13-03-2019, 07:17 PM
Nev,
Re-read your post and apologise for reading it as shed instead of metal-clad house walls. My error.
Keep in mind that metal cladding - as well as the colourbond-style fencing - doesn't actually have to have a full electrical contact (ohmic) between each piece. The metal overlaps, even though insulated by paint, still have fairly high sheet-to-sheet capacitance if the overlapped areas are large enough. The dielectric spacing is quite small ( 2 x paint thickness in most cases) and the dielectric constant is likely to be high. That "capacitance effect" is likely to provide a low capacitive reactance at HF.
As for distance, I would suggest 1 - 2 metres would be a reasonable enough separation, and as Terry suggested : Try it. Your physical environment is the determining factor so what it is, it is. Experiment.
I use my 7M squid pole (wire up the middle) about 500mm from the body of the caravan, the base is a pipe u-bolted onto the drawbar, and a similar pipe mount on the rear bumper about 300mm away from the body there. Both mounts provide similar results on HF - as attested by the reports on FT8 while wandering the countryside. Proximity doesn't seem to be an issue.
I used to live in suburbia - for some 38 years in houses we owned and with all of the limitations of suburban blocks and nearby neighbours - but about 6 years ago, we moved to a semi-rural environment. I now have a 4350 SQM block, enough space for 2 tilt-over towers complete with yagis on all bands from 20M to 23cm plus full size multi-band wire dipoles for 160 / 80 / 40 / 30M plus miscellaneous verticals for 6, 2 and 70cm. It was a big move for us but it gives me the antenna opportunities I never had access to in suburbia. The neighbours are further away and don't care what antennas - or how many - I put up (I've asked!). And less HF band noise too. Best move ever.
PS Just did a quick count : 17 antennas up in the air right now, more in the shed for FDs, caravanning, portable operations, then more 6 / 2 /70 cm yagis stored outside the shed wall. I just don't count the other things like gridpack reflectors stored outside the shed too.
Re-read your post and apologise for reading it as shed instead of metal-clad house walls. My error.
Keep in mind that metal cladding - as well as the colourbond-style fencing - doesn't actually have to have a full electrical contact (ohmic) between each piece. The metal overlaps, even though insulated by paint, still have fairly high sheet-to-sheet capacitance if the overlapped areas are large enough. The dielectric spacing is quite small ( 2 x paint thickness in most cases) and the dielectric constant is likely to be high. That "capacitance effect" is likely to provide a low capacitive reactance at HF.
As for distance, I would suggest 1 - 2 metres would be a reasonable enough separation, and as Terry suggested : Try it. Your physical environment is the determining factor so what it is, it is. Experiment.
I use my 7M squid pole (wire up the middle) about 500mm from the body of the caravan, the base is a pipe u-bolted onto the drawbar, and a similar pipe mount on the rear bumper about 300mm away from the body there. Both mounts provide similar results on HF - as attested by the reports on FT8 while wandering the countryside. Proximity doesn't seem to be an issue.
I used to live in suburbia - for some 38 years in houses we owned and with all of the limitations of suburban blocks and nearby neighbours - but about 6 years ago, we moved to a semi-rural environment. I now have a 4350 SQM block, enough space for 2 tilt-over towers complete with yagis on all bands from 20M to 23cm plus full size multi-band wire dipoles for 160 / 80 / 40 / 30M plus miscellaneous verticals for 6, 2 and 70cm. It was a big move for us but it gives me the antenna opportunities I never had access to in suburbia. The neighbours are further away and don't care what antennas - or how many - I put up (I've asked!). And less HF band noise too. Best move ever.
PS Just did a quick count : 17 antennas up in the air right now, more in the shed for FDs, caravanning, portable operations, then more 6 / 2 /70 cm yagis stored outside the shed wall. I just don't count the other things like gridpack reflectors stored outside the shed too.
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.