Hi Roger I think that is being a rather optimistic way of viewing military
"possession" of spectrum :-)) Just because they aint transmitting it dont
mean they dont intend to retain rights to control it. Several station in the
LF (and VLF) bands have not transmit much in the last few years but they
retain the kit and the aerials and "blow the spiders out" every now and
again. The lecky bill to run 100 to 500kw continuously is quite significant
and all are under financial pressures. (I havent listened lately is Marathon
still running 24/7??)
There was really no good reason why we lost 73kHz other that the "owner" of
a channel in the band changed. The frequency in question had not been used
for traffic in many years according to Rugby engineers (and I dont think it
has been used since either). It just sat in the middle of the 73kHz
allocation "idling". Like 500kHz the operators in some countries will do all
in their power to keep transmitter live or they will lose their jobs. I
would not see Ofcom thinking 73kHz was viable seeing the way most ops moved
from 136 up to the "easier" 500kHz when it became available. Still it would
be "easier" than 9kHz :-))
Alan
----- Original Message -----
From: "Roger Lapthorn" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 22, 2010 1:51 PM
Subject: Re: VLF: Changes in MSK usage
> If there really is spectrum being freed up in the LF/VLF regions should we
> be pressing our governments for further small amateur allocations below
> 100kHz? For example, how about an allocation at 73kHz (again in the UK)
and
> a band somewhere between 30-40kHz? With the improvements in weak signal
> techniques in the last few years such allocations would be extremely
> interesting and ripe for some serious research that would contribute to
> science, and be a lot of fun.
>
> Regarding Dave Gibson's thoughts on earth electrodes, I'm puzzled. As
Stefan
> says, the current is returned by a path within the soil/rock and a loop
MUST
> exist. Can the structure be modelled *both* as a magnetic loop and a
> electric dipole? In my mind I can visualise the loop and how this might
> work, but I cannot easily visualise the dipole, except as a very short one
> with a lossy resistance strung between its ends.
>
> 73s
> Roger
>
>
>
> On 22 July 2010 09:15, Markus Vester <[email protected]> wrote:
>
> > Dear VLF enthusiasts,
> >
> > browsing through saved VLF-grabber screenshots, I noticed some recent
> > changes of VLF MSK-band usage:
> >
> > 2010-06-24 06:00 20.27 kHz (ICV) QRT
> > 2010-06-30 05:00 16.4 kHz (JXN) QRT
> > 2010-07-05 07:05 18.3 kHz (HWU) QRT
> > 2010-07-08 23:00 21.75 kHz (HWU) break for 6 hours
> > 2010-07-10 06:00 22.1 kHz (GQD) switched from 100 bd to 200 bd
> > 2010-07-10 10:00 19.58 kHz (GBZ) QRT
> >
> > Thus within a couple of weeks, half of the European military signals
have
> > gone for good.
> >
> > Perhaps there is less need for submarine communications in today's
world...
> > let's hope that the submarines themselves (along with all that other
> > military hardware) may become obsolete in tomorrow's world!
> >
> > 73, Markus (DF6NM)
> >
> >
>
>
>
> --
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/g3xbm
> G3XBM GQRP 1678 ISWL G11088
>
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