Adding a Panadapter to a Classic Receiver

-

There was a time when only the richest ham radio operators could have a radio with a panadapter. Back in the day, this was basically a spectrum analyzer that monitored a broad slice of the receiver’s intermediate frequency so you could see signals on either side of the receiver’s actual frequency. Today, with SDR technology and computers, this is an easy thing for receivers to implement. But what if you want to refit a classic radio? It isn’t that hard, and [Mirko Pavleski] shares his notes on how he tackled the project. You can also check it out in the video below.

The plan is simple. A FET amplifier taps the radio’s IF stage before the first IF filter. This provides good isolation and buffering. Then, an emitter follower stage provides a matched output to the SDR through a low-pass filter. The SDR remains tuned to the IF frequency, of course. The rest is essentially software and procedures.

Of course, your exact connection to your radio will differ unless you have the same receiver shown in the video. A modern scope with an FFT should be able to help you quickly locate a good spot, though.

Of course, you could just listen through the SDR, but that doesn’t seem sporting but that’s what it looks like he does in the demonstrations. Essentially, he’s using the radio’s RF system via the first IF mixer, then letting the SDR handle the rest. But you could just use the display and tune the radio instead.

If you really wanted a cool system, you could frequency count the internal frequencies and display the correct frequencies in software. Then you could also track the current frequency. This would make it seem more like a traditional panadpater and less like just replacing most of the radio’s features with an SDR.

We’ve seen these before, of course. Many times.



from Blog – Hackaday https://ift.tt/Jcq1rHu

Comments

Post a Comment

Popular posts from this blog

Modern Radio Receiver Architecture: From Regenerative to Direct Conversion

-
Image
Modern radio receivers have a distinct advantage over the common early designs which I covered in my previous article . Most of the receivers you will have worked with over the past couple decades are designs by Edwin Armstrong ; regenerative, superregenerative, or most commonly superheterodyne. These are distinguished by a few fascinating key traits that bring both benefits and drawbacks. Today let’s dive into Mr. Armstrong’s receivers. I’ll also talk about DC receivers which, despite the name, are not made to listen to batteries. These are receivers you are much more likely to encounter in modern equipment. Regenerative and Superregenerative The regenerative receiver is all about doing more with less. You still see some of these in simple applications like RF remote controls. The idea derives from how an oscillator works. In a simple way of thinking, an oscillator is an amplifier with enough positive feedback that any tiny signal at the right frequency will amplify and then, throu...
Get this one»

Join the Movement with this Mini Cyberdeck

-
Image
The global pandemic has given many people a lot more time at home, which has undoubtedly pushed an untold number of projects over the finish line. Unfortunately, it’s also disrupted global commerce and shipping to the point that getting parts can be a lot harder than we’d like. Which is why [facelesstech] decided to put together this exceptionally mobile cyberdeck out of things he already had laying around . Now to be fair, his parts bin is perhaps a bit better stocked for this kind of thing than most. He’s built a couple of Raspberry Pi portables already, so the Pi Zero W, display, and battery management board were already kicking around. He just had to come up with a new 3D printed enclosure that holds it all together with a little bit of cyberpunk flair. To that end, he’s done an excellent job of documenting the build and has released the STL files for the 3D printed components. All things considered, we’d say this is probably the most approachable cyberdeck design currently avail...
Get this one»

Build this Cyberdeck in a Cave with a Box of Scraps

-
Image
Desktop 3D printing has been a big enabler for the cyberdeck community, as it’s allowed individuals to create unique frames and enclosures which would have been far more difficult and time consuming to produce using traditional methods. But what if you don’t have access to a well-stocked workspace, and need to do your building with the bare minimum of equipment? In that case, [ALX] recently put together a minimalistic design that can be assembled with off-the-shelf components and basic tools. It’s the ideal cyberdeck for the neophyte, as all the parts are widely available and relatively inexpensive. While it might not be a customized as something with a fully 3D printed frame, we think it nails the look and utility that are the hallmarks of a proper deck. The key to this build is the SmartiPi Touch case, which puts the Raspberry Pi and touch screen on a hinged panel. These hinges happen to be compatible with GoPro-style mounts, so with a few extension pieces, the panel can be lifted...
Get this one»