[Premium-Rx] General Coverage Antennas for HF

[W.J. Ubbels]

Hi all,

The antenna described by PA0SE was designed by professor E.H. Nordholt of
the Technical University Delft in The Netherlands, I believe that he has
retired now.
The prototype was built using a sort of "haywire"-contstruction, i.e. the
componenents are connected to eachother without using a printed circuit
board. I built mine in the same way into a small tin box, which naturally
serves as the ground connection for all the components. Some difficulty may
arrise in obtaining the 1G (yes, 1 giga!) ohm resistor , I was lucky enough
to find 2.2G resistors for sale at a local surplus store, so I put 2 of
these in parallel. As PA0SE says this resistor can be replaced by a string
of several 100 Mohm resistors but this raises the lower frequency limit a
bit.
I substituted the 2 E212 jfets by 1 U440 double-jfet (2 fets in one package)
which I had lying around, and it seems to work out well. The 2N5583
transistors might also be hard to find, but maybe they can be replaced by a
more regular type. I believe that the antenna is patented, by the way.

regards,

Wouter
PE4WJ

-----Original Message-----
From: John Kolb
To: J. Forster
Cc: W.J. Ubbels; 'Premium-RX '
Sent: 31-1-04 6:14
Subject: Re: [Premium-Rx] General Coverage Antennas for HF


Well, I have circuit boards for the active antenna shown at
<http://members.cts.com/king/j/jlkolb/site/aa-1.pdf>

The PA0SE preamp design looks very interesting - Take a bit
of parts substitution to build it from my junkbox.

John


On Fri, 30 Jan 2004, J. Forster wrote:

> Does anyone have a PC board or artwork for the preamp?
>
> Thanks,
> -John
>