To Holes

insulating strip fiberglass or other, fl.g„ strip copper from copper clao

cement or hot wax copper side tinned copper wire , no send to suit cement or hot wax copper side baseboard

Tie Points

Fig. 2 shows a method that you can use for almost any size wire you can see and any size hole you can drill. I have used common pins of .021 diameter hammered into and through .020 holes, but the method of Fig. 2 is adequate for the strips shown in that figure.


A jeweller's hack saw is useful and is a very good tool to have around in any case. One with a large number of teeth per inch, like 32, or even more is best and with such a saw you can cut the strip shown in Fig. 2 out of the insulating material of a sheet of copper-clad if you do not have thin fiberglass or epoxy sheet on hand. The sheet I used happens to be ,030 thick when the copper is stripped off. I used a knife to start the copper off for stripping and then strong

Fig. 2b. Outline, drill vise*

I have a Black and Decker VI inch drill with their drill stand, which is very useful in this work. You have to get a jeweller's chuck to handle those little #60 to #80 drills. As mentioned, you cannot get very far into subminiaturization without special tools. I use various kinds of small tweezers, small screwdrivers filed into different kinds of points, jewellers pliers and cutters galore, very small files, and several box frames 4 to 6 inches high to bring the work up near your eyes for use with the magnifying glasses. Also masking tape to hold the small baseboards down on the box, #22 five core f solder, a separate small iron for the hot wax, a good micrometer, and a good but small drill vise (in fact, two sizes of these). Just in case you haven't met this handy item, Fig, 2B shows an outline. Very handy also for soldering plugs, jacks, and all sorts of small work, "A good workman is known by his tools/'

Steel measuring rules and miniature squares help also. With the items on this list you can at least make a start.

Tuning Elements

Not having found any tuneable coils of 3/32 diameter at a reasonable price, I went to small ceramic trimmers. And found they were not obtainable at a reasonable price either! This is mainly due to the difference between "radio" components and military ones, and the fact that certain special small parts such as ceramic trimmers, are not made in sufficient quantity (millions) to get the price down to where us amateurs can buy lots of them. Also, radio parts only have to last long enough to gel out of the retailer's store, while the military ones have to last long enough to become obsolete, which is not the same thing. And some suppliers, as you probably know through experience by now, do not differentiate between these two grades unless you insist. The Erie Co., 644 West 12th St., Erie, Pa., Tel 814-4535611, makes ceramic trimmers which are small, part #518, 2.5-9. The 2.5-9 refers to the minimum and maximum pFr which works well at 147MHz. The price is a horrible $4.95 (per one ea.) which sounds like a top military price to me, and is for those, which are only .218 in diameter. For a diameter of .375 you only pay $1.97 (by onesies). You can see from this where sub-miniaturization will lead you, dollar-wise! However, don't think you can inexpensively avoid tuning. I do know how to do it (another "breakthrough" article coming up if lucky) but that one is a lot more expensive! Believe me, when, and if, I find a way to do it at a reasonable price, I will certainly tell you right away.

and that was it. Of course, there might be some slight widening of the selectivity curve skirts at rf, but probably not even noticeable. And the gain was very close to the larger coils generally used


Here we get into some of the real nitty-gritty work. Fig. 3 shows a top view of the double-compound amplifier of Fig. 1, for Two Meter FM. You will have to work hard at this one. I'm just assuming however, that if I can do it at 69, so can you at N years old, Hgure 4 shows the pin 8 to pin 14 detail for that side, and Fig. 5 shows the pin 1 to pin 7 side. I put in all the bypass capacitors first, then the resistors to ground, then the +12 resistors.

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