Creating interference with 2 antennas connected in parallel

[chapi]

I am trying to cause interference by connecting 2 antennas in parallel to a radio receiver and moving one antenna in a straight line toward a transmitter until it reaches a half wave length distance from the other antenna. I tried it with a few couplers, but was unsuccessful. Any idea how to do it? thanks.

 

[G7RUX]

What are you trying to achieve by doing this?

 

[G6FGO]

What are you trying to achieve by doing this?

I have been pondering that for a few hours. Best I can come up with is, trying to null out an unwanted signal.

 

[chapi]

I am trying to check some properties of SR.

 

[G6FGO]

I am trying to check some properties of SR.

What is "SR" when it's at home?

 

[chapi]

Special relativity.

 

[G7RUX]

Hmm.

Good luck with that.

 

[chapi]

Chat gpt says the baofeng I’m using is not good for my purpose since it’s combining both signals for maximum reception. Sdr does not works too. Any suggestions?

 

[G7RUX]

ChatGPT knows and understands nothing. It lies. Don’t rely on it for anything more than correcting your spelling.

 

[nd5y]

What kind of antennas?
What kind of receiver and transmitter?
What frequency?
How far is the transmitter from the two receive antennas?
How are you connecting the antennas?
The spacing between the antennas will be meaningless unless the electrical length of the transmission lines is the same and also if you are doing this indoors or near any conductive objects or surfaces don't expect it to work the way you think it should.

 

[chapi]

Dual band antennas, came with the baofeng

Baofeng

503 mhz

One transmitter is 200 meter from the receiver, the other one is 20 km.

Outdoor.

Can you please elaborate on the transmission lines? Thanks.

 

[nd5y]

Can you please elaborate on the transmission lines? Thanks.

I still don't know what you are trying to do.
If you are trying to move antennas around to null or peak a received signal then you need to know:
Angle (direction) of the plane of the receive antennas to the transmitter.
Distance in wavelength between the two receive antennas at the operating frequency.
Electrical length of the transmission line to each to antenna at the operating frequency.
Then you need to know how all of the above relates to the radiation pattern of the antenna array.

If this is in the US then you can't legally transmit on 503 MHz with a Baofeng or anything else.

 

[chapi]

I do not transmit, only receiving.

 

[chapi]

I tried to move the receiving antennas in many different distances and angles but got no null. the transmitter is on mount Wilson near L. A. and there is no problem getting tdoa reading with a tdoa equipment from it.

 

[MUTNAV]

You may be better off making a cheap yagi antenna for the frequency you are looking at and pointing it directly away from the transmitter.

The simplest way to check what might work is to take a metal trash can, turn your radio on, point the bottem of the trash can toward the signal you don't want, and put the radio into it as far as needed to get rid of the signal you don't want.

(you may need a trash can with good depth to it, like an outside metal garbage can vs. an office sized one).

Thanks
Joel

 

[G7RUX]

What exactly are you trying to demonstrate about special relativity with this setup?

 

[chapi]

G7,

Answer may be long and complicated, not for this forum. You may look at:

I asked chat gpt: In twin paradox, the travelling twin is younger when they are reunited. But what’s happening if the travelling twin is stationary relative to the cmbr? Let say they both started at a speed of factor gama equals 10 relative to the

www.quora.com

 

[G7RUX]

This is "Off Topic Wireless" so I would suggest you go ahead and explain to this engineer what you were trying to do.

 

[chapi]

Thanks G7, what I’m trying to do is long and complicated and does not belong in this forum but in physics Forum.

But radio forum may help a lot, either by helping me to get an interference by placing one antenna at a definite location, or even better, by letting me see on a scope a particular radio signal, could be any definite transmission, from a100 km distance at least in a nanosecond accuracy.

There is a strong radio station transmitting at 494.327 mhz which I believe is located on mount wilson, just east of Los Angeles. I say l believe because there is no record for this station even with the FCC, even though it is possible to receive the strong cw signal from the station at Palm Springs or Santa Barbara, more than 100 km from mount wilson.

I believe it’s on Mount Wilson because most fm and tv stations are located there, and my spectrum analyzer shows the strongest reading there.

What I need is:

Making sure the station is actually on Mount Wilson.

Finding a way to show the 494.327 mhz carrier wave on my scope.

I’m not sure how to do that, tried with band pass filter and signal amplifier but got no results. If there is a way to do it, inc specific equipment to purchase inc the brand’s name and where to get if, will help me to accomplish the mission.

As for the SR, as I said this is not the right place to discuss, but if you or anyone looked at the quora link I provided and find it interesting, I can present more topics but not here.

 

[G7RUX]

Oh I see.

i have encountered your type before I will not engage further.

Good luck with your Baofengs and chatGPT; one of these two is moderately useful in the right context.