Alinco DJ-G7T Triband Handheld Transceiver

Alinco DJ-G7T Triband Handheld Transceiver
PRODUCT REVIEW
Alinco DJ-G7T Triband
Handheld Transceiver
Reviewed by Bob Allison, WB1GCM
ARRL Test Engineer
There are plenty of dual band handheld
transceivers on the market, but this transceiver includes 23 cm (1240 MHz) band operation at 1 W, along with the more familiar
2 meter and 70 cm bands at 5 W output. This
23 cm band capability was enough to make
me curious and sign up to perform the review.
I had never worked this part of the spectrum
before, but a quick look at the ARRL
Repeater Directory suggests heavy usage of
the 23 cm band in some areas. I had
never worked FM satellites before
either. Any handheld radio with
2 meter and 70 cm capability can work
the FM satellites, but I was curious
about the DJ-G7T’s full duplex capability. Once again I was reminded of the
vast scope of ham radio in which there is
always room for a new adventure.
Out of the Box
When I opened the box, I was pleased to
see a drop-in battery charger included, rather
than the usual wall charger. After about three
hours, the DJ-G7T’s 1200 mAh lithium ion
(Li-ion) battery was fully charged and ready
for testing.
As with any other complicated modern
transceiver, thoroughly reading the manual
will save a lot of time. Without reading the
manual, it took several minutes for me to
simply find the POWER switch, an inconspicuous button mounted flush to the left side of
the case.
The polycarbonate body felt comfortable
in my hand. The overall size and weight would
not be a burden even with extended use. The
chassis is die-cast metal but not the case,
so take some care in handling. Although it
wouldn’t survive the steam-roller test, the DJG7T will survive a splash in a pond, or a severe
weather event. It’s rated to withstand submersion in 3 feet of water for 30 minutes.
The POWER button must be held down
for one second. My large fingers had difficulty keeping enough pressure on the flush
mounted button for the required time. Alinco
indicates that the high button pressure is intentional to prevent accidental turn-on. The
rest of the 19 buttons were manageable.
Key Measurements
Summary
0.17
The 11⁄2 × 3⁄4 inch green, backlit LCD is
easy to read and has several display options.
Display icons are intuitive and large enough
to see. The keypad is straightforward once
you learn the functions. The MAIN button
toggles among the three ham bands, while
the SUB button toggles through several bands
from 530 kHz through 1300 MHz.
The DJ-G7T sports a 61⁄4 inch flexible
antenna with an SMA connector. Next to the
antenna is a jack for an optional speaker/mic
with a heavy duty screw down cover and gasket to keep out the elements when not in use.
Most prominent are two sets of concentric
knobs (one set for each of the two receivers).
The inner knobs are used mainly for tuning
the main and sub receivers, while the outer
knobs act as VOLUME controls. The default
setting has the main receiver on the left
and the sub receiver on the right, but this
arrangement can be reversed via a menu
setting. Along the left side of the case are
the POWER switch, a MONITOR button
(momentarily opens the squelch) and
the PTT switch. The right side of the
case features a jack for external 4.5
to 16 V dc input.
The DJ-G7T comes with a wrist
strap and belt hook. The belt hook
is a cloth loop that separates with
Mark J. Wilson, K1RO
0.19
SINAD 0.25
0.17
0.1
Receiver Sensitivity (12dB SINAD, µV)
69
I3
Rx 60 62
73
90
Receiver 3rd-Order Dynamic Range (10 MHz, dB)
57*
I3
51* 53*
Rx 40
70
Receiver 3rd-Order Dynamic Range (20 kHz, dB)
57
48**
51
ChRej 50
90
Adjacent Channel Rejection (dB)
103*
104*107*
110
IF 60
IF Rejection (dB)
105*
Img 60
Snd 100
95* 100* 110
Image Rejection (dB)
490
800
Audio Output (mW)
290**
T-R 250
pr046
50
Tx-Rx Turnaround Time (ms)
Key:
2M
** Off Scale
* Measurement noise limited
at value shown.
