Aircraft Band Monitoring

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ATIS

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Like most of you here, I am interested to monitor the airband; namely civil airband (108-137 MHz), military airband (225-400 MHz), military land mobile (138-150 MHz) and the aeronautical HF (2-24 MHz).

I am aware that there are trunk tracking (vs conventional) scanner, digital (vs analog) modes and CTCSS, DTCS tone signaling. For purpose of monitoring the above mentioned bands do I need and thus be concern with any of these rather advance features, i.e.: trunking, digital mode, CTCSS DTCS tone? Are such functions use in any ATC frequencies?

Then there is the ACARS and CPDLC. For now I understand that there are numerous softwares to decode analog VHF ACARS transmissions via a receiver and a sound card. SITA mentioned that they are shifting from ACARS over analog VHF to ACARS over VHF Data Link (VDL). Also there is ACARS over the Inmarsat and Iridium satallites. So my question is, is it possible to receive and decode ACARS messages over VDL and satellites as well as CPDLC?

What's the future for airband voice communications? Will it go digital? As asked in paragraph 2, are there any ATC frequencies on a trunking system? Heard about VoIP; is it related to this?

Thanks a lot! :)
 

K4DHR

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All aircraft frequencies are simple AM. No tones and no trunking. It is unlikely this will change any time soon, as the cost of converting world-wide would be staggering.

There are no plans on going to digital radios anytime soon either. Again, it is too cost prohibitive and the existing equipment works well enough, so there is little motivation to change.
 

ka3jjz

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All aircraft frequencies are simple AM. No tones and no trunking. <snip>
Not quite true. In the 380-400 mhz band (the top of the military air band) there is a migration to house P25 trunking systems at military and federal installations. Not all frequencies in this band are being taken up - there are still 'holes' that are used for aircraft.

HFDL is a HF digital mode (also erroneously known as 'HF ACARS') that is used by many airlines when they get out of VHF range. This is a good mode to have if you are interested in tracking aircraft as they transit across the Atlantic or on long duration flights. There are some packages available for decoding this as well

73 Mike
 

Rsmims

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Like most of you here, I am interested to monitor the airband; namely civil airband (108-137 MHz), military airband (225-400 MHz), military land mobile (138-150 MHz) and the aeronautical HF (2-24 MHz).
Is there a source of the specific frequencies that specific airports use, that a person could reference for this purpose? I live in a small town in Southern Utah, (St. George) that has an airport and offers basically commuter flights thru Delta. (Skywest Airlines)

I would be interested in knowing what frequencies they are operating on for their ATC and ground control.

Thanks
 

pathalogical

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Like most of you here, I am interested to monitor the airband; namely civil airband (108-137 MHz), military airband (225-400 MHz), military land mobile (138-150 MHz) and the aeronautical HF (2-24 MHz).

I am aware that there are trunk tracking (vs conventional) scanner, digital (vs analog) modes and CTCSS, DTCS tone signaling. For purpose of monitoring the above mentioned bands do I need and thus be concern with any of these rather advance features, i.e.: trunking, digital mode, CTCSS DTCS tone? Are such functions use in any ATC frequencies?

Then there is the ACARS and CPDLC. For now I understand that there are numerous softwares to decode analog VHF ACARS transmissions via a receiver and a sound card. SITA mentioned that they are shifting from ACARS over analog VHF to ACARS over VHF Data Link (VDL). Also there is ACARS over the Inmarsat and Iridium satallites. So my question is, is it possible to receive and decode ACARS messages over VDL and satellites as well as CPDLC?

What's the future for airband voice communications? Will it go digital? As asked in paragraph 2, are there any ATC frequencies on a trunking system? Heard about VoIP; is it related to this?

Thanks a lot! :)
Welcom to this great hobby ! For regular VHF air, any scanner will do, but for UHF milair not all scanners have the 225-400 mHz range. If you have not purchased a radio yet, check the specs and freq ranges first. For VHF ACARS, any scanner will work as those freqs fall into the 118-137 range. However, for HF voice or ACARS you may want to consider a shortwave radio with Single Side Band (SSB). Aircraft use HF voice when crossing over the ocean, known as MWARA MWARA - HF Underground
 

ATIS

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Not quite true. In the 380-400 mhz band (the top of the military air band) there is a migration to house P25 trunking systems at military and federal installations. Not all frequencies in this band are being taken up - there are still 'holes' that are used for aircraft.
I see. However you mentioned "military and federal installations". Do they talk to aircrafts or are they more for military/federal ground-to-ground communications that happen to be sharing the military airband? Because I am only interested if it concerns aviation. :)

HFDL is a HF digital mode (also erroneously known as 'HF ACARS') that is used by many airlines when they get out of VHF range. This is a good mode to have if you are interested in tracking aircraft as they transit across the Atlantic or on long duration flights. There are some packages available for decoding this as well
Oh ya, read this at RadioReference Wiki. One question: Can a conventional HF receiver be use for this or does it need a digital one?

