6

A wire will pick up a GHz signal, as well as a ton of other RF signals, all mixed together. Some sort of filtering is required to separate out your desired radio signals. An Arduino has none of filtering required. Sampling a 2.4 GHz signal requires a sample rate above 5 billion samples per second. The A/D on an Arduino samples at a rate of about 9000 ...


6

It might be a good idea to start by trying to make a block diagram of what you have inside of each of those controllers... Namely, the drone controller is most likely some sort of a system on a chip, which on its own chip, in addition to having a microcontroller also has the radio interface built in. Those are two separate things, but in one package. ...


4

Small loops and full-wave loops are very different antennas. There isn't a well-defined distinction between "small loops" and "large loops", but a typical rule of thumb is a loop is "small" when its diameter is less than 1/10th of a wavelength. At such a size, the phase delay around the loop is negligible and thus the current ...


4

First you don't necessarily have to do anything. The SWR is below 3 for the bands and most transceivers can handle that OK. If you want to try to get the resonate points inside the bands you will need to lengthen the wire. it is usually a good idea to start with too much wire and trim the length to bring the resonance down, but in your case it look like the ...


4

Yes, being limited to 20 total segments for two dipoles is likely to be a problem, especially because of your hope / plan / expectation to have the model accurately predict what is built. I created an EZNEC model of a fan dipole for 40 and 20 meters; even the minimum segmentation - which, don't forget, must suffice at the highest operating frequency - ...


4

It doesn't matter. If you change the connection of the OCF dipole nothing will change from the current and voltage flow or distribution points of view.


3

A spliced joint makes very little difference to an HF antenna electrically, but if you do solder it then you should protect the solder joint from the weather, because the solder will corrode faster than the wire. Right-angle turns in the wire will affect the radiation pattern, but since the radiation pattern of a "random" length wire antenna is funny-...


2

Now I'm using the software 4nec2 (with wine) with the description from DL6GL. With this software you can generate the .out files. I hope to succeed.


2

Actually, the answer is "it depends". Polydoroff did some work on this in the 60's and documented it in his book: https://books.google.com/books/about/High_frequency_Magnetic_Materials.html?id=GC4jAAAAMAAJ I'd quote the relevant part but my copy isn't with me at the moment. He showed significant shortening of the antenna with the ferrites he tested. He ...


2

Ham radio is about experimenting, Wire antennas are relatively cheap to make. Go ahead and try it and see how well it works. I am not sating you should not read about various antennas and ask other people's opinions. You should, but at the end of day go ahead and try it. In my experience splicing wires should not be an issue. mechanically fasten the wire ...


2

Splicing the wire is just fine electrically, but if you're using multistranded cable you probably won't want to solder it. Soldering makes a stiff section which concentrates the stress at the joint, leading to premature failure. Swaging is ideal, but if you don't have the necessary tool then rope clips are an acceptable alternative.


2

The radiation pattern of an antenna laying on the ground can be easily approximated for the transmit case: it's roughly equivalent to a dummy load. Unless of course you are in Antarcitca: ice is transparent enough to HF that it's basically invisible. But I don't think there are any retirement centers in Antarctica. For a receive application, you might hear ...


2

I doubt that the segment limits of the program is your main problem. You should get accurate enough details in spite of that. Part of the problem is at the feedpoint. You need to build your fan dipole so that there are insulating spreaders* to keep the wires for the different bands parallel and farther apart from each other for most of their length. As it ...


2

Well put, Phil. According to a simulation comparing a 1-turn full-wave loop to 2-turns of the same loop, the radiation pattern is the same while the feedpoint impedance increases by a factor of four: These values are for an antenna less than a half-wave above the ground. Raising it to a half-wave above ground does move the maximum radiation to lower angles, ...


1

"EFHW" means end-fed half-wave. It is by definition a half-wavelength long, so it is not short. And it's fed at the end, so it can't be a loop, which has no ends. I wouldn't say it's a very good choice for a space-limited application. There are loop antennas too, and any wire antenna can be bent or curved, though that may make it a very different ...


1

Any of these antennas would work. My advice: do what's easy or whatever leverages what you already own. Are there any remote automatic tuners that can be fed directly with open wire? So far the only ones I found are indoor tuners. It may exist somewhere, but it's probably not very common, because: coax feedlines are popular for their ease of routing, and ...


1

All these options are bad. It's a bit like asking if it's better to drive a nail with a floppy shoe or a glass jar. If you really had to make a decision between these contrived options, you'd have to flesh out the details to make a decision. There are a few things to consider. Firstly, a half-wave dipole may have a substantially different radiation pattern ...


1

Yes, you can. If you want it to stand up physically for a long time, you should Make a good, strong splice. To make a "lineman splice" you strip several inches of each wire, overlap them, and closely wrap each one around the other one, as in this diagram (A through D are the four steps of one variation; E and F are other variations with slightly wider ...


1

Phase The only difference will be the RF phase. A "balun" is a transformer that goes between balanced and unbalanced sources and sinks of energy. Unless you are trying to use two dipoles as an array, the phase doesn't matter.


1

This problem is very easy to model with any MOM tool, like EZNEC. E and H fields can be calculated using Near Field grid. Even better, exact power transfer from Tx to Rx antenna can be modeled. Modeling should include both Tx and Rx antenna, including Rx antenna termination resistance. Ratio of transmitted power and dissipation on Rx termination resistor ...


1

Don't believe the many myths in circulation concerning which wire to use for an antenna. Most of the myths over complicate this very simple subject. In reality, it doesn't make much if any difference what type of wire you use, so long as it's strong enough to hold it's own weight and isn't too thin, you should be ok. I've used copper, stranded, solid, ...


1

There are two properties you care about for antenna wire: 1) Will it conduct well 2) Can it support its own weight. Due to skin effect, cost, conductivity, etc., the best material for conduction is copper. The best material to support its own weight is steel. You can use a large gauge (say, 14-12) of copper wire which will work. For short wires that won'...


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