The AM Forum

In haunting the various surplus places prospecting for 7/8" Heliax I discovered some "new style" Heliax at bargain prices.  However, I remember someone and I apologize for forgetting who mentioned the new style has copper that's paper thin.

Would I be better off keeping an eye out for the older style LDF5-50A and pass on the new AVA5-50?

my zero cents FWIW  ;D is that it sounds like the old stuff is better because it should be easier to put a connector on without screwing up the shield.  sounds like they're trying to cut down on the copper content to save $$$.

The older style had spiral grooves on the outer copper, the newer style has parallel grooves. You could screw a connector onto the old stuff, the new style requires entirely different connectors. The center pins on the smaller old stuff often needed to be soldered on, the new series of connectors are entirely solderless.That's the big difference.

I haven't noticed any difference in the copper content of the shields. Heliax needs to be strong enough to hoist a great distance up a commercial tower without breaking apart under its own weight.

In that case I retract my previous statement (there was a reason why it was free)--the new stuff is not a recent development as I had assumed--it seems to have been out for a few years.  By your description Bill my two LDF4-50 runs are the new stuff and they work FB.  the copper shield is not tin foil thin and has enough thickness to work with.  The connectors go on with some compression fittings and O rings but with mine, we had to solder the center pins on (Brass N connectors--all we could get--no UHF).   

Rob

Thanks Bill.  BTW,  Tomorrow I'm helping your old Navy buddy gather yet another ancient broadcast transmitter, an old Western Electric that was KFRC at one time.  Gary has a bad addiction you know. He sold the other WE to Colorado Rod, W5CZ, conned his buddies into helping move that monster and here he is doing it again.

The AVA series is not a replacement for the LDF series, rather it is a mid-attenuation between the HJ- (air-filled) and LDF foam dielectric.

AVA-Almost Virtual Air- was spawned by the 'wireless' industry.  Cheaper by the minute. :P

My a$$!

73DG

I've been to Rod's place, CZ and saw that old WE transmitter. What a beautiful piece of work and restoration.

Nevertheless, I'm of the old school, I don't care how fugly my transmitters are as long as long as they reach out on the ether.

Right now there's a 500 Pf transmitting cap dangling out of the removed top cover of my 304 rig on a pair of #14 wires.. Keep OSHA out of here.


Bill

OSHA hell, keep your damn hands, nose, ears and anything else sticking out that high, away from that thang.