Hello
I’m beginning to try getting into some RF stuff.
I decided to start with a SDR receiver, based on the LT5517 chip.
You can find it’s data sheet here: LT5517
The chip is a quadrature demodulator that it’s specified from 40MHz to 900MHz. It can be pushed to lower frequencies by increasing the LO drive.
It works pretty good down to 3.5MHz ( 7MHz LO ) with ~ 0dBm drive.
Once LO gets over 40MHz ( 20MHz RX ) the LO can be as low as -15dBm with no problems. Usually I keep it at -10dBm for convenience – the signal generator I’m using now to generate the LO has a dedicated key to modify the output signal in 10dBm steps.