"John Smith" wrote in message
...
JB wrote:
The neat thing about going full digital? You no longer have any idea
why
the signal breaks up. PERIOD. The Customer is no longer bothered by
interference of any kind. Either it works or not. If your QSO, Phone
Call,
Mayday, Police call for backup, TV signal gets knocked off the air, you
won't have a clue why.


Actually, NOT. Even the simple bars on a cell phone tell you if
communication is possible or not.

That is all it can tell you.

The software running on an up-to-date
rig can describe the exact reason to you, if your rig interfaces to your
computer screen ...

Maybe you know of a secret diagnostic menu for my DTX9900?
If I remember correctly, all they know is RSSI and data errors. Please,
tell me if there are other indications that discern multipath, interference,
or any other reception problem without either sophisticated test equipment
or an analog indication - perhaps a color coded bar graph or channel
spectra that can react faster than the stream filling the buffer. I don't
know how ATSC handles error correction, but being a broadcast stream, I
would suppose only forward error correction is possible.

If the binary signal just clears the noise floor, and not by much mind
you (I am hesitant to quote an exact figure here) a perfect signal is
quite possible ... that is simply the nature of digital.

PACTOR yes, but I don't see that with DRM or ATSC at all. How is it that an
s9 signal isn't enough? I'm truly glad to have SSB so I can tell the other
station to resend the file again. The Universe isn't digital. Certainly
not radio. The signal, no matter what modulation scheme you use to improve
recovery of usable clipped and buffered data, is still in the realm of the
analog during transmission over the air. Ok, you might not understand that
if you are only the network guy and all your traffic worries start at the
protocol level as long as the Fiber box is energized.

don't know why anyone would claim that digital signals are not
MUCH superior to analog -- remember the old analog cell phones -- who
would ever wish to "go-back-there???"

Actually the best sounding mobile phone I ever had was my full-duplex 450
Motrac linked to a mountain top site with wide area direct dialing. No one
ever suspected I was mobile. But that was because my Analog link was better
than a voice grade phone line. Digital is great if you can find the
bandwidth, but great sacrifices and compromises have often been made in
audio quality for the sake of keeping the occupied bandwidth of the RF
channel within limits. What I am seeing on DTV, are stations that are doing
one 1080i or 720p stream on one RF channel with maybe 2 more streams of 480i
(often annoyingly compressed) OR up to 6 - 480i streams not so heavily
compressed. So I hate to disappoint you, that not all channels will be
better than analog until they find a way to do better than MPEG compression
and conversion from an NTSC source.

The move to digital cellular allowed channel re-use without having the
customer hear interference from co-channel sites so that many sites could be
used to communicate with many small handsets. Do you think that will be
much of an issue on Ham radio? Ham radio's greatest protection is in the
fact that it isn't supposed to compete with other services. No privacy is
needed or allowed either. If you copy the consumer model, you have no
amateur radio anymore. So I ask you sir, wouldn't you rather be using a
digital cell phone and leave the ham bands alone? Experimentation will
continue and things will be learned, people will contest and rag chew and
chase DX, but when ham radio for free is simple enough to compete with cell
phone services or a twisted pair, there will be a problem.