Questions tagged [microwave]
Questions related to operating on frequencies above 902MHz.
44
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2
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How to calculate phase constant for a coaxial cable?
inner and outer conductor diameters of 1 mm and 5 mm respectively, is filled
with a non-magnetic PTFE dielectric having εr = 2.55. frequency = 1 GHz.
- 21
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2
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187
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Waveguide size for 2.4 GHz
I'm thinking to make a wave guide that has diameter 1/8 of the wave length.
At 2400mhz the full wave length is about 125mm.
I have aluminum pipe that is 16mm. So 8*16 = 128mm (very close to 125mm).
If ...
- 13
2
votes
2
answers
141
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Why measuring Voltage and Current becomes difficult at Microwave frequencies? Why measure Power?
I have been reading some Classic books viz. Techniques of Microwave Measurements - Carol Montgomery, Foundations of Microwave Engineering - Collins, and some other google searches and they all claim ...
- 159
2
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1
answer
220
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The Terrestar Genus was able to talk to a GEO satellite in a smartphone-sized package, where's the antenna on this thing?
Background
I'm doing some research on a company called ASTS who claims to be able to connect to regular smartphones from a satellite. Initially I wrote off their claims, but after looking into it a ...
- 45
1
vote
1
answer
106
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FCC Guidelines for Radar
I'm working on some research for a project of mine. The project requires the use of millimeter wave radar. I am having a very hard time figuring out what the FCC's regulations on frequencies and ...
- 111
1
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0
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40
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Is it beneficial to boost the transmit power from a transmitter past 2W around 2.4GHz?
I have a ready-made transmitter that outputs 2W of RF power at 2.4GHz carrier frequency (I'm trying to transmit TV using DVB-S2) into the antenna, and I was wondering if it made sense to add a power ...
- 151
2
votes
0
answers
138
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Dielectric coaxial resonator vco circuits topology?
I came across this VCO that uses a dielectric coaxial resonator, I understand how the resonator works, what I don't know is the oscillator topology, Colpitts, Clapp, et. Also I do not see any circuit ...
2
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3
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220
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Maximum frequency for discrete components bandpass filter
What is the maximum frequency that can be practical to build a filter with discrete components?
I need a band pass filter for 1090Mhz.
4
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4
answers
369
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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 ...
- 73
1
vote
1
answer
98
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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 ...
8
votes
1
answer
144
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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 ...
- 81
5
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1
answer
332
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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 ...
- 51
4
votes
1
answer
219
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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 ...
- 279
0
votes
1
answer
24
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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
vote
3
answers
726
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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 ...
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2
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173
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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 ...
- 101
5
votes
2
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795
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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 ...
- 53
3
votes
2
answers
255
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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 ...
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3
votes
0
answers
192
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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 ...
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2
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126
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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 ...
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3
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5
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303
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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 ...
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0
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0
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566
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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 ...
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votes
1
answer
144
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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
votes
1
answer
348
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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 ...
2
votes
0
answers
73
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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....
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3
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3
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341
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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 ...
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3
votes
1
answer
159
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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 ...
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4
answers
166
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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 ...
- 149
5
votes
1
answer
1k
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 ...
- 195
5
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1
answer
76
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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 ...
- 63
2
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1
answer
126
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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 ...
- 1,035
6
votes
2
answers
886
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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 ...
- 15.6k
3
votes
1
answer
2k
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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 ...
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2
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6k
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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 ?
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856
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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 ...
- 327
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1
answer
49
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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 ...
- 160
5
votes
3
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384
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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 ...
- 449
6
votes
3
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377
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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 ...
- 24.4k
3
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1
answer
3k
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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 ...
- 13.2k
2
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1
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323
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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 ...
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1
answer
374
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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 ...
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2
votes
2
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402
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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 ...
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423
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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 ...
- 1,307
8
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1
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261
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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 ...
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