Incorporating all the necessary features for station setup, regulatory compliance, and remote monitoring, Inovonics' 531N is the ultimate choice for essential FM signal monitoring. Dependable, direct input and off-air reception lets you keep a sharp eye on your total RF signal performance whether you’re right at the transmitter site or half way around the world.
The high-resolution LED bargraph displays are easy to read, and a "floating dot" program peak marker eliminates any ambiguity in the total-mod measurement. Off-air readings are qualified by Inovonics' exclusive multipath indicator, which also aids in antenna alignment during initial station build-outs. In addition, readouts of signal strength and synchronous AM noise qualify the incoming signal and validate measurements.
Synchronous AM Noise Monitoring – an exclusive with Inovonics.
Rear-panel alarms constantly check for Audio Loss, RF Loss, Multipath and Overmodulation, while advanced notifications alert personnel with e-mail or SMS messaging when any or all of the alarms occur.
- Ted Statnick - Chief Engineer @ WLMP, Milton, PA
- Nathan Owens. Caribbean Radio Lighthouse - Antigua
- Barry Mishkind Checking it Out - A Road Test of the Inovonics 531N for FM
Double-conversion superhet circuit with proprietary ultra-linear, noise-rejecting pulse-counting FM detector
76MHz – 108MHz in 100kHz increments
6 user-programmable pushbutton presets; local or remote selection
10μV (10dBf) for 50dB mono quieting; 250μV (60dBf) required for valid Total Modulation reading
±0.25dB, 20Hz - 50kHz; –1.5dB or less at 100kHz (see Figure 1); –35dB (typ) at 200kHz (see Figure 2)
BNC composite/MPX demod output; 3Vp-p at 100%-modulation.
Independent front-panel LED bargraph metering of the relative strength of the incoming carrier
Independent front-panel LED bargraph metering of the relative degree of multipath reception-distortion effects
Front-panel metering may be switched to show the relative level of the incidental, synchronous AM noise component of the FM carrier. AM noise is routed to a separate BNC output and also monitored by headphones when selected.
Adjustable BNC composite/MPX input to stereo decoder and subcarrier measurement circuitry. Accepts 100%- modulation levels (typical 3V p-p) equating to ±75kHz carrier deviation.
58-segment LED bargraph display has quasi-peak response with floating peak hold. Switchable between positive deviation, negative deviation and highest of either
1% accuracy between 80% and 100% carrier modulation; 2% resolution between 46% and 80% (100% = ±75kHz carrier deviation)
User-selectable at 0.1ms, 0.2ms, 0.5ms and 1.0ms
+0/–1%, 10Hz - 100kHz
Programmable in 1% increments between 95% and 120% of total carrier modulation.
Dual LED bargraph displays show Left and Right or L+R and L–R demodulated program audio. The display is peak responding between +10dB and –30dB, and average responding between –30dB and – 64dB.
±0.5dB, 10Hz - 15kHz
Unmodulated (stereo) carrier noise is better than 65dB below 100% modulation with de-emphasis applied.
<0.075%THD at 400Hz 100% Modulation Mono. No De-Emphasis, unweighted
55dB, 50Hz - 15kHz with an external composite/MPX input. In the off-air mode, receiver selectivity limits separation to >45dB, 50Hz - 15kHz (see Figure 3).
By the M/S or S/M (stereo-difference) method, >60dB, 50Hz - 5kHz, derated to >45dB at 15kHz with external composite/MPX input. In the off-air mode receiver selectivity limits crosstalk to >50dB, 50Hz - 5kHz, derated to >35dB at 15kHz (See Figure 4).
Mode switching is automatic with a front-panel indicator; monaural reception may be forced with a front-panel button or from the remote Web Interface.
May be turned on and off from front panel or Web Interface (indicator provided); internal jumper selects 50μs or 75μs characteristic.
58-segment LED bargraph display measures stereo pilot and subcarrier levels between 2.6% and 14% with 0.2% resolution and accuracy. Injection percentages refer to 100% = ±75kHz carrier deviation.
Peak-responding in all modes
Ground-closure output gives remote indication coincidental with the front-panel Peak Flasher
Front-panel LED and ground-closure (remote) alarm is programmable from the front panel to indicate when either stereo channel remains 10dB or more below 0dB for a period that may be set between 10 seconds and 2 minutes.
Front-panel LED and remote ground-closure alarm is fixed at a level of incoming RF signal below which modulation measurements are not valid.
Front-panel LED and remote ground-closure alarm is fixed at a degree of multipath distortion above which modulation measurements are not valid.
An RJ45 jack accepts TCP/IP Network Connections for remote setup and operation.
DHCP or Static IP address can be set from the front panel.
Supports SNMP remote monitoring and control (MIB file can be downloaded directly from the 531N)
Supports email services with or without SSL.
Supports dyndns.org, no-ip.org, and dnsomatic.com.
105 - 130VAC or 210 - 260VAC, 50/60Hz; 20 watts
3½”H x 19”W x 12”D (2U); 14 lbs. (shipping)
Continuous operation at ambient temperatures between 32ºF/0ºC and 122ºF/50ºC; 0-95% relative humidity, non-condensing, altitudes to 10,000ft/3,048m.