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As mentioned, you will need to check the bias level. There is a POT near the final for this purpose. Also as mentioned, different makers/batches of IRF520's can have different bias requirements. Short answer is usually yes you can do a drop-in replacement, but be aware its not 100% of the time...

Newer Uniden/Bearcats do seem to be using MOSFET's as standard, at least in the larger models. I've not looked that closely at their smaller models.

Here are a few more photos showing more detail. Still no closer to knowing what it is, lol! the bit in the middle looks like its holding an old razor blade or other sharp-edged item. I haven't tried to take that apart to see what it is yet.

I'm sure I'm not the first to do this, but here's an idea for reusing those old SO-239-style antenna mounting studs. If the main body of the SO239 section is in decent shape, use a punch/vice or other method to drive out the "guts". Locate a retainer nut from an old CB or HAM radio's SO239...

Yup, I remember seeing that on PSK reporter as well. I've been using FT8 on 10M to draw in new hams here at the shop with some success. Customers are amazed at just how far away you can make a contact, and it really sparks interest. The more new HAM's we can garner the better!

I almost ghosted this thread, but I was dying of curiosity. Glad I read it, there's enough wit to fill a casket! On a serious note, its a pretty interesting idea!

This wasn't an actual contact, but PSK reporter shows I was picked up just off the Northern coast of Antarctica earlier today.

Your guess is literally as good as mine, lol!

I acquired this as part of a lot of vintage radio gear (including some nice Heathkit transceivers that I'll put up for sale soon), but I have no idea what it is. My best guess is that it has something to do with a fancy crystal radio set. Anyone have the correct answer?

IC16 is an 8-pin DIP, 458.458 dual op-amp. It is used for amplifying the mic audio, and for handling transmit/receive switching. I've circled its location in yellow in the uploaded image. Incidentally, this is the same chassis as the original RCI 2950/2970 radios and their base-station derivatives.

I am about 99.999999% sure that the IRF520 was never used in that model from the factory. This is most likely after-market, either a botched repair attempt or power upgrade, but if your friend had it from new and never had any mods done, it does raise an eyebrow a bit. As for your current issue...

I agree with previous posters in that you need to identify the type of noise. Is it just general static or is there some sort of "note" to it, as in a discernible tone under neath it? If it sounds a bit like a 50/60 or 100/120 cycle hum in the static, then some of your issue is likely from the...

Amen!

I appreciate the vote of confidence, but hopefully we can figure it out without you having to make two 3-hour drives!

I'd go a step further. Check for continuity between each MOSFET's center leg and ground after lifting that leg from the board. If you see continuity, it is shorted to ground. Check final and driver MOSFETs, but final is more likely from my experience.

No problem!

This is a very rough direct-entry frequency generator I threw together several years ago using an old telephone keypad, a cheapo 4-line LCD display, an Arduino Uno, and an SI5351 clock generator chip. There is no filtering as it was only intended to generate quick test signals to check for basic...

I have a Moonraker 4 beam antenna that was never installed for sale for $600. It includes all parts. The original box was deteriorated and had fallen apart when I obtained the antenna in an estate buy-out, but all parts were present. I've since put all of the parts except for the two longest...

The 636 is not an electret or condenser mic as the OP was asking about. Niether is the Stryker noise canceling mic. Between the two, I'd pick the 636, but I don't like either one. I've attached a quick audio file doing a direct audio comparison of the Ranger SRA-198, the Astatic 636, and the...

Stating that your "audio is off" is a bit ambiguous. It could mean that its low, and/or distorted. If it was low, then increasing the mic gain or using a stronger mic would be the obvious solution. If distorted, it may be an improperly-adjusted (on non-functional) AMC and/or ALC circuit, which...