Some words about the use of amplifiers:
- If you are planing to use one you should know what you are doing. Amps can cause more damage as giving you a benefit. If you aren't sure ask somebody who knows what he is doing.
- Amps are indeed boosting noise too, but high quality LNAs (quite to awful expensive) are boosting the noise many times less than the signal. That way, signals which were below the receivers threshold without the amplifier get receiveable after the amp is installed.
- The Amp must match up with the signal strenght after the antenna, the used cable type and lenght and the receivers threshold levels. If you are using a high gain antenna (e.g. 10db) at a very short (10m/30ft) ultra low attenuation cable (e.g. LM400 or Ecoflex 15+) the amp will overdrive the receiver. That will result in a decrease of reception range or -worst case- will cause damage to the receiver.
- If you are planning to receive narrow band signals use narrow band amps that are designed to only amplify the frequency of the particular signal. In areas with many other HF transmissions an improvement of signalquality may be achieved by the use of narrowband amplifier as other fequencys get attenuated by these amplifiers.
- Although it might be possible to run one receiver at a high gain antenna with 65ft (or 100ft) of Ecoflex 15+ cable, it might be neccessary to install an amplifier, if you are planing to run more than one receiver simultaniously at the same antenna (cable).
- Amplifiers usually need DC supply voltages (e.g. 12V DC) that is usually transmitted via the coaxial cable. Make sure, that you use AC/DC power supplies with low EMI. Further it is a good idea to use single soltage supplys with a good current reserve. e.g. If the amp needs 100mA don't use supplies that can delivery 100mA or 250mA, but use supplys that can deliver at least 500mA or better 1000mA. The reason is better life time of the supply and lower rest ripple voltage on the dc voltage.
Regards Ingo
