Tuesday, November 17, 2009

Design Specification - Dixie Pixie

We are up and running, by now you've created a handful of PADs and your brain is hurting from those IIT Electronic courses (don't worry we wont go through all of them, just the basics of the basics to get you conversant with all of the concepts)


We will be building a 80m PIXIE using a color burst crystal - Why??

-- The crystals are 10x cheaper than other HAM frequency crystals, are available world-wide either new or as scrap in old television sets (see TV Set Salvage as you can see one can practically build the whole PIXIE from one old TV) Also, through some extra ordinary good luck Color Burst Crystals are resonant at 3.579545Mc, which just happens to be in the 80m CW band, and well within TECH license portion of the band, that is right I said TECH.

-- These PIXIEs are not really super-duper DX gear, so making a few local & regional NVIS QSOs with your club mates will be as much we can reasonably expect. -- Later on, you'll have the skills to build another on 30m or 20m QRP rigs for real DX power, but by then you'll understand all of the underlying matters. -- This one, remember is to better understand the HOWs and WHYs of QRP construction and radio design, we will keep simple and cheap.

Afterwards, we will look at changing out the OUTPUT tuned circuits and crystals to explorer to other bands, or even be able to bend the crystal to get more tuning range out it. These radios are notorious for also being wide, a so an active cw and notch filters are already in the drawing board.

A simple 2 CMOS chip keyer, will make the kits more cw paddle friendly, and a PC interface will show us how to integrate our little radios to our computers for QRSS beacon operation. There your little kit with the patience of a saint (at least the patience of a machine) will happily chirp out for months making 250mw contacts with far away lands and you can watch via remote QRSS grabbers.

Go ahead and order a few Color Burst Crystals and hand full of 2n2222 transistors, you'll also need some 10nF & 100nF Caps, an assortment of resistors (330, 470, 1K2, 10K, and 22K and 4M7), and small QTY of 1n34A & 1n751A diodes, you'll need these next week, after the TG holidays.

NVIS and Hope! 72 ki4SGU

2 comments:

  1. Can you explain in detail what is meant by "some 10nP & 100np Caps" for those of who might be electronically challenged? :)

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  2. ...as in less than Quantity 10, A SMALL ORDER of 10 NANO Farad & 100 NANO Farad Caps. Remember, a NANO Farad is 1000 PICO (so IN OUR CASE 10NANO is 10K PICO & 100NANO = 100KPICO) // or use http://www.translatorscafe.com/cafe/units-converter/electrostatic-capacitance/calculator/nanofarad-%5BnF%5D-to-microfarad-%5B&%23181%3BF%5D/

    Good Luck, glad to see you are keeping up

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