The Icom ID-4100A is a feature-rich dual-band mobile transceiver for D-STAR and analog FM. As with other recent Icom radios, several optional mounting brackets are available to fit different applications.
Icom ID-4100A review. VHF/UHF Dual-Band FM/D-STAR Transceiver.
Analog and digital operation with the latest features.
I’ve been operating with Icom’s D-STAR transceivers for more than 15 years, starting with a special D-STAR chip for my old IC-2200H VHF FM radio. In those days, I had to program (by manually entering character by character) the D-STAR call sign parameters: MYCALL, REPEATER1, REPEATER2, and URCALL.
With each generation, Icom’s D-STAR radios have made it easier to enter these parameters, which are essential to operate through the D-STAR network. The ID-4100A is no exception, allowing for entry of the operating parameters at the touch of a few buttons in a more user-friendly DR (D-STAR repeater) mode.
One of the many features that I like about the ID-4100A is that once users enter the call signs/ commands in the DR mode, they can easily check (by selecting CALL SIGN from the menu) to see how the mode’s four call sign fields are programmed in the current operating configuration.
On its website, Icom describes the ID-4100A as an “entry-level D-STAR mobile.” The ID-4100A is a simpler DR radio than its senior sibling, the ID-5100A, with its larger, touchscreen capability. The ID-4100’s¹ screen is significantly smaller, which is at once a liability and an asset, in my opinion (more on the display later).
The ID-4100A also operates on one band at a time (the ID-5100A operates two bands at a time). The term “entry-level” belies the radio’s high degree of sophistication and functionality, a far cry from early D-STAR radios.
¹R. Palm, K1CE, “Icom ID-5100A Dual-Band VHF/UHF FM Transceiver,” Product Review, QST, Feb. 2015, pp. 56 – 59
Icom ID-4100A review: Installation and Options
I installed the optional UT-137 Bluetooth unit, which can be used to pair the radio with a Bluetooth ear-phone/mic, such as Icom’s optional VS3, or with an Android or iOS smartphone and Icom’s RS-MS1I app. The app allows a nice graphical user interface with maps, remote control capability, and extensions of the DR functions. More on these cool features later.
A few notes on installation and options. The ID-4100A does not come with a mobile mounting bracket for either the main unit or the controller head. There are a number of mounting brackets available from Icom or third-party vendors, and you can choose one appropriate for your vehicle.
While the controller head can be attached directly to the main unit, I wanted to separate the two components. I first bought the optional MBF-4 main unit mounting bracket and placed the unit on the back panel of my pickup truck’s cab, behind the seat. I ran the controller cable under the seat to the controller, which I left lying loose on the front seat, like you would with a handheld radio or smartphone.
Next, I ran the short mic cable from the main unit over the seat to my right, but that required turning my head slightly to hold and use it, which was not optimal. After that wore thin, I extended the length of the mic cord with an RJ45 coupler and Cat 6/7 shielded ethernet patch cable, which I purchased from my local computer shop, and it worked great. I ran the extension cord under the seat and console for ease of access to my hand mic. Another option is Icom’s mic extension cable (OPC-647).
Next, I lost patience with having the controller head lying on the front seat, so I ordered an Icom MBA-8 controller head mounting plate. I mounted the two round magnets to the back of the controller, then used four small selftapping screws to mount the plate on a flat part of my dashboard. The controller then magnetically attached to the plate, which worked very well. I also could have mounted the controller on top of my dashboard with the optional MBF-1 mounting base.
Overall, I was happy with the installation with the main unit out of sight behind the seat and the controller easily removed from its magnetic mounting plate for hiding while not in use. I was a bit less happy with the added expense (almost $100) of the options needed to get my optimal install.
The speaker is mounted in the main unit, so I ran a mini audio cable from the external speaker jack on the back of the main unit to the audio input jack on my dashboard to pipe the audio through my truck’s stereo system with speakers in each door — plenty of booming audio.
Using the ID-4100A
I enjoyed operating this radio. I received fine reviews of my transmitted audio. I also played back my transmitted audio using the D-STAR echo function on a local D-STAR repeater, and I was happy with what I heard.
