On Apr 7, 7:45*am, dave wrote:
Wimpie wrote:

As far as I know the proposed antenna is a single wire (without traps)
in combination with a 1:9 impedance transformer. *www.parelectronics.com/swl-end.php
shows some details. It uses a two-hole ferrite core and is for receive
only. You can disconnect the antenna side ground from the 50/75 Ohms
cable braid to optimize for minimum noise.

The one I made myself is an autotransformer with a separate common
mode choke. * The autotransformer enables me to extend the useful
bandwidth downward without getting too much leakage inductance.

As my transformer has no galvanic isolation, I needed a separate
common mode choke. The common mode choke is a series circuit of 2
wound ferrite cores. The first core with RG174 has best performance at
the middle and upper part of HF. The second core with RG174 coaxial
cable has its highest common mode impedance around 3 MHz.

If you need further clarification, don't hesitate to contact me.

Best regards,

Wim
PA3DJS
www.tetech.nl
remove abc first before hitting the send button.

http://www.bobsamerica.com/9-1balun.html- Hide quoted text -

- Show quoted text -

This looks like a basic good design, but it is different from PAR's.

Bruce