Question about loop out

[B.J.]

Wow I am confused as pie...I have a Nuesat and a Uniden Supra Hooked to a splitter so I can use the C-Band LNB on both boxes. I also have an A/B for Ku/C-band on the Neusat. No DC Blocks at all. I can turn off LNB power on the Neusat settings so I don't need power from the Neusat to the C-Band LNB I just let the Uniden do that for me. On the Loop out from the Neusat I have a Dreambox 7020 hooked up and I use it to record because it has a built in Hard Drive. I always have the Neusat off IF I am using the DB. The power stays on all the time on the Uniden Supra. But I have never actually used a DC Block of any kind. Maybe I am just lucky...I never saw a real need to use a DC block but maybe I should consider it before something smokes besides my pipe! By the way I have had this same hookup for several years and never had any issues that I know of...

I'm guessing that you're using a 1 leg power pass splitter, which is pretty much the same thing as using a DC-block there. I am confused about what kind of A/B switch you're using. If it's a diseqC A/B, then those generally need power from the receiver, so I don't understand how it would work with the Nuesat off, but maybe you're refering to some kind of mechanical switch?

But it may be that your only issue is between the Neusat and the Dreambox, and you might be lucky with respect to the design of the Neusat passthru.... I don't know.

 

[Ironsides]

no Diseqc

I'm guessing that you're using a 1 leg power pass splitter, which is pretty much the same thing as using a DC-block there. I am confused about what kind of A/B switch you're using. If it's a diseqC A/B, then those generally need power from the receiver, so I don't understand how it would work with the Nuesat off, but maybe you're refering to some kind of mechanical switch?

But it may be that your only issue is between the Neusat and the Dreambox, and you might be lucky with respect to the design of the Neusat passthru.... I don't know.

No DiseQc Switches at all...The A/B switch is just that it's a mechanical switch. The splitter is just a cheap splitter I picked up some place. The Neusat is turned off but it displays the clock. So the main power switch on the back is on. If you turned off the main switch on the back then of course you can't use the loop out if cuts the signal off to the Dreambox.


Ok let me try to give you a better idea.

The LNB for C-Band is split. One jumper goes directly to the Uniden.
2. From splitter side 2, it goes to the mechincal A/B switch
3. From the out of the A/B switch it goes to the Neusat
4. On A/B switch side 3 I have located the Ku Satellite Lnb ( the reason for that is because I have 2 dishes one large 10 foot C-band located in one place and a smaller Ku Band Dish located in another) I could have used a DiseQC here but found it worked far better in the manner I have it connected. I would have still had to use a splitter to feed the Uniden anyway. I use the Satellite Meter on the Uniden to locate satellites. It was a pain having to unhook and hook up every time I needed to make a change. In the case of using a DiseQc I might would had to use a DC block to keep from toasting the Diseqc. Another reason of course the need to switch from Vert to Horz using the Uniden. I could of course still do that but for tuning I prefer to have the Uniden hooked up.

5. From the loop out from Neustat I go directly to Dreambox

To switch between Ku and C-Band I just press the button and you're off and running.

The power that would normally come out of the Neusat to feed the LNB is set to OFF for satellites C-BAND but on for KU Band. That is located in the software setup.

My concern is DC coming from the Uniden back to either the Neusat or Dreambox or them Sending in DC to the Uniden.

That being said it might would help people if we could find a diagram that gives instruction on how to correctly use and install DC Blocks.

I have a couple here but I wasn't sure where they should be or which Direction they should be turned in line. The kind I have appear to go inline as one side is female and the orther male.


The Loop out feature it would be my guess would have some sort of DC blocking as to not damage either reciever. No where in my manual does Neusat suggest any type of DC block be used. The diagram shows the jumper connected Directly to the 2nd reciever. Same for my Pansat which has a Loop out, the diagram shows the jumper connected directly to the 2nd receiver and no mention is made of any type of DC blocks. They must assume that power would be coming from the 2nd reciever to power and lnb or power coming from the main could damage the 2nd. Be my guess is no power comes from the main and 2nd powers the LNB? The loop is bound to be on a relay or electronic relay as it opens when the main power is turned off preventing any signal to the looped receiver.

As I said earlier it might be a good idea to have a diagram that shows the correct placement and direction in the line how DC blocks should be used when hooking up 2 receivers to the same lnb or whatever...

 

[B.J.]

No DiseQc Switches at all...The A/B switch is just that it's a mechanical switch. The splitter is just a cheap splitter I picked up some place. The Neusat is turned off but it displays the clock. So the main power switch on the back is on. If you turned off the main switch on the back then of course you can't use the loop out if cuts the signal off to the Dreambox.


