DRAKE SW 1 Manual de Instruções descarregar pdf (Página 6)

76 October 1997

tours did their job in tailoring transmit audio.

Consensus was that audio level appeared to

drop off on all four settings; you had to com-

pensate with higher gain level or by using a

bit more compression. The high-emphasis

selection successfully produced “contest”

type audio to cut through QRM; the changes

wrought by the other settings were more

subtle. But several stations said they thought

the audio sounded “best” in the default posi-

tion, with the digital equalization turned off.

The manual seems to say that you have to

enable the DSP system via the front panel in

order to take advantage of this feature, but

we found this to be incorrect.

The speech monitor comes in handy while

using the digital voice recorder during con-

tests. The clarity of audio through the FT-920

monitor was excellent.

To the Rear

The back panel is where the FT-920 shows

its practical side. Most connections use stan-

dard phono (RCA) connectors, so many set-

ups can avoid having to solder those dreaded

DIN connectors (one DIN jack provides TX/

RX switching and band data for use with a

Yaesu FL-7000 linear). SO-239 connectors

are provided for both

ANT A

and

ANT B

For computer control, you make the con-

nection to the

CAT

port via a standard DB-9

female connector (cables with the proper

connectors are available at most Radio Shack

stores). The rear panel also provides an ad-

ditional (stereo)

KEY

jack, used in conjunc-

tion with the rear-panel

PDL-KEY

switch,

which lets you use an external keying device

(a hand key or computer, for example) and

the built-in keyer at the same time—a great

idea and something that contest operators

certainly will appreciate. This allows use of

the popular contest programs for keying con-

test exchanges, while the internal electronic

keyer itself may be left on, and paddles con-

nected through the front jack, for sending

fills by key—a boon for the non-typists

among us.

The rear panel also provides a

PTT

jack

for use with a foot switch or other type of

remote switching plus a

TX GND

jack for

amplifier switching. There are two possibili-

ties for its use: With the

TR-RY

switch set in

the “RY” (relay) position, a relay capable of

switching 125 V at 500 mA is used, so you

can safely switch your old SB-220. For

break-in use with some amplifiers, the “TR”

position employs a quiet transistor switch,

rated at 50 V dc at 500 mA.

Another jack provides 13.5 V at up to

200 mA for accessories. You’ll also find an

EXT SPEAKER

jack (3.5 mm, two-conduc-

tor) and an

AF OUT

jack for low-level audio

recording, TNC, or WEFAX. It provides 100

mV into a 600-Ω and the level is not con-

trolled by the front panel

AF GAIN

control. A

similar jack for

PATCH

input is independent

of the

MIC GAIN

control.

There’s an

FSK-AFSK

switch for digital

operation. A five-pin DIN connector (the

only other one, thankfully) is available for

data input.

The

ALC

connection is provided via an

RCA jack.

We already mentioned the separate re-

ceive antenna jack. While the FT-920 does

not offer a transverter port as such, the Oper-

ating Manual includes information on how

to use the

jack and/or one of the SO-239

antenna connectors to accommodate a

transverter.

Overall, the back panel offers ample flex-

ibility. The only drawback is that, except for

the antenna and power connections, nothing

on the rear panel is marked. A legend affixed

to the top panel of the radio provides a map

to all connections, but it’s difficult to refer to

this chart when the radio is beneath a shelf

and the operator is behind it!

May I see the Menu?

Overall, operation is straightforward.

Some users got the hang of the FT-920 with-

out spending a whole lot of time with the

manual, which, as we’ve already noted, con-

tained a few errors (Yaesu says it’s working

on these). But some features are not terribly

obvious, and many of the radio’s best fea-

tures only are accessible through the menu

(shades of the FT-1000MP). For best results,

it’s wise to pay special attention to the sec-

tion of the manual that describes the 73 menu

functions.

The

switch activates the menu

mode and allows customization of many pa-

rameters. Normal menu operation is simple.

Just press the

button, dial up the de-

sired function with the VFO B knob, press

the

ENT

key on the keypad, use the VFO B

knob to set the desired parameter, press

ENT

again, and

to exit.

