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?