RTL-SDR dongle vs Bias Tee

I’ve bought, for my second station, a cheaper RTL-SDR dongle, because the blue one from Flightware is very expensive. I bought, also, a Bias-Tee. Both pictures are enclosed.
I have 2 questions:
Does the Bias-Tee will increase the gain of that RTL-SDR dongle ?
How to feed properly the Bias-Tee card ?

Thanks in advanced for any help


A bias-tee simply supplies DC power to the antenna connection. It does not do anything further itself, it’s used for powering some other device like an external LNA.

If you don’t use an external LNA or an active antenna then there’s no need for bias-tee power.


Hi, @obj

Thanks for your quick answer. So, I’m going to resell my Bias-Tee. Next time I’ll ask first, before buy :joy:

Most of the chinese bias-T’s are pretty cheap, so consider keeping it for future ‘play’.

Be careful with the connectors - it’s be easy to assemble that one backwards.
The RF-connector goes to the receiver.
The RF+DC goes the amp/LNA/combo LNA+filter. Then out to the antenna.

Do you have a link for the one you bought? The inductor looks a bit marginal for 1.1GHz.
As a rude and crude rule of thumb, the smaller the components, the higher the freq. the will work at.

A quick search has found a couple that look very similar to yours and makes my point:


10MHz - 6000MHz

Hi, @geckoVN
In fact, this Bias-Tee was very cheap. So, I’ll follow your advice and, keep it .
Thanks for your explanation