ATS-20+ DSP Receiver

[Westbury]

Just bought one of these cheap ATS-20+ receivers, basically a DSP chip in a box along with an Arduino to play around with.

For the money it works quite well, not great but well enough. Can be used straight out of the box, but the Arduino is programmable from the rear panel socket and have used Arduino's for years so has the potential for me to experiment.

Anyone else got a 20+ or even the earlier 20 ?

[Strawberry]

Hi there.
I'd never heard of the ATS-20 I had to look it up but looks OK for the price.
The biggest improvement you can make to it is to use some sort of ATU, or 'preselector' as they call it in the receiving world.
You can buy something like this cheap from China, I built one a few years ago, they work well.
https://www.aliexpress.com/item/3261521 ... ry_from%3A

Or you can build one yourself from parts, have a look here.
https://vk3ye.com/projects/projlma.htm
All the best.

[Westbury]

I bought it primarily for experimentation as I can get at the code and am familiar with programming.

Have a couple of tranceivers for receieve comparison and decent ATU to use it through (an old G4 here).

ATS works better than antipated for the cost, biggest issue is the agc bounces badly between encoder steps so unless a loud signal you have to pause a moment each frequency step to let it settle to hear weaker signals.

[Strawberry]

Hi
sorry mate

Are you planning to have a go at the AGC problem yourself?
I built an early version of the USDX a couple of years ago which is also Arduino based, I was impressed with that little thing but I managed to plug the LPF in the wrong away around, let the magic smoke out, I bought the bits to fix it but haven't got around to it yet.

I've been having a play with the ERA Microreader today, taking the rs232 ouput to a terminal with LCD monitor which makes it much easier to read then trying to read the little display on the ERA unit.

I'm hoping it will help with my Morse reading listening to on air contacts.
Did you keep up with your Morse code after passing the test?

[Westbury]

First steps which I have done was to get hold of the SI4732 DSP chip data sheet and the schematics for the ATS-20+. Have the Arduino source code and libraries. Just reviewibng it all all the moment. The reciever out of the box lets you turn agc on/off and set attenuation.

Will have to see what I can do about the agc it may be as good as it gets already due to what the chip can do.

Only just got the thing and it's just to tinker with. Retired 5 months ago and was an electronics deisgn engineer and need something to keep my mind active !

My morse isn't what it was but can keep up with slower operators, maybe a bit of work needed on my behalf !

[Westbury]

Some additional info on the DSP chip used and schematic...

SI4732 DataSheet.pdf

ATS-20+ Circuit.png

If anyones interested in experimenting, source codes readily available online.