In reply to G0VOF:
A good example would be G/SP-001 Kinder Scout
Ding, ding, ding, ding, ding… we have a winner!
Absolutely spot on Mark. On two activations I have been quite disappointed by performance from my simple J-pole. They were on Kinder Scout and Long Mynd. Myself and Brian G4ZRP had walked well over a km up up the river bed from Kinder Downfall to get some altitude. We operated from a big flat wet peat plateau. Whilst we worked 70cms and 23cms OK the 2m performance was not good. Antenna was the 300Ohm ribbon J-pole with the base about 3m AGL. I was expecting to need a big stick to beat back the chasers. As it was it was hard going. Likewise on Long Mynd where performance to the North was poor. Elsewhere it does what I expect. It’s not brilliant but it is so simple, light and easy to setup. Perfect for SOTA in the right part of the world.
Look at the OS map… Kinder is a big flat plateau, Long Mynd has a ground very gently lowering to the NE. Now maybe, just maybe, a few cm more height would have made an improvement. But it’s hard to know how many. In absolute terms doubling the height would make an improvement. Although in my case, the J-pole feeder wouldn’t reach the ground
Looking at the difference between the two summits. The steep drop off the SSW round to the N of Shining Tor makes a wonderful location to work from as it looks over a massively dense area of people. Note these results have been De-Delilah’d! Mike has done so many more activations of Shining Tor compared to Kinder Scout that he skews the results. Also he’s operated from Shining Tor during some fine tropo openings which also skew the results further. The results will include a range of antennas and heights AGL and powers. Red for 2m-FM, blue for 2m-SSB.
It would be enlightening to play with the same antenna at differing heights from Kinder and map the changes. Sadly for me, it’s a long way to come just to prove what can be seen every time you drive past a commercial antenna site.