Thread: 22KHz signal coupling through dual LNB

Brian

Just starting in C Band, so I have only the one GeoSat dual output LNB. I could pop in an old circular dual Ku LNB to see what happens on Echo/Nasa or one of the open channels. Needs some channel editing first. If the GeoSat LNB looks to cause it, what other brands & model dual output C Band LNB should I look for?

Pedro

If you are referring to the circuit diagram you provided, I have it wired that way now with the 22KHz switch between the receiver and motor.

The only other dual output C-band LNBF that I am aware of is the Digiwave unit. Couldn't recommend, but maybe someone has tested and will comment.

Swapped out the GeoSat dual C Band LNB for one of my old Ku circular LNB's. The test shows that the problem is not unique to the GeoSat LNB. Probably just as well, if there isn't any good replacement for the GeoSat to be found.

The testing both ways has shown one other symptom I hadn't noticed before. If both receivers are on a C Band channel, one or the other will freeze for a second or two a few times a minute.

Following the design concepts of KISS, removed the 2x4 multiswitch from the setup, since it seemed to neither help or hurt things.

As the distributor of the GEOSATpro C2, I am relieved to learn that the issue is not specific to the C2..... now to determine the cause.

Have you performed a blind scan on either receiver when this issue occurs? Results?

Do you have a spectrum analyzer? It would be interesting to see if this issue is related to the delivery of the satellite signal to the receiver or is it the receiver not processing the signal correctly.

If you don't have an spectrum analyzer, try splitting the feed with an additional receiver connected to the power blocked side of an HF splitter. Scan the signal and determine if the appropriate or if any signal is being delivered when this issue is occurring.

On a side note: A similar issue was in the forefront of selecting a base design for the GEOSATpro DVR1100c / DSR100c and DSR200c receivers and the dual output GEOSATpro SL2 LNBF. Developed to provide multiple room Glorystar systems, several factory samples were rejected due to undesired interaction between the tuners when connected to a dual LNBF or multi-switch.

Haven't done a blind scan.

The quality goes to zero on channels I have scanned in. Seemed the only way that would happen is if the switching mechanism is somehow being effected and blocks the signal. That's why I at first thought it was the 22KHz switching signal coupled through the C band LNB doing it. But my bench check of the 2x4 multiswitch blocked the 22KHz signal so well, I now doubt that is the problem.

Don't have a spectrum analyzer. Used one in the Navy 40+ years ago. They probably have changed a lot since then.

Don't have any power blocking splitters. Is that something you sell?

Where are you thinking the signal should be split off to see what a different receiver finds. Right at the C band LNB outputs, or directly at the input to my Pansat 9200HD? I have an old Pansat 2500 I could try, once I remember how to use it again.

This is probably a stupid question but are you sure the Antenna setup menu on each 9200 are correct, identical and with actuals as opposed to auto selections.

An easy answer to this may be to have 2 additional cheap receivers just for the c band with their own feeds direct to the tvs.

We do sell splitters with single leg power passing, but probably also available locally to save time and shipping (unless you want us to slip the splitter in with a purchase of a dish or receiver.... LOL)!

I would split at the receiver first then if the wrong or no signal is detected, work back through the switches until you reach the C2.

Originally Posted by wrdavis

Don't have any power blocking splitters. Is that something you sell?

Where are you thinking the signal should be split off to see what a different receiver finds. Right at the C band LNB outputs, or directly at the input to my Pansat 9200HD? I have an old Pansat 2500 I could try, once I remember how to use it again.

Pedro

Sounds like a good idea, just use a separate cheap receiver for the C Band.

To try the splitter idea, I have to bring my old Pansat 2500s back to life anyway. Be a few days to dig them out of the attic or where ever I put them away and install an updated channel list for the C Band.

I'll look for a power block splitter in the big city tomorrow.

Hooked an old Pansat 2500A receiver in the bedroom to only one of the dual C Band LNB's outputs directly with no switches, and the problem is masked. Only drawback is the old receiver is non HD, so can't watch C Band HSN, QVC, ION, or RFD HD in the bedroom. Every thing else functions, so far now, plan to call this done the way it is.

Luckily my universal One for All remotes had enough memory left to allow one button for the old Pansat, one for the new Pansat, and even one for the GBOX 3000.