Questions tagged [microwave]

Questions related to operating on frequencies above 902MHz.

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4
votes
3answers
82 views

3D Printed yagi antenna

I'm trying to produce a Yagi antenna for the 2.45 GHz band using a 3D dual extruder printer. The idea is to print the antenna elements using a metal filament and encasing it all in plastic. The ...
4
votes
0answers
43 views

S Parameters in HFSS

I'm new to HFSS Software and I'm trying to plot Scattering parameters for a dielectric resonator excited by a probe (shown in image). I know that the top cylinder has a higher dielectric than the ...
1
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1answer
55 views

What type of omnidirectional antenna gives the most gain for a frequency of 2.4 GHz?

I have a 2.4 GHz transceiver that outputs 4.5 DBm. I wish to amplify the signal using a 15.5 DBi antenna so that the signal reaches 20 DB, the maximum legal limit. Preferably, the antenna would be of ...
5
votes
1answer
223 views

Failing to detect Hydrogen line with 105cm dish

I've seen many examples of roughly 1 metre sized dishes being used w H+ sawbird and an SDR to detect and analyze Hydrogen line signal, and have been trying myself but can't seem to get anything beyond ...
4
votes
1answer
100 views

Frequency selective surfaces working principle

I've seen that sometimes frequency selective surfaces are used to load a certain impedance to a certain antenna (for instance for input matching purposes). These surfaces act like a filter on the ...
1
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2answers
4k views

How to calculate Return loss of cascaded system?

If system 1 has 10 dB return loss and system 2 has 20 dB return loss then what is the overall return loss of cascaded system of 1&2 ?
0
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1answer
21 views

Is this result correct ? [ impedance cavity based on emtamaterials using CST Microwave]

In the contexte of my reaserch about antenna conceptions, I'm trying to simulate using CST Microwave a cavity antenna based on metamaterial structure and a slot antenna as a GND,However I got as a ...
1
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3answers
473 views

What are the properties of the radiation of a magnetron?

It is commonly known that electromagnetic radiation from an antenna is polarized; the electric field is parallel to the rod and the magnetic component is perpendicular to it. What does the radiation ...
5
votes
3answers
295 views

How far the near-field reactive region extends from the transmitting antenna?

I am doing research on near-field harvesting. In my situation the transmitting antenna is a dipole antenna operating at 2.45 GHz and its length is 14 cm long. I am trying to find how far near-field ...
5
votes
2answers
378 views

Designing a helical antenna for a dish

I'm interested in a dish antenna with an axial mode helical feed for receiving video. My target frequency is about 1280 MHz or the 1.2/1.3GHz range. I've been able to figure out helical basics, like ...
-1
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2answers
119 views

Why can't we use a simple wire for receiving 2.4 GHz signals?

I wanted to build a small drone of my own as a hobby project. My old drones were broken so I wanted to salvage as much as I could to build a small indoor one. I wanted to use an Arduino, however, I am ...
3
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2answers
84 views

Connecting Directional Antenna To Two Antenna Ports on NIC

I want my n/ac Wi-Fi card to operate in a spatially directional manner. To achieve that I want to use a directional antenna(s). There is a slight complication though, because my Alfa AWUS036ACH ...
5
votes
2answers
679 views

Troposcatter: really all that bad?

The previous question, Packet Radio at 100 miles and specifically, Phil's answer raised an interesting question: In a 50–100 km distance situation where Line-Of-Sight beams aren't an option for ...
0
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2answers
113 views

Imaging with radio Frequency

Is it possible to image bones and tissues with radio waves (2.7GHz-5GHz) with a tiny radio frequency source and on one side and a receiver on other side which can image the data through a PC mediated ...
2
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0answers
84 views

Circular polarized antenna feed changes as I rotate it?

I had a 100cm prime focus dish laying around and I thought of making a circularly polarized feed for it, since it seemed pretty straightforward from what I've been reading. Helical feeds are supposed ...
3
votes
5answers
173 views

2.45GHz: constructing a horn of *thin* steel, what are good ways to join the edges (at least one joint along corner?)

TL/DR: How does someone make a good horn antenna system without using expensively made parts? Welding thin steel for this is not something even pro welders can do (it's a specialty app.) What are DIY ...
3
votes
1answer
106 views

What are the parameters and necessary features of a Gunn diode oscillator cavity?

There are a ton of old USSR Gunn diodes available on ebay and I'm looking for a cavity that can make use of them. I am willing to machine one myself if necessary, but I'm unable to find any decent ...
0
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0answers
137 views

Is there any 2.4 GHz tuner ICs for SDR receivers?

