```Lots of rain and strong winds all weekend, so my antenna was is 'save position' (all ropes loose) all weekend except for friday evening when I heard ON6ND with his new TX (now 599+), some G's and OH1TN with a very strong signal (579). I took some time for reading and found a couple of interesting formulas for calculating the 'free space' capasitance of wires : ```1. Horizontal wire : C(pF) = 0.24 x Er x L(cm) / log(4 x H / D) ```where Er = relative diëlectric constant (1.0006 for air), L = wire length, H = wire height and D = wire diameter 2. Vertical wire high above ground : C(pF) = 0.24 x Er x L(cm) / log(L / D) 3. Vertical wire close to ground (H << L/4) C(pF) = 0.24 x Er x L(cm) / log(1.15 x L / D) I made some calculations for a 3mm thick wire and the results are very acceptable : For a horizontal wire I got a capasitance of 7.7pF/m at 1m height, decreasing to 6.3pF/ at 5m height, 5.8pF/m at 10m height and 5.2pF/m at 30m height. For horizontal wires starting at ground level I got 9.3pF for a 1m heigh wire (average 9.3pF/m), 36.6pF for a 5m heigh wire (average 7.3pF/m), 67.0pF for a 10m heigh wire (average 6.7pF/m) and 177.3pF for a 30m heigh wire (average 5.9pF/m) 73, Rik ON7YD ```