User manual ICOM IC-280

[. . . ] The IP2 figure is a typical value. +112. 4dBm OUTPUT [dB] 250 200 START 0Hz *RBW 10Hz VBW10Hz SWP 40s STOP 2. 000 kHz ATT 10dB 150 S9 +60dB equivalent signal input 100 Band pass filter 50 OUTPUT ­140 ­120 ­100 (0. 224µV) ­80 ­60 ­40 ­20 0 (224mV) 20 40 60 80 100 120 INPUT [dBm] Double conversion superheterodyne system While multiple IF stages can become a source of distortion products and spurious responses, the IC-280 utilizes Icom's original image-rejection mixers in a simple double conversion superheterodyne. This reduces distortion and produces a much cleaner audio signal compared to triple or quadruple superheterodyne receivers. While some may lead you to believe that coils and capacitors are all created equal, at Icom we know design excellence. Rather than using switching diodes that can introduce distortion, the IC-280 design utilizes high-grade mechanical relays along with large capacitors and toroidal coils; resistant to magnetic saturation, providing superior linearity, and greatly reducing distortion. 3 DIGI-SEL (Digital pre-selector) The DIGI-SEL (digital pre-selector) is a very narrow, user adjustable, pass band filter designed to automatically track the operating frequency, attenuating interference from out-of-band signals. While the pre-selector's pass-band remains centered on the operating frequency, on the fly adjustments are possible via front panel controls. [. . . ] As a result, Two 32-bit floating point units Two independent DSP units are built-in: One for the transmitter and receiver; and one for the spectrum scope. The IC-280 ex- 4 Receiver Performance Two AGC Loops The IC-280 has two AGC loops. The AGC voltages detected in front of and behind the digital IF filter in the DSP unit. The first AGC loop prevents the saturation of the 1st IF amplifier from strong signals outside the pass-band filter, and improves the dynamic range in the presence of strong adjacent signals. The other AGC loop detects the AGC voltage at the digital IF filter output which has only passed the intended signal and draws the full potential from the digital IF filter. 2nd mixer Image rejection mixer IF AMP IF AMP IF AMP The well-selected components provide premium performance Mechanical relays Mechanical relays using gold contacts have excellent deterioration resistance and superior conductivity. DSP Circuit Hi-spec 1st IF filter 90° Phase shifter IF AMP A/D AMP BPF AMP AGC DET 90° Phase shifter AGC Loop line AGC DET The IC-280 uses custom made Hi-spec 1st IF filters (roofing filters), selected especially for excellent IMD characteristics. D/A Large coils To reduce secondary distortion, large coils and capacitors are used in the high-amplitude filter switching circuits. The use of non-linear semiconductors is minimized. The IC-280 accommodates both the "on-the-fly" operator as well as the most avid "tweaker" operator by providing tunable AGC preset and manual AGC level controls. The AGC time constants can be set in the 3 presets (slow, medium and fast), adjustable from 0. 1­6 sec. Then the addition of the AGC VR control enables the user to "tweak" or fine tune the AGC reaction time. DSP The transmitter and receiver use a 32-bit floating point DSP, offering the high performance of 1800 MFLOPS processing. Also, the spectrum scope DSP achieves 1200 MFLOPS of peak performance. High stability OCXO unit Frequency control of the IC-280 is maintained by the high stability Oven Controlled Crystal Oscillator. The OCXO achieves frequency stability of ±0. 05ppm across the specified temperature range, meaning that the frequency will deviate only 5Hz out of every 100 MHz!This specification is equivalent to that of specialized measuring equipment such as signal generators or spectrum analyzers. It also improves the scope response time and signal resolution, so that it is possible to accurately tune to the intended signal as you see it on the spectrum scope screen. The spectrum scope range can be set independently from the receiving frequency. You can monitor band conditions between the selected sweep edges (Fixed mode), as well as sweep a selected band width centered on the receiving frequency (Center mode). Digital IF filter The DSP-based digital IF filter of the IC-280 rejects signals out of the pass band, and keeps the desired signal free of any distortion or degradation of quality. Depending on the operating situation, for example handling a pile-up or receiving a very weak signal, you can flexibly change sharp and soft filter shapes or reduce or shift the filter width, even while receiving a signal. In addition, the scope has useful functions including scope attenuator (10dB/20dB/30dB), 2 types of marker (Transmit, Receiver) and Max hold function. By using the excellent performance of the 32-bit floating point DSP, this separation is made immediately