How to calculate the time delay based on a function of antenna angle?

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Discussion Overview

The discussion revolves around calculating time delays based on the angle of antennas in the context of collecting data from TV signals. Participants explore methods for determining angles between transmitters and receivers, as well as the implications of signal delays due to multipath effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • A participant describes using a spectrum analyzer to identify nearby TV stations and calculates angles between transmitters and receivers using a specific equation, expressing uncertainty about its correctness.
  • Questions are raised regarding how to calculate time delays and determine angles between different transmitters, particularly without knowing the direction.
  • Another participant requests clarification on the meaning of "height" of antennas and the specific type of delay being measured, suggesting that diagrams and labeled plots would aid understanding.
  • A later reply points out the challenge of ensuring synchronous transmissions from multiple TV transmitters, questioning whether triangulation is the intended goal and suggesting a diagram for clarity.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the calculations and methods proposed, with no consensus reached on the correct approach to determining time delays or angles between antennas.

Contextual Notes

Limitations include the potential lack of synchronous transmission between TV stations, which complicates the measurement of relative delays. The discussion also highlights the need for clear definitions and visual aids to enhance understanding of the concepts involved.

Nate Duong
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Hi everyone, I am a new student who is studying on collecting data from TV signal. I hope everyone can help me for ideas.
I am having spectrum analyzer which can define a TV station around me, so I chose 4 stations WHUT-TV [584MHz 590MHz], WPXN-TV [590MHz 596MHz], WTTG [60 MHz 608MHz], and WNVC [530MHz 536MHz].

Since I define those stations and can be easily to know location of those base on the FCC database (latitude , longitude, height, wavelength, channel, radius range, distance between stations, distance between my location and each station … ), then I can calculate the angle between TX antenna from the stations and RX antenna from my location (using equation: angle = arctan(height of TX – height of RX)/ distance of 2 antenna) I am not sure this is a right or wrong equation?

At my location, I also collected data such as: spectrum, and the delay for 10 seconds each time scan in by turning circle the antenna (0, 30, 60, …, 300, 330), using Matlab to plot it out to see the behavior of the signals.

Since I had that information which I needed, I am trying to calculate the time delay but I do not how? And how to determine different angle between 2 different transmitters? And if I do not know the direction, how I can estimate different angle between 2 antennas?
I hope everyone can help me to understand more details.


I also have some plots that I collected data and calculated spectrum and delay from Matlab.

If you still confuse my question, please let me know, I am happy to explain.

Thank you very much.
 

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Nate Duong said:
Hi everyone, I am a new student who is studying on collecting data from TV signal. I hope everyone can help me for ideas.
I am having spectrum analyzer which can define a TV station around me, so I chose 4 stations WHUT-TV [584MHz 590MHz], WPXN-TV [590MHz 596MHz], WTTG [60 MHz 608MHz], and WNVC [530MHz 536MHz].

Since I define those stations and can be easily to know location of those base on the FCC database (latitude , longitude, height, wavelength, channel, radius range, distance between stations, distance between my location and each station … ), then I can calculate the angle between TX antenna from the stations and RX antenna from my location (using equation: angle = arctan(height of TX – height of RX)/ distance of 2 antenna) I am not sure this is a right or wrong equation?

At my location, I also collected data such as: spectrum, and the delay for 10 seconds each time scan in by turning circle the antenna (0, 30, 60, …, 300, 330), using Matlab to plot it out to see the behavior of the signals.

Since I had that information which I needed, I am trying to calculate the time delay but I do not how? And how to determine different angle between 2 different transmitters? And if I do not know the direction, how I can estimate different angle between 2 antennas?
I hope everyone can help me to understand more details.


I also have some plots that I collected data and calculated spectrum and delay from Matlab.

If you still confuse my question, please let me know, I am happy to explain.

Thank you very much.
Can you show us a diagram of the TX antenna positions and your RX antenna position? And what do you mean by "height" of the antennas? And what "delay" are you working with? Delay from what to what?

And on your plots, it would help to label both axes with the variable being plotted and the units. Thanks. :smile:
 
berkeman said:
Can you show us a diagram of the TX antenna positions and your RX antenna position? And what do you mean by "height" of the antennas? And what "delay" are you working with? Delay from what to what?

And on your plots, it would help to label both axes with the variable being plotted and the units. Thanks. :smile:

@berkeman : the position of the WHUT-TV [584MHz 590MHz] TX antenna is : 38°57'1"N , 77°04'47"W and the RX antenna is 38°53' 17''N , 77°10'49''W.
I mentioned the height of antenna because we can calculate the angle of 2 antenna (by searching ideal on google) so we need the height.

The delay mean "time delay". because of the multi_path signal (reflecting from building, cars, ... ) therefore we have the delay to get all truth signal.

I have the hardware which included 2 RX antenna, (2 channels), when I collect the data, channel 1 will give me f(w) value, channel 2 will give me g(w) value (f and g are complex value). Since I have those, I can calculate the spectrum S_fg = f(w) * conj(g(w)).

Also I have attached previous plots with title and label, a plot with single channel.
 
There is no way of ensuring that the transmissions from two TV transmitters are synchronous so there is no way of finding relative delays from two ordinary broadcast transmitters..
Are you trying to find your location by triangulation? It isn't clear. If you could draw a diagram, it would give us a clue about what you actually want to achieve.
 
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