Ok let me try to give you a better idea.

The LNB for C-Band is split. One jumper goes directly to the Uniden.
2. From splitter side 2, it goes to the mechincal A/B switch
3. From the out of the A/B switch it goes to the Neusat
4. On A/B switch side 3 I have located the Ku Satellite Lnb ( the reason for that is because I have 2 dishes one large 10 foot C-band located in one place and a smaller Ku Band Dish located in another) I could have used a DiseQC here but found it worked far better in the manner I have it connected. I would have still had to use a splitter to feed the Uniden anyway. I use the Satellite Meter on the Uniden to locate satellites. It was a pain having to unhook and hook up every time I needed to make a change. In the case of using a DiseQc I might would had to use a DC block to keep from toasting the Diseqc. Another reason of course the need to switch from Vert to Horz using the Uniden. I could of course still do that but for tuning I prefer to have the Uniden hooked up.

5. From the loop out from Neustat I go directly to Dreambox

To switch between Ku and C-Band I just press the button and you're off and running.

The power that would normally come out of the Neusat to feed the LNB is set to OFF for satellites C-BAND but on for KU Band. That is located in the software setup.

My concern is DC coming from the Uniden back to either the Neusat or Dreambox or them Sending in DC to the Uniden.

That being said it might would help people if we could find a diagram that gives instruction on how to correctly use and install DC Blocks.

I have a couple here but I wasn't sure where they should be or which Direction they should be turned in line. The kind I have appear to go inline as one side is female and the orther male.


The Loop out feature it would be my guess would have some sort of DC blocking as to not damage either reciever. No where in my manual does Neusat suggest any type of DC block be used. The diagram shows the jumper connected Directly to the 2nd reciever. Same for my Pansat which has a Loop out, the diagram shows the jumper connected directly to the 2nd receiver and no mention is made of any type of DC blocks. They must assume that power would be coming from the 2nd reciever to power and lnb or power coming from the main could damage the 2nd. Be my guess is no power comes from the main and 2nd powers the LNB? The loop is bound to be on a relay or electronic relay as it opens when the main power is turned off preventing any signal to the looped receiver.

As I said earlier it might be a good idea to have a diagram that shows the correct placement and direction in the line how DC blocks should be used when hooking up 2 receivers to the same lnb or whatever...

Still not sure if you're using splitters with a power pass leg or a splitter which is passthru on all legs.

Re which way to use a DC-block, that's interesting. I've heard about different types of splitters with passthru legs, one of which used diodes, and people suggested that they might not be reliable, and I've found that one of my splitters actually passed DC between some ports in one direction but not the other. But I've always assumed that stand alone DC blocks blocked equally in both directions, either double diodes or a capacitor. HOWEVER, I recently observed some strange behavior which suggested that DC blocks may behave differently in one direction compared to the other.

Basically what I observed, is that in the past, I haven't been too careful about when connecting a slaved receiver to a passthru, whether I put the DC block on the input of the slaved receiver or on the output of the master receiver, assuming that it would be the same. But recently I observed that one of my slaved receivers wouldn't work unless I put the DC block on it's input, rather than my usual way of putting the block on the passthru of the master. Actually, it stopped working, and only started working again when I put TWO blocks in line, one on master and one on slave, which would have them in opposite directions. So now, I'm not sure if one of my DC-blocks is bad, or if they are normally direction specific. I was too lazy to pull them out and test them. It's not easy to test them anyway, since you can't really test them with an ohmmeter. You pretty much have to hook them up to 18V, and check to see if you get the 18V going through them, which suggests that they use diodes... at least the splitter I had which failed still tested good with an ohmeter, but the test failed when I used an 18V test.

I think I'll pull out my Channel Master meter, which has a built in voltmeter and 13/18V source, and test these blocks that were giving me problems.

 

[Ironsides]

After hours

After hours of researching this and not really finding any set method of using DC Blocks I just disconnected the entire system.

I am now using my Neusat for Ku Only and have it connected to nothing else.

I'm using my Dreambox for C-Band and have it connected Directly to the C-Band LNB and the loop out goes back to the Uniden Supra LNB in.

Works fine but I ran into one issue, If the Uniden is turned off I can get Channels fine on one polarity which I think is vertical. Not positive about that. In order to get the horzontal I have to put the Uniden on that polarity and leave it on otherwise it reverts to vertical as the receiver bleeds down after turning it off.

This time I have a DC block on the Loop out of the Dreambox and A surge protection on the LNB in.

