Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [microwave]

Questions related to operating on frequencies above 902MHz.

44 questions
10
votes
1 answer

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 has a radiation leak?
volatile
  • 327
  • 2
  • 8
8
votes
2 answers

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 located at roughly $\frac{1}{10}$ the distance…
on4aa
  • 1,277
  • 9
  • 22
8
votes
1 answer

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 nodes and varying signal strengths. Is there a…
K9KRB
  • 622
  • 1
  • 6
  • 12
8
votes
1 answer

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 bottom cylinder. I also know that the cavity is a…
JOHN
  • 81
  • 1
6
votes
2 answers

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 communicating data, can we, given the technological…
Marcus Müller
  • 15,225
  • 22
  • 44
6
votes
3 answers

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 appear to be fingers gripping the central pin (which…
Kevin Reid AG6YO
  • 24,195
  • 7
  • 48
  • 101
5
votes
3 answers

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 reactive region extends from the antenna. I…
Shiva Mudide
  • 449
  • 3
  • 10
5
votes
1 answer

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 to a half-duplex transceiver operating at…
mtrberzi
  • 872
  • 1
  • 5
  • 19
5
votes
1 answer

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 maybe a small whiff. I'm using a 105cm satellite…
Jack_SH
  • 51
  • 2
5
votes
2 answers

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 circumference equals wavelength, more turns is…
Gabe
  • 53
  • 3
5
votes
1 answer

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 that I can receive with SDR and got inspired by this…
Hose Dias
  • 185
  • 1
  • 2
  • 8
5
votes
1 answer

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 screws, and my goal is to find the screw position…
mpb HB9EGM
  • 63
  • 4
4
votes
4 answers

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 antenna needs to be highly directional, with 8 elements…
PHOLAN
  • 73
  • 3
4
votes
1 answer

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 equivalent transmission line that describes the…
Kinka-Byo
  • 279
  • 1
  • 7
3
votes
1 answer

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 in FM the frequency has been modulated to carry the…
MystMan
  • 33
  • 3
1
2 3