice that should be helpful for anyone trying to get cleaner video: Electrical Power There are two main aspect to the image transmission: the camera and the VTX. Whenever you have noise, the first step would be to increase power filtering as much as possible. The easiest way to do this is ...

4

Some brand-name antennae actually have the word "mushroom" in their model name. In common parlance, though, unless the model name is spelled out fully (such as "VAS Mad Mushroom"), it can refer to any omnidirectional circularly-polarized antenna that has the characteristic mushroom shape. The radiation pattern of such antennae is usually what you'd ...

4

I just want to add to FlashCactus's excellent answer... Depending exactly what you want, you can get some fairly good estimates on range on various range calculators online. You can get them pretty easily from Googling "Calculate FPV range," but here are a couple: FPV.lt MaxMyRange.com Of course, I concur with FlashCactus... it's not a perfect no-...

4

This is not possible, at least directly. Although the two technologies use the same frequency range, they are very different communication protocols. A possible solution would be to buy a compatible video receiver (which might be the goggles) which has a video output - typically composite, for analogue systems - and a USB video capture card for your laptop. ...

4

These components can be split into two functional groups, one for transmitting a picture and one for receiving it, which aren't connected to one another by wires. The Runcam camera and Eachine VTX are both parts of the transmitting section, while the receiver doesn't need to be soldered to anything else in the receiving part. Required Soldered Connections: ...

4

There's a few factors that you're missing. The first is that the RC world is dominated by traditional line-of-sight control, and 2.4GHz provides more than enough range to fly a model plane to the limits of vision. There aren't many long range system because few people need them. Even for FPV, long distance flying means a long walk or losing your model when ...

3

It is a totally different communications protocol than the 5.8GHz wifi your laptop supports but there are devices for under \$30 that let you receive the video on an android phone or a windows laptop such as Skydroid 150CH. I'm not recommending any particular product but you're basically just looking for a USB 5.8GHz FPV Video receiver. Without buying an ...

3

This can be caused by too much heat building up in the VTX causing the electronics to suffer. Try mounting the VTX to have more airflow around it or put a heat sink on it. Sometimes a VTX just can't handle its own output power. Another issue might be that electronic noise from the VTX is getting fed back into the video signal at the camera or FC ...

3

Well, the first thing I must point out is that these are far from the only frequencies used for that (and yes, I'm aware that you said "most" in the question). The reason I'm doing that is that answering the question "why do some people not use those frequencies?" can give us an insight into why the others do. Let's begin by listing the "at least somewhat ...

3

As is discussed in this Oscar Liang article, FPV hardware exists for all different kinds of frequency bands, stretching from 900 MHz to 5.8 GHz, with 5.8 GHz being the most popular today. People in our hobby have tried nearly everything under the sun. :) Probably the most well-known tradeoff in RF is that between frequency and penetrating power. In general, ...

3

To answer your main question, I'm afraid there's nothing as widely used the Ender3. It sounds like you want to build something with more lifting capacity and space than a race quad, with GPS. There are two main styles of frame that might suit you. One is based on the old 'DJI Flamewheel', which has plastic arms attached to hub of two flat plates. You can ...

2

The difference lies in how the signal is transmitted. An analog system sends a continuous signal, while the digital system first encodes it as ones and zeros before sending it. This generally leads to better reception and image quality for a digital system. Think of the signal as a light: it's much easier to see whether the light is on or off (digital) ...

2

From the information you have provided, I think you have a loose connection between your camera and your FC. My troubleshooting methodology is: We know that the VTX is functioning as there is no static. We know that the signal from your FC to your VTX is not being interrupted as the OSD is still transmitted. This leads me to believe that your VTX is ...

2

I had a similar problem on a quad: perfect image on the bench but the picture from the camera went bad as soon the quad was in the air. The error was that the sma connector of the vtx did touch the carbon of the frame. When I isolated the SMA connector (tape + plastic screws to mount it) the problem was completely gone. Might be a different problem in ...

2

Transistor junction temperature (aka junction temperature or Tjunction) is the rated maximum operating temperature for a semiconductor before it will either permanently fail or produce possibly damaging outputs to other components in the circuit. Desktop computer CPUs often have a Tjunction of ~100 °C, and this site claims that most commercial-grade ...

2

No, specific brand and specs don't matter for interoperability (aside from making sure that both antennae are built to transmit/receive the same frequency). Specific specifications about an antenna can help you figure out which will work best for your use case, like the antenna's gain, but mixing brands and types is fine. However, there are certain mixes of ...

2

As I live in the Middle Europe, I can speak for that part of world. Specifically for Slovakia, but more or less the same rules are applied across European Union. Generally as long as I know (spent some time on research as I has been also flying FPV) there are only two bands usable for video transmission and those are 2.4 GHz and 5.8 GHz band. There are also ...

2

I'll start by warning that you may have misconceptions that are leading you in the wrong direction. The reason that FPV screens built into transmitters are not more popular is that screens aren't bright enough to compete with sunlight. The primary function of goggles is to cut out bright reflections, so you can see the picture. Also, transmitters are ...

1

I believe you can do it w/scripting on FR Sky and other OpenTX system. They are a good bunch of people: https://www.open-tx.org/

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