Thanks Wolf,
Yes, a good idea. I will try to catch it :-) But how do i know that it
is the US mains instead of a 60 Hz monitor? Is the 60 Hz from the mains
more stable?
I will work on the circuit and continue tomorrow.
Also i am curious about experiments near 2 kHz, now that i have a
relatively clean RX site. I think about grounding the far end of my
inv-L and run some 10A near 2 kHz. This vertical loop would have about
2100 m^2 beaming N/S. A RX loop could show some variation of the SNR
due to the earth/ionosphere resonator...
73, Stefan
Am 03.10.2014 22:14, schrieb wolf_dl4yhf:
Hi Stefan,
The 82 Hz signal looks good... you may even catch a glimpse of "DX"
from the US and their 60 Hz mains with that setup.
It's several dB down on ZEVS but sometimes good copy here, on an active
E-field probe out in the woods (far away from old PC monitors which
sometimes operated near 60 Hz).
73,
Wolf DL4YHF .
Am 03.10.2014 21:38, schrieb Stefan Schäfer:
Hi VLF,
This evening i received ZEVS for the first time in the garden :-)
I used nearly the same circuit than in my email below. However, i found
that the J310 was damaged! Remembers me on the old discussion if
protecting diodes are necessary or not :-) But this is a large antenna,
compared to an active E probe like the PA0RDT-antenna...
Now i've replaced the JFET and added two 4148 protecting diodes on the
gate against ground and plus.
Reception looks much better now:
0...24kHz: https://dl.dropboxusercontent.com/u/19882028/VLF/wide_500msperdiv_732mHzFFT_garden3rd.png
0...4 kHz: https://dl.dropboxusercontent.com/u/19882028/VLF/0...4kHz_500msperdiv_732mHzFFT_garden3rd.png
0...500 Hz: https://dl.dropboxusercontent.com/u/19882028/VLF/0...500Hz_500msperdiv_732mHzFFT_garden3rd.png
ZEVS in 7.6 mHz, 40 sec scroll rate: https://dl.dropboxusercontent.com/u/19882028/VLF/ZEVS_1st.png
It looks like i need some more gain on the lower frequencies. Will
modify the circuit a bit...
73, Stefan/DK7FC
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