RadioBanter

RadioBanter (https://www.radiobanter.com/)
-   Shortwave (https://www.radiobanter.com/shortwave/)
-   -   The war against NOISE (https://www.radiobanter.com/shortwave/65768-re-war-against-noise.html)

[email protected] March 4th 05 03:09 AM

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.


[email protected] March 4th 05 05:46 PM

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


Michael Lawson March 7th 05 02:43 PM


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.




[email protected] March 8th 05 06:00 AM

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.



All times are GMT +1. The time now is 01:45 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com