fm
1.05 fc0.95 fc
fm
(fc - 4.0 B) 0.95 fcfm
1.05 fcfc = center frequency of bandwidth (Hz)
B = bandwidth (Hz)
10 GENERAL REQUIREMENTS.
10.1 General. By convention, frequency band allocation for the MF band is from 0.3 megahertz (MHz) to 3 MHz, and the HF band is from 3 MHz to 30 MHz. However, equipment designed for HF band use has historically been designed with frequency coverage extending down into the MF band. For new HF equipment, HF band standard parameters shall apply to any portion of the MF band included as extended coverage.
Equipment parameters will be categorized using functional use groups for radio assemblages/sets. Historically, these groups have been fixed (long-haul) installations and tactical sets. The tactical sets are subgrouped further into vehicle transportable and man-pack versions. Although these distinctions still exist in principle, the previously rather sharp demarcation lines have become somewhat blurred. The mobility of HF radio users dictates that a significant amount of long-haul requirements will be met with transportable systems; in some cases, such systems are implemented with design components shared with man-pack radios. When such "tactical" equipment is used to meet a long-haul requirement, the equipment shall meet long-haul minimum performance standards. Accordingly, within this standard, tactical use groups can contain dual value parameters. One parameter reflects usage wherein the frequency determining elements are temperature controlled. The other usage category is deployment related, wherein the frequency determining elements are not temperature controlled (the usual condition for man-pack equipment in tactical operations).
10.2 Equipment operation modes.
10.2.1 Baseline mode. Frequency control of all new HF equipment shall be capable of being stabilized by an external standard. Should multiple frequency (channel) storage be incorporated, it shall be of the programmable memory type and be capable of storing/initializing the operational mode associated with each particular channel. See par. 4.2 and pars. 10.2.1.1 and 10.2.1.2 below.
10.2.1.1 Single-channel. All new single-channel HF equipment shall provide, as a minimum, the capability for the following one-at-a-time selectable operational modes:
10.2.1.2 Multichannel. All new multichannel HF equipment shall provide, as a minimum, the capability for single-channel operation as set forth in par. 10.2.1.1 above, and the following one-at-a-time selectable operational modes:
10.2.2 Automatic Link Establishment (ALE) Mode. Should an ALE capability be included, it shall be of the channel-scanning type and shall provide for contact initiation by either or both manual and automated control. See par. 10.5 for the list of features required to support this operational mode.
10.2.3 Antijam (AJ) mode. If AJ is to be implemented, the AJ capabilities and features for HF radios shall be in accordance with MIL-STD-188-148.
10.3 Interface parameters.
10.3.1 Electrical characteristics of digital interfaces. As a minimum, any incorporated interfaces for serial binary data shall be in accordance with the provisions of MIL-STD-188-114. Such interfaces shall also include provisions for request-to-send and clear-to-send signaling. The capability to accept additional standard interfaces is not precluded.
10.3.2 Electrical characteristics of analog interfaces. See secs. 20.3.6 and 20.4.5.
10.3.3 Modulation and data signaling rates. The modulation rate [expressed in baud (Bd)] or the data signaling rate [expressed in bits per second (bps)] at interface points A and A' on Fig. 33 shall include those contained in the HF modem portion of MIL-STD-188-110.
10.4 North Atlantic Treaty Organization (NATO) and Quadripartite interoperability requirements.
10.4.1 Single-channel communications systems. For interoperation with NATO member nations, land, air, and maritime, single-channel HF radio equipment shall comply with the applicable requirements of the current edition of STANAG 4203.
10.4.2 Maritime air communications systems. For interoperation with NATO member nations, HF maritime air communications systems shall comply with the applicable requirements of the current edition of STANAG 5035.
10.4.3 High performance HF data modems. For interoperation with NATO member nations, land, air, and maritime, single-channel HF radio equipment shall comply with the applicable requirements of the current edition of STANAG 4285.
