Loss of channels

[Elkview]

Just a note to installers, do not leave cable connected that is not in use. I had loss of 72 for a week, I thought it was rain, well it was because rain shorted out a cable that was hooked to my eastern arch dish that shouldn't have been there. I removed and got all my channels back. Instead of disconnecting he stuffed the loose end down the support pipe. Back to normal now.

 

[comfortably_numb]

Just a note to installers, do not leave cable connected that is not in use. I had loss of 72 for a week, I thought it was rain, well it was because rain shorted out a cable that was hooked to my eastern arch dish that shouldn't have been there. I removed and got all my channels back. Instead of disconnecting he stuffed the loose end down the support pipe. Back to normal now.

I believe that is common practice; at least around here- they leave a third cable connected to the LNB for future dish peaking. I see it all the time.

 

[TheKrell]

Instead of disconnecting he stuffed the loose end down the support pipe.

I vote for that loose end shorting against the inside of the mast.

 

[comfortably_numb]

Was the loose end terminated?

 

[Elkview]

Cable that had an end on it.

 

[ekilgus]

Wouldn't it be better if they had put a terminator cap on this unused cable?

 

[HipKat]

Wouldn't it be better if they had put a terminator cap on this unused cable?

You're supposed to on a DPH lnbf with a Hopper 2000 or a Hopper W/Sling, because it can act as an antenna and pick up outside frequencies, but a Hooper Duo and a Hopper 3 "kill" that port. On a DPP LNBF, you cannot terminate anything connected to one of the output ports

 

[TheKrell]

I'm lost. A coax at 3GHz is acting as a transmission line. Any change in impedance anywhere in that line (or the end) will cause the signal to be reflected backward or attenuated if the signal continues forward. A proper termination of a transmission line is to add something that has the same impedance as the rest of the wire, which is 75 Ohms IIRC. A terminator that is a dead short, on the other hand, is most certainly a change of impedance and will reflect the entire signal backward and inverted in phase.

So what are we talking about? A terminator that matches the impedance of the transmission line? Or a dead short? If I were recommending terminating unused outputs of a DPH, I'd specify a 75 Ohm terminator.

 

[HipKat]

I'm lost. A coax at 3GHz is acting as a transmission line. Any change in impedance anywhere in that line (or the end) will cause the signal to be reflected backward or attenuated if the signal continues forward. A proper termination of a transmission line is to add something that has the same impedance as the rest of the wire, which is 75 Ohms IIRC. A terminator that is a dead short, on the other hand, is most certainly a change of impedance and will reflect the entire signal backward and inverted in phase.

So what are we talking about? A terminator that matches the impedance of the transmission line? Or a dead short? If I were recommending terminating unused outputs of a DPH, I'd specify a 75 Ohm terminator.

I've never though about it before, but I wonder if our terminators are 75 Ohm

 

[charlesrshell]

I've never though about it before, but I wonder if our terminators are 75 Ohm

Are there different kinds/types of terminators? I think I have seen like a cap and then I think there are some that have like a center wire.

 

[HipKat]

Are there different kinds/types of terminators? I think I have seen like a cap and then I think there are some that have like a center wire.

All ours have the center conductor in them, which is what makes me thing they make be resistive terminator caps

 

[TheKrell]

All ours have the center conductor in them, which is what makes me thing they make be resistive terminator caps

You can measure it with an ohm meter. But I'm trying to figure out how you terminate a cable which presumably has a regular F-connector on it. The F-connector has the center conductor. So a terminator for a cable would look like a barrel with a female opening where the stinger goes.

 

[JSheridan]

You can measure it with an ohm meter. But I'm trying to figure out how you terminate a cable which presumably has a regular F-connector on it. The F-connector has the center conductor. So a terminator for a cable would look like a barrel with a female opening where the stinger goes.

That's how you do it. You add a barrel then a terminator.

 

[TheKrell]

That's how you do it. You add a barrel then a terminator.

Doh! I should have gone downstairs and examined my stuff.

 

[Cheddar_Head]

That's how you do it. You add a barrel then a terminator.

I've got a boatload of barrels, t-connectors and terminators left over from the days when computer networks were built out of coax. I keep them to show the newbies.
Built a sculpture out of them.

 

[TheKrell]

I've got a boatload of barrels, t-connectors and terminators left over from the days when computer networks were built out of coax. I keep them to show the newbies. Built a sculpture out of them.

So that's what they're good for?

IIRC, this network medium was called Thinwire Ethernet. And it had a 50 Ohm impedance rather than 75.

 

[dare2be]

a female opening where the stinger goes.

 

[Cheddar_Head]

Thinnet AKA 10Base2

Sculpture sitting on Compaq laptop that is also part of my collection.

 

[TheKrell]

Sculpture sitting on Compaq laptop that is also part of my collection.

You failed to terminate many of those T's.

 

[Cheddar_Head]

You failed to terminate many of those T's.

Gotta have some open connectors for the thinnet to connect.