Need guidance on first aerial photo job

[GARealtor]

I'm a new drone pilot and I have my first aerial photography job to photograph the triangle shaped property. (See attached) There are some power lines that run parallel along the long side of the property and I'm wondering how this is going to affect my drone or compass. I'd hate to crash on my first job. Any advice would be greatly appreciated. There's also a large cell tower close by. Not sure what effect that is going to have.

 

[BluePuffin]

I don’t believe the cell tower should have too much of an effect, but you may want to stay a little ways away from the power lines.

I noticed you said you are a new drone pilot, and was wondering if you know that you need a Part 107 certification to get paid for any drone services (or for anything related to commercial use). If you have your certification you can disregard his, but if not I would seriously rethink doing this job. The only way to get around this, is if you know someone who has a Part 107 license, and is present and able to take over the controls while you are flying.

EDIT: Just looked over your profile and saw you have a certification. You can ignore my above comment.

 

[FormerMember07122019_2]

There are no definitive answers that I can find on potential electrical interference from power lines and cell towers. Although, there are many, many cases where folks have run into them and crashed however. By the way, that is too close. Ha ha. In all seriousness, they are very hard to see while flying.

There are numerous reports of people flying within 10 ft or so of them and not having a problem but then there are also a number of reports of people experiencing signal reduction and some interference when getting close. The best advice, which I read somewhere, is that if you stay far enough away that there is zero chance of hitting them you should be OK. To try to pin it down to a number I would try to stay 100 ft or more away if possible.

If you are very conservative and careful I would do a test by flying very gradually closer and closer and pay a keen eye for any signal reduction (number of bars) or compass errors (erratic heading indications) or the dreaded “magnetic interference”.

Maybe there are others on the forum with more knowledge or experience than me, or have done testing that can chime in.

 

[GARealtor]

There are no definitive answers that I can find on potential electrical interference from power lines and cell towers. Although, there are many, many cases where folks have run into them and crashed however. By the way, that is too close. Ha ha. In all seriousness, they are very hard to see while flying.

There are numerous reports of people flying within 10 ft or so of them and not having a problem but then there are also a number of reports of people experiencing signal reduction and some interference when getting close. The best advice, which I read somewhere, is that if you stay far enough away that there is zero chance of hitting them you should be OK. To try to pin it down to a number I would try to stay 100 ft or more away if possible.

If you are very conservative and careful I would do a test by flying very gradually closer and closer and pay a keen eye for any signal reduction (number of bars) or compass errors (erratic heading indications) or the dreaded “magnetic interference”.

Maybe there are others on the forum with more knowledge or experience than me, or have done testing that can chime in.

I plan on keeping my distance from the wires...I was wondering if I end up with compass errors, erratic movements or magnetic interference while I'm in the air, any suggestions on the best way to handle that? All of my practice flights so far have been uneventful. Just trying to have a plan if something goes wrong. Thanks for your input!

 

[FormerMember07122019_2]

Sorry but is a fairly standard answer; land as soon as possible and then try to figure out what the problem is. Actually, if you stay away from the cell tower and power lines you shouldn’t have any those problems. Having an extra person as a spotter is a good idea if you don’t have much experience.

 

[Meta4]

I was wondering if I end up with compass errors, erratic movements or magnetic interference while I'm in the air, any suggestions on the best way to handle that?

It's highly unlikely that you'll be close enough to notice any effects at all.
But if you did, it's a simple matter of reversing or climbing away from whatever is the source of the issue.

 

[GARealtor]

Sorry but is a fairly standard answer; land as soon as possible and then try to figure out what the problem is. Actually, if you stay away from the cell tower and power lines you shouldn’t have any those problems. Having an extra person as a spotter is a good idea if you don’t have much experience.

Thanks!

 

[GARealtor]

It's highly unlikely that you'll be close enough to notice any effects at all.
But if you did, it's a simple matter of reversing or climbing away from whatever is the source of the issue.

Thanks!

 

[Hiwayman]

Thanks!

I recently had to assess a job that had power lines nearby. I asked the electric company for advice on potential interference..I was advised that by listening to a mw radio closeby , any interference would be noticeable on that. At the moment I haven't had time to test that theory...others may add their thoughts on this ...??