10.4.4 Quadripartite Standardization Agreements (QSTAGs). For interoperation among American, British, Canadian, and Australian (ABCA) Armies, HF combat net radio equipment shall comply with the applicable requirements of the current edition of QSTAG 733.
10.5 Adaptive communications. Adaptive HF describes any HF communications system that has the ability to sense its communications environment and, if required, to automatically adjust operations to improve communications performance. Should the user elect to incorporate adaptive features, they shall be in accordance with the requirements for those features stated in this document.
The essential adaptive features are
20 DETAILED REQUIREMENTS.
20.1 General.
20.1.1 Introduction. This section provides detailed performance standards for MF and HF radio equipment. These performance standards shall apply over the appropriate frequency range from 2.0 MHz to 29.9999 MHz (DO: 1.5 MHz to 30.0 MHz).
20.1.2 Signal and noise relationships. The signal and noise relationships are expressed as signal-plus-noise-plus-distortion to noise-plus-distortion ratio (SINAD), unless otherwise identified. Unless otherwise specified, when the ratio is stated, the noise bandwidth is 3 kHz.
Figure 33. Radio subsystem interface points
20.2 Common equipment characteristics. These characteristics shall apply to each transmitter and to each receiver unless otherwise specified.
20.2.1 Displayed frequency. The displayed frequency shall be that of the carrier, whether suppressed or not.
20.2.2 Frequency coverage. The radio equipment shall be capable of operation over the frequency range of 2.0 MHz to 29.9999 MHz in a maximum of 100-Hz frequency increments (DO: 10 Hz) for single-channel equipment and 10-Hz frequency increments (DO: 1 Hz) for multichannel equipment.
20.2.3 Frequency accuracy. The accuracy of the radio carrier frequency including tolerance and long-term stability, but not any variation due to doppler shift, shall be within ± 30 Hz for man-pack equipment and within ± 10 Hz for all others, measured during a period of not less than 30 days.
20.2.4 Phase stability. The phase stability shall be such that the probability that the phase difference will exceed 5 degrees over any two successive 10-millisecond (ms) periods (13.33-ms periods may also be used) shall be less than 1 percent. Measurements shall be performed over a sufficient number of adjacent periods to establish the specified probability with a confidence of at least 95 percent.
20.2.5 Phase noise. The synthesizer and mixer phase noise spectrum at the transmitter output shall not exceed those limits as depicted on figs. 34 and 35 under continuous carrier single-tone output conditions. Fig. 34 depicts the limits of phase noise for transportable long-haul radio transmitters and Fig. 35 depicts the limits for tactical radio transmitters. See par. 10.1 for applicable statements on dual parameters.
20.2.6 Bandwidths. The bandwidths for high frequency band emissions shall be as shown in Table XXV and figs. 36 and 37. Other high frequency band emissions which may be required to satisfy specific user requirements can be found in the NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management.
| Emissions Type | Maximum Allowable Bandwidth (kHz) |
| Interrupted continuous wave (ICW) | 0.5 |
| Frequency shift keying (FSK) (85-Hz shift) | 0.3 |
| Frequency shift keying (FSK) (850-Hz shift) | 1.1 |
| Single sideband modulation (SSB) single-channel | 2.8 |
| Independent sideband modulation (ISB) | |
| Two channels | 6.1 |
| Four channels | 12.4 |
Figure 34. Phase noise limit mask for fixed site and environmentally controlled transportable long-haul radio transmitters
Figure 35. Phase noise limit mask for non-environmentally controlled tactical radio transmitters
Figure 36. Overall channel response for single-channel or dual-channel equipment
Figure 37. Overall channel characteristics (four-channel equipment)
20.2.7 Overall channel responses.
20.2.7.1 Single-channel or dual-channel operation. The amplitude vs. frequency response between (fo + 300 Hz) and (fo + 3050 Hz) shall be within 2 dB (total) where fo is the carrier frequency. The attenuation shall be at least 20 dB from fo to (fo - 415 Hz), at least 40 dB from (fo - 415 Hz) to (fo - 1000 Hz), and at least 60 dB below (fo - 1000 Hz). Attenuation shall be at least 30 dB from (fo + 4000 Hz) to (fo + 5000 Hz) and at least 60 dB above (fo + 5000 Hz). See Fig. 36. Group delay time shall not vary by more than 0.5 ms over the passband of 300 Hz to 3050 Hz. Measurements shall be performed end-to-end (transmitter audio input to receiver audio output) with the radio equipment configured in a back-to-back test setup.
