Very nice! 0,8m*0,8m is really practicable and easy to built for
everyone. Not expensive too... And our distance is 655km, well above the
garden ;-) I do not even see a too big difference in S/N compared to
Pauls signal (sure, the distance is 200km less)... So i am very
confident that there will be some QSOs when further TX stns come up!
Jim, what about the effect of your band filter? Gives this a significant
S/N improvement on 8,97? Can you show us 2 pics of an overview, say from
0...20kHz, with and without the filter? Would be interesting!
What do you think about active E-field antennas? I think i will try such
one the next time using my much liked BF862 and a simple band pass
filter, just like in your preamp. I got the idea that i can watch my own
signal receiving here in Heidelberg. Maybe i can even put up such a
grabber... The distance from my hill to Heidelberg will be a good 50km
so it is a moderate distance, a good starting point for testing E-field
antennas...
BTW: The next time i will get my new "office antenna", here in the 7th
floor of the building of the institute of environmental physics in
Heidelberg. It will be a horizontal wire, abt 60m long and 25m up! And
with a good earth! This will be a good antenna for LF :-) I plan to key
the PA via a laser beam from the roof of my flat, just over the city ;-)
Maybe going to infrared ;-) There, on this roof of the institute, i can
arrange such a VLF antenna... Will see :-)
73, Stefan/DK7FC
Am 23.03.2010 11:34, schrieb James Moritz:
Dear Stefan, LF Group,
...>Jim, M0BMU is the 2nd best DX distance! Jim, can you describe you
RX detailed, pse. Or have i forgotten an older mail? What was the new
/p QTH? And what are your observations about the change of QRM?...
I was very pleased to be able to see a signal at my first serious
attempt... I have attached the current schematic of the preamp/filter
used on Sunday.
The receive site was about 5km east of my normal QTH, I think the
locator is IO91WR, but I'll check the exact coordinates.
The /P site had considerably less man-made QRM than my home QTH. The
odd 31.5Hz/5Hz spectral lines seen at home were completely absent, but
considerable 50Hz harmonics were present, due to nearby overhead power
lines. But these did not really cause a problem on Sunday, and I think
a noise-cancelling antenna arrangement would be feasible in a future
test.
...>BTW: We could philosophize what is the definition for "DX" on LF
and VLF! Or is there a standard definition? In my ham licence i
learned that on HF, DX is outside the own continent and on VHF it is
above 300km. So, what is it for LF? And what for VLF (by hams)?...
I think on HF nowadays, DX just means stations with unusual callsigns.
On VLF, it probably should mean distances beyond those normally
achieved - which means just about any distance at all!
Cheers, Jim Moritz
73 de M0BMU
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