Terratec Cinergy DTV tuner – mobile active antenna power circuit requirements

DEM_968 · 12-23-2007, 08:43 PM

Hello,

I am going to try some flat mobile active car atenna's, with a Terratec Cinergy DT USB XS Diversity digital tuner. The antenna has the following specifications and schematic, but I believe I also need to inject +5v preferably along the coax cable or directly to the built in booster as the digital tuner itself is only passive.

Does anyone have any information on a product or the required circuit to complete this function correctly, the voltage supply could come from a local source or the car PC power supply.

Specifications:

- Frequency 170~230 / 470~806MHz
- Gain > 8dB
- Operating Voltage Range 3~7 Vdc
- Performance Voltage Range 4.5~6 Vdc
- Current consumption < 25mA @ 5Vdc
- Impedance 75ohm
- VSWR TBD
- Return Loss TBD
- Cable Length 5 Meter
- Operation Temperature Range -10~+85 C
- Storage Temperature Range -20~+85 C
- Weight Approx. 80g

Schematic:

Attached.

Regards,
DEM_968

DEM_968 · 01-26-2008, 08:02 PM

Hello,

Can anyone give me some direction to a resolution for this problem. I just need a proposed circuit to inject +5v via the coax to power the booster, without damaging the passive TV tuner.

I can get the +5v from the carPC power supply and the ariel schematic I thought might help someone.

Regards,
DEM_968

FMode · 01-27-2008, 12:07 PM

I would disconnect the wire under L3 and inject 3-7V+ there... and you should better use the Pinnacle USB Diversity because it switches automatically on Diversity if you only use Tuner 1 while Tuner 2 is not used...

Who ever knows which Frontend ever supports DVB-T over BDA - and you can't switch on Diversity via BDA...

DEM_968 · 01-29-2008, 08:59 AM

Hello Fmode,

Thanks for the response, could this power be also injected via the coax (P3) as it would be easier from the tuner end?
Just not sure of the circuit to prevent this power from also reaching the passive tuner.

How does the Terratec Cinergy turn on Diversity then, is this a problem?

Regards,
DEM_968

FMode · 01-29-2008, 02:46 PM

Quote: Originally Posted by DEM_968

Hello Fmode,

Thanks for the response, could this power be also injected via the coax (P3) as it would be easier from the tuner end?
Just not sure of the circuit to prevent this power from also reaching the passive tuner.

How does the Terratec Cinergy turn on Diversity then, is this a problem?

Regards,
DEM_968

1. Open the Cinergy and look if there is a condensator behind the antennasocket - then its sure to power up the wire at P3 ...

2. only with Terratec's HomeCinema...

Can you switch on Diversity in HomeCinema and then leave HomeCinema - now use a BDA Viewer like DVBViewer or ProgDVB (free) and connect to one of the Cinergy BDA devices ?
May be this enables Diversity "for ever" (and for BDA) ... You can check this by removeing one antenna and picture should stay okay...

Thats what I never tested !

DEM_968 · 01-31-2008, 09:00 AM

Hello FMode,

Ok, I've already been told the Terratec Cinergy is passive. Could this power be injected via the coax, by means of an inline injector? The circuit would have to prevent power from returning to the passive tuner.

ie. tuner --> coax --> antenna
^
|
+5v

Your feedback is very much appreciated!

Regards,
DEM.

FMode · 02-01-2008, 01:44 PM

you can also inject 5V there but you need to verify that the first part behind the antennasocket is a condensator (blocking your 5V DC and passing the AC parts from your antenna).
Good Screenshots (Scanner?) of PCB at antennasocket of the cinergy and I can tell you...
Or you got the schematics from somewhere...