NOTE: Although the response values given are for single-channel USB operation, an identical shape, but inverted, channel response is required for LSB or the inverted channel of a dual-channel independent sideband operation.
20.2.7.2 Four-channel operation. When four-channel independent sideband operation is employed, the four individual 3-kHz channels shall be configured as shown on Fig. 37, which also shows amplitude response for these four channels. Channels A2 and B2 shall be inverted and displaced with respect to channels A1 and B1 as shown in the figure. This can be accomplished by using subcarrier frequencies of 6290 Hz above and below the center carrier frequency or by other suitable techniques which produce the required channel displacements and inversions. The suppression of any subcarriers used shall be at least 40 dB (DO: 50 dB) below the level of a single tone in the A2 or B2 channel modulating the transmitter to 25 percent of peak envelope power (PEP). Refer to Fig. 37. The radio frequency (rf) amplitude versus frequency response for each individual ISB channel shall be within 2 dB (DO: 1 dB) between 250 Hz and 3100 Hz, referenced to each channel's carrier (either actual or virtual). Referenced from each channel's carrier, the channel attenuation shall be at least 40 dB at 50 Hz and 3250 Hz; and at least 60 dB at -250 Hz and 3550 Hz. Group delay distortion shall not exceed 1500 microseconds over the ranges 370 Hz to 750 Hz and 3000 Hz to 3100 Hz. The distortion shall not exceed 500 microseconds over the range 750 Hz to 3000 Hz. Group delay distortion shall not exceed 150 microseconds for any 100-Hz frequency increment between 750 Hz and 3000 Hz. Measurements shall be performed end-to-end (transmitter audio input to receiver audio output) with the radio equipment configured in a back-to-back test setup.
NOTE:
1. For voice operations each independent sideband channel audio input requires a low-pass filter with at least 40-dB attenuation at 2740 Hz.
2. When using multichannel voice frequency carrier telegraph (VFCT) modulation, as specified in table 5.2-1 of MIL-STD-188-100, do not use channel 16 (frequencies of 2932.5 Hz, 2975 Hz, and 3017.5 Hz).
20.2.8 Absolute delay. The absolute delay shall not exceed 10 ms (DO: 5 ms) over the frequency range of 300 Hz to 3050 Hz. The delay shall not vary by more ± 0.5 ms from the measured initial value. Measurements shall be performed end-to-end and back-to-back as in par. 20.2.7.1.
20.2.9 Lincompex. Should a voice compression and expansion capability be included, it shall meet CCIR 455-1 Lincompex requirements. In addition, such a device shall incorporate calibration techniques that automatically remove radio link frequency error for the receiver expander function with the start of reception of each Lincompex transmission. The calibration sequence is shown on Fig. 38.
20.3 Transmitter characteristics.
20.3.1 Noise and distortion.
20.3.1.1 In-band noise. Broadband noise in a 1-Hz band within the selected sideband shall be at least 85 dBc below the level of the HF transmitter's rated PEP.
20.3.1.2 Intermodulation distortion (IMD). The IMD products of HF transmitters produced by any two equal-level single-frequency audio test signals between 300 Hz and 3050 Hz, shall be at least 30 dB below each reference tone when the transmitter is operating at rated PEP. The frequencies of the two audio test signals shall not be harmonically or subharmonically related and shall have a minimum separation of 300 Hz.
20.3.2 Spectral purity.
20.3.2.1 Broadband emissions. When the transmitter is driven with a single tone to rated PEP, the power spectral density of the transmitter broadband emission shall not exceed the level established in Table XXVI and as shown on fig. 39. Discrete spurs shall be excluded from the measurement, and the measurement bandwidth shall be 1 Hz.