 

[Meta4]

I was advised that by listening to a mw radio closeby , any interference would be noticeable on that

A little intererence is commonly encountered flying in any urban area and is no worry.
There won't be any serious intererence.

 

[GARealtor]

A little intererence is commonly encountered flying in any urban area and is no worry.
There won't be any serious intererence.

Thanks!

I recently had to assess a job that had power lines nearby. I asked the electric company for advice on potential interference..I was advised that by listening to a mw radio closeby , any interference would be noticeable on that. At the moment I haven't had time to test that theory...others may add their thoughts on this ...??

Thanks!

 

[GARealtor]

I don’t believe the cell tower should have too much of an effect, but you may want to stay a little ways away from the power lines.

I noticed you said you are a new drone pilot, and was wondering if you know that you need a Part 107 certification to get paid for any drone services (or for anything related to commercial use). If you have your certification you can disregard his, but if not I would seriously rethink doing this job. The only way to get around this, is if you know someone who has a Part 107 license, and is present and able to take over the controls while you are flying.

EDIT: Just looked over your profile and saw you have a certification. You can ignore my above comment.

Thanks!

 

[Thoraldus]

Cell towers can have equivalent radiated power emissions in the megawatts. Even out of band radio frequencies can cause issues with sufficient radiated power. Look up radio receiver desense. Power transmission lines are generally not a source of RF noise except when there is arcing due to weather or broken insulators. Electrical arcing can generate RF noise well into the 100's of megahertz. Our AC/RC use FM technology that helps to mitigate interference from other sources.

 

[FormerMember07122019_2]

Cell towers can have equivalent radiated power emissions in the megawatts. Even out of band radio frequencies can cause issues with sufficient radiated power. Look up radio receiver desense. Power transmission lines are generally not a source of RF noise except when there is arcing due to weather or broken insulators. Electrical arcing can generate RF noise well into the 100's of megahertz. Our AC/RC use FM technology that helps to mitigate interference from other sources.

Hi Thoraldus,

It sounds like you know a bit about RF transmission. Have you seen any data or test results regarding the distance when it causes interference in the Mavic. I suspect there are a fair number of variables, like transmission power level, antenna directionality, humidity, temp, etc. I also suspect that the problems come from overload of the receiver front end circuitry.

Any thoughts?

 

[Thoraldus]

Hi Thoraldus,

It sounds like you know a bit about RF transmission. Have you seen any data or test results regarding the distance when it causes interference in the Mavic. I suspect there are a fair number of variables, like transmission power level, antenna directionality, humidity, temp, etc. I also suspect that the problems come from overload of the receiver front end circuitry.

Any thoughts?

For an isotropic emitter (omni-directional) the inverse square law tells us that power is reduced by taking the reciprocal of the square of the change in distance. So doubling your distance from the source would get you 1/4 of the original power. Unfortunately cell tower radiators are rarely isotropic. They usually use high gain directional antennas. For some light reading you can reference this document ... Cell Tower Radiation Report

You are correct, there are contributing factors but these are most important when it comes to desense or receiver front end overload.

1. Interfering Antenna Radiation Pattern.
2. Interfering Transmitter power
3. AC/RC Receiver Front End Bandwidth

You might be able to fly with impunity above or below the directional lobes of the typical cell tower, but get close enough and in the highest power lobe and you might lose control. It's somewhat like trying to see at night when you have oncoming traffic with their high beams on.

The DJI frequency specs for the Mavic 2 are:

2.400 - 2.483 GHz
5.725 - 5.850 GHz

The 2.4GHz channel could be sensitive to some current 4g/LTE bands. The 5.7-5.8GHz channel should provide better immunity.

 

[GARealtor]

For an isotropic emitter (omni-directional) the inverse square law tells us that power is reduced by taking the reciprocal of the square of the change in distance. So doubling your distance from the source would get you 1/4 of the original power. Unfortunately cell tower radiators are rarely isotropic. They usually use high gain directional antennas. For some light reading you can reference this document ... Cell Tower Radiation Report

You are correct, there are contributing factors but these are most important when it comes to desense or receiver front end overload.

