QEX_2005_07.pdf

$ 5

INCLUDING:

Forum for Communications Experimenters

July/August 2005

Issue No. 231

From Italy, IWØFGR and IØLVA

present an LNA for 47 GHz.

ARRL

225 Main Street

Newington, CT USA 06111-1494

The national association for

AMATEUR RADIO

Summer

Classes!

Radio Frequency Propagation…EC-011

Explore the science of RF propagation, including the properties

of electromagnetic waves, the atmosphere and the ionosphere,

the sun and sunspots, ground waves and sky waves, and various

propagation modes —including aurora and meteor scatter.

Member: $65 / Non-member: $95

There’s no better time to improve your skills . Online Classes

are Available Now through the ARRL Certification and Continuing

Education Program. Complete 100% of your training via the

Internet:

• Self-paced (asynchronous) format — you attend class

when and where you want.

• High quality web experience enhanced with graphics,

audio, video, hyper-linking and interactive modules.

• Online Mentoring . Individually assigned instructors help

advance each student toward successfully completing the

course material.

• Pre-register Now! Classes open regularly.

Radio Frequency Interference … EC- 006

Learn to identify sources and victims of interference. Tips and

suggestions for solutions and for handling those ticklish problems

that crop up with difficult neighbors and other aggrieved parties.

Tools to help foster ingenuity, intuition, and determination for

solving interference problems.

Member: $65 / Non-member: $95

VHF/UHF— Life Beyond the Repeater … EC- 008

An introduction to Internet linking, amateur satellites, direction

finding, APRS, weak signals, VHF contesting, microwaves,

amateur television, and high speed multimedia radio. Great for

both the newly licensed and more experienced hams.

Member: $65 / Non-member: $95

Technician License Course … EC- 010

The course prepares students to earn their first Amateur Radio

license. There are no prerequisites. Individually assigned online

mentors assist students as they advance toward successfully

completing the course. Registration includes the ARRL book,

Now You’re Talking! and online graduate support.

Member: $99 / Non-member: $139

Available Courses

Antenna Design and Construction … EC- 009

Students become familiar with antenna design theory and

experience hands-on construction techniques. The course

includes several optional antenna construction projects for

HF, VHF, and UHF.

Member: $65 / Non-member: $95

Antenna Modeling … EC- 004

This course is an excellent way to learn the ins and outs and the

nitty-gritty details of modeling antennas. In the last decade the

science of modeling antennas using computer software has

advanced by huge leaps and bounds. While some absolutely

unique, brand-new antenna designs have resulted from computer

studies, the real progress has been in our understanding of how

even common, ordinary antennas work.

Member: $85 / Non-member: $115

HF Digital Communications … EC- 005

Understanding HF digital Amateur Radio communications and

developing awareness and stronger skills for many HF digital

modes. Member: $65 / Non-member: $95

Level 1 Amateur Radio Emergency Communications … EC- 001

Introduction to Amateur Radio Emergency Communications. A

basic course to raise awareness and provide additional knowledge

and tools for any emergency communications volunteer.

Member: $45 / Non-member: $75

Level 2 Amateur Radio Emergency Communications … EC- 002

Intermediate Amateur Radio Emergency Communications.

A more in-depth study into amateur radio emergency communica-

tions to enhance the skills and knowledge received from previous

experience. Requires prior completion of EC-001.

Member: $45 / Non-member: $75

Level 3 Amateur Radio Emergency Communications … EC- 003

Advanced Amateur Radio Emergency Communications. Bridging

the gap between basic participation and leadership. Requires prior

completion of EC-001 and EC-002.

Member: $45 / Non-member: $75

Analog Electronics … EC- 012

Students learn about the use of instrumentation, Kirchoff’s Laws,

Diodes, Rectifier circuits, Bipolar and Field Effect Transistors,

various amplifier configurations, filters, timers, Op-Amps, and

voltage regulators. Most lessons include a design problem and

optional construction project. (College-level course.)

Member: $65 / Non-member: $95

Digital Electronics … EC- 013

Student learn about Basic Boolean, Basic Gates, Flip-Flops,

Counters and Shift Registers, Latches, Buffers and Drivers,

Encoders and Decoders, Parallel Interfaces, Serial Interfaces,

Input Devices, Displays, Logic Families, Microprocessor Basics,

Connecting to Analog Electronics, Understanding Data Sheets

and Design Resources. Most lessons include a design problem

and optional construction project. (College-level course.)