Figure 38. Digital Lincompex calibration sequence
| Frequency (Hz) | Attenuation Below In-Band Power Density (dB) |
| fm = fc ± (0.5 B + 500) | 40 (DO: 43) |
| fm = fc ± 1.0 B | 45 (DO: 48) |
| fm = fc ± 2.5 B | 60 (DO: 80) |
| (fc + 4.0 B) fm
1.05 fc 0.95 fc fm
(fc - 4.0 B) |
70 (DO: 80) |
| fm 0.95 fc fm 1.05 fc |
90 (DO: 120) |
| where: fm = frequency of measurement (Hz) fc = center frequency of bandwidth (Hz) B = bandwidth (Hz) |
|
Figure 39. Out-of-band power spectral density for HF transmitters
20.3.2.2 Discrete frequency spurious emissions. For HF transmitters, when driven with a single tone to produce an rf output of 25 percent rated PEP, all discrete frequency spurious emissions shall be suppressed as follows:
20.3.3 Carrier suppression. The suppressed carrier shall be at least 50 dBc (DO: 60 dBc) below the output level of a single tone modulating the transmitter to rated PEP.
20.3.4 Automatic level control (ALC). Starting at ALC threshold, an increase of 20 dB in audio input shall result in an increase of less than 1 dB in average rf power output.
20.3.5 Attack and release time delays.
20.3.5.1 Attack-time delay. The time interval, from keying-on a transmitter until the transmitted rf signal amplitude has increased to 90 percent of its steady-state value, shall not exceed 25 ms (DO: 10 ms). This delay excludes any necessary time for automatic antenna tuning.
20.3.5.2 Release-time delay. The time interval, from keying-off a transmitter until the transmitted rf signal amplitude has decreased to 10 percent of its key-on steady-state value, shall be 10 ms or less.
20.3.6 Signal input interface characteristics.
20.3.6.1 Input signal power. Input signal power for microphone or handset input is not standardized. Where provided, the line input signal power range shall be such that the transmitter rated PEP is obtained without manual adjustment of gain controls. For any two-tone signal input, the amplitude can vary from -23 dBm (dB referred to one milliwatt) to 0 dBm per tone; and, for single-tone input, the amplitude can vary from -17 dBm to +6 dBm.
20.3.6.2 Input audio signal interface.
20.3.6.2.1 Unbalanced interface. An unbalanced interface shall be provided with an audio input impedance of a nominal 150 ohms, unbalanced with respect to ground, with a minimum return loss of 20 dB against a 150-ohm resistance over the frequency range of 300 Hz to 3050 Hz.
20.3.6.2.2 Balanced interface. When a balanced interface is provided, the audio input impedance shall be a nominal 600 ohms, balanced with respect to ground, with a minimum return loss of 26 dB against a 600-ohm resistance over the frequency range of 300 Hz to 3050 Hz. The electrical symmetry shall be sufficient to suppress longitudinal currents at least 40 dB below the reference signal level.
20.3.7 Transmitter output load impedance. The nominal rf output load impedance at interface point B, on Fig. 33, shall be 50 ohms, unbalanced with respect to ground. Transmitters with power output ratings equal to or less than 600 watts shall provide (a) full-rated output power for voltage standing wave ratio (VSWR)s of 2:1 or less, and (b) power output derated by a factor not greater than 1.5/VSWR for VSWRs above 2:1. See Fig. 41. Transmitters with power output ratings of greater than 600 watts shall derate their output power by a factor of not greater than 1/VSWR. See Fig. 41. On transmitters using separate exciters, the interface between the exciter and amplifier shall be a nominal 50 ohms, unbalanced, with a maximum VSWR of 1.5:1 over the operating frequency range.
NOTE: The full-rated output power of a transmitter, over the operating frequency range, is defined to be (a) the rated PEP when the transmitter is driven by a two-tone signal consisting of equal amplitude tones, and (b) the rated average power when driven by a single tone. The output rating shall be determined with the transmitter operating into a nominal 50-ohm load.
