Antennas with Erdos Miller

Welcome to the official Erdos Miller podcast, where we spend our nonproductive time, talking about drilling tech, and get the latest insights from industry leaders on our show. I'm David Erdos, and Clayton Carter is our guest today. He is one of various Miller's field support technicians, and we're going to be talking about antennas and some common field issues that Clayton has seen pop up lately and how to debug them. Welcome Clayton.

Thanks for having me, David. I definitely have to say it's quite an honor. I've listened to this podcast, if you like, since the beginning, Ken had sent me a link to it a couple years back and I've followed ever since. So thanks for having me.

That's awesome. Glad to hear that. So what kind of issues have you seen with antennas in the field?

Yeah. So, funny you should bring that up David. So I would say most recently we've seen a lot of network antenna issues, so not EM antennas, but networking antennas on the wireless systems that go from the MWD shack, to the rig floor. So, I guess the question to you would be what, different types of antennas are currently out there for networking and what... oh, I guess we could start with that. How about that?

Yeah, I think most of the rig floor and MWD shack radios operating out of the two frequencies, either 900 megahertz or 2.4 gigahertz. And the antenna that you use with each of these radios has to be tuned for that specific frequency. And at the basic level, there's two types of antennas, there's directional and omnidirectional antennas. The most common type of omnidirectional antenna looks like a little line, it's called a dipole antenna or a monopole antenna. Those are two different types, but they're usually dipoles inside that. And that's an omnidirectional antenna. And so when you can get... we will stay away too far from all the nerdy details of antennas, but basically, an omnidirectional antenna is able to send and receive in all directions around it, but actually it's more like a donut shape.

Let's say my finger is the antenna. It's like a donut shape around the antenna. So directly above and directly below, you'd have the weakest signal. And then directly out to the side, you'd have the strongest signal. A directional antenna is a bit more like a... it's a focused antenna, so it radiates in one specific direction. And so there are the challenges you have to make sure that you're pointed at your other intending receiver or transmitter, and that you're within the window of radiation and within kind of the radiation beam, otherwise your signal is going to get more attenuated. For example, I think you mentioned like wind knocking an antenna off, if you have a directional antenna pointed right at the MWD shack, and the wind blows it, and it's now 30 degrees to the left, now your signal is going to get killed. Whereas if you had an omnidirectional, then you'd be fine, but you would also not have as much range. You're not going to have as strong of a signal between the two.

So, you would say in general that it's somewhat necessary to have a knowledge of the radiation patterns to be able to optimize your placement [inaudible 00:03:58]?

Yeah, it's certainly helpful. I think most the stuff I've seen in the field, and you've probably seen a lot more than I have, but it's either omnidirectional or like a patch antenna, which looks like our flat rectangle. So, ideally when you're selecting you get one with reasonably wide, not super focused beam, just so if you do have some misalignment, you'll still get a signal through.

Right? Yeah. So there's also been some difficulty that I've seen is from moving from one system to another, where they may get away with a different antenna placement or say like a less optimized placement of an antenna. And they move to a different wireless system that's with more bandwidth, and then it's requiring that they have a more optimized antenna placement. So, it seems like guys have found that to be a struggle, that concept.

Yeah. And one thing to keep into account is also, the 900 megahertz systems will typically get longer range, and a more resilient to interference in the path, but 2.4 and 5.8 gigahertz is going to have less range and be much more prone to getting the signal blocked by anything in its path, that kind of goes with the higher frequencies, can't travel through other materials as well as the lower frequencies.

Right. So like in general it would be more susceptible to attenuation, right?

Yeah.

So the higher the frequency, the higher the frequency, right?

Exactly. And so do you have any interesting stories from the field that you can share about any antenna adventures?

Well, how about this, I'll tell you about a scenario, and then you can use your knowledge to explain why this might've caused an issue or something similar.

Sure.

So get a call from a rig and the RFD is losing connection from the shack radio, and go out to location. And the first thing that you see when you go in the doghouse, is that not only is there a wire making a square pattern as like a way to block the drillers chair, that glass window from being hit, there's also a wired a window. And so it's my understanding that that might cause some issues in itself. Could you explain that?

Yeah. So in that case, what you're actually effectively having is a faraday cage because I mean, most of these rig floor, doghouses, it's all metal construction. So that's all shielded, because it's made out of a conductor, and then you have the wire mesh on the window, that then also blocks the signal, it's certainly going to attenuate it depending on the size of the mesh. It might attenuate it more or less, but you're building a faraday cage. And if you have the antenna inside that, you're not going to get a very good signal because your signal is going to be absorbed by that big metal box that you're in. So you really want to get the antenna outside the doghouse in that case.

