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.
“The SDR remains tuned to the IF frequency, of course…”
“Of course, your exact connection…..”
“Of course, you could just listen through the SDR…”
“We’ve seen these before, of course…”
Why, yes! Of course!
To those who’re wondering what it’s all about..
Back in the 1970s, advanced users (operators) of the popular Yaesu FT-101 radio line had owned a YO-100 / YO-101 monitor scope.
https://www.rigpix.com/yaesu/ft101.htm
http://foxtango.org/ft101/YO-100%20YO-101.htm
Other lines of radio transceivers had similar accessories at the time.
They weren’t mere luxury items to show off, but allowed checking modulation and signal quality.
That’s important, since hams are required to check their own transmissions and make sure everything is fine.
In principle, they were as important to amateurs as an oscillograph is to an electronic hobbyist.
A panorama adapter (pan adapter) as mentioned in the article
is that kind of analogous equivalent to a shortwave listener (SWL) or broadcast radio listener (BCL).
(Btw: Both are traditional terms used to describe listeners. An SWL doesn’t necessarily limit itself to shortwave band, either.
There are also radio amateurs that are listeners only.
Some don’t even have a license to transmit, but merely a listening sign.
To participate QSL card exchange, among other things.
In German, for example, they were historically being called “Höramateure”, listening amateurs.
Here they have DE suffix over here and must pass a telegraphy test to get their sign.
These guys are sometimes more ambitious than ordinary radio amateurs and focus on receiver technology.
Being listeners, they also must master patience. Kudos to them.)
Correction, DE prefix. Of course.
Another high-end device was a so-called spectrum analyzer.
It covered few KHz to over a GHz and was cutting-edge trchnology of the day.
Some did cost a fortune, as much as a house.
They weren’t available to most ordinary users.
What was already available to mortals, though, were wide band receivers.
The Yaesu FRG-9600 was based on a VCR tuner, for example.
Which was in the affordable range and very good for amateur needs.
(VCR tuners were highly integrated by the 80s and being mass produced.)