IF Out?

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#1
I'v noticed there is an IF Out connector on my Comag receiver. I checked the manual but there wasn't much info about it. The LNB is connected to a connector named IF In. My plan is to connect the IF Out to my pc so I can watch digital tv on it when the receiver is in standby. Could this work or is the IF Out used for something else?
 

2cvbloke

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#2
The IF out is the LNB loopthrough, usually used for attatching an analogue receiver, but it can be any type of receiver you like (sky Digibox, PCI DVB-S card, etc).... :)
 
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#3
Thank you for your reply, I was a little confused because the manual mentioned it for analogue use. Thanks again for clearing things up. :)
 

tesla

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#4
You should take into account this. The receiver that gets signal from the LNB is the "master". The second receiver (or PC card etc) is the "slave".

The "master" device send to IF in the appropriate dc voltage in order to select the polarization (horizontal or vertical) and the 22KHz tone if needed (for high band).

If the "master" device is tuned to vertical, low band (e.g.) then the "slave" device can only tune to a transponder of Low Vertical.
 
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#5
Thanks for your reply tesla. By now I have installed my DVB-S card and used a splitter in combination with the receiver. I havent tested the IF Out though, maybe I'll try it later. Just wanted to be sure it would work :p.
 

tesla

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#6
Splitter? what do you mean?
can you describe (or upload a picture) the connections you 've made?
 
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#7
Ah, well we call it a splitter here. I dont know how you call it but it's this thing. The LNB goes to the middel connector and then the receiver and the DVB-S card are connected to another each. I couldn't find a 2-way splitter so I bought a 4-way :)
 

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2cvbloke

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Near Pontop Pike, Co. Durham
#8
test0r said:
Ah, well we call it a splitter here. I dont know how you call it but it's this thing. The LNB goes to the middel connector and then the receiver and the DVB-S card are connected to another each. I couldn't find a 2-way splitter so I bought a 4-way :)
I wouldn't reccomend using a splitter on an LNB as you could and up frying one or both of your receivers, you'd be best getting a twin or quad output LNB...:)
 

tesla

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#9
Actually, it can be used with some extra components.

Like 2cvbloke said, at least one receiver could get damaged.

If the receiver (for example) is set to a vertical pol. transponder then the IF IN will have 13V dc. If the DVB-S card is set to a horizontal pol. transponder the IF will have 18V dc. The splitter will short circuit these two different dc voltages.

For that reason, all the "slave" devices should be connected to the splitter through a dc blocker.

In this page http://www.spaun.de/html/dcf_500___set.html you can see how a dc blocker looks like.

The unused outputs should be terminated. The terminating resistor should also have a dc block inside, like this one http://www.spaun.de/html/zfr_75_dc___set.html
 

pgh13

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#10
You can make a splitter very cheaply from a conventional UHF splitter/combiner by taking out the innards and then connecting a small capacitor - say 100pF in parallel with a diode - say1N4002 from the centre of each socket to the centre of the plug with the end of the diodes with the line at the common end. The capacitor gives a path for the signal to the receiver and the diode allows the dc to reach the LNB. though not an ideal solution, its workable where you want to use receiver A or receiver B, but if both are in use at once, both will only be able to access the same band and polarity (set by the receiver outputting the higher voltage etc)
 
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My Satellite Setup
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Belgium
#11
Thanks for the heads up guys. Because I got a little worried reading your replies, I removed the splitter and just used the IF Out. Does this eliminate the possibility of frying any of the devices? Or does the standalone receiver act exactly like a splitter?
 
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