Right. It can kind of be... I guess if you don't know what a faraday cage is, it could be something that's pretty difficult to wrap your head around because you're generally told to have line of sight between your two and tenants, right? And then you're like, "Well, I can see it just fine it's a window, and it's got wire in it, but they keep coming disconnected, maybe my antenna is broken." Right?

Yeah. So that is, without understanding a little bit about how faraday cages work in electromagnetics. I could certainly see the argument of, "Well it's line of sight. I see the other antenna." But the radio waves are not the same as visual actually, light is a way higher wavelength than any of these radios or shorter wavelength, higher frequency. And so to the radio that wire mesh might as well be like a metal wall.

So another scenario that I have, and I'd like to hear your take on this. So commonly we start to see is the rigs become more modern. We see more intrinsically, say doghouses and that means less holes in the doghouse to run cables. So oftentimes not always, but there's been a number of times where the holes in the doghouse to run the cables through, seemed to be on the opposite side of where the MWD shack would be. So, I know you and I had spoke earlier about the trade-off, right? So there's obviously a distance. If you're going to place your intent outside the doghouse, there's a distance there of extension cables that have to be ran. And then there's obviously the trade-off of dealing with the attenuation that might come from just trying to go straight through the window or the extension cables that you might have to add on in order to, get the antenna and in true line of sight without any obstructions. Can you give some advice on that?

Yeah, so that could be tricky. So sometimes might come down a little trial and error. I mean, if you can get a good signal through the window, [inaudible 00:10:09] wire mesh, then great. But I would think in most cases you'd be better off running an extension cable to get the antenna outside the doghouse, just because the losses from the cable, and all the connectors, just as a brief aside, anytime you have a connector or cable, your signal is going to get attenuated. So you do want to minimize that if you can, the number of connectors, especially, but also the length of the cables. But I would think that your attenuation from the cable, and running it outside, would be much less than through the window. So even if it's inconvenient, probably [inaudible 00:10:49] to have some good, long co-ax cables to extend your antenna reach width.

So if you can, let's say if you're in the field, and I'm MWD and I opened my kit box and I have some extension cables. If you're able to identify the type of co-ax cable on that, generally can the losses that you can expect to see from this particular type of co-ax cable be applied linear, like in a linear fashion, terms to maybe kind of have a maybe a rough sketch of how much is too much cable and how much attenuation?

I don't want to introduce a fear of cables, because like I said, probably getting a line of sight view with a cable in the system, versus trying to go through a window, or the wall, is definitely going to be better. But you have a loss with every connector, that's in the system, and then have a loss per foot for distance of the cable. But usually the loss of the connector contact is higher than the cable length, at least over a shorter distance. So, if you have one long cable, or you have a bunch of short cables that are hooked together, you're definitely better off with the one long cable.

Yeah. I don't want to speak for all MWDs in the field, but I know what my experience has taught me is that less connector's the better. That's one less connection to get dirt in, or bend to pain, and have to call into town and get somebody to, or make a drive to another rig to get another antenna, right?

Yeah. And same goes for [inaudible 00:12:36], the fewer connectors, the better.

Yeah, that's a good point. Definitely.

I think one of the other things that's important is to... I think this was a field issue you told me about, making sure that the antenna is for the right frequency. If you put a 900 megahertz in 10 out of 2.4 gigahertz system, it's not going to work very well. You might get a signal like really close range. So if you test it just, test both systems and then MWD Shack, you might get a signal, but once you get further away, it's going to, it's not going to work. So probably good to have all the antennas labeled with their frequencies clearly.

Yeah. Yes. For sure. And if you don't have that one thing that some people overlook and I've done myself is that, it might not say the frequency that it's tuned for, but usually there's some kind of number. You can just look it up on Google and that's a good way to do it, but yet one situation in particular on a rig recently, it's like the guys that had some connectivity issues, and I mentioned how important line of sight was, and they really took it seriously. And they were still having issues. And I'm like, "Man I got to go out there and see what's going on and help these guys out, because they put in quite a bit of effort from what they were telling me."

So, I went out and they definitely had. And I think this is probably the story that you're referring to. Brian and I were actually out at the rig, and I look up the antenna type, and I mean, these guys, they went to such a high level of effort to make sure that, they had to fill out a permit, got a man basket to lift them up to the edge of the doghouse, and put on these great looking antennas, omnidirectional, but unfortunately the cause of the issue was it was tuned for 2.4 gigs only. Whenever you looked up the [inaudible 00:14:37] number to the antenna, of course they're transmitting through 900 megahertz radio. So, that was definitely the issue, right?

Yeah. And I'm sure that can be easy to overlook when you're things up in the dark, company man yelling at you, under stress that's easy to miss, but that's certainly something to be aware of. And if you encounter that type of issue, just double check, make sure everything is the right frequency.

