FlightAware Discussions

Antenna Up High -- Finally

I was finally able to get enough cable and the right mount to move my wall-mounted antenna to a chimney-mount antenna tonight. I still don’t have QUITE enough cable to route it the way I want, so I’ll be ordering some 60’ or 75’ cable soon, but this gets me up high, and that makes me insanely happy.

Setup:

  • FlightAware ADS-B antenna & Orange Dongle into a Pi B+
  • Wilson Electronics 50’ LMR-400 coax
  • Skywalker Y-Type Chimney mount kit
  • Skywalker 4’ grounding rod
  • 50’ 10ga grounding wire
  • Gas Tube Lightning arrestor
  • Channel Master 5’ steel antenna mast

Hooked all up tonight and instantly started tracking about 3 times the number of aircraft as I did for the same time of day beforehand. So incredibly happy about it. Need to get the cable length right and routed down some conduit and then add a 978MHz antenna at some point in the future before calling it done and good.

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Just order the additional length (SMA femal to SMA male).
That way you don’t even need to get back on the roof.
And if you want you can at that junction even add an amplifier.

This combination should be plug and play without the need for further configuration/ bias-t:
https://www.amazon.com/NooElec-NESDR-SMArTee-SDR-R820T2-Based/dp/B079C3FHPG
https://rtl-sdr.com/new-product-rtl-sdr-blog-1090-mhz-ads-b-lna/

The LNA goes in between the two cables.
(closer to the antenna would be better but as you already have very good quality cable and you can install it indoors, it’s not an issue)

Should give your reception yet another boost.
That LNA has very nice filtering which improves reception quite a bit.
Be sure to get the filtered one marked ADS-B

The money you save on the one-piece cable is probably nearly enough to pay for those two devices.

@tarsi210 - nice job. Is that a 2 story house?

The preamp would be good to compensate for all the cable loses and add filtration (that’s why is better to be closer to antenna), especially for long cables.
But since you already have the orange stick (with preamp inside)… the improvement will not be that spectacular as the one given by raising the antenna.

I would recomend to do a drip loop at the bottom of that cable, before coming in the house. Unless you like rain water to be draining in the house…

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Setup looks good.
Be sure to tug on the SS straps a bit and re-tighten, they tend to loosen up a bit over time.
You could also add another 5ft segment to your mast, since you’ve got a nice size chimney.
You may want to add a split to your ground wire as well and ground the mast as well.

Definitely add another 5ft section

Hey thanks for that advice, so I have a few questions – first, I’ve already got 2 sections of cable strung, that 50’ it’s on right now is 20’ + 30’ with a connector in between, so adding yet another section sounds…ill-advised for the connector loss, yes? Better to order a 75’ section and call it good and have zero connectors at all was my thought…

The NooElec NESDR – compatible with PiAware and works fine just like the FA dongle? I’d have to put all that on the receiver side because once it converts from the small SMA cable up to the N-connector LMR-400 it’d be nice to not have to reduce it down, and then back up, for the antenna side. So the connections would go (in order): RaspPi --> NESDR --> LNA --> SMA-to-N pigtail --> 75’ cable --> lightning suppressor --> antenna. Look right?

What do you think about also adding in a FA bandpass filter for 1090? Would that further help clean up the signal as well? Or is the LNA filtering down for 1090 already?

Yup, two story house. Well, actually story-and-a-half, but yes.

:slight_smile: Yup, got that right now in the temporary configuration. Once I get the correct cable length, it will come off the roof and into a service masthead (similar to an electric masthead) and into a 2" conduit that runs inside the studspace to the basement, and then dumps out there. Because I am siding our house right now, I was able to run that inside and then have it exit the building and go into a masthead. So that will provide a drip loop and cover and so forth when done.

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I wondered about that – will do, thanks.

Ok, what I’m concerned about there (and maybe this is stupid and not even a concern) was lightning attraction. If I go another 5’ up, will I therefore greatly increase my lightning risk? At that height, it would start to be one of the tallest things in the nearest block and a half or so, although there’s still probably a tree or two that goes higher than that. Didn’t know what my risk was if I made it taller. Thoughts?

I thought about doing that. I mean, in theory, it is because the connector on the antenna is grounded to the antenna bracket and the antenna connector is directly connected to the surge suppressor HOWEVER that is only the case during a strike and not all the time. Maybe to avoid the antenna mast from resonating or getting a charge of any sort I should ground it out, too.

Yeah, see what I answered to someone else – how much do I increase my lightning risk if I do? Or none at all? That was my only concern.

xkcd talks about lightning here: https://what-if.xkcd.com/16/

To figure out where lightning is likely to hit, you roll the imaginary 60-meter sphere across the landscape (for safety reasons, do not use a real sphere).