C-Band I have a surge protection on the LNB IN....

I don't understand why it reverts to the other polarity when the power turns off. Looks to me like if it switched to that it would stay there??

I can see nothing changing on the Dreambox as in Flickering or Freezes on the Screen when turning the power off and on with C-Band.. so that is a good sign I guess...

Good luck on testing your DC blocks this is interesting and tons of information but nothing I could really find that helped me with my setup.


The only thing I could find in my Dreambox Manual about the loop out was to make sure to place it in Deep Stand by when watching the analog receiver.

Nothing in the Uniden manual about it...

 

[Ironsides]

futher testing

I tested this futher and gave it a lot more time and If I power down the Uniden I can't get any channels on either polarity on the Dreambox.

I guess it must be something to do with the lnb settings but it's not a real issue for me to just leave the uniden on. I just wanted to make sure it wasn't going to damage either box.

This has been very interesting to read about all these different DC Blocks and switches...

 

[Ironsides]

Local Experts

Seriously would like to know other peoples findings concerning this DC Block and how they use their Analog receivers with their FTA equipment

 

[B.J.]

..... But recently I observed that one of my slaved receivers wouldn't work unless I put the DC block on it's input, rather than my usual way of putting the block on the passthru of the master. Actually, it stopped working, and only started working again when I put TWO blocks in line, one on master and one on slave, which would have them in opposite directions. So now, I'm not sure if one of my DC-blocks is bad, or if they are normally direction specific. ......

I did some testing of the 2 DC-blocks involved in the above observation, and both stop DC in either direction. So I don't understand WHY the downstream receiver would only work on this one feed when I either had the one block reversed or used 2 blocks. Doesn't make any sense, and I can't remember now what specific feed was involved, so I can't try it again.
I DID, however ALSO test the passthru output of the particular receiver I was using at the time, ie the Diamond 9000, and I found that it DOES seem to pass DC out of the passthru, so if this receiver were hooked up without a DC-block, there would be a problem. I don't know if the Diamond was always like this, or if some component in the circuitry went bad, but it's definately giving off DC now.
I also tested my Azbox, my Twinhan 1020a, my Fortec Ultra, and my Fortec Mercury (I didn't test my Fortec Lifetime or Coolsat 8100, but will try those later when I get a chance). The Twinhan, Ultra and Mercury did not give off any voltage out of the passthru. The Azbox seemed to have a very small amount of DC leakage, ie less than a half volt (compared to the Diamond with gave out the full LNBF voltage). What I don't want to test, because it has caused problems in the past, is to test to see which if any of these receivers will pass DC through the passthru from the slaved receiver to the lnb when the master receiver is switched off or turned off. Apparently this works with some receivers but not with others.

 

[Ironsides]

Thanks BJ

Thanks Bj for you thoughts and testing time! This has been a real hoot to read about and learn. I am still confused as I was but at least I have some nice reading behind me.

I started another thread hoping to get some input from others who have a master and slaved system. Seems so far not a lot of interests in this thread or the new one.

I have been using the same setup for several years and never had a problem with it. Guess I was just lucky...

Today just out of purely being bored. I connected a Pansat up as the Master and Uniden as the slave and it did exactly the same as the Dreambox.

Just to make things fun, I hooked up a Yard Sale Neusat and it did exactly as the Pansat and Dreambox.
Configured as Master they all do the same thing!

The only receivers I have that are brand new or was new at one time is the Uniden and Dreambox 7020. My boss purchased the DB for me In England and I owned the Uniden and purchased it brand new moons ago!

All of my other receivers I purchased from Yard sales so they could have had some issues before I got them. If all my receivers are acting in the same manner it would say either they are all working correctly or everyone of them has a defect.

In this last go around I have No DC blocks in line and only kept the surge protectors in line and which made no differences as I could see.

I did notice with all receivers tested I had to leave the Uniden on. However I did discover that I could turn off the Uniden and Master at the same time. Leave the Uniden OFF for say 5 minutes and then Turn the Master and watch tv on one polarity. The Dreambox only uses Diceqc to switch polarity so I have to control that with the Uniden which means I have to turn it on to change channels that are on another polarity. Now that is confusing because IF you turn them both on at the same time and then turn off the slave the channels go black on the current polarity but you can change the master to channels located on the other polarity and watch tv again. Sometimes though after about 10 minutes they disappear and changeing channels doesn't seem to do anything. Now walking in have the Uniden off and Turn on the Master DB and watch TV with no drops at all on the one polarity..WHICH BOGGLES MY MIND!

The Pansat can switch so it isn't an issue with polarity for it...