In past years of multi op contesting we were continously suffering from the many different and exotic designs of peripheral devices at the operating position. Everyone had his own standards in keyers, antenna switches and preselectors.
To improve this situation we came up with the idea of a BCC standard. So the BCC Institute of Standardization (BCCIS) was founded. The BCC preselector was its first project to make an end to cooked attentuator resistors, broken preamp units, shorted switching diodes and frustrated operators.
Many a contester has developed his own device in the past years, each of them in a different way with a different operating and switching philosophy. Using such a device in a multi-transmitter environment is a must. But is is difficult to understand how to use it in the middle of the contest after endless hours of operating. That is how we came up with this concept.
Using an original design by DL7AV, we placed easily available components on a PCB and added a switch for selecting different receive antennas. The device prevents receiver damage in multi-TX environments by attenuating out-of-band signals by at least 20 dB.
Fifty such preselectors were assembled in the BCC labour camps (in Eching nr Munich, Bavaria) and distributed among the BCC membership. They are being used with continous success by their proud owners.
What we did was: take a simple circuit, make a board and use easily available parts.
Fifty such units were competely assembled in the BCC labor camps in Eching (near Munich) during March and April, 1996. All of them have been sold to BCC members. However, if you are interested, a very detailed description in German is available as a PDF file (504 kB) including PCB schematics, layout etc.