Additional Red Pitaya CW skimmer notes, last update 2018-08-22 for original detailed post see: Red Pitaya SDR as Core of CW Skimmer – Part 1 Notes and Updates 2019-02-01
Note 4, RX Antenna: The skimmer system is now using the 3.8 wave inverted L as its RX antenna full time. The only anticipated interruptions will be occasional 160m contests.
2018-08-22:
Note 1: Skimmer station outage in mid July 2018, cause appears to be rx antenna related.
Note 2, Transformer: N6TV identified a mini circuits 14:1 transformer that is suitable for use with the Red Pitaya on RX. Expect the transformer to be available from Red Pitaya, or occasionally N6TV. Available from mini-circuits vendors, but may be expensive in quantity 1.
Note 3, RX antenna: Some what by accident I discovered that the 160m L I use for transmit seems to make a fine all-band rx antenna for the Red Pitaya skimmer set up. FWIW, the antenna is about 140 feet of wire. About 60-70 feet vertical, with the remainder making a dog-leg turn from top of vertical section. From there it runs horizontally NW to second support about 40 feet away, and a second sharper turn to the east, horizontally and slightly downward for the remainder which runs west to east. The radial system is the K2AV type folded counterpoise system described in more detail at link.