QEX_2007_05_06.pdf

$ 5

ARRL

225 Main Street

Newington, CT USA 06111-1494

The national association for

AMATEUR RADIO

Complies

with New

FCC Rules.

Available Now with

12m and 10m Built-in!

This compact and lightweight 1kW desktop HF/50MHz linear power

amplifier has a maximum input power of 1.75kW. Our solid-state

broadband power amp technology makes it the smallest and lightest

self-contained amplifier in the industry .

Typical output power is 1kW PEP/SSB on HF and 650W on 6m band

with the drive power of 85-90W. Bands set automatically with the built-in

band decoder . You can forget about the band setting when the amplifier

is connected to your modern radio through supplied band data cables

for ICOM CI-V, DC voltage (ICOM, Yaesu), and RS-232C (Kenwood) .

Manual band setting selectable as well.

All these data cables are included with the amplifier.

Features

■ Lightest and most compact 1kW HF amplifier

in the industry.

■ The amplifier’s decoder changes bands

automatically with most ICOM, Kenwood,

Yaesu.

■ The amp utilizes an advanced 16 bit MPU

(microprocessor) to run the various high

speed protection circuits such as overdrive,

high antenna SWR, DC overvoltage, band

miss-set etc.

■ Built in power supply.

■ AC (200/220/235/240V) and

(100/110/115/120V) selectable.

■ Equipped with a control cable connection

socket, for the HC-1.5KAT, auto antenna tuner

by Tokyo Hy-Power Labs.

■ Two antenna ports selectable from front panel.

■ Great for desktop or DXpedition!

Specifications

Frequency:

1.8 ~ 28MHz all amateur

bands including WARC

bands and 50MHz

Mode:

SSB, CW, RTTY

RF Drive:

85W typ. (100W max.)

Output Power:

HF 1kW PEP max.

50MHz 650W PEP max.

Matching Transceivers for

Auto Band Decoder:

Most modern ICOM, Yaesu,

Kenwood

Drain Voltage:

53V (when no RF drive)

Drain Current:

40A max.

Input Impedance:

50 OHM (unbalanced)

Output Impedance:

50 OHM (unbalanced)

Final Transistor:

SD2933 x 4 (MOS FET by

ST micro)

Circuit:

Class AB parallel push-pull

Cooling Method:

Forced Air Cooling

MPU:

PIC 18F452 x 2

Multi-Meter:

Output Power – Pf 1Kw

Drain Voltage – Vd 60V

Drain Current – Id 50A

Input/Output Connectors:

UHF SO-239

AC Power:

AC 240V default (200/220/235)

– 10 A max.

AC 120V (100/110/115)

– 20 A max.

AC Consumption:

1.9kVA max. when TX

Dimension:

10.7 x 5.6 x 14.3 inches

(WxHxD)/272 x 142 x 363 mm

Weight:

Approx. 20kgs. or 45.5lbs.

Accessories Included:

AC Power Cord

Band Decoder Cables included

for Kenwood, ICOM and Yaesu

Spare Fuses and Plugs

User Manual

Optional Items:

Auto Antenna Tuner (HC-1.5KAT)

External Cooling Fan (HXT-1.5KF

for high duty cycle RTTY)

Debuting Dayton 2007

HL-1.2KFX

HF amp 750W out*

HL-2.5KFX

HF amp 1500w out*

HC-1.5KAT

HF 1.5KW Auto Tuner*

* These devices have not been authorized as required by the rules of the FCC.

These devices are not, and may not be, offered for sale or lease, or sold or leased until

authorization is obtained.”

See these and

more at

Dayton

Hamvention ™

Booths 511 & 512

Western US/Canada

1-800-854-6046

Mountain/Central

1-800-444-9476

Southeast

1-800-444-7927

Mid-Atlantic

1-800-444-4799

Northeast

1-800-644-4476

New England/Eastern Canada

1-800-444-0047

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 ofﬁ ces.

POSTMASTER: Send address changes to: QEX,

225 Main St, Newington, CT 06111-1494

Issue No 242

About the Cover

Jim Koehler, VE5FP, built “An Automatic

Noise-Figure Meter.” In this article, Jim

explains how to build the noise-ﬁ gure

meter and measure the NF of your

preampliﬁ er projects from 3 MHz

to over 400 MHz.

Harold Kramer, WJ1B

Publisher

Doug Smith, KF6DX

Editor

Larry Wolfgang, WR1B

Managing Editor

Lori Weinberg, KB1EIB

Assistant Editor

L. B. Cebik, W4RNL

Zack Lau, W1VT

Ray Mack, W5IFS

Contributing Editors

Production Department

Steve Ford, WB8IMY

Publications Manager

Michelle Bloom, WB1ENT

Production Supervisor

Sue Fagan

Graphic Design Supervisor

Devon Neal, KB1NSR

Technical Illustrator

Joe Shea

Production Assistant

Advertising Information Contact:

