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The antenna shown uses fiberglass tent poles. They are 2ft each. The
larger version uses fiberglass rods from Tap Plastics. They are cut to fit the back of my suv, something like 65 inches. I'd love to use the antenna with the amount of wire indicated on the Wellbrook site. I suspect someone could roll their own Wellbrook. I believe they use a very wideband transformer and a low noise JFET amplifier. You can find wideband transformers on ebay (North Hills). JFET amps aren't that hard to build. The transformer lets you float the loop and does the double to single ended conversion. |
I have read that in several ham antenna sites, but mine has been
in use and outside for at least 4 years. Last spring a lightning bolt took out an Chineese Elm tree about 30' from the "long" wire feeding it. When the tree fell it took the wire antenna, and our fence, with it. I was concerend about the transformer and was mildly shocked to find it unscathed. Somewhere I have a link for a "multi-set coupler" that disusses the commercial and roll your owns and mentions the techniques used by mincircuits give a "flatter wider bandwidth with less loss". The last line is a parphrase of their conclusion. It isn't that we can't wind good low loss, wide bandwidth transformers, to me being able to buy one for a few (my 9:1 cast less then $4 US) dollars will help get the project done that much faster. And in a situation where a JFET amplifier is under consideration, I supect that the FETS will get fried many more times the the tranformer. Terry |
wrote in message oups.com... The antenna shown uses fiberglass tent poles. They are 2ft each. The larger version uses fiberglass rods from Tap Plastics. They are cut to fit the back of my suv, something like 65 inches. I'd love to use the antenna with the amount of wire indicated on the Wellbrook site. I suspect someone could roll their own Wellbrook. I believe they use a very wideband transformer and a low noise JFET amplifier. You can find wideband transformers on ebay (North Hills). JFET amps aren't that hard to build. The transformer lets you float the loop and does the double to single ended conversion. The Wellbrook is definitely a balanced amp, but I've not heard of someone who's either reverse engineered it or built an approximation of one, as the demand would be pretty good, I'd imagine. --Mike L. |
The Wellbrook is great, but not a big seller, especially the ALA 100,
which is just the amp. Based on serial numbers, they sold 3 in 9 months in the US market. Other than size, the wellbrook beats out any of those loops like the Kiwa or Quantum. The Kiwa might be of some advantage if you don't have narrow band filters in you radio, but anyone forking out the $400 for a Kiwa probably has a decent rig. I suspect the US market doesn't like the hoops you need to go through to buy the Wellbrook. No secure internet website for instance. No toll free numbers. |
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