The Antenna Switch, made by NT Electronics, is designed to switch an antenna to the Mercury antenna BNC connector or to the Penelope BNC antenna connector. This function is included in the Alex filter board assembly, but for various reasons, many in the HPSDR community will opt to purchase a commercial amplifier that will operate with an input of up to 500 mw. Tokyo Hy-Power Labs makes compatible solid state amplifiers and some hams are using them with the HPSDR transceiver components developed and produced to date..
This HPSDR component was developed by Gerd, DJ8AY, who manufactures it currently. Ron, W9KFB is assisting Gerd to make it available to the global HPSDR community by listing it on eBay sites worldwide. You can find these listings by searching eBay for HPSDR components or by just searching for eBay Power Seller: red_ella on any eBay site.
Gerd can supply a small metal box with pre-formed holes (for the BNC and DB25) for 7.50 Euros each. Shipping to the USA is 6.00 Euros, and you can get two of these boxes shipped for this amount.
Ribbon cable diagram (PDF)