Alinco DX-77T Technical Information PDF herunterladen (Seite 4)

style). Operation with a straight key, of

course, is also possible. Whether you are

connecting a straight key or a set of paddles,

you must use a stereo type plug in the key

jack. Pay close attention to the paddle wir-

ing arrangement. The dot-and-dash connec-

tions are opposite to those found as the de-

fault settings on radios from other

manufacturers (ie, Kenwood, ICOM, and

Yaesu), and you can’t change this via the

menu, as some radios let you do for “left-

hand” and “right-hand” paddles.

Transmit-receive switching for CW can

be set to operate full-break-in, semi-break-

in (adjustable to seven different delay

times), or auto break-in, which will auto-

matically adjust the delay time for the key-

ing speed being used.

The DX-77T was a pleasure to use on

CW. With its wide range of interference-

fighting capabilities, built-in electronic

keyer, and smooth, multi-adjustable QSK,

it earned high marks from our reviewers.

Entry-class radios with built-in CW fea-

tures like these could potentially put a dent

in the sales of computer-generated CW

practice programs!

Shortwave and AM broadcast perfor-

mance also was quite decent. You can se-

lect an 8 or 2.7-kHz AM filter bandwidth,

and AM tuning step sizes of 1.0, 2.5, 5.0,

9.0 or 10 kHz for the front panel or micro-

phone

UP/DOWN buttons, and scan modes

make cruising for new stations easy. With

the radio’s 100 memory channels, you can

program lots of these and still have plenty

left for your 10-meter FM repeaters and

other favorite ham frequencies.

A few words on our Lab testing results

(see Table 1): The DX-77T stacked up pretty

nicely with other transceivers in the same

general price category. Dynamic range is

always an important consideration. The

higher the numbers, the better the receiver’s

ability to hear a desired signal without being

adversely affected by strong, neighboring

signals (usually exhibited by AGC pump-

ing). In this instance, the DX-77T’s two-

tone, third-order IMD dynamic range num-

bers showed up in the low to mid

90s—several dB better than we measured in

the ICOM 706MkII (see “Product Review,”

QST, Jan 1998), the Ten-Tec Scout (see

“Product Review,” QST, Dec 1993), or the

Kenwood TS-50S (see “Product Review,”

QST, Sep 1993). In the IC-706MkII and the

DX-77T, however, the level of measurement

was limited by the transceiver’s phase noise,

although the worst-case phase noise on the

DX-77T was still an improvement over what

we observed on our IC-706MkII.

The DX-77T’s receiver is not quite as

sensitive as the ICOM or the Kenwood,

however, and this results in third-order in-

tercept calculations well into the positive

numbers, preamp off or on.

Just a DX-70T in a New Box?

We had first suspected the DX-77T was

just a DX-70T in a desktop box. The famil-

iar display window and the same integrated

PA-heatsink/rear panel as those on the

DX-70 fueled speculation that Alinco had

just stripped off 6 meters and repackaged

their previous HF offering. Inquiring minds

want to know!

A quick trip across the parking lot to

liberate a DX-70T from one of W1AW’s

guest operating positions, and it was back

to the lab for a closer internal investiga-

tion. A few minutes with a screwdriver re-

vealed the truth. While it seems these ra-

dios share some of the PA components and

the LCD display, none of the internal

boards was common to both transceivers.

Those who do choose to take a look inside

will be amazed at the amount of unused

space in the DX-77T cabinet!

Modern RF engineering techniques and

miniaturized components have distilled the

amount of actual volume necessary to sup-

port the long list of capabilities this trans-

ceiver provides to an unbelievably small

level. A telephone answering machine of just

a few years ago would contain twice the

volume of electronics! Lab types gathered

round and proposed various opinions on how

best to occupy the vacant areas of its internal

cavity (battery packs for portable QRP op-

eration, home brew auto antenna tuners,

switching power supplies, transverters, etc).