I have owned and operated several D-STAR radios, including the ID-5100A, and have a good understanding of how the D-STAR network works. While the ID-4100A is not completely intuitive to learn and use, after a quick read of the Basic Manual and with the more comprehensive 273-page Advanced Manual, I was on the air in no time.
The front-panel buttons, dials, and screen are easy to work with. Across the bottom of the screen are six pushbuttons. The V/M/CALL button selects VFO or memory operation (in VFO mode, push the BAND/BANK key to change bands).
The MODE key elects the operating mode (FM, FM-N, and DV digital voice; AM for the aviation band and AM-N are available for receive only). The MW (memory write) button saves the current operating data into the next available blank memory channel when you press and hold it for 1 second.
The RX>CS (received call sign) capture key allows easy, instant transfer of a received call sign into the destination call sign field for routing. The MONI (monitor) key allows for listening on the active repeater’s input for assessment of a repeater user’s signal strength.
The QUICK/MUTE key opens a list of operating selections that are used more frequently than those on the main menu. (The QUICK button is also pushed frequently to enable editing, adding, or deleting text/numerals for various functions in the text entry mode).
On the top left corner of the radio is the MENU button, where a more extensive list of selectable operating parameters (including the set-and-forgets) is well organized and displayed for review and changes. It is often used in conjunction with the QUICK menu button for editing text.
Hold down the button for a second, and the current operating data is locked. On the bottom left corner is the BACK/DR key, which toggles between the destination TO and the access FROM fields when in DR mode, and it enters the DR mode when held down for 1 second. Push it to go back a level in the menu tree.
Turn the large tuning dial to change frequency in the VFO mode; change memory channels in memory mode; select options for the TO and FROM screens in DR mode, select menu items and options, and select characters in the text entry mode. Push the dial to change frequency bands or memory banks and to enter the scanning mode (browse scanning modes by rotating the dial).
When the POWER button on the right side of the radio is held down for a second, the frequency, operating mode, or call sign is audibly announced. The VOLUME and SQUELCH knobs are above and below the POWER button.
I was quickly able to write several FM and D-STAR repeaters and their operating parameters (including access tones for the FM repeaters, and the access and destination parameters in the DR mode) into the memory channels by pushing the MW button.
I was able to assign the memories to two banks, one for my primary residence in the city, and the other for my getaway residence in the country, allowing me to scan only those channels indicated for the area I was in. Each memory channel can be edited as necessary.
There are 1,000 memory channels available, and they can be grouped into banks. There are four call channel memories (two for each of the radio’s operating bands), and a HOME channel can be programmed and selected from the mic’s button array.
I was able to program and memorize several scans, such as the lower and upper 2-meter repeater subbands, the aircraft band, and other public safety and land mobile frequencies in the 118 – 140 MHz and 144 – 174 MHz range. I was able to program links between two programmed scans to yield a contiguous scan of both.
All scanning parameters can be set from the Main Menu. I was able to scan my memory channels in total, or by the specified memory channel bank (A or B) and even link the banks for a bank scan.
The priority watch function works well; I was able to program it to check 146.52 MHz, the national simplex calling frequency, every 5 seconds. The function can be set to change the operating frequency to the priority watch frequency whenever a signal is present, or simply beep and flash a bell icon on the screen.
DR Mode Operating Experience
The D-STAR system and protocols have evolved over the years, rendering operating more user-friendly while maintaining its sophistication. The current DR system (see Figure 1) is fairly easy to understand and use. The more operators learn and use the system, the more useful it will be in terms of communications utility.
There are a number of ways to program the TO or so-called “destination” field and the FROM or “access” field. To find and program an access repeater, I really enjoyed using the NEAR REPEATER
search function. The radio compares its current GPS location with the stored file directory of repeater positions and then displays the closest machines, ready for selecting/placing into the DR access field. I was also able to use the DR scan function to scan near repeaters for activity. The scan stops when a signal is received.
There are also many ways to populate the TO field with the various D-STAR commands to effect reflector linking and unlinking, echoing your transmission back to you, repeater status information, call sign routing, repeater node routing, local CQ, and so on.
