On 4/10/2014 6:37 AM, Channel Jumper wrote:

'amdx[_3_ Wrote:
;817912']On 4/8/2014 4:34 AM, Geoffrey S. Mendelson wrote:-
I have a copy of the book "Practical Wire Antennas" by Heyes (the
first
edition). In it is a schematic for a low noise broadband preamplifier
for loops.

This version uses the BSX20 transistor which at the time the book was
written was far more available in the UK than the 2N5179 used by the
original Hayward design.

The book mentions that it was first published in the ARRL Antenna
Handbook, I can not find it in my copy.

These days it is much cheaper and easier to order 2N5179 transistors
from China on eBay (and probably cheaper to order 10 and pick the
best)
than it is for me to order a BSX20.

However without the original schematic or construction article, I am
taking it on faith that it will work with no circuit changes,
something
I doubt.

A copy of the schematic and accompanying text would be appreciated.
References to where it appeared or links to pages describing it would
be
even better.


The original circuit I was looking at contained 1 transistor, 4
diodes,
6 1/4 watt resistors and 4 disk capacitors. The coil could be wound
from
hookup wire on a hunk of ferrite rod, which I have many of.

It's fairly "bulletproof", so high voltages from static, lightening
or nearby transmitters (all three here) won't burn it out like an
MMIC.

It's a simple design so that I can build it myself. :-)

TIA,

Geoff.
-
If you send me an email, I'll send you a pdf of an amp with high IP's,

attached to a 4ft loop, but I think you can make it work with a rod.
My address is good.
Mikek

On HF what do you think you are going to amplify besides the noise?




If you have a directional antenna that is -40dbi, you don't think an
amp would be helpful?
Mikek