1. Interfering Antenna Radiation Pattern.
2. Interfering Transmitter power
3. AC/RC Receiver Front End Bandwidth

You might be able to fly with impunity above or below the directional lobes of the typical cell tower, but get close enough and in the highest power lobe and you might lose control. It's somewhat like trying to see at night when you have oncoming traffic with their high beams on.

The DJI frequency specs for the Mavic 2 are:

2.400 - 2.483 GHz
5.725 - 5.850 GHz

The 2.4GHz channel could be sensitive to some current 4g/LTE bands. The 5.7-5.8GHz channel should provide better immunity.

It sounds like you are very knowledgeable but you just completely lost me! I'm a female drone pilot and I'm new at this. Is there any way you can put that in terms that a woman would understand? LOL. I was at the house taking the real estate photos today (it was too windy to fly). The owner of the property has a small hobby drone so I asked him if he had any trouble flying his drone with the power lines close by and he said his drone is hard to control & it tried to take off away from him. I'm wondering if this particular job is worth the risk.

 

[Thoraldus]

It sounds like you are very knowledgeable but you just completely lost me! I'm a female drone pilot and I'm new at this. Is there any way you can put that in terms that a woman would understand? LOL. I was at the house taking the real estate photos today (it was too windy to fly). The owner of the property has a small hobby drone so I asked him if he had any trouble flying his drone with the power lines close by and he said his drone is hard to control & it tried to take off away from him. I'm wondering if this particular job is worth the risk.

Keep a safe distance from the power lines and you should be fine. The biggest risk in my opinion is physically flying into the lines. When flying a drone it is easy to misjudge the distance between your drone and a power line, the top of a building, the top of trees, etc when your viewing angle gives you a false impression of the clearance.

 

[FormerMember07122019_2]

It sounds like you are very knowledgeable but you just completely lost me! I'm a female drone pilot and I'm new at this. Is there any way you can put that in terms that a woman would understand? LOL. I was at the house taking the real estate photos today (it was too windy to fly). The owner of the property has a small hobby drone so I asked him if he had any trouble flying his drone with the power lines close by and he said his drone is hard to control & it tried to take off away from him. I'm wondering if this particular job is worth the risk.

I agree with Thoraldus, you should be fine. Toy drones are notorious for being difficult to control and much more susceptible to electrical interference. The Mavic 2’s communication technique is significantly more robust.

 

[FormerMember07122019_2]

For an isotropic emitter (omni-directional) the inverse square law tells us that power is reduced by taking the reciprocal of the square of the change in distance. So doubling your distance from the source would get you 1/4 of the original power. Unfortunately cell tower radiators are rarely isotropic. They usually use high gain directional antennas. For some light reading you can reference this document ... Cell Tower Radiation Report

You are correct, there are contributing factors but these are most important when it comes to desense or receiver front end overload.

1. Interfering Antenna Radiation Pattern.
2. Interfering Transmitter power
3. AC/RC Receiver Front End Bandwidth

You might be able to fly with impunity above or below the directional lobes of the typical cell tower, but get close enough and in the highest power lobe and you might lose control. It's somewhat like trying to see at night when you have oncoming traffic with their high beams on.

The DJI frequency specs for the Mavic 2 are:

2.400 - 2.483 GHz
5.725 - 5.850 GHz

The 2.4GHz channel could be sensitive to some current 4g/LTE bands. The 5.7-5.8GHz channel should provide better immunity.

Thanks for the great information. It’s been a really long time since I was this deep into the details of antenna theory and RF transmission but I understand what you are saying.

A good saving grace is that the Mavic 2 automatically switches between 2.4 and 5.8 if it senses interference.

I was still curious if you have seen any data or test results on the specific effect of radio tower transmissions and potential drone interference susceptibility?

 

[GARealtor]

Keep a safe distance from the power lines and you should be fine. The biggest risk in my opinion is physically flying into the lines. When flying a drone it is easy to misjudge the distance between your drone and a power line, the top of a building, the top of trees, etc when your viewing angle gives you a false impression of the clearance.

Sounds good. I walked the property today so I know exactly where the power lines are and I've already got two areas selected that I can fly from that are some distance from the power lines. My biggest concern was any interference (things I can't see) that would cause a problem. Thanks for your help!