Member: $65 / Non-member: $95

Online courses are produced by American Radio Relay League, Inc. and are available

through ARRL’s partnership with the Connecticut Distance Learning Consortium

(CTDLC), a nonprofit organization that specializes in developing on-line courses for

Connecticut colleges and universities. Continuing Education Units (CEUs) are available

for all ARRL Certification and Continuing Education courses. The ARRL Certification

and Continuing Education Program is funded in part by course fees from interested

hams who support public service and quality continuing education.

For further information, e-mail your questions to cce@arrl.org , or write to

ARRL C -CE , 225 Main Street , Newington , CT 06111 .

ARRL The national association for

QEX 7/ 2005

AMATEUR RADIO

www.arrl.org/cce

INCLUDING:

About the Cover

The completed LNA levitates

above a close-up of a MMIC

and its wiring. Read about the

project on page 45.

QEX (ISSN: 0886-8093) is published bimonthly

in January, March, May, July, September, and

November by the American Radio Relay League,

225 Main Street, Newington CT 06111-1494.

Periodicals postage paid at Hartford, CT and at

additional mailing offices.

POSTMASTER: Send address changes to:

QEX, 225 Main St, Newington, CT 06111-1494

Issue No 231

Harold Kramer, WJ1B

Publisher

Doug Smith, KF6DX

Editor

Robert Schetgen, KU7G

Managing Editor

Lori Weinberg, KB1EIB

Assistant Editor

L. B. Cebik, W4RNL

Zack Lau, W1VT

Ray Mack, WD5IFS

Contributing Editors

Production Department

Steve Ford, WB8IMY

Publications Manager

Michelle Bloom, WB1ENT

Production Supervisor

Sue Fagan

Graphic Design Supervisor

Mike Daniels,

David Pingree, N1NAS

Technical Illustrators

Joe Shea

Production Assistant

Advertising Information Contact:

Janet L. Rocco, Account Manager

860-594-0203 direct

860-594-0200 ARRL

860-594-0303 fax

Circulation Department

Kathy Capodicasa, Circulation Manager

Cathy Stepina, QEX Circulation

Offices

225 Main St, Newington, CT 06111-1494 USA

Telephone: 860-594-0200

Fax: 860-594-0259 (24 hour direct line)

e-mail: qex@arrl.org

Subscription rate for 6 issues:

In the US: ARRL Member $24,

nonmember $36;

US by First Class Mail:

ARRL member $37, nonmember $49;

Elsewhere by Surface Mail (4-8 week delivery):

ARRL member $31, nonmember $43;

Canada by Airmail: ARRL member $40,

nonmember $52;

Elsewhere by Airmail: ARRL member $59,

nonmember $71.

Members are asked to include their membership

control number or a label from their QST when

applying.

Features

3 Receiver Measurements, How To Evaluate Receivers

By Dr Ulrich L. Rohde, N1UL

12 The Quest for the Elusive TBWB4EQ (The Triband

Wideband 4-Element Quad)

By L. B. Cebik, W4RNL

28 Ground System Configurations for Vertical Antennas

By Al Christman, K3LC

38 A Blind Automatic Frequency Control Algorithm

By Gary A. Geissinger, WAØSPM

45 A 47-GHz LNA

By Silvano Ricci, IØLVA, and Daniele Moretti, IWØFGR

52 A Do-It-Yourself Noise Figure Meter

By Fred Brown, W6HPH

54 A Space-Saving Antenna for 40 Meters

By Ron Skelton, W6WO

57 Octave for Signal Analysis

By Maynard A. Wright, W6PAP

Columns

62 Letters

63 Next issue in QEX

In order to ensure prompt delivery, we ask that

you periodically check the address information

on your mailing label. If you find any inaccura-

cies, please contact the Circulation Department

immediately. Thank you for your assistance.

Jul/Aug 2005 QEX Advertising Index

American Radio Relay League: Cov II,

63, Cov III, Cov IV

Atomic Time: 53

Down East Microwave, Inc.: 64

Expanded Spectrum Systems: 27

J-TEC, LLC: 64

National RF: 64

Nemal Electronics International, Inc.: 53

Noble Publishing Corp.: 64

RF Parts: 11

Teri Software: 56

Tucson Amateur Packet Radio Corp.: 44

Walter H. Volkmann: 63

League Inc. For permission to quote or reprint

material from QEX or any ARRL publication, send

a written request including the issue date (or book

title), article, page numbers and a description of

where you intend to use the reprinted material.