23 cm
70 cm
Bottom Line
The DJ-G7T handheld adds
23 cm operation to the usual 2 meter
and 70 cm bands. With a wide range
receiver and full duplex capability, it
offers a lot of value for the money.
!
Product Review Editor
!
k1ro@arrl.org
From April 2010 QST © ARRL
a plastic snap-together fastener, making it
harder to remove in a hurry. It fits a belt up
to 3 inches wide, handy for those 1970s parties. The battery pack on the back has two
1
⁄4 inch square metal pads for connecting to
the drop-in charger. Be careful not to put
the radio in your pocket along with spare
change or keys.
Lab Testing
Overall, the radio tested fairly well on the
three amateur bands it was designed for. With
a wideband receiver in a small package, some
design compromises must be made — in
particular placement of the IF (intermediate
frequency). Many models have the IF above
or below the 6 meter band, resulting in poor IF
and image rejection in that area. This is also
true with the DJ-G7T, where the IF of the sub
receiver is within the 6 meter band, so expect
images while listening to 6 or 10 meters.
You can listen to the main and sub receivers simultaneously, and even tune them to the
same band. I observed up to 6 dB of signal
degradation in the sub receiver with both receivers tuned to 2 meters in the dual listening
mode. Interestingly, with the main receiver
tuned to 2 meters, I noticed about 8 dB of
signal degradation with the sub receiver tuned
anywhere between 50 and 135.995 MHz.
Alinco attributes this to filter characteristics.
I didn’t observe signal degradation with other
main and sub frequency combinations.
The earphone jack has speaker level
output, not the lower level normally used for
earphones, so you need to be careful about
cranking up the volume. The audio was nice
and clean even at high listening levels.
I observed the specified transmitter power
output with the transceiver running from an
external 13.8 V dc supply, but was a bit less
than specified on 2 meters with the battery
pack. A nice surprise is this transceiver can
operate with as little as 4.5 V dc and still put
out a usable signal, a plus during emergencies.
Table 1
Alinco DJ-G7, serial number M000905
Manufacturer’s Specifications
Measured in ARRL Lab
Frequency coverage:
Receive,0.530-1299.995 MHz,
Cellular blocked;
transmit, 144-147.995,
430-449.995, 1240-1299.995 MHz
FM, NFM.
Receive: Main band, 136-169.995, 400469.995, 1240-1299.995 MHz FM, NFM.
Sub band, 0.530-59.745 MHz FM, NFM,
AM; 59.750-107.995 MHz WFM; 108475.495 MHz FM, NFM, AM; 475.5805.995 MHz WFM; 806-823.995 MHz,
850-868.995, 895-959.995 MHz FM,
NFM, AM; 960-1239.995 MHz WFM;
1240-1299.995 MHz FM, NFM, AM.
Transmit, as specified.
Power requirements: 4.5-16 V dc; receive,
200 mA; battery save (1:4) average, 56 mA
dual receive, 50 mA single receive;
transmit, 1.6 A @ 144 MHz, 1.8 A @
430 MHz, 0.8 A @ 1240 MHz (high power).†
Receive (max volume, no signal, lights
on) dual receive, 248 mA; battery save,
as specified.
Transmit (high, med, low 2, low 1):
146 MHz: 1.44, 0.95, 0.73, 0.55 A;
440 MHz: 1.55, 1.03, 0.84, 0.55 A;
1294 MHz: 0.75 A (high), 0.6 A (low).
Receiver
FM sensitivity: 12 dB SINAD, main band,
144/430 MHz ham bands, –15 dBµV;
1200 MHz ham band, –13 dbµV;
Sub band, 30-470 MHz, –15 dBµV;
>470 MHz, –7 dBµV.
