The National Radio Astronomy Observatory (NRAO)
Very Large Array (VLA) radio telescope

NRAO employee personal webpage for

Paul Harden (NA5N),

IF/LO Lab, X7142

pharden at nrao.edu

Last updated 14 Feb 2008

My wife, Jan (NØQT) listening on her QRP ham rig at the
Very Large Array (VLA) radio telescope near Socorro, NM

And you thought only Jodie Foster got to do that!

• The HOMBREWER'S

HOBBY PAGE •

Intended to promote an interest in electronics, engineering and science

by hams and hobbyists

Jump to

History Articles

NEW Stuff . . .

[PDF]

The

QRP-L.org Group Project rig

, by Jason Milldrum, NT7S

Test procedures and brief circuit description by NA5N (including oscope and spectrum analyzer displays)

[PDF]

The

QRP-L.org Group Project rig

Annotated schematic with test voltages and waveforms by NA5N

The QRP-L.org Group Project is a 20M direct-conversion 5W QRP transceiver designed by Jason Milldrum, NT7S.
The rig is built from scratch
"Manhattan style." Discussion is on the www.qrp-l.org group; for more information see Jason's site

http://www.nt7s.com/index.php5?page=qrplgp

Tutorials and articles:

[PDF]

Tutorial

Designing different types of transmitter PA output low pass filters (LPF)

[PDF]

Tutorial

The Handyman's Guide to

MOSFET Class D/E/F amplifiers - Part 1

[PDF]

Tutorial

The Handyman's Guide to

MOSFET Class D/E/F amplifiers - Part 2

-

- incomplete/reformatting in-progress

[PDF]

Tutorial

The Handyman's Guide to

Oscilloscopes - Part 1

(5 pages) - updated May2004 with

actual oscope displays

[PDF]

Tutorial

The Handyman's Guide to

Oscilloscopes - Part 2

(4 pages)

[PDF]

Tutorial

Solar Activity & the Solar Physics behind HF Propagation

(8 pages) - 2005 ARCI

FDIM Compendium Presentation
Learn about:

Solar Storms • Geomagnetic Storms • Solar Flux and the K- and A-Indices • When to

operate •

[PDF]

Tutorial

The Handyman's Guide to

Understanding Transistor Data Sheets

[PDF]

Tutorial

The Handyman's Guide to

Manhattan Style Construction Techniques – Thru-hole –

Part 1

[PDF]

Tutorial

The Handyman's Guide to

Manhattan Style Construction Techniques – Surface Mount

EVLA.html

http://www.aoc.nrao.edu/~pharden/hobby/Hobby.shtml

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– Part 2

[PDF]

Hints & Kinks

on building a "3rd Hand" for holding circuit boards, cables, etc. for the workbench.

[PDF]

Hints & Kinks

on doing Metal Work - tapping holes and other metal work practices

[PDF]

Hints & Kinks

on how to paint & label electronic project enclosures

[PDF]

Hints & Kinks

on building electronic circuits Manhattan Style (a proven QRP copper clad

technique)

Construction Projects:

[PDF]

Schematic – DESERT RATT (original 1996-1997 circuit as published on QRP-L, QRPp, etc.)

[PDF]

JPEG

Schematic - DESERT RATT 2 (Updated 2001 for varicap tuning, construction hints and

voltage/waveforms)

PHOTOS

of those building the DESERT RATT:

Ricardo/Mexico

[PDF]

Circuit Description – DESERT RATT 2

[PDF]

4/P CONVERTER: 74–500 MHz to 1.1–1.5 GHz Upconverter built Manhattan style

[PDF]

The 74MHz/P-Band TEST SET - front panel & top view

[PDF]

74 MHz Oscillator (part of Test Set) – built Manhattan style

[Schematic JPG]

[PDF]

Noise Source & 1024 MHz LO (part of Test Set) – built Manhattan style

[Schematic]

[PDF]

300–400 MHz Sweep Oscillator (part of Test Set) – built Manhattan style

Sweep Generator

[Schematic JPG]

— Schematic, VCO, Attenuators, etc.

[Schematic JPG]

History Articles

Some of the history articles I write for the local newspaper most requested are placed here. All files .pdf
including the original photographs from the article.

WESTERN UNION AND THE RAILROAD TELEGRAPHERS

- The history of Western Union, the

railroad telegraphers and early wireless

EL CAMINO REAL TRAIL - PART I

- The early history of El Camino Real, from the 1598 Onate

Expedition to the 1680 Pueblo Revolt

EL CAMINO REAL TRAIL - PART II

- The history of El Camino Real from 1692 de Vargas

reoccupation to the arrival of the railroad

EVLA.html

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