I've laid out a small PCB with a relay circuit that will toggle the PennyWhistle's bias low during transmit and juggle the RF connections between the Peaberry, a PennyWhistle amplifier, a Low Pass filter and an antenna.
Total parts cost of the relay board minus the PCB will be about $15, consisting of a 12vdc DPDT relay, a simple relay driver circuit, four board mount BNC connectors and a some .1" spacing header pins. All parts are in plentiful stock at Digikey. Will have 8 pcb's fabricated and will populate and test one in about 10 days. If they work as well as the prototype, will be willing to sell a few un-populated PCB's to interested parties. Or, will share the artwork and BOM if someone wishes to DIY. PDF of layout is attached.
Am Having a lot of fun with a 20 watt Peaberry!
-Rob
N4WGY