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Old 10th Dec 2017, 9:10 pm   #12
beery
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Join Date: Jun 2006
Location: Ware, Hertfordshire, UK.
Posts: 727
Default Re: 405 line TV with the HackRF

Hi fsphil,

Sounds like an interesting idea. You will need to be aware that 405 line transmissions used positive modulation for the picture, whereas nearly all other TV standards used negative modulation.
I have a very basic standards converter (I also have a couple of Auroras) which does indeed use intercarrier sound at 3.5MHz. It seems to work well on superhet sets (multi channel), but not TRF sets (fixed channel). There were a few TRF sets before WW2, but they really became popular in the late 40s to early 50s. They became less popular as more repeater transmitters came on line (still only one BBC station though) and finally disapeared off the market when ITV came along on VHF band 3 in 1955.

The Baird 240 line system used the same RF standard as the 405 line system. Details of the Baird system can be found here:-
http://www.nostalgiatech.co.uk/new_p...0line%20System

Cheers
Andy
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