On Jun 25, 5:29*pm, "Justtis" wrote:
Anyone know of a good site offering build plans. *Prefer plans from someone
who has built and used same.
I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html

I use the ALA100 with home brew loops. Damn good, but you are right
that it is expensive. The ALA100 is the cheapest of the Wellbrook
products. They have some variants of it now. You need a good radio to
use an untuned loop since it delivers a huge amount of RF.

I suspect the ALA100 is just a wideband transformer and a common gate
amp. You can get North Hills wideband transformers on ebay. I have a
few of these transformers, but haven't got around to trying to make a
home brew wellbrook. I found half a dozen North Hills 1301LB
transformers in a surplus shop and wiped out their stock at $6 a pop.
Oh, and I'm being a jerk and hoarding them.

If you don't want to pay for a North Hills transformer, I suspect any
passive video over twisted pair transformer will do the trick.

I was thinking of using one unbal to bal to feed the source of a
depletion mode JFET, ground the gate, then use the balanced end of
another transformer as the load, tying the free end to the power
supply, bypassed to ground, and of course the other end in series with
the drain. Then feed the unbalanced side to the radio.

If you had enough of these transformers, you could probably make a
multicoupler using the same dcheme. Instead of one transformer in the
path of the source, use several.

There is some misconception that the Wellbrook loops are shielded. the
pipe that you see is the loop itself.