So, while it was clear that the DX-77T

has borrowed freely from its older sibling,

it’s not really the same radio when you look

under the hood. Also, as we’ve pointed out,

it offers some features the DX-70T does

not. In addition, it provides a rich com-

puter-control interface that was not avail-

able on the DX-70T.

Read All About It

The Instruction Manual is excellent—an

improvement from earlier Alinco books, and

generating comments from the reviewers

like “maybe Alinco’s best yet” and “obvi-

ously written by hams.” It’s easy to follow

and includes lots of illustrations. A well-

organized table of contents, a “How to Use

this Manual” page with a black page-edge

tab arrangement for quickly locating specific

topics, and a complete index make locating

desired information a snap. Most of the sec-

tions on major operating parameters include

a short introduction and explanation of the

particular topic, plus step-by-step examples

to help you along. This is a real boon to

beginners.

In addition to clear, concise instructions

for operating the transceiver, the manual

includes several “tutorials” that give tips to

optimize performance in the radio’s vari-

ous modes. Newcomers also will find these

a welcome addition to the traditional

manual fare. A maintenance chapter de-

scribes the location and adjustment of the

internal controls for microphone gain, the

100 W/50 W maximum output switch, and

CW sidetone and key activation “beep”

volume. The frequency calibration proce-

dure appears as well.

Connection diagrams for Alinco’s op-

tional EDX-1 manual or EDX-2 automatic

antenna tuner also are shown, as well as

wiring instructions for Kenwood’s AT-300

and ICOM’s AH-3 tuner units! A com-

plete—though somewhat difficult to

read—schematic is included. While you

will find some typographical errors in the

manual, they are very minor and don’t dis-

tract from the content.

Consensus

The overall impression of those who got

to play with the Alinco DX-77T was that it’s

a terrific “first steps” radio or a fine second

radio. Indeed, some may find it a great

“main” radio. It’s less adaptable to mobile

use than some of the other offerings already

on the market, but it’s not very large nor very

eavy, so it’s good choice for portable use.

The inclusion of a CW keyer and a de-

cent narrow CW filter plus speech process-

ing (even though it’s at audio) make this a

slightly better than just the plain-vanilla

starter boxes available just a few years ago.

Some users felt that including a built-in

ac power supply would make the DX-77T a

killer product—sort of the latter-day

equivalent of the Heath HW-16.

With the long list of features already in-

cluded in the DX-77T, first-time buyers

may be curious as to what additional capa-

bilities they would find in the next step up.

Several other manufacturers offer mid-

level radios for an added investment of

$400 to $600. These may include items

such as built-in automatic antenna tuners,

digital signal processing (DSP), SWR me-

tering, CW message memories, voice oper-

ated transmit (VOX), remotable faceplates,

and additional IF filtering capabilities. In

addition, manufacturers will usually in-

clude a few interesting extended features

that may be unique to their products. While

these certainly may be desirable, none clas-

sifies as an absolute necessity for effective

communications.

We also were pleased to report that

everything worked the first time on our

DX-77T, and that we did not encounter any

situations where our unit failed to meet its

published specifications or where it was se-

riously on the hairy edge of not meeting

them. This increases our confidence in

Alinco’s ability to turn out a radio that you

won’t have to send back to the factory when

it doesn’t work as advertised. Other manu-

facturers should take notice.

Thanks to Dan Miller, K3UFG, Rick

Lindquist, N1RL, and Mike Tracy,

KC1SX, and Ed Hare, W1RFI of the ARRL

Lab for their contributions to this review.

Manufacturer: Alinco USA, 438

Amapola Ave, Suite 130, Torrance, CA

90501; tel 310-618-8616; fax 310-618-

8758; http://www.alinco.com. Manufac-

turer’s suggested retail price, DX-77T trans-

ceiver, $1059; EMS-14 desk microphone,

$113; ERW-4 computer interface cable, $27;

Alinco DM-340MVT power supply, $199.

June 1998 55

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