I found an old (but not in use) garage door controller. The receiver is still intact but can't be reached from souterrain. The sender transmits a single tone on 27MHz in the citizen band. The signal is very weak, I measured 2Vpp (which equals to 10dBm, 10mW). I wondered if it is possible to boost the signal. I have a few of those "5MHz - 6GHz Broadband amplifiers" lying around, which you can get on ebay: https://www.ebay.com/itm/5M-6GHz-Low-Noise-RF-Amplifier-Ultra-Wideband-20dB-Medium-Power-Amp-Board-sz98-/283714550135 Is it possible to chain those amplifiers to sum up their gain?
I asked the seller and he states, the modules can be connected together to add the gain of both modules. I connected the RF-Out of stage 1 to the RF-In of stage 2 with a 50Ohms cable and added a 50Ohm dummy load to the RF-Out of stage 2. I was quite suprised that the Gains of both stages were not added, on RF-Out I can read 3.7 Vpp so there was basically no "gain addition".
- Are those modules generally not suitable for TX power amplification or would I need other modules?
- Someone posted that one could use a Wilkinson splitter and combiner by first splitting the signal, guiding it through two amplifier modules and then combing them again. Will this sum up the amplification power of the modules used?
- Both modules use the same 5V power supply. I have read somewhere this should be avoided. Also true for this case?
- In general, can the Vpp output voltage outrank the supply voltage?
According to the comments and answers, my whole idea points into the wrong direction. That means, leaving the sender where it was the last years or increase gain on the receiver side (better antenna, LNA or upgrade the system with newer technology).