On Tuesday, 1 October 2024 05:15:34 EEST you wrote:
RF output about -50db If viewed from a spectrum analyzer£¬about -40db if
viewed from the qradiolink receiver and set RX gain 100%. These are GUI
images in attachments.
Ok, that didn't make sense. -50 dB relative to what? Full scale? milliwatt?
What I saw in your photos was just some extreme distortion in the PA or LNA
stages or both, caused by too high gain values. Not having a demodulator offset
from the LO also doesn't help. You also didn't specify what kind of SDR device
you use and other meaningful details. It is impossible to help you with such
limited information, and you also appear to lack some basic knowledge about
software defined radio. That's ok, we all started like this, but you need to
learn the basics before even starting to transmit signals.
My advice to you is to start reading up a bit on the theory, to avoid
frustration and in the worst case possibly a destroyed expensive device.
I would start with reading this excellent online book:
You don't need to concern yourself with the programming related topics, but
you need to have a good understanding of RF signals, SDR architecture and
digital signals before you try transmitting. I also recommend reading about RF
amplifier theory, linearity and non-linearity and how this matters for various
kinds of digital and analog signals.
Finally I recommend studying for an amateur radio license. Besides giving you
rights to transmit signals in the radio spectrum, it will give an
understanding about other important topics that you need to have if you want
to experiment with radio signals.
Best of luck,
Adrian
