If I remember, those yagi's have about 25 degrees bandwidth. Of course the apparent BW is wider the further the pilot is away from the end of the ILS, Instrument, approach. Since the receiver is feeding meters as a function of which tones are louder, this all that matters. I have been flying for years and the ILS approach is a very effective tool to get you down to the ground. In IFR or Instrument weather. Most of the time you come out of the soup hundreds or thousands of feet above the ground. Though, a few times, I was in the soup and only had the glare of ground lights until I was about a hundred feet AGL,above ground level. I know of commercial pilots who never saw the runway until their tires were about to make contact. The first times shooting an ILS approach in real weather or with a hood on so the pilot can only see the instruments was very hairy.. I was constantly worried if I was getting a correct reading on the meter needles or if the receivers were calibrated. Many low time pilots have perished because they didn't know how to interpret their instruments or they thought the instruments were lying since their head felt they were at a particular attitude when the plane was not.. Also known as vertigo Real Shame!!!
***** I wish I would know the answer to that. They are arrays consisting out of multiple Yagis. I think I have read about 35 degrees somewhere but I have no source. Maybe someone on here has better knowledge of that than I do.
+KF5OBS Really great demonstration,appreciate you shared this with everyone! I'm a pilot and what I can tell you about is that when on Localizer mode the sensitivity is pretty high. A full scale deflection of the CDI ( the bar swinging left or right) corresponds to 2.5° off course. From what I've seen in your viedo a half scale deflection of the needle was corresponding to one signal being double than the other (1V vs 500mV). Maybe you'd be more clever than me and try to find an answer with these information. As you have pointed out what the receiver do to display the deflection to the pilot is to mesure the difference in depth of modulation between both AM signals, for both LOC and Glide. Thanks again, you did a fantastic job!
Thank you. What is the receiver maximum RF power input? You said that there is no GP CDI. did it receive the GP frequencys? You can program GP frequency on this model?
Do you repair glide slopes receivers? What kind of attenuator did you use when connecting the 90/150 Hz generator to the receiver? Do you have 150 and 90 Hz from the generator pass through the splitter and get into another generator? Can you draw a connection diagram?
I used to but I don't repair them anymore. And you are correct, the 150/90 Hz are generated by one generator, them resistively combined and fed into the modulation input of an RF generator. I do not have a connection diagram as the exact connections would depend on your instruments. I do, however, have a block diagram in the video.
@@BalticLab I did not find the circuit in your video. The second generator, which mixes two signals of 90 Hz and 150 Hz, has 100% modulation settings, although it is advised to set 80% when checking by IFR4000. Also, the amplitude is set on the second generator minus 9 - I don't know which units ... Have you dealt with the PLL in the modules of the glide path receivers of the harmines?
Louis Brown Since they're highly directional, you won't have too much fun for it. Try the airport's VORs, they omnidirectional and usually also powered much higher.
I've also made a video on this topic (though it's more focused on making a receiver using GNURadio than testing a commercial receiver). I even captured the real signal! ua-cam.com/video/H2Wg6M0pSVg/v-deo.html
Great Video Like always, Many thanks. Q. Are they still using this technique? I mean its brilliant until you realize there is something called Camera not to mention infrared Camera. No wonder airplanes keep disappearing. Its like "Captain we are far from the runway", and the Captain be like "yeah I can see that but I prefer to trust this thing here its says we're locked in" lol
eeramzi Yes, they use it as the primary navigation source on final approach all over the world every single day. Here you can see the indicators being used in a real aircraft: ua-cam.com/video/M26X9gAQdGA/v-deo.html And There are some safety mechanisms, for instance, there are beacons along the localizer path. And the compass.. if your runway has a heading of 250 degrees and your ILS shows you're dead on but your compass shows let's say 123 degrees, something is probably wrong.
Excellent job!...I came here for a 750L tutorial but stayed to see what you had to say. 👍
Very informative! I had forgotten a lot of this from my pilot days.
Super handy demonstration :) It would be interesting to see those antennas in real life.
good explanation and simple experimental set up to get a feel of ILS
If I remember, those yagi's have about 25 degrees bandwidth. Of course the apparent BW is wider the further the pilot is away from the end of the ILS, Instrument, approach. Since the receiver is feeding meters as a function of which tones are louder, this all that matters.
