[mythtvnz] Tinfoil madness

[Dylan Hall]

Before I get into the detailed response, it's been pointed out that
it's rather poor form to attach images to messages like this, rather I
should have included a URL to the image. Sorry for my spammer like
behaviour :(

On Thu, Nov 5, 2009 at 8:11 PM, stuart <stugo at xtra.co.nz> wrote:
>
> Hi Dylan
>  I will throw in my two cents worth in. First I do not have any Sat gear
> set up, must get round to it.
> But I am a sparky so I will throw in some ideas.
>  As has been pointed out a multi meter with some testing info would
> help, a ups even a interactive and not a double conversion type will
> probably not sort out a grounding or earthing fault.
>  The think that leaps out is that the is no problem when isolated from
> the mains, on battery. But I do have a question, does your signal
> improve or do they remain the same?

The signal remains the same, just the BER and bad blocks varies.

The UPS in question is a fairly flash (but elderly) unit that does the
whole regenerate the power thing, and just to be sure I ran the tests
twice, once with the UPS connected to the mains, and once running on
battery. This didn't seem to make any difference.

I brought one of these (http://jaycar.co.nz/productView.asp?ID=QP2000)
yesterday and tested a bunch of power points around the house
including the power strips with the server/UPS connected. Everything
appears fine :)  I also verified that all my RCD's work :)

I removed the cover from the fuse box (at the suggestion of another
electrical in the know person) and eyeballed all the ground and
neutral connections to look for obviously loose connections or
blackening/scorching. I didn't go as far as sticking a screw driver in
and tightening everything. I feel thats a job for someone qualified :)
 I didn't find anything to concern me.

Dean suggested: "What happens if you remove the foil, but earth the
antenna, cable shield and the splitter?" - Anytime I remove the foil
from the USB sticks the BER rises and it becomes erratic. I tried
earthing the splitter housing but this didn't make any difference.

> I can give you instructions on how to test you earthing at power point
> and gear to a ruff level with out spending heaps of money on special gear
>  but you will need at least a cheap meter.

I have a basic digital multimeter and a rather elderly oscilloscope so
any instructions that don't involve my wife claiming on my life
insurance would be appreciated :)

> If it remains the same I would try a get that up, I may be wrong but I
> thought that getting it around 70% or above would me preferable.

I think you've hit the nail on the head. I have a new bit of data from
last night. The signal levels on all three transponders dropped around
1-2% last night due I think to some very misty weather. During this
time all three transponders experienced higher BER and bad blocks to
the point they were unwatchable.

This evening the mist is gone and the levels are back where I expect them.

This suggests to me the signal is just too weak if such a small drop
is enough to tip it over the edge.

> One last thing  as I do not now the area you are in, but is the actual
> aerial actually the correct one for the area, A electrical supplier like
> Rexel, usually will be able to check, I noticed that one I had was
> different from the neighbors and was the wrong type.

I'm in the Johnsonville (Wgtn) area, at the foot of Kaukau. I'm very
close to the transmitter, but thanks to a lump in the hill don't have
line of sight :(

It's roughly the same size/shape/style as the neighbours but I get the
strongest signal pointing it a slightly different direction than
everyone else (maybe 15 degrees).

My plan at this stage is to borrow a Fluke cable tester we have at
work (it does cat5/6 and I think coax) and just verify I haven't
munted one of the cables, for example failed to connect the shield
correctly.

I'm also going to pick up a masthead amp. I'm looking at either
http://www.freeviewshop.co.nz/kingray-24db-shielded-digital-mast-head-amplifier-p-482.html
or http://jaycar.co.nz/productView.asp?ID=LT3270 . Hopefully this
isn't throwing good money after bad :)

The Jaycar unit is a little cheaper, but for some reason the pictures
of the Kingray unit convey a sense of quality.

Thanks for everyones comments so far :)   I'll do some more tinkering
and report back next week.

Dylan