David Woolley wrote: This isn't about high attenuations. The reasoning I used here is that, if building structure losses were negligible, loft antennas would be standard for the higher bands, rather than considered a last resort. -------------------------------
We're getting far afield from the original question (whatever it was - I couldn't figure out if it was about fire danger or something else) but you've hit on a point of long-standing curiosity for me: What *is* the attenuation provided by various structures if the antenna is in the loft (attic) space? I've lived where outside antennas were prohibited and had considerable success with a 60 foot doublet fed with open wire line in the attic of a wood frame building with shingle roof. It was a two story building, so it was about 25 feet above the ground, and the building was on a small hill. When cdx were decent I literally "worked the world" using 10 watts on 20 Meter CW and got out all over north America on 40 CW. I always assumed the biggest issues with an attic antenna were generally low height in most buildings (under 15 feet for a single story structure) and coupling issues to house wiring, plumbing, etc. After all, outside antennas work well even when surrounded by or running through trees, and trees arguably carry a lot more moisture than the dry wood of a frame building. But I've never seen any studies about the losses to HF RF through various construction materials. Has anyone done any studies along these lines to collect actual data? Something like measuring the field strength from a small signal source over a fixed distance with it in open air or in a container of various construction materials (concrete, wood, brick, etc.)? Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
