Q: Slaving receivers?

[Robbert]

Hi Everyone,

Quick question that I haven't found a really clear answer on yet...

If I slave, say, a Twinhan 102g to my Fortec Lifetime Ultra (or Pansat 3500S soon) receiver, and leave the 102g's LNB Power set to on as well as give it the capability to control the motor and switch using DiSEqC commands, will the Fortec/Pansat filter out the 22Khz as well as DC from the 102g when it's on? I believe that when the Fortec/Pansat is off, it will pass everything, right?

Does turning on the LNB power on the 102g cause problems? i.e. can it fry the Fortec or the 102g?

Thanks!
Robbert

 

[Mr Tony]

when the main unit is off, the slave will control everything. But when the main is on, the slave will only work on the same polarity/satellite as the main.

 

[Robbert]

Right.. But does having LNB power on on the slave while the master is on cause any problems?

If not.. Why do I read some people recommending to put a DC blocker inbetween?

Thanks!
Robbert

 

[iammike]

Right.. But does having LNB power on on the slave while the master is on cause any problems?

If not.. Why do I read some people recommending to put a DC blocker inbetween?

Thanks!
Robbert

I have the LNB power set to on with my PC card slaved to a Fortec. I haven't had any problems. The only possible damage I could think of would be to the Fortec, but I don't think the current would be sufficient. I'm not an expert though. Could be I've just been lucky.

 

[Bob Rock]

Dc voltage from reciver could be a problem maybe

There is a common understanding or law in electronics That a higher potential can flow into a lower potential Like if one recvier would be putting out 13.1 volts and another would be putting out 13.0 volts then that difference of .1 volts would flow threw the other reciver would be a very small voltage and current so I would not really feel a danger for damage but it all dependes on the designs of the recivers in question so luck would be an issue here....Theory is just theory practical world is another.....

 

[neil_kc1]

doesn't using both receivers to move the dish lead to problems? i mean don't most motors stores satellite positions? When i have tried to use both one or the other receiver is off> is this normal? I end up having to bump my dish to receiver new positions. i found it better not to use the mover on the slave.
using satwork 3688 as main, fortec lifetime ultra as slave with .3 lnb

 

[Mr Tony]

yes neil. And in some cases, it may goof up your settings

 

[Robbert]

There is a common understanding or law in electronics That a higher potential can flow into a lower potential Like if one recvier would be putting out 13.1 volts and another would be putting out 13.0 volts then that difference of .1 volts would flow threw the other reciver would be a very small voltage and current so I would not really feel a danger for damage but it all dependes on the designs of the recivers in question so luck would be an issue here....Theory is just theory practical world is another.....

Bob, yes, I understand what you're saying, but I don't have both receivers connected to the same coax with a splitter... So... The big question here is, is whether or not the slave output on a receiver (the Fortec in this case) is connected internally to the IF input with a simple splitter circuit (couple of resistors), or with a DC blocker that is switched inbetween the IF input and slave output....

I have done some experiments this morning and found this:
- Fortec (master) on, Twinhan (slave) locked to H or V polarity, depending on what the Fortec is set to. 22KHz signal also doesn't appear to pass through from the Twinhan to the LNB (or motor, or DiSEqC switch.
- Fortec (master) off (using the standby button): 102G slave has full control of the motor, DiSEqC switch and LNB H/V switch.
- Fortec (master) off using power switch on back of unit (same as unplugging it): 102G slave gets no signal at all, regardless of H/V polarity etc. Looks like IF is completely disconnected from the Slave output.

Looks a lot like the Fortec has some kind of DC block switch it puts inbetween the IF input and Slave output depending on whether it's on or off... Can anyone confirm if this is the way these receivers work?

If that is the case, you should never need a DC blocker if you hook up other receivers through the slave connection. Obviously, if you use a regular splitter (I don't know why you'd do that... but ok), then you would use a DC blocker to prevent "clashing" with the voltage of the other receiver as Bob said...

Robbert

 

[iammike]

doesn't using both receivers to move the dish lead to problems? i mean don't most motors stores satellite positions? When i have tried to use both one or the other receiver is off> is this normal? I end up having to bump my dish to receiver new positions. i found it better not to use the mover on the slave.
using satwork 3688 as main, fortec lifetime ultra as slave with .3 lnb

I'm not sure I understand. With my setup, I fine tune the satellites with the Fortec and then save the motor positions. When I go to my PC card, I don't do any fine tuning I just enter the same position numbers I stored with the Fortec. There's not really an opportunity for the positions to get messed up. Doesn't it work the same way with 2 receivers?

 

[Diamond Jim]

The only thing I have hooked up to my Satwork slave is the C and Ku LNBs, I let the 922 do all of the work. What advantage would it serve to have the motor, polarity, ect hooked up to the slave and the main reciever at the same time?

 

[iammike]

The only thing I have hooked up to my Satwork slave is the C and Ku LNBs, I let the 922 do all of the work. What advantage would it serve to have the motor, polarity, ect hooked up to the slave and the main reciever at the same time?

PC cards with software like MyTheatre or ProgDVB can act as DVR's for FTA. You could have scheduled recordings set that would need to move the dish. On the other hand, the receiver would still be able to move the dish when you want to do blind searches. If one of the two devices is not a PC card, I'm not sure if there is an advantage.

 

[Tron]

I suggested the DC block in past threads to be on the safe side. If the Fortec blocks DC while on and passes it while off, then that's a great feature. This would mean that if the receiver is off, your PC card can control everything. If someone can confirm this on the Pansat receivers, I'll be interested in the results. Don't risk frying your Pansat to check it, just post here if you've already hooked up a PC card to a Pansat's slave IF and it works without any damage.

It would be nice if the manual had this info, but as we all know, the manuals for FTA receivers are about as useful as the roll in the bathroom.....