I performed this by simply using the dial and ENTER button to select and enter what I wanted in that field. I could then quickly check the four DV/DR call signs/parameters by selecting the CALL SIGN menu item.
There are several functions that Icom highlighted as “unique functions” in the first three pages of the basic D-STAR guide, including the NEAR REPEATER (DV/FM) search discussed above. There is a DV gateway function that allows you to make a direct gateway call via the internet — no local access repeater required. An optional data cable and PC/device are required. I did not try this function.
I found the contact audio recording function to be useful, and I can see an important application for it. I purchased an inexpensive 16 GB micro SDHC card, plugged it into the slot on the main unit, and formatted it from a menu item. I then recorded an entire session of the local ARRL ARES® net, which ran 30 minutes.
Wondering how much data storage I had used and how much I had left, I was able to check the card’s information from another menu item. It revealed that I had used only 30 MB, leaving a whopping 275 hours (10 days) more of recording time available.
As my primary interest in Amateur Radio is public service/disaster response communications, I quickly realized that the radio could record the transmitted and received communications and messages for an entire incident response, which would be helpful in debriefing and the after-action review. I was also able to remove the micro SDHC card, push it into my laptop’s card slot, and play the .wav file. I can see how this feature would be useful for training how nets run in a public service, disaster response, or traffichandling situation.
In addition to the audio recording in the DV or FM mode, I was able to store contact information into a CSV (comma-separated value) file on the card, which serves as a kind of logbook. Contents include receive frequency, operator call signs plus a note, access and gateway repeater call signs, messages included in the received call, repeater status, date/time, GPS location, course/speed, and other information.
While you can’t look at the log on the radio’s screen, you can look at it in any program that will read CSV data, such as Microsoft Excel. I was able to quickly and easily remove the micro SDHC card, slide it into the card adapter, push it into my PC’s card slot, and open the CSV file in Excel 2010. All of my log data displayed perfectly. (Note: you can look at a caller’s position, course, speed, and other data sent on the data frame of the DV signal by browsing through the RX HISTORY pages, selectable on the menu.)
There is an AUTO POSITION reply function that operates like this: When a station calls you in DV/DR mode and you are not in a position to answer, such as when you are driving in heavy traffic, the radio automatically sends back your own call sign and GPS position. You can even send a voice message, such as “I can’t take your call right now.”
There are add-on items for the D-PRS block of reporting information. D-PRS is the D-STAR position reporting system that sends your GPS position and an astoundingly extensive set of menu-selectable related information on the data frame of a D-STAR transmission (the other frame is for the digital voice).
You can select the configuration and information to send that ends up appearing as data on the other station’s radio screen: position, course, speed, SSID (for APRS applications), icons and symbols (such as a truck, which applies to my vehicle), RF power, altitude, antenna height and gain, time stamp, weather symbols, weather data from a personal weather station, and information in the NMEA (National Marine Electronics Association) standard format.
I simply used the basic position format for my transmissions, which includes GPS position, a symbol, SSID, comment, time stamp, altitude, and so on. It’s fun (and can be very useful) to look at the other station’s metadata during a contact (see Figure 2).
There is a DV Fast data mode, which I didn’t try, but is reported in the manual to be 3,480 bits per second (bps), 3.5 times faster than the low-speed data communication mode speed of 950 bps. In the fast mode, both voice and data frames are used, so no voice can be sent along with the data.
I found the band scope to be useful, but setting the tuning step before engaging the band scope is important. With mine, I set the center frequency at 147.000 MHz and the tuning step at 15 kHz to capture all of the repeater channels on the scope.
The scope sweeps across a range of ±25 times the tuning step. (The constant 25 is fixed.) So, in my case, 25 x 15 is 375 kHz, and the sweep range is almost the entire upper 2-meter repeater subband — 146.625 to 147.375 MHz. The standard channel plan and tuning step is 15 kHz for this subband, so all repeaters in that range would be detected.
Larger tuning steps can be selected, with consequent increases to the sweep ranges, but repeaters in the middle of the tuning step will be missed. You can sweep continuously or just once. When a signal is detected, the sweep stops, audio is emitted, and the signal strength is indicated.
