002: 144 to 28MHz B-mode converter

144-146MHz, NF 1.6dB, gain 24dB, DC 12V

This is a converter for Oscar mode B, making was in Jan. 1983. Because we had a lot of interference of a strong local on 2m band in those days, the receiver with an excellent not only NF but also IMD was strongly requested. And I made up my mind to build a new converter for DX QSOs via the new satellite. I chose the low noise SONY 3SK48 for the top and the diode DBM for the mixer, then sensibility (NF1.7dB) as the aim was obtained. I remember the beacon from the satellite received for the first time was powerful indeed. I actively worked AO10/B for only one year (1983-1984), and completed WAC, I enjoyed it enough. Afterwards, this converter works firmly as 144-28 down converter for a home brew automatic NF meter.

The 3SK48 has been carelessly destroyed several years ago, and I changed it to 3SK40 instead, but obtained NF was 3.0dB. I recognized the ability of MOS FET in 1970 again afresh. It is exchanged for Toshiba 3SK114Y now, and NF of has returned to the original level.
144-146MHz, NF 1.6dB, gain 24dB, DC 12V






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