John wrote:
One of the reasons cited in the FCC Notice of Proposed Rulemaking is an
objection filed by Texas Instruments, who make "smart card" readers that
work
at 121 kHz. They're afraid hams are going to operate with such huge power
and with such dirty signals that we would interfere with their lucrative
(and
totally unallocated) use of the LF spectrum.
John KD4IDY
Few hams what may do when in opposite side they have such big industry???
Little or nothing i think, this is the reason becouse i think that very soon
all the low band, 136 and top band may will be unusable for hams activity
for the jamming made by all this new digital sistem, like this unallocated
used by Texas and not only, but also from many others company, in LF, and
the others like the ADSL for fast internet.
Here, at about 500 meters or less from my house, a friend has installed a
Texas Tiris system for car identification in a big firm.
The equipment is the S251B that work (transmitt) at 134.2 khz, well, the
antenna is a big few inch underground isolated loop of 27 uH, feeded direcly
from the S251B.
In my station not a signal from this sistem is audible, also with
spectrogram, so absolutely not interference is produced between hams and
this equipment, when the all two installation are well made!!!
(The only interesting thing from this product is that Texas produce also a
very very little TX, i dont know the power but it use two big final Fet,
that may be used from USA hams in 136, i think without any modification,
look on internet at "Texas Tiris")
About the limitations in BW by FCC, i think that with 800 Hz many mode used
in LF may be used, like slow cw, qrs, dfcw and Jason that have also more or
less the same BW...., yes for high speed cw the better is use another band.
For the bandplan i agree with James, bandplan in all band is ever in
evolution, new digi modes in few years may change the cw / digital bandplan
in all the band, and not only in cw, there are experiment also in digital
voice, in LF here in Europe there are very little activity in digi mode, not
so many in qrs dfcw and, i think more in aural cw in central Europe
(loocking the PCL), so the conclusion is that our EU bandplan in LF for this
time is good, but tomorrow we also may need to change this situation.
Now the only problem that we can have in reception USA signals at top end of
the band is that they are in the middle of qrs EU band, so may be better use
for NA to EU window the segment between 137.3 to 137.4 Khz, far from
137.6/137.8, and near to digi band not much used here.
Only an opinion!!
73 to all de IK2DED Giulio.
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