SS 2 HD - moving the dish works only without LNB

[Davor]

I am using SkyStar HD2 with Selfsat H21D-2 satellite antenna and Selfsat HH90 motor and latest version of DVBViewer and drivers soft_skystar-hd-2_version_1.2_6612. The problem that I have is that the motor will not turn if connected to the LNB. The motor makes short stuttering noise (but doesn’t turn) as if it lacks power, and sometimes doesn’t do anything at all. When I disconnect it from the LNB, then it works well.

First I thought the cable between motor and Skystar was too long, so I connected it with an 2m coax (75Ohm), but the problem remains.

I checked the amperage, and the motor consumes some 100-150mA on 17-18V when turning. While turning, if I connect it to the LNB, the turning speed reduces, and the setup consumes some 300-350mA. When the motor stops, and I try to turn again (through DVBViewer), it will not work. I always have to disconnect the LNB to let the motor turn.

This makes me think that the Skystar doesn’t supply enough power to the motor when LNB is connected to it. This is strange as I explicitly bought the Skystar because it has an external molexconnector for extra power, which is connected to the computer’s 450W PSU.

Note that this is a similar issue as described in this thread.

I have mailed Technisat about this issue and am still waiting for a reply. I’ll keep it updated here.

I don’t know what to do except to buy some powered amplifier, but then again I am not sure if that will work either. I want to make it work with Skystar alone which supports DiSEqC 1.2 and has an external power capability. Is there any software option that can solve this issue?

 

[Analoguesat]

The lnb is drawing most of the available current from the Skystar device leaving insufficient for the motor.

You could try another lnb and see if you can find a lower current draw device

 

[Davor]

You could try another lnb and see if you can find a lower current draw device

That's not an option. It's a flat antenna with a specially designed LNB, so there is only one kind of LNB for sale.

Note also that while turning the motor and connecting it to the LNB, the motor remains turning, which suggests that the card can supply enough power. But why it doesn’t do so from the start beats me.

It could be because of a significant voltage drop (which I haven’t tested), so that the motor can not start in the first place. A simple motor that starts makes an open circuit before creating enough backEMF (i.e. building up resistance).

 

[BombedOne]

well, I've checked a lot of ku band LNB's for power consumption. None exceeding 120mah. So, your "special" dish seems to have "special" lnb inside.