Janet L. Rocco, W1JLR

Business Services

860-594-0203 direct

800-243-7768 ARRL

860-594-4285 fax

Circulation Department

Cathy Stepina, QEX Circulation

Ofﬁ ces

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 A Direct-Conversion, Phasing-Type SSB Rig — Revisited

By Rod Brink, KQ6F

16 Designing the Z90’s Gaussian Crystal Filter

By Jack Smith, K8ZOA

27 The Integration of Amateur Radio and 802.11

By Roderick D. Mitchell, KL1Y

33 Network/Data Layer Messaging Protocol for Stand-Alone,

By Lindsay J. Robertson, ZL2LJR

39 An Automatic Noise-Figure Meter

By Jim Koehler, VE5FP

49 ARRL Seeks Comments on New HF Digital Protocol

Columns

47 Upcoming Conferences

50 Antenna Options

By L. B. Cebik, W4RNL

56 Tech Notes

By Doug Smith, KF6DX

60 Next Issue

61 Letters

63 Out of the Box

By Raymond Mack, W5IFS

In order to ensure prompt delivery, we ask that

you periodically check the address information

on your mailing label. If you ﬁ nd any inaccura-

cies, please contact the Circulation Department

immediately. Thank you for your assistance.

May/June 2007 QEX Advertising Index

American Radio Relay League: 13, 48, 60

ARA West: 64

Array Solutions: 55

Atomic Time: 38

Communications Specialists, Inc: 32

Down East Microwave Inc: 64

Elkins Marine Training International: 64

FlexRadio Systems: Cov III

Kenwood Communications: Cov IV

National RF, Inc: 64

Nemal Electronics International, Inc: 26

Radio Design Group, Inc: 57, 59, 61, 63

Teri Software: 38

Tokyo Hy-Power Labs, Inc: Cov II

Tucson Amateur Packet Radio: 49

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

ofﬁ ce of the Publications Manager

( permission@arrl.org ).

May/June 2007 1

Free-Field Communications Systems

THE AMERICAN RADIO

RELAY LEAGUE

Empirical Outlook

Doug Smith, KF6DX

kf6dx@arrl.org

The American Radio Relay League, Inc, is a

noncommercial association of radio amateurs,

organized for the promotion of interest in

Amateur Radio communication and experimenta-

tion, for the establishment of networks to provide

communications in the event of disasters or other

emergencies, for the advancement of the 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 organization

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 three years by the general membership. The

ofﬁ cers are elected or appointed by the Directors.

The League is noncommercial, and no one who

could gain ﬁ nancially 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 ﬁ de interest in Amateur Radio is the only

essential qualiﬁ cation 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:

Amateur Radio: At the State of the Art

For what must seem like eons, many

have bemoaned the decline of experimen-

tation and homebrewing in Amateur Radio.

Look at the numbers participating in that

sort of activity and you might indeed ﬁ nd

a signiﬁ cant downward trend. If you were

to examine instead the level of technical

accomplishment of the new and remain-

ing participants, we think you’d ﬁ nd quite

a different situation. We try to support the

latter view — and combat the former — on

a regular basis here on these pages.

As delineated in rules and regulations,

the Amateur Radio Service charter ad-

dresses content and means equally: what

we communicate and how we communi-

cate it. In actual fact, our roles in emer-

gencies and disasters tend to outshine our

technical prowess, at least in the main-

stream press. Regular folks are concerned

chieﬂ y with what the technology does for

them and not with how it’s done. That atti-

tude carries over to ham radio and to most

other facets of our lives, really. No matter

how elegant is some solution, its prime

value lies in how well it ﬁ lls a need.

It’s hard to do innovative design in

this era, but experience has shown that

the best inventions are relatively simple

in concept. Furthermore, they create ca-

pabilities that the end user didn’t know

he needed but which make life better

somehow. VCRs, cellular telephones,

e-mail and cable television are among

our favorite examples. Remember: All

that stuff came along only in the last

30 years or so!

Now in Amateur Radio we have digital

signal processing, high-speed data, digi-

tal voice and image, and a host of other

tools at our disposal. The doors are open

to experimentation on all fronts. Just look

at what Flex Radio Systems have done

(see the advertisement in this issue and in

May QST ). You could elect to write some

software for the SDR-5000 to make it do

new things, or you could choose to use its

considerable capabilities to set up an emer-

gency communications network, a cross-

band repeater, Internet gateway, or other

useful systems — the sky’s the limit.

Some of the inspiration for Flex Ra-

dio came out of the ARRL Software

Radio Working Group, now headed by

Bob McGwier, N4HY, who works with

Flex. The technology is so far advanced

that interest extends far beyond ham

radio.

The same is true of what the ARRL

High-Speed Multimedia Working Group

are achieving. Now we’re seeing radios

with Internet remote controls and other

networking features. The D-STAR sys-

tem has been well documented here, for

example. Opportunities exist for com-

mand, control and communications that

were undreamed of just ﬁ ve years ago.

The use of inexpensive spread-spec-

trum equipment by hams on our shared

microwave bands helps establish and

maintain our presence there so we don’t

lose them.

