This product has been discontinued. Datasheet VME 1508 EN Datasheet VME 1508 DE
VME 1508 – VHF/UHF Measuring Receiver
The VHF/UHF Measuring Receiver VME 1508 is intended for service and maintenance measurements on aeronautical radio-navigation equipment. In particular, when used with VOR installations, it allows the reproduction of low modulation frequencies down to the DC component. The three frequency ranges cover 72 MHz to 100 MHz, 100 MHz to 140 MHz, and 320 MHz to 340 MHz.
A precision calibrated attenuator permits level measurements over a range from below 0 dB(µV) up to 115 dB(µV). As the internal noise level is below –10 dB(µV), voltages down to 0.3 µV can still be measured using the substitution method. Extension of the upper measurement range is possible by means of external plug-in attenuators.
In contrast to interference measuring receivers, from whose design concept this instrument series originated and which are calibrated by means of an internal pulse generator, the VME 1508 is intended for external calibration using commercially available RF signal generators.
| Frequency ranges | 72–100 / 100–140 / 320–340 MHz |
| Frequency indication | 300 mm linear scale, switchable; 17 rev./range; 200 div./rev.; ±0.5 % of reading on directly MHz-calibrated scale; interpolation up to 10* |
| Input voltage range | 0.5 mV…0.5 V (–6 dB…+114 dB rel. 1 mV) |
| Voltage accuracy | ±1.5 dB (absolute, after calibration with signal generator) |
| AM output | 3 V DC reference; 3 Vpp AF at 50 % AM |
| Sensitivity | NF 7–8 dB (typ.); 0.25 µV; SINAD 10 dB: 1.2 µV @ 50 % AM; can be increased with narrowband post-selector (e.g. FSME 1515) |
| IF bandwidth | –3 dB: 50–60 kHz; –6 dB: 65–85 kHz |
| Image rejection | 75 / 115 MHz: 90–100 dB (typ.); 330 MHz: ~50 dB |
| IF rejection | 75 MHz typ. 100 dB; 115 MHz typ. 90 dB; 330 MHz typ. 90 dB |
| Distortion | 50 % AM; sideband spacing 50 dB; 30 dB IF attenuation; AF output (BNC) typ. 0.6 % |
| Noise & hum | >60 dB below nominal signal (1 kHz, 50 % AM) |
| Large signal behaviour | +50 dB overload; 30–470 MHz; >2 MHz offset; indication remains below 0 dB (0 dB IF attenuation) |
| Spurious signals | Not detectable with terminated input |
| Front panel outputs | 1st IF: 21.4 MHz, ~10 µV, BNC; 2nd IF: 2 MHz, 0.5 V RMS @ 0 dB; AM output 0–3 V DC @ 0 dB, max. 6 Vpp @ 100 % AM; output impedance ~1.5 kΩ; AF frequency response –1 dB @ 15 kHz (typ.) |
| Power supply | 220 V AC (205–245 V), 50–400 Hz, 20 VA; 3-wire mains connector with PE; alternatively 2 × isolated batteries 24 V (0.3 A / 0.1 A) |
| Mechanical data | 485 × 210 × 270 mm (W×H×D); weight 12 kg |