I have been flying for years and the ILS approach is a very effective tool to get you down to the ground. In IFR or Instrument weather. Most of the time you come out of the soup hundreds or thousands of feet above the ground. Though, a few times, I was in the soup and only had the glare of ground lights until I was about a hundred feet AGL,above ground level.
I know of commercial pilots who never saw the runway until their tires were about to make contact. The first times shooting an ILS approach in real weather or with a hood on so the pilot can only see the instruments was very hairy.. I was constantly worried if I was getting a correct reading on the meter needles or if the receivers were calibrated.
Many low time pilots have perished because they didn't know how to interpret their instruments or they thought the instruments were lying since their head felt they were at a particular attitude when the plane was not.. Also known as vertigo Real Shame!!!
Good video. Thanks for making it.
Interesting! I never knew how those systems worked. What is the typical beam width of the antennas?
***** I wish I would know the answer to that. They are arrays consisting out of multiple Yagis. I think I have read about 35 degrees somewhere but I have no source. Maybe someone on here has better knowledge of that than I do.
+KF5OBS Really great demonstration,appreciate you shared this with everyone! I'm a pilot and what I can tell you about is that when on Localizer mode the sensitivity is pretty high. A full scale deflection of the CDI ( the bar swinging left or right) corresponds to 2.5° off course. From what I've seen in your viedo a half scale deflection of the needle was corresponding to one signal being double than the other (1V vs 500mV). Maybe you'd be more clever than me and try to find an answer with these information. As you have pointed out what the receiver do to display the deflection to the pilot is to mesure the difference in depth of modulation between both AM signals, for both LOC and Glide. Thanks again, you did a fantastic job!
+ -10º at 25 NM; + - 35º at 17 NM & + - 90º at 10 NM
Thank you.
What is the receiver maximum RF power input?
You said that there is no GP CDI. did it receive the GP frequencys? You can program GP frequency on this model?
The max RF input I don't know. The GS frequencies are in the UHF range and can not be received by this radio. Unfortunately.
@@BalticLab thank you
Do you repair glide slopes receivers? What kind of attenuator did you use when connecting the 90/150 Hz generator to the receiver?
Do you have 150 and 90 Hz from the generator pass through the splitter and get into another generator? Can you draw a connection diagram?
I used to but I don't repair them anymore. And you are correct, the 150/90 Hz are generated by one generator, them resistively combined and fed into the modulation input of an RF generator. I do not have a connection diagram as the exact connections would depend on your instruments. I do, however, have a block diagram in the video.
@@BalticLab I did not find the circuit in your video.
The second generator, which mixes two signals of 90 Hz and 150 Hz, has 100% modulation settings, although it is advised to set 80% when checking by IFR4000.
Also, the amplitude is set on the second generator minus 9 - I don't know which units ...
Have you dealt with the PLL in the modules of the glide path receivers of the harmines?
great video. thanks for making it!
Awesome, thanks so much
Cool! Thank you! ❤✈
thank you very much for this video :)
Very informative! Thank you.
could you show how to demodulate the signal ? thanks
According to the specifications, the 550 does have GS capability, too.
not according to what i'm reading. 750 adds the g/s.
nice video. thanks
W9DES GREAT VID
I wonder if anyone has picked up ILS DX? I'll have to bring my scanner next time a go to the airport.
Louis Brown Since they're highly directional, you won't have too much fun for it. Try the airport's VORs, they omnidirectional and usually also powered much higher.
I've also made a video on this topic (though it's more focused on making a receiver using GNURadio than testing a commercial receiver). I even captured the real signal! ua-cam.com/video/H2Wg6M0pSVg/v-deo.html
hpux735 I watched both your ILS and VOR videos, pretty good!
Great Video Like always, Many thanks.
Q. Are they still using this technique? I mean its brilliant until you realize there is something called Camera not to mention infrared Camera. No wonder airplanes keep disappearing. Its like "Captain we are far from the runway", and the Captain be like "yeah I can see that but I prefer to trust this thing here its says we're locked in" lol
eeramzi Yes, they use it as the primary navigation source on final approach all over the world every single day. Here you can see the indicators being used in a real aircraft: ua-cam.com/video/M26X9gAQdGA/v-deo.html And There are some safety mechanisms, for instance, there are beacons along the localizer path. And the compass.. if your runway has a heading of 250 degrees and your ILS shows you're dead on but your compass shows let's say 123 degrees, something is probably wrong.