MT First Look - Alinco DJ-G7T
F
IRST LOOK
MT Takes a Look at the Latest Tech
Alinco DJ-G7T Hand-Held, Tri-band Transceiver
By Bob Grove, W8JHD
T
he universal appeal of a
compact, hand-held radio is well acknowledged.
Whether it’s a telephone, a ham
radio set, a fireman’s or police officer’s radio, or a scanner, clutching
one of these is reassuring. Instant
communication, a market well attended by myriad manufacturers.
Alinco’s recent entry into the
fray is well placed. The DJ-G7T
is compact (2.33 inches wide, 4.5
inches high, and 1.25 inches deep)
and weighs 9.5 ounces. It comes
equipped with a Li-Ion battery, rubber whip,
drop-in charger with 120 VAC/12 VDC adapter,
belt clip, hand strap, and a comprehensive, 113
page manual.
A top-of-the-case, water-tight jack is
provided for an optional earphone/microphone
combination. An SMA connector is used to attach
the antenna.
So what makes this radio stand out in the
crowd? First, it’s a tri-bander, transmitting in
the 144-148, 430-450, and 1240-1300 MHz ham
bands. Second, it has continuous reception coverage from 530 kHz-1300 MHz (cellular blocked)
in AM, FM, and WFM modes.
This offers the dual capability of licensed
amateur radio service as well as scanning the
spectrum for monitoring broadcast signals and
two-way VHF/UHF communications. Tuning
steps in the VFO mode may be chosen as 5.0,
6.25, 8.33, 10, 12.5, 15, 20, 25, 30, 50, 100, 125,
150, 200, 500, and 1000 kHz.
Pressing the transmit button when non-ham
frequencies are selected will bring up a “Disabled…” message and the transmit attempt will
be ignored.
The keypad is intuitive to follow and allows
a large number of options available to the operator.
A ‘scope function permits a spectrum display of signals present within +/-30 kHz of the
displayed frequency. A top-panel knob may be
rotated to slew the frequency bands. Discrete
frequencies may also be entered directly from the
keypad.
It is also possible to start a scan sequence
and watch the signals drift by as the frequencies
shift. The sequence can pause
automatically as a busy spike
passes the center of the screen to
be monitored, then the sequence
activated again with the scan key.
The keypad is a busy place,
but it’s well marked with its functional responsibilities:
70
MONITORING TIMES
February 2012
7
8
9
0
.
ENT
MAIN
SUB
V/P/M
SCAN
FUNC
1
This wild key allows assignment of user-chosen memory functions
2 Transmit power selection
(multiple values from 0.3-5 watts)*
3
Signal attenuation for strongsignal environments (four levels)
4 Modes may be chosen for
AM, NFM, or WFM modulation
5 CTCSS tone squelch, digital
code squelch (DCS), or modulatecarriers may be selected or cancelled
6 The channel scope shows a
selectable swatch of spectrum with
signal spikes**
Step intervals for slewing across a reception
band
Microphone gain may be adjusted to suit
the environment (four levels)
Press to recall the channel that was previously selected
Priority frequently samples important frequencies for activity
The decimal key is used in direct frequency
input as well as clearing memory channels
Is used to determine input/output frequency
separation on a repeater
Allows switching between main frequency
band and the dual/mono band
Switches between the sub band frequencies
and dual/mono band frequencies
Alternates memory registration, editing,
and naming
Is the standard automatic sequencing of
memory channels to find activity
Selects the second function of each key
* Power levels vary with use of internal battery or
external DC source, and band chosen.
** Spectrum displayed is 11 adjacent frequencies
or memory channels
A side-located pushbutton powers on the rig,
and it’s rather cantankerous. Roughly 1/4 inch in
diameter, hard-rubber covered, and flush with the
case, depressing it with a thumb is impossible, and
with a finger tip unlikely. Pressing it substantially
with my fingernail was the only way I could activate it.
But once it’s activated, the green-lit LCD
display reveals its information. Two frequencies,
one from the primary and the other from the
secondary receivers, may be displayed. The multipurpose, concentric controls on
the G7T’s top can be rotated to
change those frequencies and
also serve to control squelch
and volume levels.
A sampling of the LCD
window shows the familiar
lockout key symbol to prevent
accidental or intentional resets. Battery condition
charge level is also revealed by the standard cell
segments symbols. ATT reminds you that you’ve
activated the attenuator when you can’t figure
out why signals sound so weak. Relative signal
strengths are revealed by a bar graph.