Yeah. It can definitely throw you off as well, when you're used to receiving a kit box and everything is plug and play. All the drivers are installed, all IP addresses are set properly and all the network settings, and then all of a sudden you get these antennas in your box and you plug them in and nothing works, "Well, what did I do different?"

Yeah. Well it was a lot of these fields connections, if the cables mate, if you can plug them together, that's probably the right one. But with a lot of antennas, you can have the same connector and they might fit, but it still be the wrong antenna for the radio.

Okay. So, I have another question for you. So, a couple of connector types that I'll see in the field, one of the primary ones I've seen recently are the big in type connectors, the larger ones. And then it seems like on some of the more modern equipment you'll see in the SMA, or RP-SMA, can you speak any about maybe the difference in these, or is this just a mechanical rigidity or is this a difference in efficiency as well?

From what I understand, the biggest difference is just mechanical size. As things get smaller, the RF connectors get smaller and smaller. Like back in the day, you used to have like a wireless card in your laptop, and you plug in PCI wireless card, and you had a little antenna connector on the end, and they just had to get smaller for that. And then the SMA was kind of I think a good balance between small, but not too small for typical use.

Yeah, no, for sure. And on the rig, I would say that generally the challenge is it's like... well, one of the ones that I would say most MWD texts would relate to, is you're usually dealing with one tiny three inch hole in the corner of a trailer, that you're trying to feed all these big cables through. And it's like you can never have enough room to run cables through that hole. I feel like it's always a fight. But I feel like that in terms of the mechanical rigidity of the doghouse side, it's just that much more important, because all the... we're talking about line of sight of they're going to run these antennas outside the doghouse and no telling, but either they might have lifts subs up against the same mall that you have to run the intended to, or just large iron in general, color class, tools that [inaudible 00:18:00] be like, just slice a SMA style cable in half, right?

Right. So, the field ruggedness consideration is certainly a factor. And just to mention, just in case, it's not clear that you can have an omnidirectional on one side, and the direction on the other side, that works too. You don't need to have necessarily two directionals pointed at each other or two omnidirectionals.

Interesting. So I have a question for you. So in terms of the industry and its general direction, it seems like push to go, remote or manless, I guess, where do you see MWD systems and where do you see them going? I mean, is it they're going to go back to just a hard line, or are they going to keep it wireless and we're going to see the intended technology improve as well? What do you think?

Well, I should ask you that question a little bit as far as what you're seeing in the field, but from my perspective, I don't think people are going to want to go back to hardwired anytime soon, just the radio technology is going to get better, speeds are going to go up, reliability and ease of use will hopefully continue to go up. Are you seeing anything different from what you're seeing in the field support side and in the actual field?

They're definitely using some more modern wireless systems I would say. Of course, I feel like being the industry, what it is, you're always going to have the guys that are real stuck in their ways and want to do it just the manual way, because you can see it, and it's simple, but like you say, I mean, when the main concern there, if you have a wired system, of course, is that you might deal with a forklift, or a piece of equipment and it could cut that, but, or your cable could go bad and you don't have anybody to replace it.

But then on the other end you have your wireless systems, and somebody could, knock an antenna. And not realize that you've done that. I guess I'm not really sure about that one, I'm yet to see any ultimate solution, as far as I'm concerned, I mean, like the newer directional antennas, obviously they have a lot of bandwidths capability, which is really nice, but again, they are directional and like you pointed out the radiation pattern is super important in terms of making sure you get the signal. And that opens up an opportunity for failure there, if you asked me, so...

That should include laser pointer in some of these directional antennas, so you can make sure it's pointed the right thing.

Yep. No, exactly. Some of them, I know Ubiquiti makes an antenna that has a level on the back. And then it's got LEDs to indicate the sending received strength, but-

That's really handy.

It is very helpful, but I just don't know how helpful that would be to, a guy when you're remote. I guess David you could designed us like a little joystick where we get in a motor. To adjust the antennas or something.

[inaudible 00:21:21] .

Yeah. Send a drone out to location, pull it over.

Yeah. Yeah. A lot of the drones actually ground systems, have antennas that track the drone, the fancy military ones. So fortunately the rig typically doesn't move that much, that we need to have a tracking system to track the rig.

Right. Well, I'm sure you can handle it. You probably do it. Have it done by Sunday?

Yeah. I can whip something up over the weekend.

Yeah.

All right. Well that's all the time we have for today. Thanks Clayton for bringing us some of your field experience and giving us the opportunity to discuss some troubleshooting.

Yep. Super honored to be here, David. Thanks for having me.

That's awesome. Thanks again. And thanks for listening, be sure to check out our podcasts on iTunes, Spotify, and YouTube. Thanks for tuning in to today's episode.