BATC Forum

To switch two (or more) LNBs between a single receiver. These used to be plentiful in the past, but all I can see for sale now are splitters.
There are of course RF switching boards around, but I assume those can't handle the LNB current needs.

I might not understand the big Q. but what do you want to switch..

1 LNB needs 2 different Bias voltages (12 and 18 Volt normally) and 1 LNB can feed 30 meter reasonable coax or 4 receivers on a short cable and a coax splitter (only 750 Mhz is not zo bad for the regular splitters).
You might want more and use a reasonable TV coax amplifier.. But switching is not needed for LNB. I use a dual LNB witch has 2 outputs.. 1 is powered with 12 volt and the other is 18Volt. so i have narrow and use a splitter to connect that to 1 pluto, and a sdr receiver.
other is wideband and i connect that to an 10 port amplifier and have connected several receivers, winterhill, pico, minitiouner etc...

Benno

Why not use a coax switch or relay? E.g. the SMA relays often seen at rallies? I doubt the 75 vs 50 ohm will matter much.

Mike

To Benno, I want to switch between two LNBs on different dishes, to feed into a satellite rx.

Mike, I'd rather avoid that if I can, I do have two high quality RF relays, but I'd prefer to be using those for TX/RX. I'll have to use a relay though, if there's no alternative.

You could use bias-Ts and switch the LNB supplies, then just combine the two LNBs in a resistive combiner. No coax relay needed, just two DC blocks, which you could build in to the combiner.

Mike

I assume you mean a diseq switch.
If your receiver supports disec that is the easy option and you can find them cheap everywhere.

PE1BR wrote: ↑

Sat Apr 12, 2025 3:31 pm

I assume you mean a diseq switch.
If your receiver supports disec that is the easy option and you can find them cheap everywhere.

Thanks, but no, it needs to be a manually operated switch. Another option I guess would be to use a separate DiSEqC generator, to effectively act as a manual switch, but they're quite pricey. If anyone knows of a DIY project, please let me know.

Hi,

probably I could be of assistance: Have a design for a Diseqc generator 1/4 using a PIC.
For more info please contact via PM

dc1op, Hub

Seems a lot of effort. Just take it apart and wire a switch in place of the microcontroller inside. The internet came up with this after searchingg for "diseqc switch schematic"

https://goughlui.com/2015/02/21/teardow ... -wsd-2041/

and this forum where someone has hacked one to do exactly what you wanted

https://empegbbs.com/ubbthreads.php/top ... nswitch_v3.

So it looks like these are simply PIN switches controlled by the micro, which may also by switching the LNB supplies. It would be easy to build one, but not worth it as you can buy one on Amazon for £5.

Mike

G4GHD wrote: ↑

Sat Apr 12, 2025 4:39 pm

PE1BR wrote: ↑

Sat Apr 12, 2025 3:31 pm

I assume you mean a diseq switch.
If your receiver supports disec that is the easy option and you can find them cheap everywhere.

Thanks, but no, it needs to be a manually operated switch. Another option I guess would be to use a separate DiSEqC generator, to effectively act as a manual switch, but they're quite pricey. If anyone knows of a DIY project, please let me know.

Just to note, the Picotuner, with the LNB supply fitted, should be able to generate the 22kHz tone commands, given the right software.