EL
I did remember that this blogger in Finland (at the time she was a teenager, her blog is very cool) did it 6 years ago while googling around.
http://www.windytan.com/2014/02/mystery-signal-from-helicopter.html
http://www.windytan.com/2014/02/mystery-signal-from-helicopter.html
IS
There are a few downlink sites in London. They're all COFDM and omnidirectional, they don't have someone on the towers pointing an aerial in the direction of the helicopter any more.
However I don't think they're used as a network that will amalgamate the data from the receive sites into one
However I don't think they're used as a network that will amalgamate the data from the receive sites into one
RK
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Thanks, it does seem like quite a few stations in America aren’t using omnis, mainly due to size of service area maybe?
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Last edited by Rkolsen on 5 June 2020 9:17am - 3 times in total
MA
That's 7 years old, things (even in the US) must have moved forward significantly since then?
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Worth taking a look at this.
That's 7 years old, things (even in the US) must have moved forward significantly since then?
NG
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
noggin
Founding member
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Worth taking a look at this.
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
Last edited by noggin on 5 June 2020 9:03am
RK
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
I was talking specifically about the US there are direction receive and transmit antennas that are constantly in motion.
I should have quoted el marko’s post about quite a few not using omnis in the US.
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Worth taking a look at this.
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
I was talking specifically about the US there are direction receive and transmit antennas that are constantly in motion.
I should have quoted el marko’s post about quite a few not using omnis in the US.
Thanks, it does seem like quite a few stations in America aren’t using omnis, mainly due to size of service area maybe?
RK
That's 7 years old, things (even in the US) must have moved forward significantly since then?
A lot of stations use backpacks but most use ENG and the band plan as described there is mostly the same (however wireless companies and WiFi device manufacturers are trying to get that spectrum). The highly directional parabolic reflectors are still being built (sometimes stations may put the old one on a new truck) and some SUV ENG trucks such as “mobile weather labs” have directional horn antennas. These new transmitters and receive sites are still regularly licensed and renewed. The microwave transmitter licenses usually list their area of use within 50km of a specific receiver. Although I don’t think the FCC would get involved if you were still in your market and outside the specified range shooting to a different receive site. The FCC only gets involved when there’s repeated interference and it cannot be worked out between the two parties.
One LA station used Dejeros entirely and their control software had a melt down and they had a huge problem - many of the photogs have not been trained to dial in a microwave shot at said stations. Some stations are no longer building ENG trucks which is stupid as it’s free and they essentially own it.
Also if the US helicopters used omnidirectional receive antennas there would be no need for that squawk/screeching noise to constantly send out the GPS location of the helicopter. The helicopters antenna would only need to know where the receive site is and send it directionally there, thereby rendering that noise/system useless.
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Worth taking a look at this.
That's 7 years old, things (even in the US) must have moved forward significantly since then?
A lot of stations use backpacks but most use ENG and the band plan as described there is mostly the same (however wireless companies and WiFi device manufacturers are trying to get that spectrum). The highly directional parabolic reflectors are still being built (sometimes stations may put the old one on a new truck) and some SUV ENG trucks such as “mobile weather labs” have directional horn antennas. These new transmitters and receive sites are still regularly licensed and renewed. The microwave transmitter licenses usually list their area of use within 50km of a specific receiver. Although I don’t think the FCC would get involved if you were still in your market and outside the specified range shooting to a different receive site. The FCC only gets involved when there’s repeated interference and it cannot be worked out between the two parties.
One LA station used Dejeros entirely and their control software had a melt down and they had a huge problem - many of the photogs have not been trained to dial in a microwave shot at said stations. Some stations are no longer building ENG trucks which is stupid as it’s free and they essentially own it.
Also if the US helicopters used omnidirectional receive antennas there would be no need for that squawk/screeching noise to constantly send out the GPS location of the helicopter. The helicopters antenna would only need to know where the receive site is and send it directionally there, thereby rendering that noise/system useless.
Last edited by Rkolsen on 5 June 2020 7:50pm
RK
This is an amazing story. KFOR a TV station in Oklahoma City rescued an amputee who was doing a river float (floating down a river on a tube) and his inner tube hit something and deflated around 6pm the previous night. He was holding on for life for about 20 hours, the police were looking all over for him and as KFOR was flying for breaking news and spotted him struggling in the middle of the river. The chopper landed on a sandbar and rescued and and waited for rescuers to come.
See the story here. If for some reason it’s geoblocked it’s here on YouTube:
Also, Brian over at TVNewsTalk made an impressive tracking list using ADBSExchange tracking all the helicopters in my list on the air. ADBS Exchange is open source and doesn’t mark helicopters or other aircraft that are marked “as do not track” such as military aircraft. You can view all the helicopters flying over the US here here.
