On 11/22/09 12:18 , Too_Many_Tools wrote:
On Nov 22, 11:51 am, "D. Peter
wrote:
On 11/22/09 11:23 , Too_Many_Tools wrote:

With my recent purchase of a DX-394, I have again taken an interest in
SWL.

Upon seeing stations going to Internet only broadcasting, are we
seeing a trend where SW radios will become obsolete?

TMT

The big guns have all abandoned SW to developed countries. BBC
still broadcasts to africa. DW, RNW and the others have moved to
satellite and internet distribution.

But as politics in the world heat up, SW will become an
important element of communcations again once tensions reach the
point where walls start going up. Internet streams can be censored.
Satellite radio can be shut off. That leaves terrestrial radio.
500,000 watts can't stopped at national boarders.

The Cold War was the reason for the pervasion of SW broadcasts.
Of course, there were jamming attempts. Some more successful than
others. But, the messages got where they were intended through radio
beamed in from out of country.

The technology isn't dead. It may be dormant, now. But it's not
dead. And when communications are down, Radio is one of the few
technologies that can be brought to bear quickly, and competently.
With organized traffic nets in every state.

So, no, SW radios are not obsolete. Nor will they be for some
years, yet.

Good comments.

Do you think frequencies will be reallotted for other purposes?

Unused spectrum is valuable in today's wireless world.

TMT


On HF...maybe. But probably not as much as you think. A lot of
digital services can be squeezed into a handful of channels. About
10 years ago, I looked at a QEI Quick Link for my remote broadcast
business. A digital site-to-studio link that was frequency agile
over 12 channels, and used a number of different pn codes to
digitally encode the audio on the transmit end, and then decode it
on the receive end. I may have the numbers wrong on that, it has
been a decade or more. But the point was that the audio was clean,
reasonably secure.

When I asked about intereference, the rep showed me the results
of a test that had 20 or so of these devices all
transmitting/receiving on the same channel with different pn codes,
and non could see any of the others.

Where digital will be the mode of choice, spectrum space will be
less of an issue. Meaning that a few channels here and there could
be reallocated to digital modes, without significantly crowding
remaining spectra while still accomodating a large number of users.

And DRM is still in use in some broadcast bands by SW broadcasters.