> "its magic. Here I use an old AMECO PLF2 or a Gary Nichols KD9SV 160m" <
One comment about the six BF981 preamplifier. The circuit is correct, but the construction needs a lot of reworks. Any preamplifier needs 20db to 30 db more isolation than its gain, any wire in or out of the box needs to be RF ground using bypass capacitors inductors or choke. The 6xBF981 gain is over 30 db, at that gain you need double shield box, just a simple aluminum box is not enough, it is necessary to cut magnetic field using TIN plate or a steel plate. However, it is easy to know is you have done the right shield. Connect a 50 ohms load on the input of the 40 db gain preamp, check the S meter on the radio, turning on the preamplifier you will hear some increase of noise, but the S meter should be near S0 to S1. If you see S9, all that noise is pickup by common mode noise and poor isolation. Here is good example of isolation for a high gain preamp. https://lea.hamradio.si/~s53ww/4xbf998/n4isfile1.pdf 73's JC N4IS _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
