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

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1. Nov 30, 2016

### Nate Duong

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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2. Nov 30, 2016

### Staff: Mentor

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.

3. Nov 30, 2016

### Nate Duong

@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.

4. Nov 30, 2016

### sophiecentaur

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.