Welcom to this great hobby ! For regular VHF air, any scanner will do, but for UHF milair not all scanners have the 225-400 mHz range. If you have not purchased a radio yet, check the specs and freq ranges first. For VHF ACARS, any scanner will work as those freqs fall into the 118-137 range. However, for HF voice or ACARS you may want to consider a shortwave radio with Single Side Band (SSB). Aircraft use HF voice when crossing over the ocean, known as MWARA MWARA - HF Underground
Thanks for mentioning however I am fully aware of it. What I like to know is if whether I need and thus should be concerned with advance features like trunking, digital mode and CTCSS DTCS tone for the monitoring of civil airband, military airband, aviation related activities on military land mobile and aeronautical HF.
 

ka3jjz

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I see. However you mentioned "military and federal installations". Do they talk to aircrafts or are they more for military/federal ground-to-ground communications that happen to be sharing the military airband? Because I am only interested if it concerns aviation. :)



Oh ya, read this at RadioReference Wiki. One question: Can a conventional HF receiver be use for this or does it need a digital one?

Thanks for mentioning however I am fully aware of it. What I like to know is if whether I need and thus should be concerned with advance features like trunking, digital mode and CTCSS DTCS tone for the monitoring of civil airband, military airband, aviation related activities on military land mobile and aeronautical HF.
As to the 380-400 mhz migration; I understand that some of these trunking systems include ground control or maintenance teams for aircraft; it varies from installation to installation. No way to properly categorize this, except to say that if you hear P25 squawks while tuning in this band, you know what you have found. An analog scanner, such as the BCT15X would not be able to copy this - a digital one, such as the BCD996XT would do it.

There really isn't any such thing as a 'digital' HF receiver (unless you're referring to the digital readouts, which became much more common in the 80s). Any good stable receiver with sideband capability will do. I'm unsure if HFDL could be copied with a portable, but you risk very little by trying it. If there's enough signal, and it's not interfered with, it would likely work, although a good desktop (or a HF Ham transceiver, most of which these days have general coverage radios built in - a plus if you ever decide to get your license) would enhance your chances of a successful decode.

73 Mike
 

ATIS

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As to the 380-400 mhz migration; I understand that some of these trunking systems include ground control or maintenance teams for aircraft; it varies from installation to installation. No way to properly categorize this, except to say that if you hear P25 squawks while tuning in this band, you know what you have found.

There really isn't any such thing as a 'digital' HF receiver. Any good stable receiver with sideband capability will do. I'm unsure if HFDL could be copied with a portable, but you risk very little by trying it.
I see. Thanks a lot! :)

So apart from the 380-400 MHz range where there is maybe P25 trunking systems do you know of more trunk system(s) in the civil airband, military airband, aviation related activities on military land mobile or aeronautical HF?

Well so far it appears to me that digital modes and CTCSS, DTCS tone signaling are not use at all in aviation voice communications. Can anybody confirm that?

Lastly what about tracking data communications like ACARS over VDL and satellites as well as CPDLC? Don't seem to know of any way to receive and decode such digital messages. Only types that I'm aware of its possibility for tracking so far is ACARS over analog VHF and HFDL.
 

dngnkeeper

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ATIS Let me give you a quick rundown.

ALL airband voice (regardless of freq) is AM analog. As mentioned before there are no plans to change this.

As for receivers unless you plan to monitor some other type of coms none of the fancy stuff will be of any use to you. For VHF (108-137 MHz) any scanner will cover this range. If you must have the UHF military band (225-400 MHz) your options are limited and you need to check the specks before buying. You will be looking at the top of the line stuff and possibly an amateur transceiver. In the HF band you need to look at Amateur gear.

That said you need to remember that Air Band VHF and UHF are line of sight. That means that it is very easy to pickup the airborne part of the transmission and very hard to get the transmission from the ground station or planes on the ground. In reality unless you are closer then about 4 miles to the airport you want to monitor you are probably out of luck for the ground end. That is assuming you are using an outdoor antenna tuned to the proper band. Using the attached antenna will work if you are at the airport.

As for HF You should have good luck if you are within a hundred or so miles of the coast as HF is not line of site. The drawback is that the freqs change according to the propagation conditions.

Basically for Air Band it is all about the antenna and your location in relation to the airport as the receivers are not that far apart in performance, particularly in the VHF band.