Audio clarity is excellent; no tininess as
familiar on many teensy speakers, and voice contoured to reduce extraneous hiss. At loud levels,
the voice is clear and undistorted.
In strong-signal environments, an attenuator with four successive levels of signal-strength
suppression may be selected to reduce adjacentchannel interference.
❖ Menu Settings
The G7T offers a considerable number of
menu options to customize your personal settings.
These include power source, screen appearance,
sounds, transmitter keying, receiver settings,
memory characteristics, scanning functions, and
keypad assignments.
❖ Flexible Memory
The G7T has seven memory banks:
1. General (Stores and recalls up to 1000 frequencies)
2. Program Scan (Searches between a span of
frequencies)
3. Dual Frequency (Memorizes up to 100 pairs of
frequencies)
4. Priority Scan (Favors up to 100 frequencies for
preferred recall)
5. Call Channels (Registers frequencies to be used
for calling)
6. Search Pass (Allows skipping up to 100 frequencies during search)
7. Transmitter Detection (Memorizes up to 100
found frequencies during search)
Additionally, a permanent memory of
commonly-used bugging frequencies may be
interrogated for activity.
Memory channels can be moved from one
bank to another. Channel identification may be
displayed and described alphanumerically with
up to 16 letters and numbers.
❖ Scanning
In the VFO mode, scanning across a selected band can be customized by choosing the
step size. A custom range of frequencies may
also be programmed. The scan function will also
work in memory banks and presets.
During any of the scan sequences, scanning can be stopped by simply pressing the
push-to-talk (PTT) button. Pressing the function
(FUNC), SCAN, or W/P/M key will also stop
the scan sequence.
But the G7T is foremost a transceiver, and
secondarily a scanner. Scan speed is a sluggish
five or six channels per second compared to
the lightning-fast 100-200 steps per second of
a Uniden dedicated scanner.
Determining the squelch tone or DCS code
being used by a transmitter is done automatically by selecting the Tone Scan or DCS Scan
function. When operating, the display will show
the progressive standard tones or codes in rapid
order, then stop when the correct tone frequency
or code has been resolved. A beep will confirm
the find.
❖ Transmitter Detector
Not really a bug finder, this interesting
feature allows you to enter a discrete frequency,
then change your location while listening to the
pulsing tone. As you get closer, and thus the
signal gets stronger, the tone will pulse faster.
While this function does not allow listening
to the contents of the transmitted signal, that can
be heard by pressing the monitor key (MON).
Using a directional antenna will help
with direction finding. If the signal gets closer
(stronger), the attenuator can be called into
use to prevent overloading the detector and
confounding the pulse tone.
This is a good gimmick for radio fox hunts,
and can act as a bug detector if the frequency of
the hidden transmitter is known.
❖ Bug Detection
The G7T does include a method for
searching for surreptitious listening devices. A
special memory consists of known frequencies
utilized by bug manufacturers. By invoking that
function, the scanning sequence will search for
activity on those known frequencies.
If a signal is discovered a “DETECT!”
message will show on the screen accompanied
by an unpleasant sound from the speaker (or
earphone if used for stealth). The sound grows
louder as the signal source is approached.
❖ The Bottom Line
The Alinco DJ-G7T is well thought out,
cleverly designed, and highly functional. It has
the reassuring feel of a substantial “brick,” and
the white-against-black key legends are easy to
read.
Naturally, multifunction keys and submenus take a while to learn, but it’s the only way
a limited-size piece of equipment with multiple
functions can operate.
The Alinco DJ-G7T lists for $289.95 and
is available from MT advertisers.
SPECIFICATIONS
Receive Frequency Range: 530 kHz-1299.995
MHz (Cellular Blocked)
Transmit Frequency Range: 144-147.995, 430449.995, 1240-1299.995 MHz
Antenna: 6-1/2 inch rubber, SMA base, 50 ohm
impedance
Operating Voltage: 7.4 VDC (Li-Ion battery pack
supplied)/4.5-16 VDC external supply
Current Consumption: 1.8 A max (430 MHz
transmit)/200 mA receive/56 mA battery save
Operating Temperature Range: +12 to +113
degrees F
Frequency Stability: +2.5 parts per million (-10 to
+45 degrees C)
Dimensions (Excluding Projections): 2.35 inches
W x 4.53 inches H x 1.18 inches D
Weight: 9.55 oz.
