Ranger Communications RCI-2970 DX Manual de instrucciones descargar pdf (Pagina 10)

From October 2001 QST © ARRL

SHORT TAKES

Steve Ford, WB8IMY  Editor

Thanks to the boom in sound-card-based Amateur Radio

software, there is a burgeoning market for devices to interface

computer sound cards to transceivers. These devices are de-

signed to handle audio signal interfacing as well as transmit/

receive switching. Functionally speaking, the interfaces have a

lot in common, but there are some features that set them apart.

The SignaLink SL-1 is a contender in the miniature inter-

face field. The SL-1 is slightly smaller than a pack of cigarettes

but attractively designed to make the most of its meager surface

area. The front panel includes a

POWER ON/OFF

pushbutton

switch, a pushbutton

DELAY

switch (to toggle between longer

and shorter transmit/receive switching times) and two bright LEDs

to indicate power (green) and PTT activation (red). These LEDs

are especially handy; you know at a glance when the

SL-1 is powered on and when it is keying the PTT line to transmit.

Installing the Interface

The SL-1 is designed to work with just about any computer

and radio combination. Two

/8-inch stereo jacks on the rear

panel are for the audio cables to your sound card. One cable

attaches to your sound card

MIC or LINE input; the other con-

nects to the

SPEAKER or LINE output.

The next task is getting audio to and from your radio, and

dc power to the interface itself. The SL-1 allows you to make

most of these connections through your rig’s microphone jack.

You can order the SL-1 with a pre-prepared cable for 4- or

8-pin round mike connectors, or for RJ-45 telephone-style

connectors. For this review we ordered the RJ-45 cable for

compatibility with my IC-706 transceiver. The SL-1 sports an

internal IC socket that functions as a jumper block. By insert-

ing short wire jumpers (supplied) and carefully following the

instructions, you can configure the SL-1 according to the type

of radio you are using. The manual provides detailed examples,

showing jumper block diagrams for almost every common

transceiver model. You simply locate your rig’s model

number, study the adjacent diagram and insert the jumpers

accordingly. It takes all of about 15 minutes, including the

time required to open the SL-1’s enclosure.

Depending on the type of transceiver you own, you may be

able to tap the receive audio at the mike jack. Just install the

correct jumper and you’re good to go. This is elegant in that it

eliminates yet another cable, but there is a drawback. The re-

ceive audio that is available at most microphone jacks is not

fixed. In other words, you’ll need to crank up your radio’s

receive audio gain to provide an adequate signal to your sound

card. The audio level at the microphone jack is usually less

than what is supplied to the radio’s speaker (or external speaker

jack). I often found that I had to turn the audio up to the point

where my external speaker was blaring at objectionable levels

just to get a usable signal for my sound card software. This

makes it difficult to operate when the rest of the family is

asleep! Fortunately, the SL-1 includes an alternate input jack

for audio from your radio. You can tap the audio at the

transceiver’s accessory jack where the level is fixed and un-

affected by the audio gain setting. Yes, you have to use yet

another cable, but it is a small sacrifice for domestic peace.

While you can power the SignaLink SL-1 from an external

dc power source, you may also be able to use “rig power.”

Many modern transceivers, including my own, supply between

8 and 13.8 V at one of the microphone jack pins. This is just

enough juice to power the SL-1. Install the correct jumper and

you’ll eliminate the need to run wires to an external supply.

Where is the Serial Port?

One of the first things you’ll notice when you unpack the

SL-1 is the absence of a DB-9 or DB-25 serial port. In most

interfaces this port connects to a serial cable that, in turn, con-

nects to your computer’s COM port. The sound card software

uses the COM port to send transmit/receive switching pulses

to your radio (through the interface, of course). So where is

the serial port in the SL-1?

The SL-1 lacks a serial port because it relies on audio

switching to key your radio. That is to say, it uses a VOX-style

circuit to detect transmit audio from your sound card. When it

senses audio from your computer, the circuit grounds the PTT

line to your transceiver and switches it into the transmit mode.

The advantage of this approach is that it frees your

computer’s COM port for other applications. (I use mine with

an FSK switching interface to run FSK RTTY with my sound

card.) The disadvantage is that the SL-1 will key when it senses

any audio from your computer—whether it is a bona fide trans-

mit signal or a random beep. The solution is simply to switch

the SL-1 off when you are not using it. The green

PWR LED is

a good reminder, but you need to be careful.

Conclusion

If you’re looking for a compact, affordable interface, the

SignalLink SL-1 is a worthwhile model to consider. I found it

to be dependable, easy to install and virtually invulnerable to

RF. The manual is quite thorough—perhaps a little too thor-

ough. It communicates a strong sense of caution (telling you,

for example, to use a VOM to double-check the results of your

jumper wiring). I found myself skipping over several para-

graphs just to get to the basic what-goes-where information.

On the other hand, for hams with minimal technical training

and computer familiarity, the SL-1’s manual is right on target.

Manufacturer: TigerTronics, 400 Daily Ln, Grants Pass, OR

97527; tel 800-822-9722; www.tigertronics.com. $49.95.

SignaLink SL-1 Sound Card/Transceiver Interface

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Ranger Communications RCI-2970 DX Manual de instrucciones Pagina 10

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