Receiver Dynamic Testing
Main band, for 12 dB SINAD: 146 MHz,
0.17 µV; 440 MHz, 0.17 µV; 1294 MHz,
0.19 µV. Sub band: 29 MHz, 0.16 µV;
50 MHz, 0.16 µV; 146 MHz, 0.17 µV;
222 MHz, 0.6 µV; 440 MHz, 0.17 µV;
902 MHz, 0.62 µV; 1294 MHz 0.29 µV.
WFM sensitivity: 76-470 MHz, –6 dBµV;
>470 MHz, –3 dBµV.
100 MHz, 0.58 µV; 500 MHz, 0.52 µV;
1000 MHz, 0.71 µV.
AM sensitivity: 10 dB S/N, <50 MHz, –1 dBµV;
>50 MHz, –6 dBµV.
10 dB S+N/N, 1-kHz tone, 30% modulation:
Sub band, 1 MHz, 0.53 µV;
3.8 MHz, 0.47 µV; 14 MHz, 0.4 µV;
50.4 MHz, 1.3 µV; 120 MHz, 0.68 µV;
145 MHz, 0.36 µV; 222 MHz, 1.0 µV;
440 MHz, 0.39 µV; 902 MHz, 1.0 µV;
1250 MHz, 0.44 µV.
Two-tone, third-order IMD dynamic range:
Not specified.
20 kHz offset*, Main band:
146 MHz, 57 dB; 440 MHz, 53 dB;
1294 MHz, 51 dB. Sub band: 29 MHz,
59 dB; 52 MHz, 63 dB; 146 MHz, 57 dB;
222 MHz, 56 dB; 440 MHz, 53 dB;
902 and 1294 MHz, 51 dB.
10 MHz offset: Main band:
146 MHz, 69 dB; 440 MHz, 73 dB;
1294 MHz, 62 dB. Sub band: 29 and
52 MHz, 56 dB; 146 MHz, 65 dB;
222 MHz, 71 dB; 440 MHz, 64 dB;
902 MHz, 67 dB; 1294 MHz, 83 dB.
Two-tone, second-order IMD dynamic range:
Not specified.
Main band: 146 MHz, 84 dB; 440 MHz,
88 dB; 1294 MHz, 90 dB. Sub band:
29 MHz, 55 dB; 52 MHz, 74 dB; 146 MHz,
82 dB; 222 MHz, 48 dB; 440 MHz, 88 dB;
902 MHz, 94 dB; 1294 MHz, 80 dB.
radio offers a variety of scanning modes.
With testing complete, W1AW Station
Manager Joe Carcia, NJ1Q, set up to work
me on 1294.5 MHz (national simplex calling frequency) at lunch time. Joe helped me
adjust the DJ-G7T’s microphone gain, easily
set by pressing FUNCTION and then MIC and
then selecting one of four levels with a rotary
knob. Joe gave me a good audio report and
found that level 3 worked best for me, as I
like to speak a foot away from handhelds. The
receive audio from the 13⁄4 by 3⁄4 inch speaker
grill sounded good as well.
repeater satellites such as AO-27 and AO-51.
The dual bank memory is perfect for satellite
work because several frequency pairs are
necessary to compensate for the Doppler
shift that occurs during a pass.
On a late November afternoon, I checked
the AMSAT Web site and found an AO-27
pass only minutes away. I hurriedly entered
the frequency combinations necessary and
soon heard a QSO taking place — noisy,
with lots of fading. Clearly, a better antenna
was in order at my end.
I got an Arrow dual band Yagi designed
for portable use and was ready for another
pass. With headphones on, I could clearly
zero in on AO-27. After listening to a few
passes to observe the routine, I aimed the
On the Air
As previously mentioned, review the
manual to understand the use of the various
settings and functions. I found the manual
that came with our DJ-G7T difficult to understand and follow. Since then, Alinco has
revised the manual, and the new version is
available for download from their Web site
and is shipping with current production units.
With the new version (PS0597A, printed
on the back cover of the manual), I had no
trouble understanding the configuration
steps, most of which start by pressing the
FUNCTION button and rotating the concentric
knobs at the top of the radio.
