The AM Forum

Hi All,

I'm making plans to put a station together, pulling stuff out of the garage where it's been boxed up for a few years after a divorce (I can put the station in the living room now....8^).

I threw together a small receive loop thats ok for the duplex I'm in and have been pleasantly surprised with the performance, so I'm going to go with a mag loop for transmitting as well.

I have had this old russian vacuum variable I plan to use, but it has what appear to be steel end caps and I'm wondering what the best metal to metal way to connect to them would be. Easiest would be if I could just use copper, should be able to rig something up relatively painlessly, but I'm concerned about the connection and longevity, especially with the connection quality required for a mag loop. Any advice?

Thanks,

Larry, kz0e.

Stainless steel hose clamps from the auto store.

Thanks Roy,

That helps connect whatever it is to the cap. I'm thinking I want something flexible to wrap around it and clamp on, then braze that to the copper loop, get max surface area to surface area.

And, I just tried a fridge magnet on it, didnt stick. Maybe it's aluminum? If so problem solved. Dont know.

Maybe I'm doing my usual and over complicating all this.

More likely nickel plated brass... ??

How about post a nicely lit jpeg of the item, use the closeup setting (the flower) and let's see what it looks like?

           _-_-bear

Thanks Bear,

I'm just going to rig something up with maybe copper, polish it all up  and clamp it on, see how it goes. After all it's not like it's going to be up on a tower and tough to get to if it doesnt work out.

Thanks for the help.

I agree it's probably plated brass.  I'd try some copper pipe straps from the plumbing department. Two clamps help together with two stainless screws and nuts, and a little no-ox grease and you should have a good low R connection. Have you asked K1QAR what he uses? He's made a few of these for high power you know. :)
good luck.
Mark

please to use non-ferrous screws/nuts around rf .... steel tend to get hotty .... make for loose connection ....beefus

What bands would you like to work?
Mag Loop antenna might get unmanageable below 80M.
Are you going to mount the antenna outside?
A duplex might be a small yard. You'll have to describe more about the future station

Fred

Thanks for all the help everyone.

Fred,

I have a small yard, and not sure how long I'll be here or where I'll end up next, so a loop that can go nearly anywhere sounds good, and I suspect it may be better than anything else I've compromised with in the past.

I'm planning on a square loop, whatever pipe length they have available either 8' or 10' per side. That'll get me right around a quarter wave on 40 (maybe a little more) and still be over an eighth on 80.

This all started when I ordered a Wellstone loop, which still hasnt arrived, and I got antsy and threw together a coax loop in the living room. Like I said I'm pleasantly surprised, especially since it's still indoors. But thats probably more a comment on how crappy my antennas have been all along.

I wanted the Wellstone for the no-tune feature for band criusing, should be fine for that.

Pulled my B&W 5100B out of the mothballs yesterday. if I remember right it ran fine except for tuning getting squirly on 40m, still have to check it out. It's either that or the Valiant. For a receiver I've got an sp-600 and a few years ago I bought Buddly's R390a (that I havnt done anything with, think it just needs an alignment).

So we'll see how the loop does. Lots of info out there, and lots of suspect info too. Having fun with it.

Larry