A few days ago I had the brilliant idea of replacing the ugly antenna of a 40MHz car remote control with an extendable one. Now the range decreased from 50 meters to 3-4m.
I don't know exactly what I broke so I have some questions, maybe I can fix it:
- How long exactly the antenna has to be? I broke the original antenna so I cannot measure it exactly, but it was about 37.4cm long (+/-2cm). The problem is that if I divide 7.5m to 1/4 or 1/8 I don't get near the original antenna length? So, which is the closest 'round' number to 37cm?
- The wire from the PCB to the new antenna behaves as an antenna and i has to be taken into account. Right?
- How exact the length should be? Do I loose lot of power if my antenna is 2%-3% longer than it should be?
- Maybe the problem is not the antenna but something else. For example: the new antenna is longer and goes very close to the PCB (to the quartz crystal). About 1.5-2cm close. Could it influence the correct functioning of the PCB?
I put the antenna back. Still doesn't work. I think accidentally touch and deformed some coils in the receiver.