Sup 2400 converter mods

[F5BCB]

Hello,
M0DTS gives information for mods in the converter Sup 2400 here:
http://www.m0dts.co.uk/datv_converter.htm
Is there a diagram of this converter in order to understand the purpose of these changes ?

Particularly, why should we avoid the 5v in the cable (Dan EI9FHB mods)?

Thank you in advance
73,
Jeff F5BCB

[M0DTS]

Hi Jeff,

Sorry i do not have a schematic, maybe someone else has seen one?
The modifications i made were to improve sensitivity, EI9FHB mods enable this to be used with a small mod but less sensitive when used without an LNA.

If you use EI9FHB mods and use a good LNA then it will work well.

DC on the RF cable can be a problem if the antenna is a short circuit at the driven element.

73

Rob
M0DTS

[F5BCB]

Hello Rob,

Thank you for your response and your explanations.
After some further researchs it seems that these changes are related to the Disecq commands sent by the digital demodulator equipment. Basicaly an end user digital satellite receiver is able to send commands to all acessories Disecq compliants located on the bus (ie for change of LNA polarization for example)
A pair of these commands are used to set On and Off the acessories (LNA, amplifiers, converters ...).
To prevent converter shut-down due to these unexpected commands sent by non-compliant equipment, the TM58PC10 microcontroller ports PA0 and PA1 were isolated from the PCB and the pads connected to +5 volts.
In this way, the converter is always ON regardless of the type of receiver (STB or PC card)
You can find the Disecq specifications here:
http://www.eutelsat.com/satellites/pdf/Diseqc/Reference% 20docs/bus_spec.pdf

The other mods related to filtering bypass are out of the scope of this explanation.

Ref documents available here : http://www.eutelsat.com/satellites/4_5_5.html

73,
Jeff F5BCB

[FRANCOIS F1CHF]

by the way
nobody found a diagram (schematic) for this unit ?
thanks
f1chf at free dot fr