20.4 Receiver characteristics.
20.4.1 Receiver rf characteristics. NOTE: All receiver input amplitudes are in terms of available power in dBm from a 50-ohm source impedance signal generator.
Figure 40. Discrete spurious emissions limit for HF transmitters
Figure 41. Output power vs. VSWR for transmitters with broadband output impedance networks
20.4.1.1 Image rejection. The rejection of image signals shall be at least 80 dB for HF receivers (DO: 100 dB).
20.4.1.2 Intermediate frequency (IF) rejection. Signals at the intermediate frequency (frequencies) shall be rejected by at least 80 dB (DO: 100 dB).
20.4.1.3 Adjacent channel rejection. The receiver shall reject any signal in the undesired sideband and adjacent channel in accordance with Fig. 36.
20.4.1.4 Other single-frequency external spurious responses. Receiver rejection of spurious frequencies, other than IF and image, shall be at least 65 dB for frequencies from +2.5 percent to +30 percent, and from -2.5 percent to -30 percent, of the center frequency, and at least 80 dB for frequencies beyond ±30 percent of the center frequency.
20.4.1.5 Receiver protection. The receiver, with primary power on or off, shall be capable of survival without damage with continuously applied signals of up to +43 dBm (DO: 53 dBm) available power delivered from a 50-ohm source.
20.4.1.6 Desensitization dynamic range. The following requirement shall apply to the receiver in an SSB mode of operation with an IF passband setting providing at least 2750 Hz (300 Hz to 3050 Hz) of bandwidth at the 2-dB points. With the receiver tuning centered on a sinusoidal input test signal and with the test signal level adjusted to produce an output SINAD of 10 dB, a single interfering sinusoidal signal, offset from the test signal by an amount equal to ±5 percent of the carrier frequency is injected into the receiver input. The output SINAD shall not be degraded by more than 1 dB as follows:
a. for radios whose frequency determining elements are temperature controlled, the interfering signal is equal to or less than 100 dB above the test signal level
b. for radios whose frequency determining elements are not temperature controlled, the interfering signal is equal to or less than 90 dB above the test signal level.
20.4.1.7 Receiver sensitivity. The sensitivity of the receiver over the operating frequency range, in the sideband mode of operation (3-kHz bandwidth), shall be such that a -111 dBm (DO: -121 dBm) unmodulated signal at the antenna terminal, adjusted for a 1000-Hz audio output, produces an audio output with a SINAD of at least 10 dB over the operating frequency range.
20.4.1.8 Receiver out-of-band intermodulation distortion (IMD). Second and higher order responses shall require a two-tone signal amplitude, with each tone at least 80 dB greater than that required for a single-tone input, to produce an output SINAD of 10 dB. This requirement is applicable for equal amplitude input signals with the closest signal spaced 30 kHz or more from the operating frequency.
20.4.1.9 Third-order intercept point. Using test signals within the first IF passband, the worst case third-order intercept point shall not be less than +10 dBm.
20.4.2 Receiver distortion and internally generated spurious outputs.
20.4.2.1 Overall IMD (in-channel). The total of IMD products, with two equal-amplitude, in-channel tones spaced 110 Hz apart, present at the receiver rf input, shall meet the following requirements. For frequency division multiplex (FDM) service, the receiver shall meet the requirements for any tone spacing equal to or greater than the minimum between adjacent tones in any FDM library. The requirements shall be met for any rf input amplitude of 0 dBm PEP (-6 dBm/tone) and for any audio output of +12 dBm PEP (+6 dBm/tone) or less. All IMD products shall be at least 35 dB (DO: 45 dB) below the output level of either of the two tones.
20.4.2.2 Adjacent channel IMD. For multiple channel equipment, the overall adjacent channel IMD, in each 3-kHz channel being measured, shall not be greater than -35 dBm at the 3-kHz channel output with all other channels equally loaded with 0 dBm unweighted white noise.
