Re: VLF: looking for a simple-to-build sub-9KHz E-probe

[Andy Talbot <andy.g4jnt@googlemail.com>]

Use your existing or whatever loop, but before any preamp add a high pass filter.

 

Take a look at  http://www.g4jnt.com/LF_HPF.gif    for a design using off the shelf component values for a 50 ohm design with Fc = 6kHz (to allow you to receive the 6900 kite signals, and provide > 80dB of rejection of 50Hz and its harmonics.

 

If you want a another design - for a different Zo, Fc etc -  have a play with AADE filter designer.   It whiles-away a wet sunday afternoon (meanwhile checking there are no smoke signals) if nothing else :-)

 

Andy
www.g4jnt.com

On 3 October 2010 12:31, Daniele Tincani <danieletincani@yahoo.com> wrote:

Hello VLF,

 

just to try to improve a bit my reception at < 9KHz, I'm looking for a easy-to-build E-probe design.

Currently I'm using a very simple system (http://www.vlf.it/easyloop/_easyloop.htm) which works very good but
unfortunately it has to succumb to the intense hum I have all around. In fact, I live on the 5th floor of a 6-floors
jointly-owned building in a sub-urban area (in Livorno, Italy). I have a motorway, a railway, electric powerlines, mobile phone antennas, etc. all within a few hundreds meters.

I don't know if an E-probe would survive better than a loop in such an hostile enviroment :-) However, a short whip is for sure easier to build and to handle than a 70 cm x 70 cm, 40-turns loop like the one I have currently.

I'm also looking for an homebrew design as off-the-shelf receivers look to me a bit costly compared to my VLF budget :-)

Any suggestions/references?

 

Best regards

Daniele