The DJ-G7T has 1000 regular memory
channels that can be organized into banks of
100 channels. One is called a dual bank, which
stores both main and sub frequencies. The
From April 2010 QST © ARRL
My First FM Satellite QSO
With full duplex capability, this transceiver appears to be well suited for FM
Manufacturer’s Specifications
Measured in ARRL Lab
Adjacent-channel rejection: Not specified.
Main band, 20 kHz offset: 146 MHz, 57 dB;
440 MHz, 51 dB; 1294 MHz, 48 dB.
Sub band: 29 MHz, 56 dB; 52 MHz, 65 dB;
146 MHz, 56 dB, 440 MHz, 51 dB,
902 MHz, 49 dB, 1294 MHz, 48 dB.
Spurious response: VHF, 60 dB; UHF, 50 dB.
IF rejection, Main band: 146 MHz, 103 dB,
440 MHz, 107 dB; 1294 MHz, 104 dB.
Sub band, 29 MHz, 22 dB, 50 MHz, 26 dB,
146 MHz, 83 dB; 222 MHz, 87 dB;
440 MHz, 110 dB MHz; 902 MHz, 92 dB;
1294 MHz, 97 dB.
Image rejection, Main band:
146 MHz, 105 dB*;
440 MHz, 100 dB*; 1294 MHz, 95 dB*:
Sub band: 29 MHz, 67 dB; 50 MHz, 1 dB;
146 MHz, 105 dB*; 222 MHz, 27 dB,
440 MHz, 92 dB*; 902 MHz, 95 dB,
1294 MHz, 94 dB*.
Squelch sensitivity: Not specified.
At threshold: 146 MHz, 0.11 µV; 440 MHz,
0.13 µV; 1294 MHz, 0.13 µV.
Maximum squelch: 0.45 µV, typical.
Audio output: 400 mW at 10% THD into 8 !.
Maximum volume 490 mW at 8.8% THD;
1.5% THD at 1 VRMS.**
Transmitter
Power output with 13.8 V dc: 144/430 MHz
(high/med/low 2/low 1), 5 / 2 / 1 / 0.3 W.
1294 MHz (high/low), 1 / 0.3 W.
With EPB-73 battery: 144 MHz (high / med /
low 2 / low 1), 5 / 2 / 0.8 / 0.3 W; 430 MHz,
4.5 / 2 / 0.8 / 0.3 W; 1240 MHz, 1 / 0.3 W.
Transmitter Dynamic Testing
With 13.8 V dc: 146 MHz, 5 / 2 / 1 / 0.4 W;
440 MHz, 5.4 / 1.8 / 1.1 / 0.6 W;
1294 MHz, 1.2 / 0.6 W. With EPB-73
battery @ 8.4 V dc: 146 MHz, 4 / 1.9 /
1.0 / 0.4 W; 440 MHz, 3.8 / 1.8 / 1.1 /
0.6 W; 1294 MHz, 1.2 / 0.6 W. Power
output at 4.5 V dc: 1.3 W maximum.
Spurious signal and harmonic suppression:
60 dB or better.
146 MHz, >70 dBc; 440 MHz, 66 dBc;
1294 MHz, 53 dBc (<25 µW).
Transmit-receive turnaround time (PTT release
to 50% of full audio output): Not specified.
Squelch on, S9 signal, 290 ms (typical).
Receive-transmit turnaround time (“tx delay”):
Not specified.
Squelch on: 146 MHz, 57 ms; 440 MHz,
47 ms; 1294 MHz, 138 ms.
Size (height, width, depth): 4.5 × 2.4 × 1.2 inches; weight, 10.6 ounces with flexible antenna.
Price: DJ-G7T, $330; EMS-62 speaker/mic, $55; ERW-7 PC interface USB cable, $55;
EDS-10 plug adapter cable, $15.
