A use for OLD Boxes? Amateur Television

zg3409

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Hi all,

I have a few old Nokia DBox2 DVB-C boxes and I am trying to find a good use for them.

PLEASE DON'T DUMP YOUR BOXES YET!

I am involved in Amateur Television Broadcasting, where (with a legal licence) hobbiests can broadcast TV signals. Normally these cannot be picked up by normal TV's as the frequencies given to us are normally not picked up on normal TV's. Normally we use home-made or modified equipment.

In the past we broadcast analogue (non-digital) signals either just below or just above the normal TV band.

Lately we have started using digital transmission methods, again outside of normal TV channels. Up to now we have normally used the satellite modulation method (Called DVB-S) normally at 1200Mhz using special aerials and specially modified Sat receivers.

However I would like to try broadcasting DVB-C signals which could (potentially) be picked by any dodgy cable box hooked to a TV aerial.

I hope to test in the coming months a transmitter on 438Mhz (normal TV starts at 470Mhz upwards) and use the DVB-C mode. Boxes for cable television cover below 470Mhz as they are designed to be used on a closed system The cable system uses a DVB-C standard which is not really meant for being sent over radio signals but it should work.

Anyway please don't dump your boxes as I may be looking for some cheap boxes. :Clap:

For those that understand we want to transmit on 436.0 MHz and hopefully 2Mhz actual bandwdth. I am not sure of the symbol rate we plan on using.

I have some questions?

1)Is the frequency shown on the DBOX the actual frequency as my receiver seems to have a few mentions of Satellite in some options?

2) How do I disable decryption/enable ordinary receive?

3) Also what are the allowable symbol rates for the nokia DBOX II?

The transmitter can send qam16 , qam32
or qam64. Most cable systems use 256 QAM. Where do I set these in the D-Box?
What do I change the cables.xml file to?

I found this online
"
You have to edit the cables.xml.
modulation="6" means automatic configuration and fec_inner="9" automatic for FEC.
A line for you could look like this:
<cable name="Telmico" flags="7">
<transponder frequency="320000000" symbol_rate="6900000" fec_inner="9" modulation="6"/>
</cable>
"
So What does fec_inner= 1 mean etc?
So what does modulation=1 mean etc?
I would prefer to have them fixed for scan speed.

This is the transmitter I am thinking of using:
http://d-atv.org/D-ATV-Modulator.pdf

The national group:
BATC

Dan
 
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