See the story here. If for some reason it’s geoblocked it’s here on YouTube:
Also, Brian over at TVNewsTalk made an impressive tracking list using ADBSExchange tracking all the helicopters in my list on the air. ADBS Exchange is open source and doesn’t mark helicopters or other aircraft that are marked “as do not track” such as military aircraft. You can view all the helicopters flying over the US here here.
NG
A lot of stations use backpacks but most use ENG and the band plan as described there is mostly the same (however wireless companies and WiFi device manufacturers are trying to get that spectrum).
What do you mean by ENG in the US context?
In the UK ENG = Electronic News Gathering - and means either :
1. Shoot on video not film (!) - that's where the phrase originally came from. ("TVS switched from film to ENG in the early 80s'") In this context it's pronounced EE-EN-JEE
2. Shoot an interview separately to a down-the-line interview ("Can you ENG him after he's done the down-the-line please?") (i.e. shoot him answering similar questions, but not looking directly to camera). When used as a verb it's pronounced "ENJ".
Are you using ENG to mean 'digital microwave' as opposed to bonded cellular?
noggin
Founding member
A lot of stations use backpacks but most use ENG and the band plan as described there is mostly the same (however wireless companies and WiFi device manufacturers are trying to get that spectrum).
What do you mean by ENG in the US context?
In the UK ENG = Electronic News Gathering - and means either :
1. Shoot on video not film (!) - that's where the phrase originally came from. ("TVS switched from film to ENG in the early 80s'") In this context it's pronounced EE-EN-JEE
2. Shoot an interview separately to a down-the-line interview ("Can you ENG him after he's done the down-the-line please?") (i.e. shoot him answering similar questions, but not looking directly to camera). When used as a verb it's pronounced "ENJ".
Are you using ENG to mean 'digital microwave' as opposed to bonded cellular?
CO
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
There are directional tracking antennas on receivers used in the UK, but not for helicopters that I am aware of (always happy to be corrected though!).
They tend to get used for planes at around 24,000 feet which are relaying signals from mobile sources, such as cameras on motorbikes following a marathon course. They are rigged for single events, and not left in operation for news helicopters.
Diversity reception has made life so much easier, so although many sites have been refered to as having omni-directional receive patterns, in practice it is made up of 4 or more sector antennas, which have gain compared to a single omni antenna.
Almost every if not all helicopters in the US use directional antennas. I believe there is a omni antenna that is constantly sending back telemetry data. In fact I’m some videos of just helicopter footage or live feeds it you may here squawk like noises (in the link) and that’s apparently the omni signal. Directional antennas are used because stations in the US only have two to four ENG microwave frequencies to use. So they have to be careful and can’t be jamming up one frequency. Normally helicopter receive sites are at the top of their tower with a a steerable antenna and the same frequencies can be used on the ground at lower receive sites. Omni antennas are not because the same ENG receive frequencies are used in adjacent markets, so you don’t want to risk of overshooting the signal.
Worth taking a look at this.
Worth taking a look at this.
I think there is possibly some confusion between receive and transmit antennas going on.
Inspector Sands pointed out that the RECEIVE antennas (or aerials as we'd call them over here) are omnidirectional - so the receiver sites can receive from any direction, not just a single direction (and don't have to have active steering to point at the source)
The transmission antenna/aerial on the helicopter or other source may well be directional (to increase the TX gain) and use GPS or other automatic steering systems to point the TRANSMIT antenna (which may well be directional to increase gain) at a receive site. However I think Omni transmits may be in use in London though I may be wrong.
You may see directional aerials used on point-to-point ground links - particularly from golf buggy mid-points back to receive sites (so you can have an Omni TX on the camera head, an omni or directional receiver on a buggy, and then a directional transmitter on the buggy to get back to the main receive point?)
The way frequencies are licensed in the UK and the US differs quite significantly I suspect. In the UK you often book guaranteed licensed RF spectrum (whether for talkback, radio mics or microwave video links) with the JFMG (Joint Frequencies Management Group) who ensure you are the only user in the area that you are licensing that frequency. (Those licences can be long-term or ad hoc for a single day) That avoids the jamming issues. If you are doing an OB at Ascot Race Course with 4 RF cameras roaming the course, the frequencies used for that won't be allocated to a helicopter working within tens of miles of you.
There are directional tracking antennas on receivers used in the UK, but not for helicopters that I am aware of (always happy to be corrected though!).
They tend to get used for planes at around 24,000 feet which are relaying signals from mobile sources, such as cameras on motorbikes following a marathon course. They are rigged for single events, and not left in operation for news helicopters.
Diversity reception has made life so much easier, so although many sites have been refered to as having omni-directional receive patterns, in practice it is made up of 4 or more sector antennas, which have gain compared to a single omni antenna.