[Lf] [Fwd: LF: RE: Transatlantic Tests]

[Andre' Kesteloot]

Talbot Andrew wrote:

>  Jim's comment applies to most of us ! Why transmit
> continuously for transatlantic beacon monitoring anyway
> ?   If the path is going to open, this will be for several
> minutes or tens of minutes. In which case, why not
> transmit for say 1 to 2 minutes in every 10 to get the
> duty cycle / electricity costs down.    Time the minutes
> accurately so software only looks when it needs to and
> gives a reduced probability of generating false
> alarmsCarry this a stage further, coordinate all beacons
> on the same frequency and monitor based on time alone. It
> is not really necessary to actually read the callsign for
> propagation purposese ither - we know the beacon is there
> on a particular frequency, and for a scheduled
> transmission the time the signal appears identifies it.
> In reality, the callsign need only be sent for regulatory
> purposes at normal CW speeds.  In fact, the callsign could
> be sent this way continuously and in narrow bandwidths the
> transmission would just appear as a carrier from a Tx
> equivalent to around half the power, the keying sidebandsh
> aving been filtered outAll this does of course require
> more than the average non-ovenned crystal, along with
> decent timekeeping, so presumably sure somed etracters
> will argue against this "high tech" approach but  "Why
> spoil the ship for a hap'orth of tar". Anyway, an accurate
> time source is an accurate frequency source.I'm currently
> getting quite encouraging results using CFAR signal
> detection algorithms on data produced from the 56002EVM
> for narrow band automatic monitoring.  Wolf, DL2YHF is
> progressing using the same techniques on a Soundcard based
> system.  There is a bit further to go before considering
> it reliable enough to wake me up in the middle of the
> night if a signal appears though.  I may be asking some of
> the operators on this reflector to provide random timed
> transmissions on particular frequencies some time in the
> future.Andy G4JNTFrom M0BMU:> Transmitting continuous
> beacon signals for more than a few hours at a time is not
> really possible > forme for various practical and safetyr
> easons -
>
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