I have a hackrf one sdr, which i use to transmit test signals. I am using ISM bands, so I can omit transmitting my callsign, checking correct sub band (FM, digital) etc. And one of most interesting ...
-4
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1answer
104 views

Wifi inside a rocket

I want to understand, as most rocket uses LAN cable and switches to communicate between stages. Is it possible to replace with WiFi? Although it's will be complex system but one idea to make each ...
0
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1answer
197 views

Passive antenna system as a Wi-Fi repeater [duplicate]

I want to extend WiFi signal using a passive repeater between two isolated boxes (have to make both box wireless). Transmitter antenna from box A is placed in the gap between box A and B. In the same ...
1
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0answers
59 views

Microwave kiln for glass [closed]

I am building a 1000W microwave kiln for glass jewelry. The internal capacity needs to be around 5 litres. What internal dimensions of the cavity should I avoid, or strive for, to ensure even heating....
3
votes
3answers
182 views

Applications for 100 GHz band?

I was reading this paper and I found it very interesting and the following question came up, What are the main applications (what is used for) 100 GHz band? I couldn't find any reference on what is ...
0
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4answers
138 views

Cell tower identifier antenna isolator cannon

There are several cell towers on the hills around me. Usually I just walk around their base in a circle with one of the many CellID apps to get their ID. Then I can impress my friends, "That's tower ...
5
votes
1answer
650 views

How to create a simple 1296MHz transmitter?

I have asked this quesion on other sites, but want to try to repeat it here. Also I have asked question about multiplier, and this is a different question. I discovered a 1296MHz beacon in my city ...
5
votes
1answer
62 views

What is the best approach for measuring return loss of a home-made 3cm horn?

Let's assume I have built a SMA-to-waveguide transition that flares out into a horn antenna. There's no flange between transition and horn, it's made of a single metal sheet. The antenna has tuning ...
1
vote
1answer
104 views

RF inert adhesive for building antennas in the UHF to low GHz region

I want to experiment with different mechanical designs for some Yagi antennas for 440 MHz through perhaps 2.3 GHz. I am looking for some adhesives and/or potting-like materials that would be ...
10
votes
1answer
813 views

Faraday cage in Microwave oven

If I put my mobile phone in my microwave oven and close its door, Should I be able to get incoming calls ? Because, I tried it and I was able to get calls, what does it mean? Does my microwave oven ...
3
votes
1answer
2k views

Why are FM radio waves less susceptible to interference than AM?

When studying modulation of radio waves (or of most electromagnetic waves for that matter) I came across this question: Why are FM waves less susceptible to interference than AM waves? I know that ...
6
votes
3answers
333 views

What is this large, flat microwave coaxial connector?

I picked up a random piece of RF hardware at a flea market. I'd like to know what these unusual connectors on it are. The jack is flat on its face except for the gold ring. Inside the gold ring ...
1
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1answer
45 views

Picostation Not Accepting AREDN Firmware

Help! I got a PicoStation off of Ebay. When trying to upload the Amateur Radio Emergency Data Network firmware to it, I get Bad firmware update image. How do I get ...
3
votes
1answer
2k views

How to build the smallest directional antenna (ISM band)?

What kinds of configurations should I try when trying to make the physically smallest 2.4 GHz (ISM band) antenna that is significantly directional front-to-back. "Smallest" meaning in in cm maximum ...
1
vote
1answer
271 views

why fiber optics replaced microwave [closed]

I was recently reading an article where they mentioned about abandoned microwave towers being replaced by fiber optics. From what I understand microwave technology is better at speeds, is cost ...
2
votes
2answers
351 views

Linksys WRT54G turned in to a brick

I just bought my first WRT54G (V3), and wanted to build a mesh network (Using the Broadband-ham firmware, http://www.broadband-hamnet.org/ , which as I understand is based on OpenWrt). I wasn't paying ...
5
votes
1answer
304 views

What is a general procedure for aligning directional antennas?

I want to establish a microwave link (1.2GHz) between two stations using antennas with a directional radiation pattern. The stations have a clear line of sight to each other. Each antenna is attached ...
8
votes
2answers
371 views

Have hams ever used (clusters of) geostationary satellites as passive microwave reflectors?

A number of geostationary satellites are quite large and/or appear in clusters. Moreover, many of them have large reflectors pointing to Earth (e.g. satellite TV sats). Finally, these satellites are ...
8
votes
1answer
254 views

What is a good way to bench test a mesh network?

I've been experimenting with some 2.4ghz based mesh networks similar to http://hsmm-mesh.org/. I'd like to have something on the bench where I could simulate roving between nodes, and create hidden ...