[hpsdr] Antenna Switch Version 3

[Ronald Cox]

For those of you who have considered using Gerd's (DJ8AY) HPSDR antenna switch, but were concerned over the RX isolation provided, version 3 is now available. See this message from Gerd:

"I am selling now antenna switch V3 with improved rf rejection from the RX
connector and slightly better impedance match 50 Ohm. (see plot). Instead of
shorting RX to GND while transmitting there is now a second relay with the
open isolating the RX connector very short after the connector pad on the
pcb. The protection Diode is kept unchanged.
It results in an rf rejection of better than 70dB and a reflection of the
transmit signal (S11) < -30dB.

There are also decoupling capacitors at all incoming lines to shorten noise
to GND.

The pcb dimension are slightly changed to fit the pcb in a housing available
from Schubert. If desired I can deliver this housing for a low price (tbd)
but without the openings for connectors a.s.o."

Ron W9KFB
Indianapols
(red_ella on eBay)