I'm new to amateur radio, and as a beginner project, I wanted to use some of the basic components I have to create an AM receiver.
Anyway, what I'm trying to do is create a simple AM receiver that simply detects if a radio station is transmitting, or not. I'm not interested in listening to that station, I just want my receiver to detect the radio waves (basically, I'm just trying to detect a carrier wave).
I've spent a lot of time researching how to make what I'm trying to make, but all of the websites I visited explain how to make radio receivers with speakers (such as crystal radios, or very complicated AM receivers). For example, I tried building this one by modifying it (aka replacing the speaker with an LED), but it doesn't work even after tinkering around for a couple days, so I thought I'd ask you guys for some help :)
To be more specific, I would like to receive the AM signal/carrierwave using an LC circuit to detect a specific frequency, and then amplify that signal to drive an LED (since the station's AM signals are too low: around 50-100 μV).
I'm pretty new to radio and circuitry, but I've done some research and I think I have a general understanding of what's going on. Regardless, I was hoping to make a detector that is super simple, using basic components such as those used on the site I linked. Lastly, for the sake of simplicity, we can leave the LC circuit permanently tuned to, let's say, 1000 KHz (also because I don't have variable capacitors or inductors). I've struggled with this for a while, so I truly appreciate guidance from you guys!
EDIT 1: When I say that replacing this circuit with an LED didn't work, what actually happened was that the LED simply turned on the whole time, regardless of whether or not the receiver was picking up a signal (which was confirmed by disconnecting the antenna and LC part). I deduced that the reason for this to happen is that since there is a constant current running in the base of the NPN transistor, there is also a constant current running thorugh it's collector and emitter, and therefore the LED has current running through it, keeping it on. I haven't been able to solve this issue, so if anyone knows how to keep it off (until it receives a signal), let me know!!