The initial round of work by the ARRL

Digital Voice Working Group is largely

ﬁ nished. Witness the AOR AR-9800 as

developed by Yoshi Nishimura, JA6UHL,

and similar, compatible units developed

by Dennis Silage, K3DS, and his stu-

dents at Temple University. It all started

with the work of Charles Brain, G4GUO,

several years ago.

Amateurs have also done extensive

work on adaptive, so-called “smart” an-

tennas; deconvolution for “moonbounce”

(EME) and other dispersive channels; and

MF and LF narrowband modes, among

other areas.

The point is: Amateur Radio is on the

leading edge of technology, perhaps more

so than ever before. It doesn’t matter

whether you concern yourself with what

or how you communicate. You have the

ability, resources and assistance to make

a difference in the future of our Service.

Write us a letter and let us know what

interests you most. We want this forum

to reﬂ ect your likes. It’s a medium for the

exchange of ideas and information, put-

ting people together for a common goal.

Slow-scan fans in Southern and Central

Florida take note: Joshua Heath, KI4NNQ,

has started a slow-scan net on the

146.625 MHz machine (W4JUP/R) out

of Jupiter (TX = 146.025 MHz, CTC-

SS = 114.8 Hz). It’s called the Jupiter/

Tequesta Repeater Group Slow-Scan and

Ragchew Net. It meets at 7:30 PM every

Wednesday night. Check-ins are welcome

whether you have slow-scan capability or

not. The group is also interested in digital

slow-scan via the G4GUO/AOR/K3DS

digital voice/image/data format. Many in

the group are now reading QEX .

ARRL, 225 Main Street, Newington, CT 06111 USA.

Telephone: 860-594-0200

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

Ofﬁ cers

President: JOEL HARRISON, W5ZN

528 Miller Rd, Judsonia, AR 72081

Chief Executive Ofﬁ cer: DAVID SUMNER, K1ZZ

The purpose of QEX is to:

1) provide a medium for the exchange of ideas

and information among Amateur Radio experiment-

ers,

2) document advanced technical work in the

Amateur Radio ﬁ eld, and

3) support efforts to advance the state of the

Amateur Radio art.

All correspondence concerning QEX should be ad-

dressed 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 in

word-processor format, if possible. We can redraw

any ﬁ gures 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 or high-resolution digital images (300 dots per

inch or higher at the printed size). 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.

2 May/June 2007

A Direct-Conversion,

Phasing-Type SSB

Rig — Revisited

If carefully built and adjusted, a phasing-type SSB rig can sound

better than a superhet. Here’s an improved version of a previously-

published transceiver for ragchewing on 75 and 40 meters.

Rod Brink, KQ6F

Campbell, KK7B, and his work with

direct-conversion phasing-type rigs. 1

I began playing around with these types of

circuits and built a two-band transceiver

that performed well enough to merit a QEX

article. 2 The tinkering continued, and im-

provements have been made. This article

discusses those improvements and presents

an updated design.

Figure 1 illustrates a single-balanced version.

It can be visualized as a four-position rotary

switch revolving at a rate equal to the carrier

frequency. The 50 Ω antenna impedance is

connected to the rotor and each of the four

switch positions is connected to a sampling

capacitor. Since the switch rotor is turning

at exactly the rate of the RF carrier, each

capacitor will track the carrier’s amplitude

for one-quarter of the cycle and will hold its

value for the remainder of the cycle. The ro-

tating switch will therefore sample the signal

at 0°, 90°, 180° and 270°, respectively. Stated

another way, the rotating switch performs a

downward conversion to audio baseband and

the sampling capacitors each store 1 ⁄ 4 of the

RF cycle. If we connect the sampling capaci-

tors to differential-input op amps as shown

in Figure 1, we obtain the I and Q channels

necessary for sideband selection.

This circuit may also be thought of as a

digital commutating ﬁ lter . This means that

it operates as a high-Q tracking ﬁ lter, where

Equation 1 determines the 3-dB bandwidth,

Diode Mixers Are Okay, but A Tayloe

Detector is Better

The original design employed two con-

ventional diode mixers for developing the

in-phase (I) and quadrature (Q) channels.

While ubiquitous and easy-to-use, diode mix-

ers suffer from a 7 dB mixing loss. For proper

termination, I used 6 dB resistive pads at the

IF outputs and this increased the total loss to

13 dB. Additional downstream ampliﬁ cation

was required in the receiver to compensate

for the loss, and this added to the overall

noise. There had to be a better way.

Enter the Quadrature-Sampling Detec-

tor, known in some literature as the Tayloe

detector. Its beauty is found both in its simple

elegance and its exceptional performance.

1 Notes appear on page 12.

25950 Paseo De los Robles

Corral de Tierra, CA 93908

kq6f@arrl.net

Figure 1 — Quadrature Sampling Detector — The switch rotates at the carrier frequency,

so that each capacitor samples the signal once per revolution. The 0° and 180° capacitors

differentially sum to provide the in-phase (I) signal and the 90° and 270° capacitors

differentially sum to provide the quadrature (Q) signal.

May/June 2007 3

A few years ago I was inspired by Rick

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