QST
®
– Devoted entirely to Amateur Radio www.arrl.org
Reprinted from December 2013
QST
43
Key Measurements
Summary
6 o’clock position is the
DR
key, which turns
on the D-STAR Repeater mode and doubles
as the down arrow selector. Clockwise, at the
9 o’clock position is the
CD
(call sign display)
button, which, when held down for a second,
places received calls on the display with mes-
sages and repeater info. It also serves as the
“back” key. At the 12 o’clock position is the
RX->CS
button, which captures the received
station’s call sign and repeaters and places the
call sign into the UR field for call sign routing.
The key also serves as the up arrow key. And
at the 3 o’clock position is the
CS
or call sign
select button, which, when held down for one
second, displays the call sign information cur-
rently stored in the four ubiquitous D-STAR
operating fields that are at the heart of the
system: UR call, MY call, Repeater 1, and
Repeater 2. This is a handy feature to have as
the operator can quickly confirm that the
proper information is coded into the four slots.
I used it all of the time. The button also serves
to select different menu tiers as does the
CD
key. At the center of these four buttons is the
ENTER
key. All of these keys and the menus
they are associated with worked very well.
Power levels are selectable from the
V/MHZ
key
described above — there are five levels (
SLO
,
LO1
,
LO2
,
MID
, and
HIGH
).
Audio Quality
There have been critical comments circulating
about the transmitted audio quality, which
some have categorized as “muffled.” This was
caused by the membrane that is apparently
incorporated into the microphone to allow
for some measure of water resistance. While
the first production units had the thicker
membrane, Icom was quick to implement a
fix with an upgrade plan that solved the issue
in short order. You can tell if you have the
new material by looking into the mic open-
ing. If it is white, it is the new membrane.
I looked: The test unit has the white mem-
brane and the audio was not at all muffled.
You can check your transmitted audio by
two methods. By using the echo function on
your local D-STAR repeater, you can hear
your audio repeated back to you. Or, you can
record transmissions (and indeed both sides
of a complete QSO) by using the radio’s
record function (recordings are made onto a
microSD card that is inserted into a slot on
the side of the radio). There’s even a voice
recorder function for simply recording your
own notes — reminders, lists, anything. You
can evaluate your own audio and compare
it to others participating in the QSO. I tried
both methods, and the audio quality seemed
absolutely fine to me.
Review of Functions
Some might question the utility of recording
him on Reflector 037C. The software and
cable work great with the ID-51A. It is easy
to use, and will have your memories uploaded
and in use within just minutes. All of the nec-
essary memory channel data fields are there,
and many more.
Icom’s
CS-51
programming software comes
on the CD packed with the radio. Further, a
programming cable is not absolutely neces-
sary because the .icf programming file can
2 M
70 cm
Note: Measurements shown
are for Receiver A.
Key:
**
Off Scale
pr080
250
50
T-R
126
Tx-Rx Turnaround Time (ms)
124
100
800
Snd
218
Audio Output (mW)
60
110
Img
Image Rejection (dB)
135**
82
60
110
IF
135**
IF Rejection (dB)
102
ChRej
50
90
66
Adjacent Channel Rejection (dB)
65
40
70
I
3
Rx
66@20 kHz
Receiver 3rd-Order Dynamic Range (dB)
65@20 kHz
I
3
Rx
78@10 MHz
90
Receiver 3rd-Order Dynamic Range (dB)
75@10 MHz
0.25
0.1
SINAD
0.12
Receiver Sensitivity (12dB SINAD,
m
V)
0.13
your QSO onto your radio’s SD card, but I
immediately realized its value in the context of
disaster response and public service commu-
nications for served agencies. It helps to have
a hard record of messages sent and received
during the heat of battle on the disaster field
for not only the after-action hotwash, but also
in case questions arise. Incident Commanders
won’t need to rely on subjective answers when
they can hear the actual messages themselves.
Not as dramatic as all that, listening to your
QSOs after the fact can help you hone your
basic QSOing and social skills on the air!
And, well, truth be told, it’s just plain fun, too.
This function worked well for me: you can
automatically parse the QSO recording into
transmissions and receptions, or just keep the
recording running.
The GPS receiver discussed briefly at the out-
set of this review works well, not only for the
benefit of finding and entering your nearest
D-STAR repeater for almost instant access to
the system when mobile, but it also does a fine
job of providing your position, elevation, and
speed. This information can be transmitted
automatically via D-PRS in the Digital Voice
mode every time you key the mic, if desired.
Software installed in most D-STAR gateways
will convert the D-PRS data packet into stan-
dard APRS packets and send it on the Internet,
allowing your position to be viewed on APRS
servers. The GPS logger function stores posi-
tions along your course on the microSD card
for display using mapping software.
BC Radio and Two Band Monitoring
As with many radios nowadays, the operator
can monitor two bands at once, along with
the broadcast radio receiver incorporated into
this radio. The operator can listen to each
one separately, too, of course. The broadcast
radio works fine, and it sounds better than my
car’s FM radio. Both AM and FM bands are
available and favorite stations can be stored
in memory. Again, from the perspective of
an emergency or disaster response commu-
nications operator, having access to the AM
and FM broadcast bands for general disaster
information and alerts is very useful.
Memory Channels
The transceiver has 500 regular memory chan-
nels, 50 scan edge channels (25 pairs) and 4
call channels. Also, 26 memory banks, A to
Z, can be used to store groups of operating
channels, and so on. Up to 100 channels can
be assigned to a bank.
I programmed memory channels using the RT
Systems (
www.rtsystemsinc.com
) software
and cable, with thanks to Scott Freudenthal,
K2LSF, from Jacksonville, Florida, for send-
ing me his incredible memory channel file,
and for his patient mentoring — you can catch
