I am back from the megalocation at CR3L Madeira Island after working CQWW SSB with the R25 RRDXA team. It was a great weekend and we achieved good run rates however our targets were set at a higher QSO number. Since CR3L is in AF zone 33 we worked three pointers both to Europe and US and got a good score. That was fun. Claimed score looks like we will be around number 9 worldwide (a bit above 15M points). The CR3L Madeira station is located at Santana in a mountain side on Madeira overlooking salt water. Thanks to the team! Ops: DF4UM, DH4JQ, DJ5KW, DJ8VC, DL1EK, LB3HC . Stay tuned for 2013 events.
LB3HC receives special callsign 8S7X
Antenna isolation calculator for colocated contest / DXpedition antennas
I have made some quick isolation calculations (dB) for the scenario of two rigs with 100W output power collocated using two dipoles mounted some meters apart on the same support but with separate feedlines.
A Preliminary conclusion is that a BPF + notch is likely necessary for interference free operation. With good filters and notch, the second harmonic will be at a 7uV level and the hash will be at a S1 level on the antenna connector of RIGB which is equivalent to a moderately strong signal on 20m with low noise. Without filters, the second harmonic will be S9+50dB. The phase noise "hash" will likely be at S3. This will likely be a significant problem.
Download the calculator here: isolation_calculator_nine_islands. The calculator is posted under a Free Beer license. You owe me a beer if you use it! Please give feedback and peer review the calculations.