What's the proper DC Block to buy?

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John Popper

SatelliteGuys Pro
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Dec 11, 2009
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Central Mexico
I need to get one since I think I already messed up my LNBF so I wanted to know which one is the proper one to use if I want to connect to the RF input of my Uniden analog receiver and slave it to the Coolsat?

a store down here offers this one =


16bh577.jpg


Steren

description says it goes from 5mhz to 1 ghz


Is this ok?

Thanks!
 
I need to get one since I think I already messed up my LNBF so I wanted to know which one is the proper one to use if I want to connect to the RF input of my Uniden analog receiver and slave it to the Coolsat?

a store down here offers this one =......
....
Is this ok?

Thanks!

That looks like it might be an attenuator, not a DC-block, although my spanish is poor. It "looks" like a DC-block, but attenuators look similar. (although most attenuators that I have are BNC, not F connectors). Can you translate the description? It looks to me like it's saying that it's a 3 Db attenuator with DC PASS, not DC-block, but again, it's been about 50 years since I did poorly in a Spanish class.
BTW, it's pretty hard to mess up an LNBF by mixing receivers without a DC block. I think the main danger is to one of the receivers.
 
Would you explain the issue, please? Slaving a Coolsat receiver to a Uniden analog receiver should not be a problem. Could that be a problem?

How is the LNBF messed up?
 
to the folks asking about my LNBF situation, here's what I asked in the c band section but got no answer!

someone suggested that my problem might have been due to sending twice the voltage by using the uniden analog receiver and the coolsat at the same time


I think that is what happened because I have tested every which way possible and this LNBF simply does not change polarity and now isn't even tuning TELEFUTURA which was the one channel I was able to catch.
I replaced the LNBF with my old Chaparral Feedhorn and LNB (without servomotor) and I have been adding channels first horizontal polarity and then I manually rotate the thing where the servomotor is supposed to be and I do the vertical pol channels. I am now getting many of the channels on the Skyvision list. I guess I can just buy a servomotor and use it on the old Chaparral feedhorn, but I spent almost 80 bucks on the LNBF and wanna also grab the KU band feeds. :rant:

As you can all gather by now I am a neophyte when it comes to voltage and electrical stuff but is there a way of knowing if indeed I blew the LNBF like can I take it to a electrician and ask him to test the voltage?

now if the LNBF is ok could the other possibility be that my used Coolsat is not regulating voltage therefore the LNBF doesn't work properly? have you guys heard of such scenario?
 
John, I haven't read through that entire thread. But, I would be surprised if you have blown the LNBF by slaving the receiver and having LNB power turned on. Yes, it is unnecessary to have LNB power on for the slave, but don't receivers have DC blocks on their slave connections?

You can test your Coolsat with a DC volt meter to see if it produces voltage for the LNBF. Measure the center of the coax to the shield. Do this for a horizontal TP and a vertical TP.

My guess is that the LNBF needs to be polarity aligned for the dish. If so, you need to rotate the LNBF in the scalar ring so that it will pick up both polarities.

I will try to find instructions for the BSC621-2 LNBF and post them.

EDIT:

Here you go:

BSC621-2 install guide
 
Last edited:
One more thing...

Is that stuff in the picture exactly what you have? It looks like an old style BSC621-2 (without an integrated DiSEqC switch) and a 22khz switch.

Universal LNBFS don't work with 22khz switches.

yeah that is exactly what I have, I took that pic

but im not even using the 22k switch at this moment, I haven't even tried KU band yet and I tinkered so much with the LNBF that I am now getting wrong polarity even on analog channels, I think I made it unusable.

looks like Im gonna have to buy a new LNBF
 
When you use a universal LNBF, the 22k is switched on automatically (on most U.S. satellites, the universal must be switched into high band, which requires 22k). This is why universals don't play well with additional 22k switches... They already have one built in.
 
Voltage from your receivers do not "add together" to create a higher voltage than the LNBF can accept. You could potentially damage one of the receivers by back feeding a voltage, but this is also unlikely.

