Архив за 21.02.2020

Signal Identification Help • Re: How to interpret this signal?

hotpaw2 wrote:
Fri Feb 21, 2020 3:46 pm
One possibility for multiple evenly spaced carriers would be some form of OFDM.
Im going to give it a try in GNU Radio to demod this signal as OFDM. Thanks for the hint.

Statistics: Posted by royb — Fri Feb 21, 2020 11:27 pm


Building 1691MHz ~ 1707MHz (L-Band) Patch-excited pot antenna for NOAA and Meteor Birbs HRPT Reception 📡🛰

Building 1691MHz ~ 1707MHz (L-Band) Patch-excited pot antenna for NOAA and Meteor Birbs HRPT Reception 📡🛰 submitted by /u/Macak787
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Quadrifilar vs. Octafilar antennas?

Hello all,

I am researching helical antennas for a project that I'm working on, and see lots of options for helical architectures (bifilar vs. quadrifilar vs. octafilar) for my use case. I'm a total beginner here, and a lot of the references I'm finding are a bit too academic and theory heavy for me to build an intuitive understanding.

I have a few questions regarding how different antenna parameters affect the performance, beam patterns, directivity, and other specifications.

  1. If you increase the number of helices in an antenna (bifilar vs octafilar), how does that manifest in terms of performance?
  2. How does the length of the antenna and the number of turns of the helix affect the antennas performance? How do you choose these parameters for your particular needs?
  3. In general, what is the purpose of adding more antenna wires to create a more complicated helix structure?
  4. If you know of any specific resources regarding quadrifilar vs. octafilar antennas for beginners, do you mind sharing them here?

Thank you!

submitted by /u/octafilar
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Comment on Look4Sat: An Android App for Tracking and Predicting Amateur Radio and Weather Satellite Passes by Roy

Lots of missing sats (like AO-91, HuskySat-1, etc.).
Any chance of using another set of TLEs? Specifically – nasabare.txt from Amsat.org? Otherwise nice software. Including doppler shift calculations would be a cool addition.

First images from NOAA 19 with my QFH antenna! Could be better, but not too bad for a first test. (Separate post as many people wanted to see)

First images from NOAA 19 with my QFH antenna! Could be better, but not too bad for a first test. (Separate post as many people wanted to see) submitted by /u/Mark267019
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Comment on MEMESat-1: A Meme-Beaming Cubesat Currently In Development by Roy

Indeed.

Comment on About RTL-SDR by Clint Mclean

Actually I have been specializing in this area for a while now.

Note what I said above about how I determined that it was microwaves that were used on the diplomats in Cuba and China before the official investigators started admitting that.

I know because of years of research in this area and I was also referencing the scientific research that was later referenced by others, such as the New York Times article that was essentially the first to say that it’s most probably microwaves.

https://www.nytimes.com/2018/09/01/science/sonic-attack-cuba-microwave.html

I was saying it scientifically long before that.

Signal Identification Help • Re: How to interpret this signal?

Thanks hotpaw2, do you by any chance know any software that allows me to demodulate an OFDM signal?

Statistics: Posted by royb — Fri Feb 21, 2020 7:34 pm


RTL-SDR Discussion • Re: Kerberos SDR 4 Channel Coherent RTL-SDR how to use ?

Cool , thanks :D

Statistics: Posted by Brucedg — Fri Feb 21, 2020 4:04 pm


Signal Identification Help • Re: How to interpret this signal?

One possibility for multiple evenly spaced carriers would be some form of OFDM.

Statistics: Posted by hotpaw2 — Fri Feb 21, 2020 3:46 pm


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