This is my latest and probably last contribution to the Boat Anchor saga. I say Last because it will be hard for me to out-do these two, following examples...
.
Last week they were both sitting on my desk for a couple of days,- one remains; the other had to be put back in its display case for reasons I will get to. The first little example I was looking at - is a 3X4" double sided printed circuit broad with 3 transistors- it was made by my grandfather sometime in the 60's. It's an RF pre-amp for 432 Mhz; what I find notable about it is that it is a UHF transistorized unit- coming about at the time of the great transition from tubes to solid state. It has 3 Texas Instruments TIXMO5,-- PC board strip- line inductors and 1960's era 'surface mounted' variable capacitors. Previous to this time everything he built used tubes. There is a Magic-Marker encyption on it: "20Db gain and (smeared) NF figure." Maybe someday I'll run it thru some measurements. I know, 1960's transistor stuff is sort a toss up as to 'boat anchor' status, but it should put the next example squarely in there.
.
This next one is a beautifully constructed little pre-amp. It comes from our office's cache of curios, and normally resides in a old government grey-metal glass display cabinet (circa Spanish American war--well, not exactly,- but it is Old-- and very appropriate for displaying dinosaurs.) The pre-amp is constructed of heavy silver plated bass; opening it up, there are +gold!+ plated coils, ceramic air variables, etc.--- but what stands out most, to me, are the little metal "thimbles" on the top- Nuvistor 7586's. The Nuvistors filled the transition between what tubes could do superbly and transistors were only dreaming of. On a slightly darker side, they date to the Cold War era- they were tough radiation resistant components that-- well, had other uses than in commercial radios and television sets. This unit, which I had to put back in the case- bears a few labels and tags--- project numbers, frequencies-- other technical parameters. The label I like the most , though says "Shot wxyz/abcd, date _______,"** There is also a "radioactive" warning label (that is why its back in the cabinet). This pre-amp was used years ago by "the other guys" out here, during the days of the Pacific atmospheric nuclear tests.... it apparently preformed well, for it bears "passed" stampings, and one that says "recovery within 20u/sec." Today its just slightly 'hot,' but enough so that no one should want it on their desks for long..
.
From what I gather, Nuvistors had a relatively long-lived run. They found their way into ham radio, especially in VHF/UHF converters. We still have a few of the commercial versions- 6CW4's, 6DS4's in parts boxes... any one remember those? Some people have suggested to me that the Nuvistor was developed for a commercial market to cloak the military applications... ah well-- makes for a colourful history, No?....
............. and I hope qualifies it as a unique chapter in radio, 'boat anchor or not.
.
..................................................CF
.
________________________________________________
.
*I am not going to put those in here for various reasons