without a delay and extracts signals from noise components. The noise reduction suppression level is variable in 16 steps to adjust the balance between the S/N ratio and clarity. S/P DIF optical interface (Input/Output) SSB data mode When you narrow the IF filter passband to 500Hz or less in SSB mode or SSB-data mode operation, the IC-280 automatically selects special band pass filters (BPF). The BPF has a very sharp edge like a CW filter for better rejection of interfering signals. Along with the BPF setting, the IC-280 has a 1/4-tuning step function for easier tuning operation. Digital voice recorder The digital voice recorder (DVR) is a convenient function for contests, DX-peditions, portable operation and even regular operation. Easy-to-access independent "Record (REC)" and "Play" buttons are on the front panel. Firmware upgrade for maintaining the best performance Digital voice memory (Record and Play buttons) RX audio HPF/LPF setting The IC-280 has a separate RX HPF/LPF setting for each mode. The high-pass filter and low-pass filter are adjustable for each mode. Icom will always provide the latest firmware for keeping the radio up to date. Just download the latest firmware from the Icom web site whenever a new version has been uploaded, and update your IC-280 via the USB memory. [. . . ] In addition, the transmit bandwidth is selectable from 100, 200, 300, 500Hz at the lowpass edge, and 2500, 2700, 2800, 2900Hz at the high-pass edge, respectively. Three types of high and low combinations can be stored in the memory as favorite settings. With this flexibility of DSP-based waveform shaping, transmit audio quality is adjustable to your preference. 9 Other Features Other outstanding features [Antenna line] · BNC type RX IN/OUT connectors for receiver antenna or external attenuator [Operation] · Set mode function for flexible and speedy setting · Memory pad stores up to 10 (or 5) operating frequencies · Quick split function enables split operation with a single action · SSB/CW synchronous tuning · Single knob control from squelch volume to RF gain · RIT and Tx variable up to ±9. 999kHz · Quick RIT/TX clear function · UTC/Local Clock and timer function · 1Hz pitch tuning and 1Hz indication · 101 memory channels with 10-character comment · Built-in voice synthesizer announces operating frequency, mode and receiving signal strength · Programmed scan, memory scan, select memory scan, VSC scan and F scan · Auto tuning step function · Band edge beep · Main dial tension control and dial lock · CI-V interface capability and RS-232C connector for PC connection · BNC type Transverter connector · Triple band stacking register · FFT scope wave averaging function · Screen saver function [Receiver] · General coverage receiver covers from 30kHz to 60MHz (* Some frequency bands are not guaranteed, depending on version) · 4-step attenuator (6/12/18dB and OFF) · Twin peak audio filter for RTTY operation [Transmitter] · Low distortion RF speech compressor · Tx monitor · 50 CTCSS tone encoder and decoder · All mode power control · VOX capability (Voice operated transmission) [CW] · Multi-function electronic keyer with adjustable keying speed, dot-dash ratio and paddle polarity and bug key function · DSP controlled CW keying waveform shaping · Frequency lock function for split operation · The normal (default) CW carrier point is selectable from USB and LSB · APF (audio peak filter) function with soft/sharp filter shape · Double key jack system · Full break-in function · CW pitch control from 300 to 900Hz · CW/AM auto tuning function Rear Panel View q w e r t y u i o !0 !1 !2 !3 !4 !5 !6 !7 !8 !9 @0 @1 @2 Antenna Connectors Ground Terminal Breaker Switch External Display Connector (D-SUB 15-pin, VGA) Ethernet Connector CI-V Remote Control Jack RS-232C Connector Main Switch AC Power Cord Receptacle Receive Antenna Connector Transverter Jack External DC Output Jack S-meter Output Jack External Memory Keypad Jack External Speaker Jack ACC Sockets A/B Tx/Rx Control Jack (Relay) ALC Input Jack ALC Level Pot Key Jack S/P DIF In/Out Jacks Reference Frequency In/Out Jack q w e r t y u i o !0 !1 !2 !3 !4 !5 !6 !7 !8 !9 @0 @1 @22 10 SPECIFICATIONS GENERAL · Frequency coverage*1 : U. S. A. Version Rx 0. 030­ 60. 000MHz*2 Tx 1. 800­ 1. 999MHz 3. 500­ 3. 999MHz 5. 3305, 5. 3465, 5. 3665, 5. 3715, 5. 4035MHz*3 7. 000­ 7. 300MHz 10. 100­10. 150MHz 14. 000­ 14. 350MHz 18. 068­18. 168MHz 21. 000­ 21. 450MHz 24. 890­24. 990MHz 28. 000­ 29. 700MHz 50. 000­54. 000MHz Europe, UK Version Rx 0. 030­ 60. 000MHz*2 Tx 1. 810­ 1. 999MHz 3. 500­ 3. 800MHz 7. 000­ 7. 100MHz (Europe version) 7. 000­ 7. 200MHz (UK version) 10. 100­ 10. 150MHz 14. 000­14. 350MHz 18. 068­ 18. 168MHz 21. 000­21. 450MHz 24. 890­ 24. 990MHz 28. 000­29. 700MHz 50. 000­ 52. 000MHz *1 Frequency ranges vary depending on version. [. . . ]