I am a very new user here, I have successfully programed in my local tower, ground, and ATIS channels into my BCT15X, however, I do not know what the appropriate modulation is for these frequencies (AM, NFM, FM, WFM, FMB), does anyone know what modulation I should choose (will auto do the trick)? Thank you
Aircraft are all AM
aprswatcher
Member
The BCT15X is one of the Best airband scanners! It handles VHF and UHF communications well.
Use “Airnav.com” to look up new frequencies for surrounding airports and military bases.
Select the “airports” tab, enter airport/base name, then scroll down to the “communications “ section for frequencies.
Welcome to Radio Reference and enjoy your new scanner!
73, Rex
Use “Airnav.com” to look up new frequencies for surrounding airports and military bases.
Select the “airports” tab, enter airport/base name, then scroll down to the “communications “ section for frequencies.
Welcome to Radio Reference and enjoy your new scanner!
73, Rex
“Auto” will work for those frequencies you don’t know what mode they use (the scanner will choose for you) but commercial aviation uses AM. Military may use both AM and FM. When in doubt use “Auto”.
You can (and should) experiment with your new scanner. In this case, simply entering the frequency in question twice, using AM on one and FM on the other, should give you a good idea of how the signal sounds using the different modes of modulation. Once you hear the difference you will know which mode you should use.
The tower and the commercial airliners both use AM. Because AM behaves differently than FM. On AM if two airplanes are transmitting at the same time on the same frequency the two signals “mix” and produce a squealing, called “heterodyne”… it’s the same squealing noise prevalent on AM CB. If FM were used the stronger signal may win out and completely cover the weaker signal. Control towers can discern when two aircraft are transmitting at the same time when AM is being used. AM heterodyning alerts the tower that two seperate airplanes are responding to the tower’s instructions. It comes in handy when two aircraft are thinking the tower is instructing them to land for example. The tower hears heyrodyning, realizes there are two aircraft thinking the tower is talking to them and corrects the mistake, avoiding the chance two planes may collide while landing.
Smaller airports that do not have Air Traffic Controllers on duty use a common frequency assigned to that airport. Each airplane transmits their intentions to land or take off on that one common frequency and all other planes that are in the vicinity of the airport listen intently when they want to enter the landing pattern for the airport. (They fly parallel to the runway, making their final turns to line up with the runway, transmitting each time they make a turn with their intentions. These smaller airports without ATC (air traffic control) all use AM.
You can (and should) experiment with your new scanner. In this case, simply entering the frequency in question twice, using AM on one and FM on the other, should give you a good idea of how the signal sounds using the different modes of modulation. Once you hear the difference you will know which mode you should use.
The tower and the commercial airliners both use AM. Because AM behaves differently than FM. On AM if two airplanes are transmitting at the same time on the same frequency the two signals “mix” and produce a squealing, called “heterodyne”… it’s the same squealing noise prevalent on AM CB. If FM were used the stronger signal may win out and completely cover the weaker signal. Control towers can discern when two aircraft are transmitting at the same time when AM is being used. AM heterodyning alerts the tower that two seperate airplanes are responding to the tower’s instructions. It comes in handy when two aircraft are thinking the tower is instructing them to land for example. The tower hears heyrodyning, realizes there are two aircraft thinking the tower is talking to them and corrects the mistake, avoiding the chance two planes may collide while landing.
Smaller airports that do not have Air Traffic Controllers on duty use a common frequency assigned to that airport. Each airplane transmits their intentions to land or take off on that one common frequency and all other planes that are in the vicinity of the airport listen intently when they want to enter the landing pattern for the airport. (They fly parallel to the runway, making their final turns to line up with the runway, transmitting each time they make a turn with their intentions. These smaller airports without ATC (air traffic control) all use AM.
tvengr
Well Known Member
Welcome to the forums! What is your closest airport?
nd5y
Member
That's not how it works. Auto sets the mode according to a built in band plan, it doesn't change based on the actual received signal.
Agreed. But my “Scanner 101” explanation was not implying otherwise. As far as the aviation bands go, my explanation stands. Band plans is included in the advanced “Scanners 102” course.
Besides, if the menu includes the option of “Auto”, when manually programming within any particular band, it’s assumed it’s available on that band. How many bands do you know of that don’t include the “Auto” choice?
Besides, if the menu includes the option of “Auto”, when manually programming within any particular band, it’s assumed it’s available on that band. How many bands do you know of that don’t include the “Auto” choice?
wtp
Member
auto just means a preset band plan.
it can be edited.
it can be edited.