20.4.2.3 Audio frequency total harmonic distortion. The total harmonic distortion produced by any single frequency rf test signal, which produces a frequency within the frequency bandwidth of 300 Hz to 3050 Hz, shall be at least 25 dB (DO: 35 dB) below the reference tone level with the receiver at rated output level. The rf test signal shall be at least 35 dB above the receiver noise threshold.
20.4.2.4 Internally generated spurious outputs. Spurious signals at the output of the receiver, produced in the absence of rf signals by mixing of signals that are generated internally in the receiver, shall not exceed -112 dBm (DO: -122 dBm).
20.4.3 Automatic gain control (AGC) characteristic. The steady-state output level of the receiver (for a single tone) shall not vary by more than 3 dB over an rf input range from -103 dBm to +13 dBm.
20.4.3.1 AGC attack-time delay (nondata modes). The receiver AGC attack-time delay shall not exceed 30 ms.
20.4.3.2 AGC release time (nondata modes). The receiver AGC release time shall be between 800 and 1200 ms for SSB voice and intermittent continuous wave (ICW) operation. This shall be the time period from rf signal deterioration until audio output is within 3 dB of the steady-state output. The final steady-state audio output is simply receiver noise being amplified in the absence of any rf input signal.
20.4.3.3 AGC requirements for data service. In data service, the receiver AGC attack-time shall not exceed 10 ms. The AGC release-time shall not exceed 25 ms.
20.4.4 Receiver linearity. The following shall apply with the receiver operating at maximum sensitivity and with a reference input signal that produces a SINAD of 10 dB at the receiver output. The output SINAD shall increase monotonically and linearly within ±10 percent for a linear increase in input signal level until the output SINAD is equal to at least 40 dB (DO: 60 dB). This requirement shall apply over the operating frequency range of the receiver.
20.4.5 Interface characteristics.
20.4.5.1 Input impedance. The receiver rf input impedance shall be nominally 50 ohms, unbalanced with respect to ground. The input VSWR, with respect to 50 ohms, shall not exceed 2.5:1 over the operating frequency range.
20.4.5.2 Output impedance and power. The receiver output impedance shall be a nominal 600 ohms, balanced with respect to ground, and designed to drive a minimum of six paralleled 600-ohm loads without decrease in output power greater than 2.5 dB relative to a single matched-load output. Electrical symmetry shall be sufficient to suppress longitudinal currents at least 40 dB below reference signal level. The receiver output signal power, for operation with a headset or handset, shall be adjustable at least over the range from -30 dBm to 0 dBm. For operation with a speaker, the output level shall be adjustable at least over the range from 0 dBm to +30 dBm. As a design objective, an additional interface which can accommodate speakers ranging from 4 to 16 ohms impedance should be provided.
20.5 Automatic link establishment (ALE). If ALE is to be implemented, it shall be in accordance with this standard. The ALE requirements include selective calling and handshake, link quality analysis and channel selection, scanning, and sounding. These requirements are organized in the standard as follows:
a. requirements for ALE implementation are given in secs. 1 through 5.
b. details on ALE waveform, signal structure protocols, and orderwire messages are contained in secs. 5.1 through 5.5
30 NOTES. (This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)
30.1 Intended use. This standard contains requirements to ensure interoperability of new long-haul and tactical radio equipment in the MF and HF bands.
30.2 Issue of DODISS. When this standard is used by the Department of Defense in acquisition, the applicable issue of the DODISS must be cited in the solicitation (see pars. 2.2.1 and 2.3).
30.3 Subject term (key word) listing:
30.4 International standardization agreements. Certain provisions of this standard in secs. 10.2, 10.4, 20.2, 20.3, and 20.4, are the subject of international standardization agreements, STANAGs 4203 and 5035 and QSTAG 733. When change notice, revision, or cancellation of this standard is proposed that will modify the international agreement concerned, the preparing activity will take appropriate action through international standardization channels, including departmental standardization offices, to change the agreement or make other appropriate accommodations.