Hello John,
In fact Valerio's signal looks rather clean for BPSK, so I guess that he
did a similar thing as Jim and 'cleaned up' the output spectrum by AM
envelopping the signal. Real BPSK (hard phase switching) has a much wider
bandwidth, Jim (M0BMU) has a nice picture this.
I am sure that one 1 W ERP real BPSK signal can cause enough QRM to make
weak signal reception impossible for any other station in a 1000km range.
For sure the sitation in Europe is very different from the US lowfer scene.
In Europe we have over 100 stations active on 2.1kHz wide band (I believe
the south UK there are over a dozen stations in a 100 by 100km square). Any
of this stations can run up to 1W ERP if he (she) wants.
In the US (lowfer) the band is 35kHz wide and stations are limited to 1W
input and 15m wire as antenna, so unless you live in a salt water swamp the
ERP will be no more than a few mW.
73, Rik ON7YD
At 14:13 11/04/01 -0700, you wrote:
Hi all, I saw the spectrum plot Alberto provided of Valerio's wolf
transmission. What an ugly sight. It takes between 15 and 20 Hz of
specytum space.
With 30 sec dots I can receive and separate a station every 250
millihertz. In other words In the space of one wolf transmission 60 to
80 QRSS stations could be trying to have QSOs. I do not doubt the fact
that the wolf experiments are worthwhile from a testing of technology
point of view. I feel, however, that wolf as currently configured is
not a worthwhile mode for general amateur operation in the small 136kHz
band. I especially resent the attitude of VA3LK that he would transmit
regardless of potential QRM to others as stated in one of his emails.
Current transmissions above 137.5 kHz will not cause much
trouble. As interest in the band grows and more countries get on the
band, We will have to very carefully choose modes of operation which
provide the best combination of bandwidth consumed compared with
communication efficiency, coupled with ease of use. So far I vote for
DFCW and QRSS. I looked last night but saw nil.
73 de John VE1ZJ
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