John, Roelof,
I feel that WSPR can be used 2 ways (on 137kHz / 500kHz):
1. using low power TX (let's say ERP< 100mW) for continental and occasional
intercontinental reception
2. using high power TX (let's say ERP > 1W) to allow more or less regular
intercontinental (in casu NA - EU) reception
For low power TX the receiver overload should not be an issue unless 2 stations
are really close together. In these rather seldom cases "synchronized"
transmitting of both stations could be a solution.
But for hight power TX the receiver overload can occur even if the distance is
serveral 100km. I just checked the PA0A (running 5W ERP) reports on wsprnet.org
and from stations up to 900km he gets SNR reports of > 13dB (what might cause
overload).
I see an advantage in having two WSPR "waterholes", one at each end of the
501-504kHz band:
- A low power waterhole (503.9-504.0) for continental (and occasional
intercontinental) reception
- A high power waterhole (501.0-501.1) for intercontinental reception. Here we
could have seperate NA transmit periods and EU transmit periods (eg NA stations
transmit xx:00 to xx:02 , xx:04 to 00:06 etc... and EU stations transmit xx:02
to xx:04 , xx:06 to xx:08 etc...)
73, Rik ON7YD - OR7T
________________________________________
Van: [email protected] [[email protected]]
namens John GM4SLV [[email protected]]
Verzonden: zondag 7 november 2010 0:37
Aan: [email protected]
Onderwerp: Re: LF: WSPR T/A hole discussion
On Sat, 06 Nov 2010 22:25:33 +0100
"Roelof Bakker" <[email protected]> wrote:
> Looking forward to your comments,
Roelof, LF,
Erudite points well put, as ever.
One point keeps nagging at me.
If Jay is correct, and the number of strong (high power/efficient
antenna/high ERP/groundwave path) W stations is large enough to prevent
adequate reception of weak signals from Europe, then this also means
there will be no possibility of weak signal reception from other WD/WE
stations.
Why are they using such high power on WSPR?
What is the point of this if, as Jay says, everyone will continually be
being overloaded by their strong groundwave neighbo(u)rs?
Are the high power stations that Jay describes only interested in
reception reports from Europe, rather than from other W stations? If
they do want reports from W-land, then by Jay's argument, they will only
get reports from their near-neighbo(u)rs, as the weaker long distance
stuff will be blocked due to RX overload.
This can't be right?
I don't believe there is a problem of RX overload preventing reception
of weak signals (from where-ever), and if there is a problem then the
solution is to reduce TX power to the point that allows maximum
transmission distance, and minimum RX overload, rather then segregating
us into separate parts of the spectrum.
I still don't understand.
John
GM4SLV
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