AT-2000 coupler from Mizuho, Japan - part I.

Hello,

listeners and DXers often encounter the need for preselection or some version of a bandpass filter at the input of their often very wideband receivers.

One option is factory equipment, which is sometimes available on online marketplaces such as eBay.

One of these is the AT-2000 coupler, which was manufactured in the past by the Japanese company Mizuho. (also made by Global and some others)

This unit should cover 0.5 - 30MHz range and would be able to work with wire antennas and in/out impedance range 50-600 Ohms. Unfortunately, do not expect the balun transformer in between unbalanced and balanced antenna input.

Here is what you will get when you purchase it on the flea market. In most cases it is in good conditions...

This coupler circuit applies the Pi-match method, and the "heart" of the unit is 25mm diameter single layer winding coil.

User manual to download