![]() ![]() As I recall, in the US at least, 109.1-111.9 Mhz is reserved for localizers. The LOC will be received by the aircraft's VOR antenna, as LOC frequencies occupy the lower portion of the NAV frequency band (108.1 Mhz-117.9 Mhz). LOC frequencies are tunable by every VOR receiver ever made (and, to the original poster, there is to transmit function on a VOR receiver The only transmitting involved is if you are using DME, or Distance Measuring Equipment, which is another beast entirely). The phase shift principle used by the VOR receiver is the same for a localizer-the difference is that, when tracking a LOC, the receiver ignores the Omni Bearing Selector (OBS) setting. So, as long as an ILS approach has an associated LOC (localizer only-left/right guidance), you may still shoot the approach using a VOR receiver (to localizer minimums, which are typically much higher than with LOC/Glideslope guidance). Not entirely true.a VOR receiver, by design, will also receive the localizer portion of an ILS. I also stand corrected if someone with deeper knowledge of these systems finds any mistakes. When the crew selects approach (APP) or localizer (LOC) mode on the mode control panel and an active ILS frequency is tuned an automatic transfer to the localizer antenna inside the radome happens. It receives VOR stations enroute and receives the localizer signal during the initial approach if it is tuned to do so. The B737NG for example uses a combined VOR/localizer antenna on top of the vertical stabilizer. A VOR receiver can not do this calculation! But a VOR antenna can receive the localizer signal as this is working in the same frequency range as a VOR. Both signals are received and a deviation is calculated (amongst other things) for display to the flight crew. Automatically a dedicated glideslope frequency is tuned. The ILS receiver is tuned to a localizer signal. A VOR receiver can not receive or compute ILS signals. ![]() For an ILS approach you need an ILS receiver tuned to an ILS frequency.
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