A great resource for Air Band monitoring is LiveATC.net. You can find info on gear, setup, and frequencies etc. And live feeds too.
 

ka3jjz

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<snip>
As for receivers unless you plan to monitor some other type of coms none of the fancy stuff will be of any use to you. For VHF (108-137 MHz) any scanner will cover this range. If you must have the UHF military band (225-400 MHz) your options are limited and you need to check the specks before buying. You will be looking at the top of the line stuff and possibly an amateur transceiver. In the HF band you need to look at Amateur gear.
</snip>
A couple of misconceptions are evident here. First, the number of scanners that copy the 225-400 mhz area is anything but limited. There are a great number of them, some of them are older, but the number of them that are capable of hearing this band is growing steadily. This wiki article makes that point quite nicely...

Milcom Receiving Equipment - The RadioReference Wiki

As for HF, while I agree amateur gear is more readily available, there are some older desktops that show up from time to time that will do the job quite nicely, although it does take a bit of care to make sure you get a radio in good working order. Examples of this are the Yaesu FRG-100, Icom R71A and Kenwood R5000.

<snip>As for HF You should have good luck if you are within a hundred or so miles of the coast as HF is not line of site (sic). The drawback is that the freqs change according to the propagation conditions.
Fortunately most of the HF Aero systems are well documented, and while the frequencies that are in use at any one time may change, it's usually pretty easy to find where they have gone. A basic understanding of HF propagation would narrow this field down, at times considerably. It's the quality of the receiver and antenna, along with the frequency and propagation conditions, that influence how far away you hear a flight, not just location (although it is true that sometimes being near the coast, conditions are quieter).

73 Mike
 

R1VINCE

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All aircraft frequencies are simple AM. No tones and no trunking. It is unlikely this will change any time soon, as the cost of converting world-wide would be staggering.

There are no plans on going to digital radios anytime soon either. Again, it is too cost prohibitive and the existing equipment works well enough, so there is little motivation to change.


ALL airband voice (regardless of freq) is AM analog. As mentioned before there are no plans to change this.
There are alot of FM, NFM, and P25 in some Civil Air Patrol frequencies.
 
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CalebATC

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There are alot of FM, NFM, and P25 in some Civil Air Patrol frequencies.
True. Alot of the SHARK## and MAKO##'s I get down here for Avon Park MOA are FM. They use the 13X.XXX and 14X.XXX when doing air-to-air, while on center. Then they switch back over to the UHF Avon ops. Ops are UHF. They are always monitoring the 13X.XXX and 14X.XXX frequencies.
 

ATIS

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There are alot of FM, NFM, and P25 in some Civil Air Patrol frequencies.
Alot of the SHARK## and MAKO##'s I get down here for Avon Park MOA are FM. They use the 13X.XXX and 14X.XXX when doing air-to-air, while on center. Then they switch back over to the UHF Avon ops. Ops are UHF.
Thanks a lot for the info, especially on the intro on NEXCOM. Have not heard about NEXCOM and VDL3 before (only aware of VDL2) so it's a wonderful insight. :)

So to date, how widely have digital voice (VDL-3) been implemented? Are there any available receivers in the market that can receive and decode such digital communication signals?

Are those CAP frequencies with FM, NFM and P25 mentioned above referring to only military air-to-air frequencies?
 

ECHO03

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NW Florida scanning

I live in NW Florida near the national forest and Gulf of Mexico. We see F22's and F15's just about everyday doing air to air training. Last week one of the fighters dropped about 10 flares and that really got my attention. Does anyone have some pointers and frequencies for finding these guys.
 

K4DHR

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There are alot of FM, NFM, and P25 in some Civil Air Patrol frequencies.
Let's clarify this though, these are for VERY SPECIFIC purposes. It is NOT used for general ATC to aircraft communications. Some military, non-ATC, radar facilities (ie., those units used for monitoring exercises inside a MOA, for example) may use these frequencies but without going into specifics I can assure anyone reading this that there are no plans (not to mention no money) to convert the FAAs radios to digital anytime soon.
 

R1VINCE

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Let's clarify this though, these are for VERY SPECIFIC purposes. It is NOT used for general ATC to aircraft communications. Some military, non-ATC, radar facilities (ie., those units used for monitoring exercises inside a MOA, for example) may use these frequencies but without going into specifics I can assure anyone reading this that there are no plans (not to mention no money) to convert the FAAs radios to digital anytime soon.
Sorry to throw anyone off...i should clarify-

The FM, NFM, and P25 modes are not used in air-to-air traffic and do not fall anywhere in the 108-137Mhz or the 225-380Mhz airbands but are used in the military land mobile range, as far as I know.
 
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