March, 2003 Product Reviews and Short Takes
Contents
1. 1 speaker and the right side audio will appear in the SP 2 speaker On the front side you ll find RJ45 connectors for the microphone and separation cable There is also a 6 pin mini DIN data connector for 1200 or 9600 baud packet Bit error rate tests in the ARRL Laboratory indicated adequate packet performance at 9600 baud See Table 1 Dual Band Versatility As I ve mentioned previously you Bottom Line Dual band operation and wide range receive combine to make the compact IC 2720H an attractive mobile transceiver gt have the option of configuring the dual band capability of the 2720H to suit your interest du jour This rig offers wide receive coverage 118 550 MHz on the left band and 118 174 375 550 and 810 999 MHz cellular blocked on the right band One combo I enjoyed was setting 440 MHz as the main band so that I could monitor my home Echolink simplex station see my article VoIP and Amateur Radio in the February 2003 issue of QST I then set the sub band for my favorite 2 meter repeater so that I could flip flop one or the other as the need arose One push of a button changes the main sub band assignment You can only transmit from the main band This dual band flexibility also means that you can work the FM repeater satellites such as UoSAT OSCAR 14 and AMRAD OSCAR 27 More about this later Memories and Scanning The IC 2720H offers 212 memory channels You can pr2. 70 dB UHF 67 dB Meets FCC requirements for spectral purity S9 signal 146 440 MHz 175 ms 146 440 MHz 60 ms 146 MHz Receiver BER at 12 dB SINAD 5 0x10 BER at 16 dB SINAD lt 1 0x10 BER at 50 dBm lt 1 0x10 5 transmitter BER at 12 dB SINAD 4 4x10 BER at 12 dB SINAD 30 dB 1 0x10 440 MHz Receiver BER at 12 dB SINAD 1 0x10 BER at 16 dB SINAD lt 1 0x10 BER at 50 dBm lt 1 0x10 5 transmitter BER at 12 dB SINAD 9 2x10 BER at 12 dB SINAD 30 dB 2 0x10 Size height width depth main unit 1 6x5 5x7 4 inches weight 2 8 pounds remote head 2x5 5x1 inches weight 5 3 ounces Note Unless otherwise noted all dynamic range measurements are taken at the ARRL Lab standard spacing of 20 kHz Measurement was noise limited at the value indicated Worst case for left and right bands manipulating the multifunction micro phone There are several types of scanning options available plus four scan resume conditions to choose from With the broad receive coverage this makes the 2720H a more than competent scanner I should note that the 2720H can also scan for subaudible CTCSS tones That s handy when you need to figure out which CTCSS frequency a repeater system is using There is also DTCS decoding and encoding for paging applications with the pocket beep function to give you an audible and visual indication of an incoming call More Bells and Whistles The
3. 80 1000 MHz 1 0 uV FM adjacent channel rejection Not specified FM two tone third order IMD dynamic range Not specified FM two tone second order IMD dynamic range Not specified S meter sensitivity Not specified Squelch sensitivity lt 0 13 uV Receiver audio output 2 4 W at 10 THD into 8 Q Spurious and image rejection 60 dB Transmitter Power output H M L 144 MHz 50 15 5 W 430 MHz 35 15 5 W Spurious signal and harmonic suppression 60 dB Transmit receive turn around time PTT release to 50 audio output Not specified Receive transmit turn around time tx delay Not specified Bit error rate BER 9600 baud Not specified Measured in the ARRL Lab Receive and transmit as specified Receive 0 76 A transmit 9 1 A Tested at 13 8 V As specified Receiver Dynamic Testing AM 10 dB S N N 120 MHz 0 59 uV For 12 dB SINAD 144 MHz 0 14 uV 222 MHz 0 2 uV 430 MHz 0 16 uV 902 MHz 0 86 uV 20 kHz channel spacing 146 MHz 68 dB 440 MHz 62 dB 20 kHz channel spacing 146 MHz 61 dB 440 MHz 62 dB 10 MHz channel spacing 146 MHz 78 dB 440 MHz 73 dB 71 dB S9 indication 146 MHz 2 0 uV 440 MHz 2 3 uV At threshold 146 MHz 440 MHz 0 09 uV 2 9 W at 10 THD into 8 Q First IF rejection 146 MHz 123 dB 440 MHz 132 dB Image rejection 146 MHz 99 dB 440 MHz 68 dB Transmitter Dynamic Testing 146 MHz 53 15 3 4 4 W 440 MHz 35 14 6 5 2 W VHF
4. ICOM IC 2720H Dual Band FM Transceiver Reviewed by Steve Ford WBSIMY QST Editor The IC 2720H is the latest entry in a well populated field of dual band FM mobile rigs To stand out among competing transceivers a radio has to offer features designed to entice Amateur Radio buyers The IC 2720H does this by combining an interesting lineup of bells and whistles with ease of operation and enough output power maximum 50 W on 144 MHz 35 W on 440 MHz for just about any application The IC 2720H also sports an interesting physical design Lots of mobile transceivers offer detachable front panels but in the 2720H the front panel is detached permanently although it can be mounted to the main unit with the MB 85 combination bracket sold separately The main unit the guts of the IC 2720H is a compact 5 x 1 5 x 7 5 inch brick outfitted with various connectors The front panel is about the size of a chocolate bar and is connected to the main unit with an 11 foot separation cable You can plug the backlit multifunction microphone a de facto controller unto itself into the front panel or directly into the main unit if you can live without a frequency readout The mobile operating advantage of this arrangement is obvious The IC 2720H can find a home in any conceivable vehicle Using the 2720H as a base unit is more of a challenge but who is to say that you couldn t mount the front panel on a desk with the main unit tu