Send the request to the office of the Publications

Manager ( permission@arrl.org )

Jul/Aug 2005 1

THE AMERICAN RADIO

RELAY LEAGUE

Empirical Outlook

The American Radio Relay League, Inc, is a

noncommercial association of radio amateurs,

organized for the promotion of interests in Amateur

Radio communication and experimentation, for

the establishment of networks to provide

communications in the event of disasters or other

emergencies, for the advancement of radio art

and of the public welfare, for the representation

of the radio amateur in legislative matters, and

for the maintenance of fraternalism and a high

standard of conduct.

ARRL is an incorporated association without

capital stock chartered under the laws of the

state of Connecticut, and is an exempt organiza-

tion under Section 501(c)(3) of the Internal

Revenue Code of 1986. Its affairs are governed

by a Board of Directors, whose voting members

are elected every two years by the general

membership. The officers are elected or

appointed by the Directors. The League is

noncommercial, and no one who could gain

financially from the shaping of its affairs is

eligible for membership on its Board.

“Of, by, and for the radio amateur, ”ARRL

numbers within its ranks the vast majority of

active amateurs in the nation and has a proud

history of achievement as the standard-bearer in

amateur affairs.

A bona fide interest in Amateur Radio is the

only essential qualification of membership; an

Amateur Radio license is not a prerequisite,

although full voting membership is granted only

to licensed amateurs in the US.

Membership inquiries and general corres-

pondence should be addressed to the

administrative headquarters at 225 Main Street,

Newington, CT 06111 USA.

Immaculate Reception

We tend to dote on receiver articles

here at QEX . That’s probably because

receivers are some of the more complex

and perhaps the most difficult machines

that one can design. We’ve certainly seen

some good designs lately, too. But the

recent rise of direct-conversion and simi-

lar DSP-based designs has given rise to

fresh discussions about test methods. It’s

becoming increasingly difficult to make

comparisons among new and old receiv-

ers, as in the ARRL product-comparison

chart. If our test methods change—as

they have done several times in the

past—then that difficulty may increase.

But change they must because we

have to be sure that we’re measuring

what we think we are. Increased dy-

namic ranges and bandwidth capabili-

ties of receivers may force changes in

test instrumentation as well. Here are

a few of the issues as we see them.

One of the first mandatory measure-

ments for any receiver is to ascertain

its noise-floor power. For proper com-

parisons with other receivers, that

must be specified in a standard band-

width. Then it’s possible to compute a

noise figure, which we feel is the best

figure of merit when it comes to noise

performance. But simply selecting, say,

a 500-Hz filter on an SSB rig doesn’t

guarantee that the actual bandwidth is

the same as another receiver’s 500-Hz

filter. Yes, you can measure the band-

width to get your result, but what

about the shape of the passband and

stopbands? One way to compensate for

those factors would be to compute the

equivalent rectangular bandwidth for

the filter (infinite shape factor). There

are other ways to measure noise figure,

but then you must reverse the process

to compute the noise-floor power.

That’s because it’s used in dynamic-

range calculations. So, we must have

that number.

A possible pitfall of using an audio

voltmeter during noise-floor testing

arose a few years ago. It turns out the

engineer was using a meter that did

not read true-RMS, but more like aver-

age-reading calibrated to RMS. That

meant that the peak-to-average ratio of

what he measured affected the result.

During his procedure and with no sig-

nal into the receiver, he calibrated his

meter to 0 dB; then he injected a signal

producing a 1-kHz tone and increased

its level until the meter reading rose

3 dB. It turns out his results were off by

almost 2 dB because the peak-to-aver-

age ratio of the noise was about 2 dB

different than that of the sine wave.

To measure the upper end of any type

of dynamic range, a good way to go

seems to be to examine the receiver

output on a spectrum analyzer. Then

it’s easy to determine when the inter-

ference produces the effect sought. But

it’s possible to design a receiver with an

AGC knee at the noise floor. If that

AGC could not be turned off or the knee

not raised, the receiver’s peak output

level would remain constant. Then dur-

ing a so-called blocking dynamic range

measurement, an increase in on-chan-

nel noise would force the on-channel

signal’s level downward, giving a possi-

bly false indication. You wouldn’t be

measuring blocking at all but some

phase-noise effect. That could be a

problem for testing of FM rigs.

Then there is this accuracy and preci-

sion business, which I’ve discussed be-

fore. Those are just a few of the things

currently being considered. Your com-

ments are welcome!

