Reprinted from December 2013
QST
ARRL, the national association for Amateur Radio
®
www.arrl.org
Table 1
Icom ID-51A, Serial Number 05001656
Manufacturer’s Specifications
Measured in ARRL Lab
Frequency coverage: Receive, 108-174,
Receive: 137-174, 380-479 MHz (FM,
380-479 MHz, 0.520-1.710 MHz, 76-108 MHz;
DV); 76-108 MHz (WFM); 0.520-1.710,
transmit, 144-148, 430-450 MHz.
108-136.995 MHz (AM).
Transmit: as specified.
Modes: FM, NFM, DV, AM (receive only).
As specified.
Power requirements: At 7.4 V dc: receive,
Battery power: FM, receive, internal
FM, <350 mA (internal speaker), <200 mA
speaker, 225 mA (max volume, backlight
(external speaker): DV, <450 mA (internal
on), 82 mA (standby), 59 mA (standby,
speaker), 300 mA (external speaker);
backlight off). Transmit: 146 MHz, 1.79 A
transmit, <2.5 A (5 W output).
†
(high),1.28 A (medium), 0.98 A (low2),
0.62 A (low1), 0.41 A (s-low); 440 MHz,
2.69 A (high), 1.88 A (medium), 1.21 A
(low2), 0.91 A (low1), 0.53 A (s-low).
External power (13.8 V dc): Receive,
138 mA (max vol, backlight on), 107 mA
(max vol, backlight on, external speaker).
Transmit: 146 MHz, 1.76 A (high),
1.25 A (medium), 0.88 A (low2), 0.61 A
(low1), 0.35 A (s-low); 440 MHz, 2.59 A
(high), 1.79 A (medium), 1.15 A (low2),
0.86 A (low1), 0.48 A (s-low).*
Receiver
Receiver Dynamic Testing**
Sensitivity, FM (12 dB SINAD): <0.178 µV;
FM, for 12 dB SINAD, 146 MHz, 0.13 µV,
DV, 0.282
m
V.
440 MHz, 0.12 µV; 162.4 MHz, 0.127 µV,
100 MHz, 0.45 µV.
Sensitivity, AM (10 dB (S+N)/N: Not specified.
AM, for 10 dB S+N/N, 1.0 MHz, 0.7 µV,
120 MHz, 0.3 µV.
FM two-tone, third-order IMD dynamic range:
146 MHz, 20 kHz offset, 65 dB, 10 MHz,
Not specified.
offset, 75 dB; 440 MHz, 20 kHz offset,
66 dB, 10 MHz offset, 78 dB.
FM two-tone, second-order IMD dynamic range:
146 MHz, 69 dB, 440 MHz, 108 dB.
Not specified.
Adjacent-channel rejection: >55 dB.
20 kHz offset, 146 MHz, 65 dB,
440 MHz, 66 dB.
Figure 1
— Despite the size constraints of a
handheld radio, the ID-51A’s display resolution
is high enough to show quite a bit of data clearly.
Figure 2
— The built-in broadcast band radio is
a plus for public service operators who need to
keep an ear on local news updates.
Figure 3
— The ID-51A features a built-in GPS
receiver. The receiver is used to determine which
D-STAR repeaters are closest to you. The trans-
ceiver can also use the GPS receiver to track
your position and share the information over the
network.
be written to the micro SD card by the
CS-51
software on a PC and then read by the radio
after transferring the card to the radio’s card
slot. You also have the ability to utilize the
SD card storage to backup your configuration.
In fact, the SD card can hold multiple .icf
files allowing you the ability to restore any
configuration file in the field without the need
for a computer or cable.
Other Features
The microphone audio can be recorded. It
worked fine for me, with some 68 hours of re-
cording available per the display note; I can’t
imagine listening to myself for all 68 hours!
But, for 15 seconds, I could stand it.
Two band monitoring from the two VFOs
works well, and the broadcast band radio can
be monitored, too, all at the same time: The
volume control adjusts the BC radio output to
a level where the operator can hear the channel
output versus the radio output as a matter of
operator preference. This worked well.
An Auto Position Reply function can auto-
matically send your call sign, with or without a
GPS position and brief (10 second limit) voice
message, when you receive a call and cannot
immediately answer. A Voice TX function
allows the operator to transmit recorded audio
once or repeatedly, from either the main
MENU
key, or the
QUICK
menu. It works fine,
although I question the utility of repeating the
voice memo transmission over and over again
for up to 10 minutes — I couldn’t figure out
why anyone would want to do that.
The Speech function allows the various
modes, frequencies, and call signs (DV) to be
announced, which is nice while driving — you
don’t have to look at the radio’s display to
