[QCWA] Receiving Digital TV

[Gerd Schrick]

I have been receiving Digital TV for a few years and can state that 
there will be a big problem if no changes are made.

 This was one of the Observations in the previous post on Dig TV*

"I'm also wondering about a couple things simply speaking as a TV viewer: 
A)  Will the switch to digital TV be a phased-in thing or just a sudden 
overnight occurrence next February? 
Right now I've got one digital equipped TV attached to an outside 
antenna.  I get all the normal analog
signals that I've always gotten, but when I enter the menu to scan for 
digital signals, I only get one
channel, and that one is so weak as to be useless. *

There are several things that do not wash.
*All stations *that are presently on the air and want to continue in 
digital have *at least one program *on the air (usually the same as 
analog) right now and had so for a number of years. There ought to be 
plenty of usefull information out there.* BUT it Is NOT!* To check out 
an articlel ask if the writer has tried it at his house! That includes 
the so called experts! What we deal here with, is the *propagation *of 
the signal. And that is where we *hams can do a lot of good.* I urge 
everybody to get a converter and hook it up to a regular tv antenna; the 
output is video, so your old TV needs to have a video input (all but 
very old TVs have that).

If you receive analog (many converter boxes have a bypass for that) than 
you should receive digital, because the digital signal does not have to 
be so strong as the analog. A digital signal is either there or not! If 
it has "dropouts" that is in 90 % of the cases *NOT * sign of a weak 
signal, but of a modification of the signal in its travel from thr TX 
antenna to your Rx antenna. We are talking propagation here! The 
modulation format that the FCC chose unfortunately at the frequencies 
that are allocated (400 to 800 MHz) has *problems.* One is called 
multipath and I have been trying to eliminate that from my reception. I 
came to the conclusion that in my  case this is not the problem and may 
not be the main problem in general. Seems like my dropouts occur mostly 
in windy weather so I surmise the leafy trees (since in the winter it is 
better) are modulating the signal, to cause dropouts. The solution, get 
the antenna high enough to have a clear shot to the TV TX antenna. 
Fortunately I have a 100' tower and I plan to have my TV antenna at 
about the 80' level shortly. I will use a small yagi with corner 
reflector. I have presently at least 15 db of extra signal so a 100 foot 
cable of RG-6 is no problem

One final comment. The digital format provides for 5 standard TV 
programs or one HDTV and a few standard! At present only public TV has 5 
programs on the air. The commercial stations have just one or two. 
Unless one is a HDTV the channel is *not fully occupied *and probably 
works with no dropouts! That is Not a valid test, of course. So if you 
experiment, keep this in mind!

I hope this helps.
Vy 73, Gerd WB8IFM
**