The Lowe PR-150 Antenna Preselector.

Lowe produced a antenna preselector for the HF-150 to overcome the problems associated with overloading from strong signals, Lowe PR-150 preselector and preamp. The PR-150 covers 100 kHz to 30 MHz in seven bands segments. Each band segment comprises of a dual-tank LC filter circuit, each of which can tune over 2.5:1 within the intended...

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More 1928 Hartley

Well, it's in the log...the first QSO. Tonight I worked Lou, VE3AWA, on 3565. We were 549-559 both ways and had a nice contact going until 80 meter QRM caught up with us. Lou was using his Push-Pull TPTG transmitter with a NC101X. I had my HRO Sr paired with the Hartley running 10 watts input and about 3 watts out.For this contact I added...

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A short diatribe about floating point numbers

Floats. They're great! You can store really large or really small numbers in them with ease (provided they're supported by your compiler). Most processors even have built in instructions for playing with them. However, they are an imprecise number, which means that whatever value you try to put in may not be the value you get out.Take for example the counter system I installed in a factory - the processor we used could only support...

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More 1928 Hartley

After a little debugging it works!When I first put power to my version of Ross Hull's Hartley transmitter I could only get it to oscillate if the cathode clip is either not attached at all or clipped to the tank coil near the plate (rather than grid) end. RF with the clip this high on the tank coil is detectable on a nearby receiver but not...

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More 1928 Hartley

Except for a couple of coil clips my clone of Ross Hull's 1928 Hartley is complete. It's ready for power and checko...

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More 1928 Hartley

Today we have surface-mount-technology, before that we had pin-in-hole printed circuit cards, before that point-to-point wiring and before that we had breadboards. With breadboard construction came solid bus bar wiring. Bus bar is stiff enough that wiring takes on a 3D sort of aspect. Wiring of a transmitter such as this Hartley has height...

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More 1928 Hartley

Working through this project has given me a new appreciation of the homebrewing skills of many of the hams during the twenties and thirties. The article on this particular transmitter has some gaps in the construction details....for coil turn information the builder is referred to the coil photo, to count the turns himself....and....Keying...

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More 1928 Hartley

That pile of old parts, wood and copper tubing is starting to look like a transmitter. The eight parts left are mostly to be wired into place so things should speed up a little.The unsung hero of any project like this is a drill press. Without one you could never get all of the holes rig...

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More 1928 Hartley

With (plexi)glass rods ordered and one additional National DX capacitor in the mail from a friend the next step is some table saw ti...

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