Ultra-Wideband Radio, Amateur Radio, Radio-Astronomy and other RF Projects

          This is my receiver setup.  My main VHF/UHF receiver is an  Icom IC-R7000.  It features  all-mode (AM/FM/WFM/SSB) reception between 25Mhz and 2GHz.  This receiver is great for general-purpose “scanning” as well as for hydrogen-line radio-astronomy.   An Icom IC-R71A receives <10kHz to 30MHz (it’s specified 100kHz to 30MHz, but can be easily tricked into going all the way down to a few kHz.  It’s great to receive subcarriers from the R7000).  An Atlantic Electronics model SM-7071 “pan-adaptor” spectrum analyzer completes my setup.  The SM-7071 acts as a spectrum analyzer within the IF of either the IC-R7000 or the IC-R71A.

This is my home-made spectrum analyzer.  It covers 100kHz to 1.5GHz in 3 bands.  It includes a tracking generator, selectable bandwidth filters, AM or FM demodulation and a computer interface.  The main RF blocks are modified TV tuners available from “The Science Workshop”       

RF Equipment

This home-made synthesized RF signal generator covers 100kHz to 1Ghz with 1Hz resolution.  It’s capable of digitally controlled FM, analog direct FM and AM modulation. Level flatness is within +/- 2 dB and maximum output level is +10 dBm.

  This is my main linear power amplifier.  It came straight from the dumpster at Intermedics!  It outputs 25W and covers 1MHz through 500MHz with no tuning.

My RF rack includes a lot of equipment that was salvaged from the dumpster or purchased as surplus from Metro-CAD after the Intermedics plant was closed. 

Recommended Books

          This simple spectrum analyzer adapter is described in D. Prutchi, "Sniffing EMI in the Near-Field", CCI—The Computer Applications Journal, Issue #71, 30-41, June 1996. [Circuit schematic diagrams and expanded information available in the book: Design and Development of Medical Electronic Instrumentation]

Ultra-Wideband (UWB) Radio and Radar Information [.pdf]

· Barrett, T.W., "History of UltraWideBand (UWB) Radar & Communications: Pioneers and Innovators", Proceedings of Progress in Electromagnetics Symposium 2000 (PIERS2000), Cambridge, MA, July 2000.

· Simple ultra-wideband transmitter

· Simple ultra-wideband baseband receiver uses tunnel diode

· Tunnel diode pulser 20ps risetime

· Ultrawideband transceiver pair

· McEwan’s Micropower Impulse Radar

· McEwan’s fast pulser

· Simple step-recovery-diode (SRD) pulse generator

· Recent Applications of Ultra Wideband Radar and Communications Systems (paper) -- Ultra-Wideband, Short-Pulse Electromagnetics, KLUWER ACADEMIC/PLENUM PUBLISHERS, 2000

· C. Leonard Bennett and Gerald F. Ross, Proceedings of the IEEE, Vol. 66, No. 3, March 1978, pp. 299-318 (3.26 MB)   (This IEEE Proceedings article by Bennett and Ross is the fundamental paper on ultra wideband (UWB) technology development from the early 1960's through 1978. The authors discuss the origins of time domain electromagnetics (now commonly referred to as UWB).

· Low-Cost Ultra-Wideband, Ultra-Short-Pulse Transmitter with MESFET Impulse-Shaping Circuitry is described in:

· Jeong Soo Lee and Cam Nguyen, Novel Low-Cost Ultra-Wideband, Ultra-Short-Pulse Transmitter with MESFET Impulse-Shaping Circuitry for Reduced Distortion and Improved Pulse Repetition Rate, IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, VOL. 11, NO. 5, MAY 2001. [PDF]

· Jeongwoo Han and Cam Nguyen, A New Ultra-Wideband, Ultra-Short Monocycle Pulse Generator With Reduced Ringing, IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, VOL. 12, NO. 6, JUNE 2002 [PDF]

  This plot was generated by Daniel B. Fox  using his home-built radio telescope, measuring hydrogen line emissions along the plane of our galaxy. The long sweeping arcs are due to the hydrogen, in various arms of our galaxy, moving at different speeds relative to us resulting in a Doppler shift of the hydrogen line emissions. There is also a shift in the frequencies of the emissions due to the motion of the Earth around the Sun.  I expect to be generating similar graphs very soon.

Amateur Radio-Astronomy

My hydrogen-line radiotelescope consists of a horn antenna in “bird-bath” configuration, a low-noise amplifier and a 1,420MHz to 2m amplified and filtered downconverter.  An Icom IC-R7000 is used to detect the downconverted signal.  The downconverter  (picture) was designed by the SETI League for amateur SETI in the water hole.

· Microwave (gunnplexer) amateur weather radar (page 1, page 2, page 3)

Amateur Microwave Radar

· D. Prutchi, “Passive-Detector Receiver Keeps You Informed, Entertained During Flights”, Design Idea, EDN, 98-99, May 12, 2005. [PDF]


· FAA regulations generally forbid the use of receivers onboard commercial aircraft because a superheterodyne receiver’s local oscillator can radiate signals that could interfere with aircraft communication and navigation systems. The crystal radio of this project directly detects nearby AM signals in the very-high frequency aircraft band, 118 to 137 MHz, and thus cannot interfere with aircraft equipment. Communications between the pilot and the flight controllers are brief and infrequent, and listening to the airplane band as a passenger can get boring. However, the circuit in this project improves on an earlier passive aircraft-band receiver by allowing you to enjoy an aircraft’s in-flight-entertainment system while monitoring pilot-to-ground communications…  EDN’s schematic contains a few mistakes.  Here is the corrected schematic: [ERRATA pdf]

Aircraft Band Radio

© 2005 David Prutchi.  All rights reserved.

73 de HC1DT

CLICK HERE  for information on our Amateur Radio Astronomy Station!

QSL Info:        HC1DT, Dr. David Prutchi

                      Asuncion 721 (Oe4-27) y Venezuela

                      Quito, ECUADOR