†EBP-73
battery pack (7.4 V, 1200 mAh Li-ion) and EDC-173T charging stand
supplied. Available options: Replacement EBP-73, $70; EDH-35 battery case
(4 AA cells; TX power limited), $25; EDC-36 cigarette lighter cable with filter, $35.
*Measurement was noise limited.
**Measurements made in single receiver mode. Total output power, full volume, dual
receive is 600 mW at 20% THD.
antenna where I thought the bird might
be and called a quick CQ. I received a
prompt reply, but in the excitement I fumbled
the other station’s call sign and asked for
a repeat. Memories of my first contact
years ago flashed through my head. The
other operator kindly repeated his call while
I stumbled to find a pen… oh no... no pen!
I blew it! Unlike the operator, the radio
clearly did its job. Using headphones and
a suitable antenna, the DJ-G7T with its
full duplex capability works well with FM
satellites.
Satellite operation gave me a chance
to observe the full duplex function.
While transmitting with high power at
145.850 MHz on the main band and receiving simultaneously around 435.795 MHz on
the sub band, I heard only slight interference
with the squelch open. Transmitting with the
sub receiver squelch open is not a good
operating technique, since the roar of an
open squelch will be transmitted along with
your voice. Headphones will prevent echoing
and feedback during transmission. If you
must use the speaker, the sub band audio can
be set to mute during transmit.
Other Features
Listening to the sub band receiver is
entertaining. With the internal bar antenna,
local AM broadcast stations are heard fairly
well. FM broadcast performance is adequate
using the supplied antenna. An external
antenna brings the DJ-G7T to life! Tuning
across the shortwave bands, the receiver
overloaded at times with my inverted-L antenna. Not to worry: there are four attenuator
settings available.
The DJ-G7T can be set up as a cross band
repeater. This feature can be useful for temporary operation in an emergency situation,
but you must avoid causing harmful interference to other stations. Carefully choose
a frequency pair and review the FCC rules
before operating in repeater mode.
Other interesting features of the DJ-G7T
are a band scope that indicates nearby activity, a bug detector that allows you to find
hidden transmitters, and a transmitter detecting function. This last feature is intended for
radio foxhunts. Speaker audio is disabled and
instead the ’G7T sounds an occasional beep,
with the beep sounding at shorter intervals as
the hunter closes in. The adjustable attenuator is put to use at close range, and before
you know it, you’ve caught the fox.
Clearly, this is a fun radio to use. I did
find some issues that I hope will be corrected by updated firmware. At the top of
my list is the automatic repeater shift, which
turns off for the five channels between
145.11 and 145.19 MHz. There are locally
coordinated FM repeaters in this range and
I had to disable the auto shift function and
manually enter the minus offset for this part
of the band. Furthermore, in sections of the
band where auto shift functioned as expected, I was unable to change the repeater
shift manually — prohibiting me from going
to simplex mode if needed.
I also found that while programming
memories, the repeater shift was not stored
in memory from the VFO with the auto repeater shift on. I ended up leaving the auto
shift function off most of the time and used
the FUNCTION and MAIN buttons (continued
pressing of MAIN toggles the repeater offset
from + to – to simplex).
Cloning software is available via a free
download from Alinco’s Web site, as are
firmware updates. You will need the optional
EDS-10 plug adapter cable and ERW-4C
(serial) or ERW-7 (USB) cable for connection to your PC.
The DJ-G7T is an affordable three band
handheld that is well suited for talking across
town, listening to a wide range of frequencies, or working the FM satellites. Operation
on 23 cm is a big plus if you have an active
repeater in your area.
Manufacturer: Alinco Inc, Yodoyabashi
Dai-Bldg 13F, 4-4-9 Koraibashi, Chuo-ku,
Osaka 541-0043, Japan; www.alinco.com.
US distributor: GRE America, 425 Harbor
Blvd, Belmont, CA 94002; tel 650-5911400; e-mail alinco-sales@greamerica.
com; www.allinco.com/usa.html.
From April 2010 QST © ARRL
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising