Dear Dave, LF Group
At 11:28 16/05/2002 +0100, you wrote:
I see from yesterday's ARRL Letter that the proposal for the USA 136 band
is for 1W
ERP and bandwidth less than 100Hz. I am puzzled why they are putting this
stipulation on bandwidth,
I suppose it makes sense - otherwise someone could decide to monopolise the
entire band sending SSTV or something.
It could be a
disincentive for normal CW operation (although hopefully most CW will be
in this
bandwidth), and presumably will be difficult to enforce.
It's very easy to measure the bandwidth of signals with spectrogram
software, or a spectrum analyser. Some people would be surprised to see
what their signals look like! How difficult it would be to maintain that
bandwidth depends on the complete specification - how many dB down at 100Hz
BW? If it is 20dB down, no problem, but if it is 60dB down, difficult in
any mode - the mains hum sidebands are usually more than that.
On a similar note, it would seem premature to start rushing in to band
plans again - remember that the original reason for having the
"transatlantic" signals at the bottom of the band was to avoid CFH on
137.0kHz in the middle of the band - It is still there, and in the
north-east US states this will certainly have a very direct influence on
operating frequencies for all modes, which could well end up rather
different to those in Europe. Arbitrarily imposing a band plan at this
stage would be less than helpful, and it would be better to wait until US
amateurs have a chance to gain operating experience on the band.
Cheers, Jim Moritz
73 de M0BMU
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