A DC block could be used in place of turning OFF the LNB power in the receiver's menu if one of the receiver's is to be assigned as the master or controlling unit. Otherwise, the LNBF polarity will be set by the highest voltage. Example: if receiver "A" is set to vertical (13vdc) and receiver "B" is set to horizontal (18vdc), the LNBF will be set by the higher voltage outputted by receiver "B" and only tune horizontal polarity.
 
John, I haven't read through that entire thread. But, I would be surprised if you have blown the LNBF by slaving the receiver and having LNB power turned on. Yes, it is unnecessary to have LNB power on for the slave, but don't receivers have DC blocks on their slave connections?

You can test your Coolsat with a DC volt meter to see if it produces voltage for the LNBF. Measure the center of the coax to the shield. Do this for a horizontal TP and a vertical TP.

My guess is that the LNBF needs to be polarity aligned for the dish. If so, you need to rotate the LNBF in the scalar ring so that it will pick up both polarities.

I will try to find instructions for the BSC621-2 LNBF and post them.

EDIT:

Here you go:

BSC621-2 install guide


update: I tested voltage on my coolsat and everything is working appropriately so the next step is waiting for the new LNBF to arrive, that way I can replace the one I messed up.

btw, re-reading this thread I wondered if the culprit of all my problems could be the coaxial cable itself, it is the same coaxial that I've had for close to 20 years and had been using on the old analog receiver. I guess my question is would that same coaxial cable work with these FTA Digital receivers that send voltage to the LNBF? or do I need to replace it with a newer one?
 
What kind of coax is it? RG-6? RG-59? Usually it is marked or printed on the outer insulation.

Does the shield have foil in it?

Is the braid copper or aluminum color?
 
Harry!

Unfortunately the black coaxial cable has nothing marked on it but here are a couple of pics I just took of it:

1e85s8.jpg


vpujyp.jpg








I also have this cable available, I recently bought it for the Ku Band part of the LNBF which I havent even tried yet, in case the black one doesn't work, could I use this instead?


21e5d7l.jpg
 
The Belden 9116 is economy-grade CATV RG-6, with a copper-clad steel center conductor. It should work, but again it is economy-grade cable. I wouldn't put bandstacked LNBs on it.
 
Its impossible to tell from the picture, but chances are pretty high that its RG-6. Not sure of the center conductor construction. Both would probably be adequate. Be sure to use compression fittings if possible, not the quick push-on or screw-on fittings.
 
update: I tested voltage on my coolsat and everything is working appropriately so the next step is waiting for the new LNBF to arrive, that way I can replace the one I messed up.

btw, re-reading this thread I wondered if the culprit of all my problems could be the coaxial cable itself, it is the same coaxial that I've had for close to 20 years and had been using on the old analog receiver. I guess my question is would that same coaxial cable work with these FTA Digital receivers that send voltage to the LNBF? or do I need to replace it with a newer one?


well the LNBF is here and ive spent the past 3 hours trying to set it up, I am back to square one, I have tried every possible combination on the coolsat 6000 (LNB Universal, Single, Disecq Switch ON/OFF) and I just can't get it to show me anything like I was getting with the old chaparral feedhorn.

Now I know it's aligned properly because I can see an almost picture perfect analog signal on HSN Channel 10 @ 135 but when I try the Coolsat and the feeds on 135 like G4, Bloomberg and Telefutura Mountain I get nothing. Ive also tried with both cables I showed above, with the same result.

Anyone got any suggestions? what am I doing wrong? is this LNBF universal, single?


btw this is the LNBF I have:


t8ryg7.jpg


1z4yidz.jpg
 
The box says its a KU_Universal, with the LO freq it's showing. That's the KU side anyway. C-band LO freq is 5150 as you already know. There's a review of that lnbf somewhere , I'm pretty sure this is the same one that some other members had headaches with, trying to get both c and KU to work. I think Stogie had one of those.
 
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