Been using Dimension4 for several years now on a number of different
computers. You can pick any time server and choose the synchronization
down to seconds - if necessary. Not sure if this is accurate enough for
your work but it might be worth a look.
http://www.thinkman.com/dimension4/index.htm
Jay W1VD WD2XNS WE2XGR/2
----- Original Message -----
From: Andy Talbot
To: [email protected]
Sent: Monday, February 11, 2008 3:07 AM
Subject: Re: LF: Windows Beacon TX/RX Software .. can anyone code such a
thing ?
A problem with the scheme you suggest, Graham, is that PC clocks maintain
time badly, and will drift by several seconds overnight which makes a
mockery of the idea of precisely timed sequential listening. They may be
able to acheive Internet synchronisation, but can this be set up to
automatically update at the rate you will need, ie. every hour or two
based on some of the clock drifts I have seen.
That is why the existing beacon chains, both 5MHz and the IBP set, use GPS
timing. Passive receiving stations have their timekeeping reset by the
actual 5MHz transmissions themselves. On your website, you do mention MSF
timing, but to do that in real time would consume another receiver /
soundcard channel. GPS is the only obvious way to go for transmitting
stations. PCs are not reknowned for their timekeeping abilities!
Otherwise, the software is straightforward, although rather a waste of a
PC. If the GPS is available, then a £1 PIC is all you need to control and
key a standalone transmitter that doesn't need soundcard drive.
Andy G4JNT
www.scrbg.org/g4jnt
On 10/02/2008, Graham <[email protected]> wrote:
Hi all,
This is something that may be of interest .. To a programmer or two or
three ? There exists collectively the expertise, but can anyone see a way
of
producing the system?
The idea came initially from the 'Beacon Bedlam' , that existed south of
Watford gap .. about the only time the skip distance on 500 was 'useful'
in
that band conditions in the north west where quite quiet, later to prove
a
hindrance,
There already exists a similar system on 5 Mhz , however the transmission
sites are defined and participation is only possible by 'passive
reception'
not too appealing for 'experimentation' This is a 'proposal' the concept
is
proven , but 'we' need the
services of a programmer or two !! Similar thing's exist but are coded to
use 'pics' ,
One of the main criteria is , that 'anyone' with a windows based pc should
be able to download and install the tx/rx software and join in, be it as
a
TX station, simply claim a 'time slot' , or a passive observer being
presented with all 5 slots as a amplitude/time plot.
One of the main attractions would be : TX stations will be able to
observe
the other beacons in the chain , eliminating the lonely vigil of being in
perm ante
transmit mode, while providing , at a glance, band conditions for all
involved as well as reducing tx duty cycle time !
The number of TX stations is proposed as 5 in the chain , more may be
possible , but the time control factor may prove too difficult to achieve
within windows , but cw type software in beacon mode would appear top
make
a reasonable job of time control ?
Click on
http://groups.google.com/group/uk500khz/web/the-big-beacon-project
- or copy & paste it into your browser's address bar if that doesn't
work.
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