RM-MS1I: Remote Control, Extended D-STAR Functions
As mentioned earlier, I purchased the UT-137 Bluetooth chip and installed it to try the RM-MS1I iOS app for remote control and extended D-STAR features. I downloaded the free app from the App Store on my iPhone 5. Pairing and connection between my phone and the radio worked seamlessly. I was able to program the access (FROM) and destination (TO) fields quickly and easily using any one of several menu options, including the receive history and the NEAR REPEATER search function.
There is a good map application, which allowed me to view the locations of D-STAR repeaters anywhere in the world. Pinch the screen to change the scale of the map; press and move your finger on the touchscreen to change the map area of interest. Click on the repeater icon and up pops a box with the station’s data displayed. You can then click on the data to populate the
DR fields efficiently. When a transmission containing GPS coordinates is received, you can browse the received history, tap on the transmission record, view the information, and show the transmitting station’s position on the map screen.
There is also a function to transmit and receive images with GPS coordinates (photos of disaster damage with GPS positions would be valuable to served emergency management agencies during assessment surveys), and another one to exchange text messages (the texting window looks and works like a standard iPhone texting window).
You can also adjust some of the transceiver settings remotely, such as output power, GPS D-PRS parameters, along with just a handful of others. Another file on the app allows for basic app settings for communication with the radio.
The app has a lot of good functionality, and seems to work well. It helped me to program the radio more easily than with the controller head while I was driving. I would recommend it.
The ID-4100A’s GPS receiver seems to be more sensitive than the receiver in my ID-5100A of a few years ago. When the ID-4100A is turned on, it takes only 25 seconds for the GPS receiver to acquire the satellites and report the radio’s position.
As mentioned earlier, the display screen is smaller than the ID-5100A screen, which is both an asset and liability. The characters and icons on the ID-4100A screen are necessarily smaller, of course, and it took a bit more effort to see and read them. On the other hand, the controller head doesn’t take up as much room on my small pickup truck’s dashboard. I also found the ID-4100’s screen a bit more difficult to read because of the low contrast between the background and characters, despite having tried two different placements on my dashboard.
It was a broiling hot summer here in Florida, and the radio was installed in my truck for more than a month in oven-like temperatures in the cab. I discerned no ill effects to the radio’s performance from its extreme operating environment.
The power of this radio is in its extensive, useful functionality, sensitive GPS receiver, and the comprehensive array of related D-PRS features/functions. The radio is feature-rich, with many functions that I really enjoyed using.
Many would be very useful in operating public events, as well as for emergency and disaster incidents in the field, at Emergency Operations Centers (EOCs), and at home.
Rick Palm, K1CE QST Contributing Editor
Lab Notes: Icom ID-4100A
Bob Allison, WB1GCM, ARRL Assistant Laboratory Manager I found no issues during testing of the Icom ID-4100A. All harmonics and spurious emissions were greater than 70 dB below the desired transmitted signal, well in excess of FCC requirements. Impatient operators will be happy to know the receive-to-transmit and transmit-to-receive turnaround times were well under 0.1 second.
I found the receiver to be very sensitive and fairly selective. The FM-N (FM narrow) mode does improve the selectivity by 5 dB, which may help reception of a weak signal in the presence of a strong, adjacent channel signal. No IF bleed-through or images were detected with potential offending signals up to a very strong +10 dBm.
The squelch range is very usable. Set to its minimum, the squelch will open with an FM signal that is barely audible, about -130 dBm, and can be maximized to -97 dBm squelch threshold level. This is helpful in locations with RF interference. Noise isn’t always obvious on FM, but it can open the squelch at times, a kind of “false trip.” Some VHF/UHF transceivers have such a narrow squelch range that strong noise cannot be squelched out. This is not so with the ID-4100A.
Audio output exceeded the manufacturer’s specified 2 W at 10% THD (total harmonic distortion). At a comfortable listening level, 1 VRMS of audio level, the THD was a respectable 1.2%. Low distortion at a normal listening audio level is important to reduce listening fatigue.
Reprinted with permission from December 2017 QST ARRL,
the national association for Amateur Radio® www.arrl.org