RF Output Power (Approximate): 144/430 MHz,
5/2/1/0.3 W; 1200 MHz, 1/0.3 W
Modulation Modes: 5 kHz FM deviation transmit;
FM, AM, WFM receive
Spurious Transmit Emissions: -60 dB or less
Receive System: Double conversion superheterodyne (single conversion on WFM)
First And Second IF: Main band FM, 51.65
MHz/450 kHz; Sub band AM/FM, 50.75
MHz/450 kHz; Sub band WFM, 10.7 MHz
Sensitivity: -15 dBu typical on main band
Selectivity (-6/-60 dB): AM/FM, 12/35 kHz; WFM,
130/300 kHz
Audio Output Power: 400 mW at 8 ohms, 10
percent THD
CC GOZO
AM/FM Radio
By Larry Van Horn, N5FPW
The C.Crane Company has an impeccable
reputation for providing consumer-driven radio
products, and their newest entry, the CC GOZO
AM/FM radio, is another in a long line of electronic hits.
The hallmark of this newly-introduced radio
is high audio fidelity normally found in more expensive desktop radios. Voice replication is clear
and precise while delivering natural sounding
vocals. This is accomplished with an additional
passive radiator speaker. C. Crane says this is
the first radio in their line that was specifically
developed for high fidelity audio.
Although it doesn’t pull in weak AM stations as well as some of the other C.Crane radios
I have tested, the FM reception on the test unit
was very good. I was receiving FM stations with
full quieting from Nashville, Tennessee more than
200 miles away using the whip antenna included
with the radio.
This radio is the epitome of simplicity: an
ON/OFF knob, a TONE knob, an AM/FM/AUX
knob, and a large tuning knob on a backlit analog
dial. The dial light turns off 11 seconds after the
power is turned on, the band is changed or the
tuning is adjusted. That’s all the controls you get
and it’s really all you will need with this radio.
On the rear panel there’s an MP3/AUX input
should you wish
to plug your MP3
player or smartphone into the radio
to share your music
using the radio’s robust speaker. They
have included a short
cable for use with
an iPod/MP3 player
or other aux input
device. The other
two jacks on the rear panel include a headphone
jack for personal listening (no headphones or buds
included) and the input jack for the AC adapter.
Powered with six AA batteries for portable
use, the company says new alkaline batteries rated
at 2500 mAh will last for 12 hours at a moderate
volume level. The unit does come with an AC
adapter that is a linear wall transformer power
supply, so there is no noise from the supply as
there can be with switching supplies.
The CC GOZO is only 7.5 inch wide x 4.5
inches high and 3.25 inches deep. It weighs 1.5
pounds (without batteries), and the 2.25 inch six
ohm speaker puts out 10 Watts.
The CC GOZO is a unique AM/FM radio
with audio that is best described as surprisingly
full, pleasant and bright. The cabinet has a nice
solid feel and the operating controls all work
smoothly, although the main tuning is a bit stiff
on the unit we tested. At $109.95, the CC GOZO
gives you the quality of more expensive desktop
radios in a size that is flexible for home, boat, or
RV.
You can get more details on the company
website www.ccrane.com or phone them from the
U.S. and Canada at 1-800-522-8863. Local and
international callers should use (707) 725-9000.
SPECIFICATIONS
Input Power: AC Adapter: 12 VDC 650 mA tip positive or (6) AA size (not included)
Power Consumption: AM 3.5W, FM 4W
Audio Output: 3.5W
Speaker: 2 .25 inches, 6 Ohms, 10 Watts
Frequency Coverage: AM 520 - 1710 kHz, FM
87 - 108 MHz
AM Antenna: Internal Ferrite Bar, FM Antenna:
Telescopic whip antenna
AM Sensitivity: ≤ 3mV (S/N=20dB)
FM Sensitivity: ≤ 3uV (S/N=30dB)
AM Selectivity: ≥ 25dB (±10kHz)
FM Selectivity: ≥ 40dB (±400kHz)
One Signal Selectivity: ≥30dB
Earphone Jack: 1/8 inch (3.5mm) Stereo 32 ohm
Aux in Jack: 1/8 inch (3.5 mm) stereo
Dimensions: 7.3 inch W x 4.2 inch H x 3.25 inch D
Weight: Approximately 1.5 lbs without batteries.
Warranty: One Year Limited Warranty
Included Accessories: AC Adapter and Manual
Note: Specifications are subject to change without
notice.
February 2012
MONITORING TIMES
71
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