Alinco DR-735T VHF/UHF FM Transceiver
Reviewed by Steve Ford, WB8IMY
QST Editor
wb8imy@arrl.org
If you’re in need of a dual-band
FM mobile transceiver with a big
display and hefty RF output specs
to match, the Alinco DR-735T
may be worth considering.
The DR-735T has one of
the largest and brightest
displays that I’ve ever seen
in an FM mobile transceiver. As anyone who has
operated on the road will
tell you, an easy-to-read
display is a key feature.
Distracted driving can be even
more distracting when your eyes can’t
find the display, much less focus on it. You
won’t have that problem with the Alinco
DR-735T.
When it comes to RF power, I’m accustomed to dual-band radios that tend to offer
reduced output on UHF compared to VHF.
Not so with the DR-735T; it offers 50, 20,
or 5 W output on both bands. The transceiver case is compact, which means that
space for a heatsink is limited. To solve
that issue, Alinco added a powerful cooling fan to the DR-735T. The fan is a bit
noisy, but not objectionably so. Still, you
can change the way it functions — when
it operates and when it doesn’t — in the
menu system. For example, you can set the
fan to activate whenever you transmit and
remain active for 2 minutes afterward. At
the opposite extreme, you can set the fan to
activate only when the internal temperature
exceeds 158 degrees, although the manual
seems to discourage this (for good reason).
The DR-735T’s control head detaches
quickly from the main body of the transceiver, allowing you to place the head
under your dashboard while the rest of the
unit hides beneath a seat or in your trunk.
To separate the radio in this fashion, however, you’ll need to purchase the EDS-30
separation kit that includes a 16-foot cable.
You can plug the microphone into the control head when it is separated, but the head
lacks a jack for speaker. This means you
may need to mount an external speaker in
proximity to your operating position if the
radio isn’t close enough for you to hear its
internal speaker. The radio has plenty of
audio power, though, so I suspect the internal speaker may suffice for a nearby underseat installation.
Other features of note include the DR735T’s full crossband repeater operation,
expanded 2 meter receive range to include
the AM aviation band, and 1000 memories
that can be scanned. The DR-735T can also
function as a digital voice transceiver if you
install the optional EJ-47U GMSK board.
However, you’ll only be able to communicate with other similarly equipped Alinco
users. We did not install the board for this
review.
Indoor Exploration
I began by trying the DR-735T indoors,
running it from my 13.8 V dc station power
supply. When running at full throttle (50 W
output), the transceiver draws about 10 A
of current when transmitting.
Bottom Line
The Alinco DR-735T is a rugged
dual-band FM transceiver with plenty
of RF output power, a full feature set,
and a bright, easy-to-read display.
With the DR-735T on the bench, I connected it to my dual-band ground plane
antenna. Fortunately, the transceiver has a
built-in diplexer feeding a single antenna
jack. All I had to do was attach my feed line
to the radio and I was ready to go. Some
rigs sport separate 2 meter and 70 centime-
ter antenna jacks, which is fine if you have
separate antennas, but for those of
us with dual-band antennas
(which includes the majority of mobile antennas these
days) it is a blessing not to
have to invest in an external
diplexer.
While exploring the DR-
735T, I noted that it had two
external speaker jacks. This
is a very useful feature for
base or mobile operating, al-
lowing you to send the audio from,
say, the 2 meter band to the left speaker
and the 70 centimeter band to the right
speaker.
On the rear panel I also spotted a small
DIN jack for connecting an external packet
radio terminal node controller (TNC) for
APRS and other activities. However, after
consulting the manual, I discovered that
the DR-735T is only designed for packet
operation up to 4800 baud; you can’t use
the DR-735T for 9600 baud packet.
On the Road
The Alinco DR-735T is a fine indoor transceiver, but it really shows its talents on the
road. Since I lacked the separation kit, I
mounted the radio vertically on the console
between the driver and passenger seats of
my automobile. It was far from an ideal
installation, but it was also just temporary.
Thanks to the strong audio output, I had no
difficulty hearing the DR-735T’s internal
speaker. Considering the fact that I had the
heatsink wedged up against the side of a
leather seat, I was grateful for the potent
cooling fan.
One feature I appreciated instantly was
the fact that Alinco designed the DR-735T
with independent sets of volume, squelch,
and VFO controls for each band. This is
a godsend when you’re driving and you
don’t want to take your eyes off the road to
make an adjustment. I could find and grasp
QST® – Devoted entirely to Amateur Radio www.arrl.org Reprinted with permission from October 2016 QST
the knob I wanted by “feel” alone.
With a dual-band mag-mount antenna, I
received excellent reports from local and
distant repeaters. Operating at the 50 W
level, I found myself enjoying simplex
chats on both 2 meters and 70 centimeters.
In one instance, I made a simplex contact
on 2 meters with a fellow in New Jersey
while cruising around central Connecticut.
Granted, he was using a Yagi antenna on
a hilltop station at his end, but he reported
that my signal was quite strong, with outstanding audio.
