----- Original Message -----
From: "James Moritz" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 16, 2002 4:24 PM
Subject: LF: Re: USA 136kHz proposals
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.
I think Jim you have missed the point about the band plan. In EU as you say
we operate at the bottom end of the band 135.920 khz approx to avoid a
receive problem at the Canadian and USA end because of CFH, which hardly
effects us here in Europe, and therefore if they transmit on 137.6 khz
approx that avoids any problem. So what is your point!!!!!
A lot of experience has already been gained over this past couple of years
transatlantic about how to conduct a LF QSO.
We need a plan for QRS as I suggested before and above and normal CW
operations. These will be the most popular modes and have worked well so
far. Other modes FSK/BPSK/JASON etc that take up more b/width will have to
be kept separate to avoid qrm and frequency swamping.
This is normal procedure for HF dxing ie split frequency working to avoid
blocking the dx frequency and mode separation designated frequency areas
G3KEV
G3KEV
Cheers, Jim Moritz
73 de M0BMU
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