Walter is quite right, of course, that amateurs are not bound by the 24hr -
365 days/year service requirements imposed upon professional LF systems
engineers. However, the examples he cites abundantly demonstrate that the
tradeoffs amateurs sometimes have to make are still poor engineering
practice, even if not intended for professional ends.
The use of kilowatts of transmitter power to produce 1W ERP imposes a
burdensome cost on what is fundamentally a hobby activity, results in serious
electrical and (potentially) fire safety hazards, and requires extraordinary
effort to satisfy the neighbors' aesthetic values and keep their television
receivers happy.
Let me be very clear: I'm absolutely NOT a big-antennas-or-nothing advocate.
I realize that not everyone has hectares of open land, and may have to adapt
to their surroundings. On the other hand, I also hold the view that RF
egalitarianism is not always feasible, and at some point we have to accept
that LF in a garden plot is not likely to achieve 1W ERP unless we can throw
almost as much money and/or work into the transmitter as we would into an
"antenna farm."
Nor does it matter that we radiate 1W if we can't receive as far as we
transmit, thanks to urban or suburban noise levels on LF. Our goals have to
fit our means.
Where I live, I'm surrounded by neighbors who watch a distant TV station on
US channel 2. The result is that I cannot reasonably figure to work DX on
6m. By the time I resolved all the RFI issues, I would have to pawn most of
my radio gear. Therefore, I must plan the occasional field expedition if I
choose to work 6m.
We will have a very serious limitation over here, if or when the FCC approves
LF ham regulations. The "California kilowatt" stations won't be on this side
of the pond.
You may be aware that a 2W ERP limit has been proposed. However, out of
safety and EMC concerns, a 200W PEP transmitter power limit has also been
proposed. There won't be any 3kW transmitters here. We will just plain
_have_ to do the job with semi-efficient antenna systems! Hence, not every
US ham who wants to participate on LF will be able to do so; at least, not at
anything remotely approaching maximum radiated power.
Again, let me emphasize: I am NOT advocating big-antennas-or-nothing. I'm
happy for anyone who wants to try radiating from a Tesla coil in the garden
to do so. I'm only saying that understanding the reasons behind professional
practice will let us have more realistic expectations about what we should
expect from the resources available to us.
73,
John KD4IDY
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