Thread: 22KHz signal coupling through dual LNB

I just noticed in your first thread and I am wondering why the ecoda switches outputs are fed back through the motors to the receiver. Should these not be between the receiver and the motors? Only the Diseqcs need to be between the motor and LNBs. This would avoid passing the C band signal via the motor. Maybe some RF coupling there?

I think a diagram would be easier to see the hookup.

Originally Posted by wrdavis

I think a diagram would be easier to see the hookup.

Yep that's what I thought. How about this? No C band signal through the motor loopout.

I've read that having a switch between the receiver and motor can burn out the switch with the motor current.

So I did the receiver direct to the motor, then to the switch as the best practice.

I think this refers to the delicate Diseqc as opposed to Ecoda switches. If I am not mistaken Brian at Sat AV at his shop has runs this configuration for some time.

Brian has been on this thread give him a PM

While it is recommended to place the motor after the switch, we have run our test motor with GEOSATpro 90cm dish on the output with no issues. The switch easily handles the draw. Note: We are careful not to perform switch commands while the motor is in operation.

I'll keep this idea in reserve, if the 2x4 switch doesn't do it. The 2x4 switch only needs me on one lower roof where the C band dish is located.

Both the 2x4 multiwitch and non Ecoda 22Khz switches came Friday night. So this morning, bench checked them with my Digisat meter and scope. The 2x4 multiswitch killed nearly all 22Khz signal from the Digisat into one the RX ports and out the other three. With the scope amplification at max, the 22KHz was only barely visible. Looked like, if 22KHz was the problem, the 2x4 switch would cure it.

The non Ecoda 22KHz switches were another problem altogether. First off they weren't non Ecoda 22KHz switches, second they weren't 22KHz switches at all, but signal splitters. Got to return them.

Installed the 2x4 multiswitch. BTW, it was also ground bonded in addition to the coax ground. Tried it and had the same result where C band on one receiver effects Ku on the other. So removed the 2x4 switch to try the wiring change where the 22Khz switch and 1M dish motor locations are swapped.

This change was complex enough to label the 4 connectors before disconnecting them to make certain I didn't get things even more crossed up in the process. Tried first on the easier antenna location, tested and same thing. Decided maybe both changed would be different, so did the other 1M antenna. Same thing again.

And finally reinstalled the 2x4 multiswitch to see if the combo of everything would make some difference. Still the same.

Out of ideas for now, other than to have both receivers on the same band, C or Ku. Good thing we don't have kids living here.

Just as an experiment, swap any test dual output LNBF in place of the C2 and see if the issue is related specifically to the C2 LNBF or will occur with any LNBF in this configuration.