5. cked out of sight About that Front Panel The 2720 s front panel LCD displays frequencies for two bands You can display 144 and 440 MHz or a different combination such as 144 144 MHz two frequencies within the same amateur band or 144 and 127 MHz working 2 meter FM while listening to the aviation band simultaneously There are separate sets of controls for tuning volume and squelch as well as separate sets of backlit function keys for each band And unlike some dual band transceivers the volume and squelch knobs are not concentric they are completely separate controls If you ve ever cursed the ergonomics of multiband mobile rigs you know what a blessing this is AS BD 5450 6009 oh se ru Reem HOU The front panel buttons have individual labels In my opinion this beats the heck out of a row of nondescript buttons with ever changing labels in an LCD display nearby Main Unit There is one SO 239 antenna jack on the rear panel of the main unit With the built in diplexer only one jack is necessary If you are using separate VHF and UHF antennas however you ll need to add an external diplexer In addition to a dc power pigtail there are two external speaker jacks The jack designated SP 1 outputs the audio from both bands But if you plug another speaker into the adjacent SP 2 jack the left side audio from whichever band is on the left side of the LCD display will appear in the SP
6. ntelligibility with external speakers In my installation I put the 2720H under the driver s side seat and found that the audio from the main unit couldn t quite overcome the ambient road noise From March 2003 QST ARRL Figure 1 Close up view of the IC 2720H s microphone a control panel in itself Users who for some reason really don t need a display may plug the microphone directly into the main unit bypassing the stand alone control panel An external speaker cured the problem in short order The main chassis has a flow through cooling design with a sizeable fan I noticed that the fan was extremely quiet The multifunction microphone is a clever feature but it took me a while to master It was just as easy to reach out and adjust the front panel controls To each his own depending on the constraints of the installation of course Signal reports received while using the IC 2720H were consistently good The transmit audio has plenty of punch and the RF output is more than sufficient for both close in and fringe locations The dual band aspect of the IC 2720H makes it a joy to use for more than just terrestrial conversations While driving to work one morning in December I heard the UoSAT OSCAR 14 satellite downlink on 435 070 MHz I switched the main band to 2 meters and dialed up 145 975 MHz the UO 14 uplink frequency With just 15 W to a dual band mobile antenna I easily worked K8WYT in Iowa al
7. ogram the repeater offsets in each channel as well as 50 subaudible tones 67 254 1 Hz for repeater systems that require them and DTMF transmit memories for autopatch access and other functions You can also split the memory channels into 10 banks designated A J This is convenient when you want to group memories for repeaters in specific cities for example Programming the IC 2720H is straightforward If you can program a handheld s memories you can program the 2720H The user manual offers clear instructions with a strong emphasis on Brennan Price N4QX Assistant Technical Editor n4qx arrl org From March 2003 QST ARRL Table 1 ICOM IC 2720 serial number 01024 Manufacturer s Claimed Specifications Frequency coverage Receive 118 550 810 1000 MHz cell blocked transmit 144 148 430 450 MHz Power requirement Receive 1 58 A max audio transmit 12 A high power Modes of operation FM AM receive only Receiver AM Sensitivity 10 dB S N 118 160 MHz 0 45 uV 220 260 MHz 0 79 uV 260 350 MHz 5 6 uV 350 375 MHz 1 0 uV 375 400 MHz 0 63 uV FM sensitivity 12 dB SINAD left band 118 160 MHz 0 18 uV 160 180 220 260 350 375 MHz 500 550 MHz 0 32 uV 180 220 MHz 3 5 uV 260 350 MHz 3 2 uV 375 430 450 500 MHz 0 22 uV 430 450 MHz 0 18 uV right band 118 160 MHz 0 18 uV 160 174 MHz 0 2 uV 375 430 450 550 MHz 0 22 uV 430 450 MHz 0 18 uV 810 880 MHz 0 45 uV 8
8. ong with several other stations I continued to listen to a full quieting signal from the satellite for nearly 10 minutes That s pretty darn good for a mobile radio Manufacturer ICOM America 2380 116th Ave NE Bellevue WA 98004 tel 425 454 8155 fax 425 454 1509 www icomamerica com Suggested list price 479 99 IC CS 2720 software 45 IC OPC 478 programming cable 45
9. re are more clever goodies in the IC 2720H that bear mentioning You can change the display color from amber to green I preferred the default amber Brightness is variable too The 2720H defaults to the AM mode when you tune into the aviation band but you can also select the AM mode manually for the odd AM signal you may encounter elsewhere The IC 2720H includes the weather alert feature found in other recent ICOM models When you enable this function the From March 2003 QST ARRL radio will scan through the 162 MHz NOAA Weatheradio broadcasts every five seconds If a station transmits a weather alert tone an alert message will appear on the display This feature works well except for the fact that it causes an audio dropout at 5 second intervals on the frequency you are monitoring That s a small price to pay for the ability to stay on top of weather alerts especially if you live in an area where they occur frequently With the cloning function you can swap memories with another IC 2720H or and this was the feature I liked load data into the 2720H s memories from your PC You ll need the optional CS 2720 software and OPC 478 cable to do this Operating Impressions If you don t intend to install the main unit nearby you ll probably have to attach external speakers to adequately hear the IC 2720H You can rely on the speaker ensconced in the main unit but you ll enjoy greater fidelity and i
Download Pdf Manuals
Related Search