Recently I acquired for free two 7.6’ unimesh dishes with actuators and orthomode Chaparral feeds with mini mag LNBs (two LNBs one for V and the other for H C-band, no Ku). This is my first time to try to setup a C-band system (I’m very experienced with Ku setup), and I’ve been reading this forum for information and recommendations. I need help regarding connecting the two separate V and H lines from the Chaparral feed to my Digital receivers. I’ve been reading about how to use multi-switches with power insertion (for the 13 volt side), but at the moment I do not want to acquire a multi-switch until I’m sure my setup works. Therefore, I figured directly connecting the H coax line from the feed to one digital receiver, and the V coax line to another digital receiver (with added power inserter to boost the voltage to 18). This would be a temporary setup until I gain experience with the C-band setup. Would this setup work? Any advice? Thanks.
Orthomode Chaparral feedhorn setup?
- Thread starter skipticum
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no power inserter required
If you set both receivers to H, they'll both put out 18 volts.
One will get the actual Horizontal signals.
The other will get the Vertical transponders 'cause it's hooked to the Vert LNB.
Also, check the Classified Department.
Stogie5150 may have a modified Multiswitch all ready to go.
Don't know if he sold all his or not.
Come to think of it, Linuxman is selling some hardware, and I know he had several, too.
If you set both receivers to H, they'll both put out 18 volts.
One will get the actual Horizontal signals.
The other will get the Vertical transponders 'cause it's hooked to the Vert LNB.
Also, check the Classified Department.
Stogie5150 may have a modified Multiswitch all ready to go.
Don't know if he sold all his or not.
Come to think of it, Linuxman is selling some hardware, and I know he had several, too.
Thanks Anole for the feedback.
I still don't understand your statement regarding setting the receiver (that will get the Vertical transponders) to H to get out the 18 volts. My understanding is that a digital receiver will put out 13 volts to the LNB when a channel associated with a vertical transponder is selected. I don't understand how to put the receiver to H and at the same time get vertical transponders channels which are vertical?
what he means I think is some LNB's need from 15-24 Volts DC to work properly. They dont like 13 Volts. So set both receivers to horizontal on all transponders so 18 volts is output all the time so the LNB's are happy. since the selection of H and V is physically fixed by the Chaparral feedhorn you don't need the receiver to do polarity voltage switching.
Maybe I'm missing something skipticum but if you have two dishes with dual c-feeds don't you have 4 coax lines? Or are you gonna combine them somehow ? You can't permanently hook up 4 coax lines to 2 receiver ports unless you combine them somehow. Thats what the modified power inserter/multiswitch Anole mentioned does. If you don't combine the 4 lines with a switch you can only hook up 2 at a time. Or are you just gonna keep changing which lines are connected depending on which satellite you wan't to watch?
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Modern LNBFs use a voltage controlled switch to choose which polarity is delivered to your receiver. However, with the orthomode feed, it has two separate LNBs on it. They need 18 volts each to operate. Regardless of what voltage you send to the LNB, one LNB is in the physical horizontal position, and one is in the physical vertical position. Most receivers these days assume your LNBF has a voltage controlled switch in it to pick which polarity it is going to receive. The H and V part in your receiver is the "switching action" that controls it.
That all said, again, most LNBFs use voltage to choose which polarity a receiver is going to get. The "standard" is 13 volts delivers the vertical polarity, and 18 volts delivers the horizontal polarity. Your vertical LNB on your orthomode needs 18 volts to operate. So to fool your receiver into giving your vertical LNB the 18 volts needs to operate you can tell your receiver the signal is horizontal, thereby sending 18 volts to your vertical LNB. The receiver thinks the signal is horizontal. You and and everybody else knows it's a vertical signal. But your receiver doesn't really care and doesn't have to know. It's getting a signal and displaying a picture. That's all you want.
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my vertical Norsats run fine on 13v. i used power inserters once and the signal quality didnt change. i know the norsats 8515 is stable on 13v with my ortho feed.
No, for the time being I'm playing with one dish. As I've mentioned previously, this is a temporary setup until the system proves to be stable (in terms of tracking reliably). Eventually, I'll get into the multi-switch business. I like to start simple to be able to resolve any setup issues efficiently, then move on to a more complex and practical setup later.
Thanks cracklincrotch. Your excellent explanation confirms my initial understanding, and supports what I was thinking of doing with the receiver connected to the vertical LNB. On other words, to be sure again, to setup the receiver I will (manually) choose the polarity as H (instead of V) for the vertical transponders, but provide all the other information correctly (i.g., FEC rate, frequency, etc.), and scan for (vertical) channels.
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