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Hello my friends, because on my new qth, the antenna is only possible under the slate roof, I want to ask if anyone has experience with this, is it even worth dealing with it?. It would be a multiband verical approx. 3m long.
Thank you in advance for any reactions
Stefan OM4TW
Hi,
far better, than three meters “multiband” any magnetic loop antenna will work. It is also easy to hide under the roof and the magnetic field passes through the roof covering perhaps even better, than the electric field from an extremely short radiator. Not to mention the interference of the surrounding equipment in the house by the high intensity of the E field.
In today's state of the art, remote tuning mg. he can do the loop just fine, copper pipes don't cost a damn …
73, EAR
Hi, Steve, I have it under the roof 4. the yaginu na 2 m and until some attenuation there is no problem. The construction of the roof is wood. foil and tiles. Surrounding objects will bother you more, which are part of the attic space and the height of the antenna above the floor, distance from the tile, lightning rod on the roof. The characteristics of the antenna will definitely change, but I say, Take a look at the DK7ZB website and find the length around it.
Len taka vtipna rada.
Mag.loop is an excellent antenna, but it has its little flies.
Especially control, split capacitor, very strong near field, very high voltage on the capacitor plates.
It works, remote control can be done at home on your knee, but it is quite laborious.
If it is about “invisible” antenna, or short for antenna in the attic, rather I recommend it for less work, use a remote-controlled tuner, best SGC, which can also tune low-impedance loops, various shortened antennas, etc.
If it's possible, so use as much of the loop circuit as possible, or make more twists, or make a horizontal slit as well.
It won't get any worse, but not significantly better, I will loop.
But the wide range of retunability of the entire antenna, if he has at least 5 and more meters edge of the creature, makes an assumption, that it will somehow work from 80m to 6m.
If they are used 2 twisted and the creature will have at least one side of 10m and the other side not less than 8m, it works already from 160m compromise, but the 80m band is like a poorly stretched dipole.There is an advantage, that tuning is practically automatic, no fine-tuning is necessary, it's instant, for transitions through all bands, bez cakania, it's in the tuner's memory.
Efficiency is not god knows what, but if enough guide mushrooms are used, 2,5-4mm2 losses are acceptable.
http://www.sgcworld.com/239ProductPage.html
That tuner is actually destined for similar applications.
The cheapest version, he deserves at least a box for food, which has snap locks, or a waterproof installation box.To control, just upload FTP, or UTP cable, it can be reliably powered and controlled up to 100m, the box.
http://www.sgcworld.com/Publications/Manuals/239man.pdfIt can be used in many ways, it's a fast way, how to do it at least somehow well, without the need for compromises and wiring the surroundings.
The biggest advantage is, with signal distribution via coax, from TRX, we work with minimal losses, because the signal distribution from the TRX to the remote tuner, is tuned, the coax does not radiate.
Of course, a full-size antenna is a real antenna, but when it doesn't work, it's a cheap and fast way, how it will work, without the need for an uncertain result and tinkering.
