Great tutorial and works great! I used a 100uA meter I got from an old metal detector and a 10-turn 1K pot. The multi-turn pot makes it much easier to zero in. I also tried a 500mA gauge which worked, but was less sensitive. I attached a telescoping antenna which increased the range dramatically to several meters away. I had to turn the sensitivity way down. I used a fixed 100nH inductor in the tank circuit with a germanium diode and a 820p cap. The JFET is a J211. I'm using 9V, but I was able to get it working with proper sensitivity at 3V. At 1.5V it lacked sensitivity. I'm using it to adjust an FM transmitter I built based on the KZfaq video "Quality FM transmitter" from andydaviesbythesea, to which I've added a power amplifier stage. BTW, I also copied your square loop transmitter, which works very well, and your mains-powered LED indicator. I use it to monitor my soldering iron so I remember to switch it off...Thanks again to all of you who provide informative videos.

It was designed for VHF/UHF, but I don't see why it would not detect HF. I would experiment with different value coils. Maybe 2-3 turns of 20ga wire around a 1/2" form. Also need to make sure the antenna is the proper size(1/4 wave or 1/2 wave) for the strongest signal detection.

Got it working all the way down to 3.5 MHz, prob a bit lower. Really worth the time to build.

Beautiful job! I have to biuld one! Cheers from Australia

Many thanks great tutorial. Acquiring JFET 2N4856 and 100uA class 2.0 ammeter to build my very first RF Strength Meter.

I have a couple old CB' radios I could salvage parts out of . ANY Advice and or tips would be much appreciated .

Brillian! :D

I find the size of the antenna needs to be roughly the same size as that of the transmitter I'm detecting. A full sized telescoping antenna detects my 17'' ground plane transmitter antenna, but I need to use a small wire antenna to detect an FM bug transmitter. Any thoughts?

Can we replace with bjt or mosfets ?

How about 50 uA panel?, I couldn't find 2N4856, which values Is the important in the data sheet for finding an equivalent transistor?

Can I use an schottky diode instead of germanium one for better sensitivity?

What about HF 30MHz and below?

Yeah I don't care about the cartons or graphics its the knowledge I'm here for and you my friend come with it with no bull shizzllin... I know here in the new world order america this will be forbbiden soon so I'm taking notes ( 11 out of 10 STARS) THANX

Anyone know how to detect a 500 htz signal and help me out?

Why should a simple, nice, and clean intro video bother you? Your still getting the exact same content/highly detailed videos. I don't intend on using that intro video all the time anyway. I will still be using my older intro video/music. The reason for the newer intro video is to make the videos look more professional, and draw in more subscribers/views. I should be getting more subscribers/views than I get,so if a good portion of my subscribers are not spreading the word, I have to take action

I love your videos, but I don't think those fancy new graphics on the intros go with your style. They are cold and modern, and your style is warm and friendly. The graphics push me away and your style of presentation draws everyone in. What if you just used a piece of paper with the video title on it in big letters handwritten. Then that would go with your style of presentation which I think is just outstanding. And I like your choice of circuits.

I find the size of the antenna needs to be roughly the same size as that of the transmitter I'm detecting. A full sized telescoping antenna detects my 17'' ground plane transmitter antenna, but I need to use a small wire antenna to detect an FM bug transmitter. Any thoughts?