Telephone: 860-594-0200

FAX: 860-594-0259 (24-hour direct line)

Officers

President: JIM D. HAYNIE, W5JBP

3226 Newcastle Dr, Dallas, TX 75220-1640

Chief Executive Officer: DAVID SUMNER,

K1ZZ

The purpose of QEX is to:

1) provide a medium for the exchange of ideas

and information among Amateur Radio

experimenters,

2) document advanced technical work in the

Amateur Radio field, and

3) support efforts to advance the state of the

Amateur Radio art.

All correspondence concerning QEX should be

addressed to the American Radio Relay League,

225 Main Street, Newington, CT 06111 USA.

Envelopes containing manuscripts and letters for

publication in QEX should be marked Editor, QEX.

Both theoretical and practical technical articles

are welcomed. Manuscripts should be submitted

on IBM or Mac format 3.5-inch diskette in word-

processor format, if possible. We can redraw any

figures as long as their content is clear. Photos

should be glossy, color or black-and-white prints

of at least the size they are to appear in QEX.

Further information for authors can be found on

the Web at www.arrl.org/qex/ or by e-mail to

qex@arrl.org .

Any opinions expressed in QEX are those of

the authors, not necessarily those of the Editor or

the League. While we strive to ensure all material

is technically correct, authors are expected to

defend their own assertions. Products mentioned

are included for your information only; no

endorsement is implied. Readers are cautioned to

verify the availability of products before sending

money to vendors.

In This Issue

Ulrich Rohde, N1UL, brings us dis-

cussions and examples of receiver tests

using European standards. Contribut-

ing Editor L. B. Cebik, W4RNL, dis-

cusses three-band four-element quads

with an eye toward bandwidth, among

other things. Al Christman, K3LC, has

some notes on ground-system configu-

rations for vertical antennas. Gary

Geissinger, WAØSPM, shows how SSB

voice signals might be tuned automati-

cally. Our Italian friends Silvano Ricci,

IØLVA, and Daniele Moretti, IWØFGR,

relate their recent experiences on the

6-mm band with a 47-GHz LNA. Fred

Brown, W6HPH, has a neat homebrew

noise-figure meter design. Ron Skelton,

W6WO, delivers a space-saving an-

tenna for 40 m. Maynard Wright,

W6PAP, has more on Octave . This time,

the subject is signal analysis.— 73,

Doug Smith, KF6DX, kf6dx@arrl.org .

2 Jul/Aug 2005

How To Evaluate Receivers

Want to test your receiver? Here’s the right way.

By Dr. Ulrich L. Rohde, N1UL, ex KA2WEU

is useful to have a set of

guidelines by which to evalu-

ate the receiver. In this paper, I am

focusing on some specific modulation

and tests because there are agreed

upon measuring standards. They can

be used for AM if the carrier is modu-

lated 60%, as an example, instead of

FM deviation. By not modulating the

carrier, they are applicable for SSB,

too. Some of modulation tests are ap-

plicable for all three modulation types

(AM/FM and SSB).

For evaluation of the quality of a

receiver, different procedures of mea-

surements with different standard

values have been developed. All these

receiver measurements, however, have

in common that the RF–input signal

is varied and the corresponding AF–

output signal measured. The AF sig-

nal is a function of the RF signal.

Two groups of measurements apply

• Single–generator measurements,

with one RF signal at the receiver

input

• Two–generator measurements, with

two RF signals at the receiver in-

put

In the following, some test proce-

dures specified by FTZ (German gov-

ernment standards) or recommended

by CEPT (Conference of European

Telecommunication Administrations)

will be used as examples. The US stan-

dards follow these rules or vice versa.

Table 1 shows the guaranteed /mea-

sured characteristics of a high perfor-

mance short wave receiver, Rohde &

Schwartz model EK895. The measure-

ments are done with the preamplifier

off. If the preamplifier is switched on,

the large signal parameters deterio-

rate. Please note that this receiver

does not have FM capabilities.

Note: In most cases, the “receiver

sensitivity” is specified as the criterion

for receiver measurements. This fun-

damental parameter is defined either

by the S/N of the modulated to the

unmodulated RF signal (FTZ) or by

the so-called SINAD method (CEPT);

see Figs 5 and 6. Fig 1 shows the

basic setup. RT refers to the trans-

ceiver. The signal generator or both

signal generators (they need to be

combined with a hybrid coupler) must

be connected to the antenna terminal

Synergy Microwave Corp

201 McLean Blvd

Paterson NJ 07504

ulr@synergymwave.com

Jul/Aug 2005 3

Receiver Measurements,

W hen evaluating a receiver, it

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: