FlightAware Discussions

Bias-t and USB Power Combined

I have an LNA that is powered via USB. I would like to use a spare SMArTee v2 dongle with it, but the bias-t cannot be turned off. Can the extra 5v input damage the LNA? I can buy a voltage block, but that defeats my purpose of using spare parts.

Which LNA?
  

Nooelec Barebones Wideband LNA. It really needs external power because the RPi doesn’t have enough power to feed bias-t.

Use a DC blocker between SMArTee v2 dongle and the Coax from LNA.
The DC Blocker is basically a few hundred pF capacitor, put in series of the central wire of coax.

https://www.amazon.com/s?k=sma+dc+block

1 Like

@abcd567 Thanks for the info.

@ua549
Be careful. Some of the search result for DC Blocker at Amazon are Attenuators.

Nooelec has a DC block on their site for 20 bucks.

Quote from the Nooelec description page:

Each module allows for 3 different power options, but you should only power with one option at any given time!

https://www.nooelec.com/store/lana-barebones.html

I know about “should”. I was asking about “could”.