BCT15-X Auto Step Sizes/Auto Modulation |
| Band Defaults | |
| Frequency Range | Step (kHz) | Mode | Band | Frequency Range | Step (kHz) | Mode | Band |
| 25-27.405 | 5 | AM | CB/Business | 174-215.95 | 50 | WFM | VHF TV |
| 27.41-27.995 | 5 | AM | Business/Forest | 216-224.98 | 20 | NFM | 1.25 Meter Ham |
| 28-29.68 | 20 | NFM | 10 Meter Ham | 225-379.975 | 25 | AM | UHF Air |
| 29.7-49.99 | 10 | NFM | VHF Low | 380-399.9875 | 12.5 | NFM | Military Trunked |
| 50-53.98 | 20 | NFM | 6 Meter Ham | 400-405.9875 | 12.5 | NFM | Miscellaneous |
| 54-71.95 | 50 | WFM | VHF TV | 406-419.9875 | 12.5 | NFM | Federal Trunked |
| 72-75.995 | 5 | FM | Astronomy | 420-449.9875 | 12.5 | NFM | 70 cm Ham |
| 76-87.95 | 50 | WFM | VHF TV | 450-469.9875 | 12.5 | NFM | UHF Standard |
| 88-107.9 | 100 | FMB | FM Broadcast | 470-512 | 12.5 | NFM | UHF TV |
| 108-136.9916 | 8.33 | AM | Commercial Air | 758-787.99375 | 6.25 | NFM | Public Service |
| 137-143.9875 | 12.5 | NFM | Military Land Mobile | 788-805.99375 | 6.25 | NFM | Public Service |
| 144-147.995 | 5 | NFM | 2 Meter Ham | 806-823.9875 | 12.5 | NFM | Public Service |
| 148-150.7875 | 12.5 | NFM | Military Land Mobile | 849.0125-868.9875 | 12.5 | NFM | PS Trunked |
| 150.8-161.995 | 5 | NFM | VHF High | 894.0125-960 | 12.5 | NFM | Public Service, 33 cm Ham |
| 162-173.9875 | 12.5 | NFM | Federal | 1240-1300 | 25 | NFM | 25 cm Ham |
| When you select 'AUTO' for a channel or mode’s modulation or step, the above values are used unless you’ve edited the Band Defaults. Although TV bands are listed, the scanner cannot decode digital TV audio. |
So, you’ve just answered my question with “Pretty much all”… not that it’s going to mean much to the “newbie” OP who probably hasn’t a clue as to what you are describing.
Your input, while correct, is “too much information” if it’s an attempt to answer the OP’s question. He’s a newbie.
If it’s an attempt to respond to my post, then not only are you hyjacking the original post, you are attempting to admonish me with your initial reply “That's not how it works”, meaning what I wrote is incorrect, when in fact it is not. Now that you have showed everyone how much you know, you can relish in the thought “Boy, I guess I showed him!” and be on your way.
Your input, while correct, is “too much information” if it’s an attempt to answer the OP’s question. He’s a newbie.
If it’s an attempt to respond to my post, then not only are you hyjacking the original post, you are attempting to admonish me with your initial reply “That's not how it works”, meaning what I wrote is incorrect, when in fact it is not. Now that you have showed everyone how much you know, you can relish in the thought “Boy, I guess I showed him!” and be on your way.
Thank you all for the help, I am now finding some success in listening to ATC. One final question I have is if I am about 15 miles from kbtr, is there any antenna or antenna placement that could pick up those channels or should I call it a day? The only frequencies I can pick up currently are some hazy Houston Center frequencies.
aprswatcher
Member
Program in the frequencies for Ryan Field, you never know what you will hear. The back of the set telescoping antenna is ok, but not great. If you’re real serious about hearing more communications, I would suggest an external antenna. A discone antenna covers numerous frequencies or get an air band specific antenna. Check out DPD production for some excellent antennas.
73, Rex
73, Rex
kayn1n32008
ØÆSØ Say it, say 'ENCRYPTION'
Air Traffic Communications will ALWAYS be AM. Even for military ATC.
tvengr
Well Known Member
Here is a list of ATC frequencies for Ryan Field. There is one UHF frequency for the tower and another for approach/departure. You will need to lockout the ATIS frequency. It is a continuous transmission with airport info.
| BatonRouge Metro | |
| 118.450 | KBTR Tower VHF |
| 257.800 | KBTR Tower UHF |
| 121.900 | KBTR Ground |
| 119.400 | KBTR Clear Deliv |
| 122.950 | KBTR Unicom |
| 125.200 | KBTR ATIS |
| 120.300 | KBTR App/Dep W |
| 133.225 | KBTR App/Dep E |
| 278.300 | KBTR App/Dep UHF |
| 121.500 | Aero Emerg VHF |
| 243.000 | Aero Emerg UHF |
wtp
Member
colerey,
i sent a PM (personal message) to you, look to the top right of this page.
i sent a PM (personal message) to you, look to the top right of this page.
