Advice Needed Multiswitch and electric current to lnb

nadal liu

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My Satellite Setup
120cm offset dishes for 124e and 128e with emp centauri profi multiswitch 9x16, and 5x20
,180cm prime dish with lo 10678 ku lnb for 110e bs/cs
My Location
Hong Kong
I have a question regarding multi-switch and electric current to LNB.
To put it simple, does multi-switch provide electric current to lnb from the power adapter that we plug into the wall socket? Or the multi-switch pass the electric current from stb to lnb?

I know that multi-switch needs to know if we need vertical or horizontal signal and it tells that by the voltage of electric current provided by stb. I, however, don't know if the multi-switch then passing the electric current to lnb or not.

The reason I asked is that I am receiving the signal of Japanese satellites, 124E and 128E. Each of them has vertical and horizontal signal and in hi band only. Japanese stb has a different voltage that it provides to lnb, 11v for vertical and 15v for horizontal. I have two multi-switches from emp centauri, 9x16 and 5x20. They are at different sites. On the 9x16 I have an external electric current adapter that provides electric current to lnb. On the 5x20 I don't have. The lnbfs are general 11300 single LO dual output ones that accepts 13v/18v. If I hook up Japanese stb to the 9x16, it seems to work fine for both vertical and horizontal signal. It won't work well, however, on the 5x20, specifically the horizontal signal is lost. I assume it is because the voltage from stb is 15v and it is not enough for the 5x20 multi-switch to know that we want horizontal signal. But, why does it work on the 9x16 multi-swtich? I have no idea. I am assuming that 9x16 is working because it happen to accept lower voltage of 15v and send horizontal signal to stb, and 5x20 is not working because it has a higher threshold of voltage, and the multi-switch provides electric current to lnb on its own and not from the stb.

Please kindly shed me some light.
Thanks.
 

nadal liu

Regular Member
Joined
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My Satellite Setup
120cm offset dishes for 124e and 128e with emp centauri profi multiswitch 9x16, and 5x20
,180cm prime dish with lo 10678 ku lnb for 110e bs/cs
My Location
Hong Kong
I made an experiment on the stb hooked up to 5x20. 5x20 doesn't have external power provider to lnb.
I turned on one of my non-japanese stb that send 13v/18v on 124E on horizontal channel. Leave it there. On the second stb, which is japanese stb, I checked that both horizontal and vertical channels are there viewable. That concludes my theory: multi-switch doesn't always send signal from its own power, it pass the current from stb and pass it over to lnbs. In my case, because my regular non-japanese stb sends 18v to multiswitch, the current is passed on to lnb. When 124E and H is watching on stb 1 that sends 18v to multiswitch and multiswitch pass on to stb. On stb 2, the horizontal signal is ok, because lnb already is powered by stb 1 and the electric current from stb 2 is not send to stb to avoid problem. If my theory is correct, then a external power adapter to lnb will solve my problem. Just a wild guess. Please advise if it is correct. Thanks.
 

a33

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XSAT410
Rebox RE-9000
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NL
Hi nadal,

I would say the 11/15 volts have two functions:
- information supply (for switching-function between V and H),
- power supply.

If you use your 11/15 volt stb for power supply, the voltage would drop a little. I would think your 15 volts would drop below the information-function-threshold, which would be around 15 volts.
If you feed the switch and LNB also with a (higher!) voltage from another stb, that stb takes over the function of power supply, and the 15 volts wouldn't drop so much.
So I think your theory is about correct! And your proposed solution would work, I guess, if you supply "extra" power to switch and LNB (power inserter before the switch, not after; that would be best I guess).

What I would like to know: How about testing the other stb supplying power to switch and LNB, but 13 volts instead of 18 volts? Does your 11/15 volt stb function properly then, also? Or only with 18 volts (i.e.: more than 15 volts)?

greetz,
A33
 
Last edited:

nadal liu

Regular Member
Joined
Jan 16, 2014
Messages
38
Reaction score
3
Points
8
My Satellite Setup
120cm offset dishes for 124e and 128e with emp centauri profi multiswitch 9x16, and 5x20
,180cm prime dish with lo 10678 ku lnb for 110e bs/cs
My Location
Hong Kong
Thanks for your reply.
I am a little confused at my current setup.
Like I said, my Japanese stb functions well on the 9x16 multiswitch with an external power supply.
Well, it doesn't work on just any port of the multiswitch.
It works well on certain port but on others the H signal is lost.

Also, on my 5x20 switch without external power, I found out whether a Japanese stb has H signal is a random walk.
Therefore, I think I am lucky to have a setup that works with a Japanese stbs and a standard multiswitch, and it is not replicable.

To sum up, it is better to not to mess up with a Japanese stb and a standard multisiwtch, because we don't know if they will work at all.
 
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