Production of 13/18V two-way switch

The picture below shows a 13/18V two-way switch, which is composed of two 13/18V single-way switches and a two-power divider.

Circuit principle: When the switching voltage input from the IRD1 interface is sent to the switch, if the V polarization signal is selected, the input voltage is 13V. After the voltage is divided by R1 and R2, the base voltage Vb of the transistor Q1 is less than 0.7V, Q1 is cut off, and the relay J1 does not work without power, and its normally closed contact connects the LNBV interface; when the H polarization signal is selected, the input voltage is 18V, Vb>0.7V, Q1 is turned on, and its normally open contact connects the LNBH interface. Similarly, IRD2 is switched in the same way. Diodes D1 and D3, capacitors C1 and C2 form a two-power divider, which is used to isolate the output voltages of the two receivers to prevent the voltage of one receiver from being reversed when it is not working.

Component selection: J1 and J2 are small-volume, low-power DC 12V relays. The outer shell uses a distributor shielding box with four wiring ports. Remove the parts inside, put the prepared device inside, and pay attention to insulation. During debugging, if the relay still does not work when switched to H polarization, the values ​​of R2 and R4 can be appropriately increased until the relay can switch freely when the polarity is switched.