A handy panel menu feature retains five

frequently used menu items for quick recall,

including the display dimmer, VOX hang

time in CW, multi-panel display choice, en-

hanced tuning scale display, and CTCSS tone

frequency. In addition, the FT-920 has a

quick menu option that lets the user pick out

certain menu items for quick and easy ac-

cess. This quick menu bank operates almost

identically to the normal menu mode except

it only gives you the menu items you’ve

asked to make available. To get to the quick

menu, you press the

button momen-

tarily; to access the normal menu, you hold in

the

button for one-half second. Pretty

nifty.

On the Air

While the profusion of knobs and buttons

on the front panel might suggest a steep learn-

ing curve, the FT-920 is really pretty simple

to use.

For instance, for SSB operation, just

touch the

SSB

button. The LCD display

shows which sideband has been selected.

While the default is according to convention

(LSB below 10 MHz, USB above), you can

swap sidebands by pressing the

ENT

button

again. Adjust the

MIC GAIN

control for proper

ALC metering, and you’re all ready to go.

VOX operation is smooth. There are two

different menu settings available, one for

voice, the other for semi-break-in CW.

The FT-920 provides effortless CW op-

eration, both semi-break-in and full-break-

in (QSK). Full-break-in CW was free of the

pops found in some radios, and it was pos-

sible to hear between dits at 35 WPM or so.

When using a non-QSK linear amplifier,

you’ll want to use semi-break-in with the

proper VOX adjustment. It’s easy to adjust

the delay for just the right balance between

fast transition to receive and absence of relay

chatter.

We did notice we could still hear a very

strong CW signal on the opposite side of zero

beat, even with the 500-Hz filter enabled. The

opposite side signal was down by more than

50 dB, however.

Receiving with the radio was a pleasure.

It handled strong signals well, but the combi-

nation of a good basic receiver with DSP

resulted in excellent overall performance for

a radio in this price class (see Table 1). Two

filters are available as options: a 500-Hz CW

filter and a 6-kHz AM filter. The radio can

only accommodate these filters, and Yaesu

does not offer an optional narrow SSB filter.

We found out that you must install the

AM filter in order to transmit on AM (Yaesu

now offers a free “pass-through” board that

enables AM transmit). Our unit had both fil-

ters installed, and filtering was very good,

although the AM filter is too narrow for suit-

able AM broadcast reception. On CW, you

can further reduce the bandwidth by using

the DSP, and the combination of the two pro-

vided excellent single-signal CW reception.

By the way, the FT-920 receiver is

double conversion on HF (68.985 MHz and

8.215 MHz). The accessory filters are in

the 8.2 MHz IF. The radio is triple conver-

sion only on FM, where the lowest IF is at

455 kHz.

The CW memory keyer works well, but

some users felt its two-button operation was

less than convenient. The keyer allows for

automatic character spacing to be enabled or

disabled, or use as an electronic “bug” type

key. Especially noteworthy was the fact that

you can adjust dot and dash lengths (ie,

weighting) separately, not just the dot-to-

dash ratio. The keyer has six memories, and

it permits sequential contest serial number-

ing. The primary drawback is that, as with

the digital voice keyer, you have to press the

PLAY

button, then (quickly) the memory

number to air a message. On the other hand,

the CW memories may be controlled by a

computer program.

The noise blanker worked well against

electric motor noise. At my place, there is

usually no noise, so I generated some S9

noise by turning on a vacuum cleaner. The

blanker reduced the noise to a negligible

level. Other users also found the noise

blanker to be very effective, especially in

combination with the DSP noise reduction.

When our unit first arrived, it exhibited a

strange hissing or buzzing sound (sort of like

a small nest of tiny hornets) whenever the

noise blanker was engaged and the

MONI

LEVEL

control was turned up (it made no

difference if the monitor was engaged or not).

We returned our unit to Yaesu, which deter-

mined that some earlier production units like

ours suffered a crosstalk problem. Yaesu

fixed our FT-920 and says it has corrected

this problem in subsequent production units.

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