Connecting two antennas with a BNC T?

[rwgast]

Idk why I am just curious if i use a BNC tee to connect two identical 800mhz rubber ducks will this give me a 1600mhz quarter wave and an 800mhz half wave?

I am in to SDR and I would like to do some work with the iridium sat constellation which is located in the L band at 1600 something, and all my police services are in the 800mhz region so this could be a cool concept if I am not totally wrong....

What would happen if you teed two whips/ducks of different frequency's together? Mind you we are talking straight in to the bnc t so there should be no phasing issues from wire lengths?

 

[N8IAA]

Nope, no 1.6Ghz antenna Just a 800Mhz dual antenna.
Larry

 

[rwgast]

So is there any posotive effects to this? More gain anything? I dont understand how doubling the length doesnt double the fequency?

 

[Voyager]

Diversity reception is an advantage (likely the only one unless you need the length to hang the antenna combo between two items).

You can Google Diversity Reception if you don't know what that is.

Now, if you had a Tee that fed the center to one side and the ground to the other (both on the center conductor of the antennas), it would give you a duck dipole.

 

[rfradioconsult]

Antenna theory 101. When you lengthen an antenna its operating frequency goes down not up. A 150 MHz antenna is roughly be 18 inches, a UHF 450 MHz antenna would be 6 inches long.

 

[prcguy]

If each 800MHz rubber duck is 50 ohm impedance then paralleling two of them on a T connector with a very small fraction of a wavelength of adapter between them will result in around 25 ohm impedance to the radio and no real advantage. You may get some diversity at the expense of higher loss in the antenna system.

A true diversity system will have a separate receiver for each antenna and the antennas will be many wavelengths apart.
prcguy