Luckily - most of the world is not the US and gains of over 15dB are legal and common in non-us amplifiers. Modern FETs have much more gain than older devices and it would be quite normal to have 20dB gain from a stage - even after some feedback. There is an interesting design in the latest Dubus for a 1kW 2m amplifier that requires only 5W input. That is tetrode territory.
The popular THP 1.2KFX and 1.5KFX amplifiers use a 6dB input attenuator. Bypassing this allows you to drive them with less power under 25W, though it is not encouraged. The attenuator serves a couple of other purposes - it prevents serious over-drive with a 100W rig and it improves the input match. Incidentally - someone said with a 3dB pad the VSWR can't be more than 3:1 - that is only true if the PA does not have a negative impedance or to put it another way, return gain. That can happen when an amplifier takes off. Mike -- View this message in context: http://elecraft.365791.n2.nabble.com/OT-modifying-your-amp-for-lower-drive-requirement-tp5854009p5865633.html Sent from the [QRO] mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
