Noise Problem with AMRAD LF antenna

[Frank Gentges KØBRA]

Brooke,

Some rectifier diodes create a sharp spike at the zero crossing.  Try a 0.1 
capacitor across the secondary of the power transformer.

73,

Frank K0BRA


At 02:04 PM 2/6/02 -0800, Brooke Clarke wrote:
>Hello:
>
>I have one of the LF antennas and when I look at the spectrum plot and compare
>it to my DA-100 the baseline noise increases at frequencies below about 200
>kHz.  At 60 kHz the noise is about 30 dB higher than the DA-100 and WWVB which
>has a 25 dB s/n on the DA-100 is not even visible on the AMRAD antenna.
>
>When the power cord is removed and a few 9 Volt batteries are clipped 
>across C1
>the noise improves 20 dB, but it could be better.
>
>Is there a better choice for the active regulator that will provide more line
>noise rejection,
>or is there something else needed?
>
>I have about 80 feet of bare #10 wire connected to the antenna gnd lug and 
>just
>ran it along the ground.
>
>Thanks for any ideas,
>
>Brooke Clarke, N6GCE
>Attached three 0 to 200 kHz, 30 Hz RBW spectrum plots taken with HP 4395A
>
>

Frank Gentges KØBRA
<fgentges@mindspring.com>
LF web site at <http://www.amrad.org/projects/lf>