Questions tagged [microwave]
Questions related to operating on frequencies above 902MHz.
32
questions
4
votes
1answer
92 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 ...
0
votes
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
vote
3answers
446 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 ...
-1
votes
2answers
112 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 ...
5
votes
2answers
308 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 ...
3
votes
2answers
52 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 ...
2
votes
0answers
76 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 ...
0
votes
2answers
110 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 ...
3
votes
5answers
150 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 ...
0
votes
0answers
103 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
votes
1answer
96 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
votes
1answer
169 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
vote
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
170 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 ...
3
votes
1answer
103 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
votes
4answers
133 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
555 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
61 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
97 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 ...
5
votes
2answers
634 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 50ā100 km distance situation where Line-Of-Sight beams aren't an option for ...
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 ...
1
vote
2answers
3k 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 ?
9
votes
1answer
802 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 ...
1
vote
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 ...
5
votes
3answers
285 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 ...
6
votes
3answers
320 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 ...
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
259 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 ...
5
votes
1answer
286 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 ...
2
votes
2answers
333 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 ...
8
votes
2answers
363 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
250 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 ...
