[opendtv] Re: I have installed DVB-T
- From: Jeroen Stessen <jeroen.stessen@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 12 Jul 2007 12:45:57 +0200
Hello,
Jeroen:
>> I haven't measured, but the whole city is only like
>> 10x10 km2 and the tower is within the city limits. So my
>> guess is 6 km.
Bert:
> So this provides a good point of comparison. I'm assuming 600 MHz
> channels here (UHF).
UHF 21 = 470-478 MHz until UHF 66 = 830-838 MHz . YMMV.
> The 10 KW transmitter, approximately 6 Km as the crow flies, is
> problematic for indoor reception downstairs, but is solid with an
> outdoor antenna.
It's not the indoor/outdoor difference, it's a telescope half
dipole versus a Yagi with (I forgot to count) ~12 elements.
Here at work, on the south-west end of the town, we receive DVB-T
from the same transmitter that is somewhere between south-east and
the center. We are on the 8th floor (9th for the Americans), but
this indoor antenna is on the wrong side of the building. It would
have a perfect view of the planned Eindhoven 1 transmitter, but the
active Eindhoven 2 is blocked by the building. Reception is lousy,
even though the indoor antenna is amplified. And as far as this
antenna is directional (it looks like a dish, but that could be
just plastic) it seems to be directed the wrong way (south-west).
It's just not worth updating the installation until September,
when the 2nd transmitter right in front of our window becomes
operational. That might be only 1-2 km away, i.e. just perfect.
> Even if I just use free space propagation loss, which of course
> is not valid at such long terrestrial distances, a 550 KW transmitter
> 46.6 miles away creates a received signal that is 4.53 dB weaker than
> the 10 KW station at 6 Km.
I have that kind of reserve with the (unamplified) Yagi.
> The other point is that Eindhoven seems to be a good case for a
> two-tower SFN, which should even be doable using 8K mode with a GI of
> 1/16. This should allow about 9 Km tower spacing safely.
This is a part of the planning, for channel 33 and the entire country:
City Coord N Coord E Province Chan Freq ERP(kW) Height(m)
Pol. Operational/Planned
Smilde 52N54'14 6E24'15 Drenthe 33 566-574 30 295 V O
Nijmegen 51N51'25 5E49'44 Gelderland 33 566-574 15 103 V O
Groningen 53N12'01 6E36'58 Groningen 33 566-574 20 128 V O
Hertogenbosch 51N42'53 5E16'32 Noord-Brabant 33 566-574 10 102 V P
Breda 51N36'14 4E45'47 Noord-Brabant 33 566-574 20 127 V O
Eindhoven 2 51N26'56 5E31'55 Noord-Brabant 33 566-574 5 87 V O
Eindhoven 1 51N25'16 5E25'56 Noord-Brabant 33 566-574 15 94 V P
Oss 51N45'17 5E33'27 Noord-Brabant 33 566-574 10 105 V O
As you can see, I receive this channel from only a 5 kW transmitter
that is operational. The 15 kW mast comes on line some time between
now and September. That should improve the situation a lot.
And all the transmitters in Brabant plus the one in Nijmegen seem
to be forming a Single Frequency Network, that much is obvious.
Regards,
-- Jeroen
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| From: Jeroen H. Stessen | Phone: ++31.40.27.40246 |
| Deptmt.: Philips Applied Technologies | Mobex: ++31.40.27.99650 |
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