Going Magnetic Loop

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vincent:
I posted this link because maybe (if interested) part of the argument, I do not know the performance of these antennas and I don't know the manufacturer/seller.

http://www.ciromazzoni.com/English/Loop%20Antenna.htm

flintstone mop:
Quote from: Opcom on October 19, 2011, 01:17:57 AM

How are magnetic loops at rejecting line noise?

That's the beauty of magnetic loops.....The line noise is electrical which is part of our Electromagnetic radio signal. The loop is only listening for the magnetic part. I'm not into the good tech talk using $.25 cent words. But when I switch to my magnetic loop on receive the noise floor goes down over 10dB and those little signals lost in the grass are now readable.

Thanks for the reminder link Steve.........3 inch pipe starts to be real nice. What I picked out of the QST article was losses. You need to make extremely good mechanical/electrical connections and you have to deal with distributed capacitance. That is why the Ham in QST made a 2 turn loop for his project.
And legal limit is possible. You need a 30kv vacuum variable......the only expensive part.......I'm looking at these other links......
EDIT....looking at Steve's link for one of our guys and his loop. The 3 inch aluminum pipe and big vac variables were a lot more than I thought for cost. And there were some complications to get it on the air.........
I have a nice big lot, but nothing high to hang a decent antenna for 160 or 75M.
Fred

flintstone mop:
Thinking whilst driving a school bus....
WHAT IF:
instead of using expensive metal for the loop.......make the loop FORM using 3 inch dia. Fiberglass or even thick cardboard tubes epoxied together keeping the 3 inch dia. in mind
WRAP the entire circular or octagon or rectangular Fiberglass form with overlapping 2 inch wide copper strap??
Overlapping will allow one to SOLDER the overlaps to make it like one continuous piece of copper. It would be lighter than using copper pipe or even aluminum pipe. The goal seems to be big diameter pipe and big size of the actual loop.

Please read warnings about RF exposure. These magnetic loops at legal limit can be lethal. Something about running a vacuum cleaner 200 feet from the loop antenna from the radiated RF
here's the link again: http://www.bulldogtrust.com/index12.htm

Steve - K4HX:
"I have a nice big lot, but nothing high to hang a decent antenna for 160 or 75M."


What do you have up for 160 now?

A mag loop is not going to give you any better signal than a dipole. An inverted-L with a good ground system may out perform the loop.

W0BTU:
Quote from: flintstone mop on October 19, 2011, 10:45:37 AM

WHAT IF: instead of using expensive metal for the loop.......make the loop FORM using 3 inch dia. Fiberglass or ... WRAP the entire circular or octagon or rectangular Fiberglass form with overlapping 2 inch wide copper strap?? ...

That's pretty much what K8NDS did, and I was thinking of doing the same. But when I priced all that, it cost (and likely weighed) more than 1" (actual OD is 1.25") type M copper water pipe. Two 10' sections plus the elbows is <$100 at Lowe's or Home Depot.

Having said that, perhaps your idea would work great for a ~3" OD loop.

Other ideas (which I haven't pursued) are paralleling two loops made from copper pipe, or using large Heliax.

Keep in mind that the bigger the loop diameter, the smaller pipe you can use for the same efficiency. You can see that by downloading AA5TB's loop calc spreadsheet and playing with the numbers.

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