The DR-735T seemed to have a reasonably sensitive receiver, although I did notice occasional “intermod” reception when
driving through areas where commercial
two-way transmissions were particularly
strong. This was an issue that some amateurs reported in the DR-735T’s predecessor, the DR-635T. To help mitigate this
problem, Alinco has added a function in
the DR-735T menu system that allows you
to activate what the manual calls “Image
Signal Rejection.” Unfortunately, ARRL
Lab testing revealed no difference in the
adjacent channel rejection, IMD dynamic
range, or image with this feature on or off.
You can toggle on an attenuator if local
interference is severe. Lab testing indicated
that turning on the attenuator improves
adjacent channel selectivity by about 5 dB
and IMD dynamic range by about 8 dB.
The tradeoff is a 10 dB loss of sensitivity.
An attenuator is a good function to have on
an FM mobile transceiver.
This transceiver distinguishes itself by offering full duplex operation, which in this
instance means that you can transmit on
one band (the “main” band) while listening
to the other (“sub”) band. I would imagine
this would be highly useful during public
service operations where it may be important to monitor activity on one band while
transmitting on another. On the other hand,
should you find this feature annoying, there
is a menu function that will allow you to
automatically disable subband reception
whenever you transmit.
And There’s More
The DR-735T offers more features that are
sure to appeal to FM enthusiasts, especially
mobile operators. The scanning function
Table 3
Alinco DR-735T, serial number M00580
Manufacturer’s Specifications Measured in ARRL Lab
Frequency coverage: Receive, 108 – 135.995 Receive and transmit, as specified.
MHz (AM), 136 – 173.995 MHz (FM), 400 –
479.995 MHz. Transmit, 144 – 147.995 MHz,
430 – 449.995 MHz (FM).
Modes: FM. As specified.
Power requirements: Receive: 600 mA At 13.8 V dc: Receive, 840 mA (max
maximum, 400 mA standby. Transmit, 12 A, volume, max lights, no signal, one
at 13.8 V dc ±15%. receiver); 900 mA (max volume, max
lights, both receivers); 553 mA (standby,
max lights); 323 mA (standby, no lights).
Transmit (hi/med/low):
146 MHz, 8.5/5.7/3.2 A,
440 MHz, 10.4/6.3/3.3 A.
Receiver Receiver Dynamic Testing*
Sensitivity: FM (12 dB SINAD), 0.16 µV FM (12 dB SINAD): 0.16 µV (144 MHz),
0.17 µV (440 MHz), 0.14 µV (WX).
AM (10 dB S+N/N): 0.63 µV.
FM two-tone, third-order IMD dynamic range: 20 kHz offset: 146 MHz, 53 dB; 440 MHz,
Not specified. 58 dB. 10 MHz offset: 146 MHz, 69 dB;
440 MHz, 60 dB.
FM two-tone, second-order IMD dynamic range: 146 MHz, 80 dB; 440 MHz, 102 dB.
Not specified.
Adjacent-channel rejection: Not specified. 20 kHz offset: 146 MHz, 66 dB;
440 MHz, 65 dB.
Spurious response: Not specified. IF rejection: 146 MHz, 132 dB (main RX),
129 dB (sub RX); 440 MHz, >132 dB
(main & sub RX). Image rejection:
146 MHz, 57 dB (main RX), >133 dB
(sub RX); 440 MHz, >132 dB
(main & sub RX).
Squelch sensitivity: 0.14 µV (144/430 MHz). At threshold: 146 MHz, 0.16 µV
(0.4 µV max); 440 MHz, 0.09 µV
(0.48 µV max).
S-meter sensitivity: Not specified. S-9, signal: 144 MHz, 1.27 µV;
440 MHz, 1.70 µV.
Audio output: >2 W at 10% THD into 8 Ω. 2.8 W at 10% THD into 8 Ω.
THD at 1 V
Transmitter Transmitter Dynamic Testing
Power output: 50, 20, 5 W (hi, med, low) At 13.8 V dc (hi/med/low):
at 13.8 V dc ±15%. 146 MHz, 53/22/2 W,
440 MHz, 47/19/4 W.
High power output at minimum specified
voltage: 144 MHz, 49 W; 440 MHz, 44 W.
Spurious signal and harmonic suppression: ≥70 dB. Meets FCC requirements.
–60 dB.
Transmit-receive turnaround time (PTT release Squelch on, S9 signal, 146 MHz, 166 ms;
to 50% of full audio output): Not specified. 440 MHz, 167 ms.
Receive-transmit turnaround time (“tx delay”): 146 MHz, 67 ms; 440 MHz, 65 ms.
Not specified.
Size (height, width, depth): control panel, 2.3 × 5.5 × 2 inches (including protrusions).
rear Chassis, 1.5 × 5.5 × 7.3 inches. Weight, 2.9 lbs (panel, rear chassis, and cable).
Price: $340. EDS-30 head separation cable (16 ft), $55; ERW-7 USB cable, $50;
EJ-47U digital voice adapter, $200.
*Main and sub receivers measured identically, unless noted.
RMS
, 1.85%.
Reprinted with permission from October 2016 QST ARRL, the national association for Amateur Radio
®
www.arrl.org
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