Quick question. I'm in the situation of many many others in having my shack on an upper story. Now I've NEVER had any RFI issues. I have a 'serious' amount of copper in use inside and outside the shack and I'm using balanced antennas with common mode currents dealt with as far as practicality allows. However when all is said and done my 'RF ground' (sic) has to travel a distance of 4.14m from shack to ground rods. It's a 9" wide copper strip. Regardless, it's clearly going to show a high RF impedence at higher HF frequencies...
My question is driven more by curiousity than necessity (I stress again I don't have any apparent problems); my ground is:
- x1.6 quarter waves on 10 metres
- x1.4 quarter waves on 12 metres
- x1.2 quarter waves on 15 metres
- as near as dammit a quarter wave on 17 metres (clearly pretty uselss there)
On 10, 12 and 15 metres, is there any effective RF grounding taking place, or is an RF ground basically useless on all higher frequencies once the ground length exceeds a quarter wavelength?
Thanks in advance.