Radio Society of Greater Bixby

Tom NMH has switched back to his old callsign, WA5MAZ from the mid 1960s. At the Thurs 03.26 meeting he brought in two (2) Motorola handy t – well, back then they were more like lunch boxes, the one from 1958 mostly transistors (except driver and final tubes – little ones, 1W out), and the other from 1948, one year after Shockley and the other two guys invented the point contact transistor, It was all tubes, a bunch of them, like 19 little ones, mostly mounted in replaceable/fixable modules like the one shown above, part of the crystal multiplier chain that makes 146 Mc from a crystal in the 12 Mc area. Tom has used the old ‘Lunch Box’ Motorolas on the 146.91 repeater. It’s a little trick to do that since Int’l Crystal Co. doesn’t make crystals any more, and that’s another story about Tom, using a freq synthesizer chip to program not only a 12 Mc crystal, but also a PL tone. We asked him, Why don’t you just buy a Baofeng, but I guess he likes to display his talents

Kenny KJ5EKW brought in a heavy 14 VAC transformer and asked about making a power supply. The linear Astrons start with a little more voltage that comes out around 21VDC. One idea was to use the 7812 type regulator chip which can regulate with as little as 2 Volts difference. (14VAC times 1.414 yields 19.7; less 1.4 for loss in hte bridge rectifier; now 17.3; less maybe a Volt of ripple with a large (80,000 uF) filter capacitor; down to 16.3 that could be regulated to the 13.8 – 14.0 DC range.