11-07-17 21:30 Holger Granholm wrote to Ed Vance about Re: Ham Radio Digital
od
Howdy! Holger,
HG> @MSGID: <5A02D5FF.1704.amtradio@capitolcityonline.net>
HG> In a message on Tuesday 11-06-17 Ed Vance said to Daryl Stout:
HG> Hi Ed,
HG> I'm just busting in, not because I have any experience of digital Ham
HG> Radio, but I have experience of TV.
No need to apologize for making a comment, these BBS Echos are the same as
a Amateur Radio ROUNDTABLE on 80 Meter AM. afaik (as far as I know)
EV> I watch Television using a Digital TV Convertor box.
HG> Here called Digibox'es.
EV> I remember that back when Analog Television was being broadcast if
EV> the Picture messed up the sound portion could still be heard on
EV> those TV Sets
HG> That is correct. The same was true with the so called digital channels
HG> via Digiboxes.
HG> Those old Digibox channels are now called analog and are still
HG> available on modern TV sets, along with true digital and HD channels.
If the Digibox signal are Digital, calling them Analog would sound strange
to me.
HG> In most cases when the digital/HD signal becomes too weak to give a
HG> picture, the sound also disappears. In rare cases there may be sound.
This new fangled stuff we just have to get adjusted to, don't we?
EV> One of the local Amateurs who owned a TV and Radio Repair Shop
EV> talked about taking courses and buying Test Equipment so He would be
EV> able to service Digital Television Sets when they needed any fixing.
HG> There's no special test equipment needed, except a signal generator
HG> that can give a digital TV signal, and in case you do service on
HG> antenna distribution nets, a field-strength meter that is compatible
HG> with HD and digital signals.
I didn't know He only needed to get a Digital TV SigGen to work on the
newer gear.
I never learned how to fix a TV Set, I know a little bit about Audio
Amplifiers and Radio RX's and TX's, but always shied away from what
was inside of a TV Set, except for taking some 7 Pin and 9 Pin Tubes out
and taking them somewhere there was a Tube Tester.
The TV Sets I have now only have One Tube in them, the Picture Tube.
EV> Have You noticed if there any lapses or delays to the transmission
EV> that You are listening to when You're using any of those Digital
EV> Modes wheather during a QSO or You're SWL'ing the Band?
HG> What I have noticed is that the more compressed a TV-signal is, the
HG> more is the time delayed. Finnish TV hasn't noticed that or corrected
HG> it, but swedish TV has.
HG> The delay is only in the class of seconds but still irritating.
HG> We did also have some "digibox" channels compressed with a MP4 compres-
HG> sion, and even there the delay was greater than the uncompressed
HG> digibox channels.
As I mentioned to Richard, I'm wondering if the Digital Modes used in
Amateur Radio experience any QRN or QSB that would cause pauses or
distortion of the received signal.
73 de Ed W9ODR ..
... PCDOS&MSDOS&CP/M&WINDOWSI'LLFIDDLEWITHOS/2WOULDN'TYOU
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