From: "Mike Dennison" <mike.dennison@ntlworld.com>
To: rsgb_lf_group@blacksheep.org
Date: Tue, 15 Dec 2009 10:48:51 -0000
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Subject: Re: AW: LF: "Gain" between qrss3 and qrss10?
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On 15 Dec 2009 at 11:03, Stefan Sch=E4fer wrote:

> If the "gain" or better said SNR between qrss30 and qrss3 is 10dB, so
> can I do a QSO to VK with 1W TX Power and an antenna efficiency of
> 1/1000 if I choose QRSS10000000000? That's a litte jokingly formulated
> but you know what I mean. In other words, where are the limitations of
> this rule?=20
=20
This is certainly theoretically possible, but only if 'ground-wave'=20
is being used. If you are using sky-wave - as all intercontinental=20
QSOs have so far - you are limited by the length of time that the=20
path is open.  Between UK and eastern US, this is a maximum of a few=20
hours, but often very much less, which is why the speed must be a=20
compromise between length of the 'opening' and the length to transmit=20
the information. This compromise usually result in using QRSS60.=20
Between Europe and VK/ZL any 'opening' is likely to be only a few=20
minutes making a two-way QSO extremely difficult.

> So, qsos could be done much faster if choosing 10x the
> power and stay in qrss3. The additional advantage would be, if I try
> to do a TA QSO I could just stay in the region of 137.7 and those who
> are qrv in qrss3 and only watch the qrss3-sector would get a nice
> signal and thus more fascination for the LF-hobby=20

Yes, in theory, and very occasionally over the last few years VE/US=20
beacons have been recorded at QRSS3. In the UK, a few stations can=20
manage to transmit 1W ERP. Despite that, there is no evidence of a=20
QRSS3 two-way across the Atlantic.=20
=20
I suggest you monitor the US beacon transmissions around 137.777kHz=20
each night. These are very well engineered high power stations and=20
you will be surprised how difficult the path is, even at their speeds=20
of about QRSS60..=20

Better still, try running some overnight transmissions of your own -=20
there are US stations who will monitor for you if you announce it to=20
this group.

Good luck.

Mike, G3XDV
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D