Marcus, LF,
Ref : My split 8270Hz & 8970Hz grabber.
I had difficulty getting the sample rate detector running, getting
message frequency too far off or similar, SL version v2.79 b04.
I gave up in the end & re-started using an older version of SL
(which I have no problem with) & is detecting MSK reference
OK, SL version v2.78 b05.
73, de Gary - G4WGT
MF-LF-VLF Grabber : http://myweb.tiscali.co.uk/wgtaylor/grabber2.html
Web : http://myweb.tiscali.co.uk/wgtaylor/index.html
.
On 03/01/2014 13:27, Markus Vester wrote:
Gary
great, thanks for pointing this
out. I really like that side-by-side comparison. Assuming you
are using nonresonant input circuitry and equal brightness
settings, 8.27 kHz seems a tad noisier than 8.97. But it looks like 8270 is least QRM free.
Best 73,
Markus (DF6NM)
Sent: Friday, January 03, 2014 2:15 PM
Subject: Re: LF: Re: 8.3 kHz
My grabber at 8270 is loading. Lets
see what QRM does here between 8234 and 8305 Hz
(did just start it at 23h00)
----- Original Message -----
Sent: Thursday, January
02, 2014 1:12 PM
Subject: VLF: 8.3 kHz
Sorry,
first email was corrupted because I had forgotten to fill in
the subject line. 73, Markus
-----Ursprüngliche Mitteilung-----
Von: Markus Vester <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Do, 2 Jan 2014 2:07 pm
Dear Sub-9kHz'ers,
Marco DD7PC just made me aware of new German
regulations, which also includes a change of the
unallocated VLF range. The latest version of the
"Freqenzverordnung" (FreqV)
http://www.gesetze-im-internet.de/bundesrecht/freqv/gesamt.pdf
has become effective already on August 27, 2013, and
includes an allocation of 8.3 to 9 kHz to the passive
weather observing service (ie. lightning locator
networks). Strictly speaking, this would make 8.97 kHz
transmissions illegal in Germany (although there may be a
loophole with national footnote 2 regarding
"Induktionsfunkanlagen"). If I recall right, a similar
legal change in the UK had been announced in this group
some time ago, leading to the installation of some grabber
windows around 8.27 kHz.
In practice, radiated powers achievable by amateurs
(milliwatts at best) are ten orders of magnitudes below to
that emitted by lightning events (100 megawatts). The
chance of amateur interference to a broadband lightning
locator would thus be absolutely neglegible. Even if
somebody happened to activate his kite within one
kilometer from a detector station, any further effect of
interference would still be suppressed by redundancy in
the lightning location network.
Still, for publicly visible work (like claiming
first contacts etc), we should consider moving below 8.3
kHz. Of course there are disadvantages, like
- local interference eg. from railway lines seems to be
much denser and stronger at lower frequency,
- at same antenna voltage, radiated power will be 1.4 dB
less,
- more coil winding is required,
- acoustical side-effect of transmitting may be more
disturbing,
... es nervt einfach!!
But then, one should always embrace change...
positive aspects may be
- lower QRN background in quiet locations,
- with common international legislation, the necessity of
sub-9kHz NOV's in the UK might become obsolescent,
- EA5HVK might be motivated to provide an Opera version
with flexible frequency assignment.
In my location, I am mostly affected by 16.67 / 33.3
Hz modulated interference emitted by railway overhead
lines, in addition to the usual 50 Hz related junk. To
possibly identify a sweet spot with relatively low
interference, I have temporarily shifted the frequency
range of my faster VLF grabber windows:
http://df6nm.darc.de/vlf/vlfgrabber.htm
Judging by the first hours, near 8280 Hz may be
significantly better than 8270. But interference comes and
goes with time, so longer observations are needed. Note
that the heavy interference between 11 and 12 UT could
have been exacerbated by my noise blanker settings as it
is much less severe in the wideband window. At this time,
I would like to encourage other receiver operators to
closely investigate their noise levels just below 8.3 kHz.
Best 73,
Markus (DF6NM)
No virus found in
this message.
Checked by AVG - www.avg.com
Version: 2014.0.4259 / Virus Database: 3658/6971 - Release
Date: 01/02/14
No virus
found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4259 / Virus Database: 3658/6971 - Release Date:
01/02/14
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