Signal splitter

[Lucas Leopoldino]

Hello guys! I would like to split my signal from one antenna to two adsb devices, I can use those TV splitters from 5 to 2500 MHz.What do you tell me?

Thanks

[abcd567]

Splitting signal to two devices make strength of each signal 1/2 of original (1/2 + 1/2 = 1).
Halving the strength of signal, expressed in dB, is 3 dB loss.
In addition to above 3 dB loss, there is additional loss in the components inside the splitter. This loss depends on quality of splitter. Very good quality splitter may have as low as 0.25 dB component's loss, making total loss 3 + 0.25 = 3.25 dB. Cheap TV splitter on average have component loss 2 dB (some may have even higher), making total loss 3+2 = 5 dB loss.

Try the TV splitter you have suggested. If splitted signal becomes too weak, you will need to insert a LNA (low noise amplifier) between antenna and splitter to boost the signal before it is splitted.

[Lucas Leopoldino]

thanks, i will take the test!

[Lucas Leopoldino]

HELLO abcd567, would this cable work instead of putting a splitter?

[abcd567]

Yes, it will work.
(1) The connectors are RP-SMA type in which male has a hole and female has a pin. This type is not suitable for DVBT dongles. The DVBT dongle require SMA type which look very similar (almost identical) to RP-SMA type, but if look carefully at their center, the male has a pin, and female has a hole. Do NOT buy RP-SMA type. Please see attached image which shows the difference

(2) As this will split signal into two equal parts (1/2 + 1/2), it will also have 3 dB loss.

(3) There is no isolation between two branches, so if one or both of your dongles are noisy, each will pass its noise to other. Normally dongles are not very noisy, so this Y will be ok. However if one or both are noisy, performance will drop.

Difference Between SMA and RP-SMA.jpg

[Lucas Leopoldino]

Thanks for the answer, I hadn't tried the connector, but I ordered the right connector, SMA! Regarding noise, there will be a flightware noise filter before this cable!

[abcd567]

Regarding noise, there will be a flightware noise filter before this cable!

The noise filter you mentioned is for filtering out noise in atmosphere which is picked by antenna.

The noise I mentioned is the one generated inside the dvbt dongle, travels to other dongle through Y. There is no filter in this path, as shown by red & green lines in attached diagram.


20211117_210253.jpg

[Lucas Leopoldino]

Got it, I'll wait for the cable to be ready, install it and see how much loss I will have! If it's too much maybe install an LNA!