mal hamilton pisze:
vlf
As a guide for those interested in VLF 9 Khz it would be useful if
each station could use the Alpha station on 11905 Khz as a benchmark
for quality of reception.
and let us all know hown efficient their RX system is.
In my case using an inv L 150 metres total length not resonated the
report is minus 60 dB with a sig over noise of 25 dB. This seems an
acceptable system for 9 Khz reception.
I can do better by resonating the antenna, or using my 136 antenna
system re-resonated for 9 Khz
I get the impression that at some locations receiving is a problem,
for various reasons including noise from being in the middle of a
Urban environment.
Can we have some data.
de mal/g3kev
Hi Mal, LF group,
Attached, you will find one of the capture files i have sent earlier
this month to SAQ at Grimeton as my 'signal report' due to their extra
transmission at Jan,4th.
The SAQ staff decided to give an extra opportunity to US/Canada based
stations so the transmission took place abt midnight utc time
During the SAQ transmission i have made several capture files and as a
'side product' 3 Alpha stns were also captured/recorded. As i do not
have a properly calibrated rx'ing
system i cannot state the absolute values. Instead, i can only say the
alpha were at least 15-20db over the noise
/please, note the size of fft bin has been adjusted for the normal cw
speed /
this is my best vlf reception so far. i live in a heavily populated area
/city downtown/ so when all my neighbours switch off their fancy ,
plasma, super tv's
i can switch on my vlf receving equipment :)
as the antennae are concerned... i have tried different configurations:
wires through my balcony window, part of my w3dzz hf antenna,
mini-whip, recently constructed vlf antenna
proposed by Stefan, dk7fc and finally what gave me the best reception:
60 cm loop with OP27 as op.amplif. i have used the idea of Klaus
Betke, dl4bbl when constructing the receiving loop
http://ik4hdq.net/doc/testi/smlloop.pdf
the next/final part of my vlf rx system is SDR-IQ receiver along with SL
(btw, using this system i successfuly received Stefan,dk7fc 137 kHz
signal from his 100m kite antenna at Jan. 8th)
73, Piotr, sq7mpj
qth: Lodz /jo91rs/
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