The tl;dr as I understand it is that increasing your mast height will only really make a difference if there are nearby things that are a similar height to your current mast.

Well, if you put everything at the receiver, a one piece cable and having less cable loss is desirable.
But with LMR400 and N connectors i wouldn’t worry too much about having sections.

But the point of the LNA is to be as close to the antenna as possible.
Once the signal has been amplified, a few dB loss isn’t as critical anymore.
That’s why i proposed the LNA for extending the cable, no worrying about connector losses once it’s amplified.

So If you want to avoid going back to N connectors, maybe just place the LNA at the end of your existing cable combination.
Then you can go the rest of the way to the receiver with a cheaper LMR200 cable with SMA connectors. (which still has quite low loss)

Or put the LNA after the first 20’ section, if that’s already indoors.
As i said converting back to N shouldn’t be an issue.
Or you could get the rest of the cable run to the receiver in SMA to SMA LMR200.
After all N to SMA adapters do cost something as well :slight_smile:

After the LNA you have to use really bad coax to degrade the signal noticeable.

That i would only think about with the Pro Stick Plus.

The LNA cleans up the signal very nice, no need for further filters.

Definitely ground the mast and run that ground wire down to the ground rod, it’s required by the electrical code. You won’t get insurance to cover the lightning strike fire/damage if mast is not grounded.
The #10 wire is probably OK, but recommended is something beefier like #8, mainly for mechanical protection.
I would not run that under the siding. You want the source of fire (in case of a strike) close to the wood studs? Just run it outside, even if is ugly.
Even if the lightning strikes only the antenna, the isolation of the cable means nothing, it will arc trough to the mast.

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Yeah, or if my object is THE tallest in the area, which would then the be next logical spot for the leader to branch to. Thanks, I had read that before but didn’t remember the points. I’ll have to go back up and scope out the area and see; if I recall correctly, at its current height, there are still plenty of trees nearby that are taller. Add another 5’ and it’d probably be even with the trees. Another 5’ on that and it’d be the tallest thing around. So…

Got it. Now the question becomes – can I somehow box in the LNA so it can be mounted on the antenna? And if so, can I have the Bias-T device on the receiver end and push the power up the line to the LNA? I presume so. I’m afraid I’m a newbie when it comes to this stuff – far as I can tell, a Bias-T is just a power injector, right? So in theory I can have that on the receiver side of the line with the LNA on the antenna side and feed it up the line? Or does it need to be near to the LNA to work?

Sorry for the questions, learning quickly. :slight_smile:

The rtl-sdr receiver i linked has the bias-t built in, if you use that you don’t need to worry about that.

The bias-t injects 5V and the rtl-sdr LNA will work fine down to 3 V according to spec.
I’ve used it at 2.5 V without a problem.
So you can have as much coax in between as you like.

I’d suggest saving yourself the hassle and just installing the LNA at the first opportunity indoors.
With LMR400 the loss is minimal anyway for 20 or 30 ft.
Even after the combined 50 ft it’s gonna be fine when using LMR400.

I just looked at your receiver and you already have quite good reception.

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Fair. And for the record, I am – and was always planning – on running the ground wire outside of the house, even if the signal cable was running inside the conduit.

Yeah, I’m pondering on that. See below for pictures of what my setup is with the masthead and so forth. I have a DTV dish, a WiFi directional antenna (for Internet off the local water tower), and a few upstairs coax runs that I’m planning on sending down through it, along with (originally) the ADS-B antenna setup to ensure that, from that point in the process, it was in conduit and not exposed for neatness/weather exposure/etc. Yes, you’re right, there’s likely a higher risk from a fire caused by a strike so it’s not a non-concern. It’s a balance. Thinking…

:slight_smile: It’s greatly improved over the little whip antenna I started with in my basement howevermany months ago. But as you probably understand, once you get a little better performance in this hobby, you’re like, “HEY! How much MORE can I get!??” It’s a never-ending pursuit to see what you can eek out.

I ‘push’ 5V along 100 ft of RG-6, no problems.

Then everything is ‘ruined’. One is not happy with anything anymore.:joy::rofl:

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That was me when the power supply couldn’t cope with the heat and the Pi was running undervolted and underclocked :slight_smile:

Ok, I took the advice and purchased the RTL-SDR LNA, a 1-meter lead, an N-to-SMA adaptor, a waterproof box, and the NooElec NESDR Smartee and tonight installed it all.

Holy crap! What an improvement! :slight_smile:

I was impressed that PiAware just recognized the NESDR without any further fiddling around – it just worked out of the box. That made life easier.

I mounted the LNA inside the waterproof box and sent the N-to-SMA converter and the 1-meter lead through the bottom and also sealed with silicone caulk to ensure it wouldn’t get water inside. Then climbed on the roof tonight and installed on the mast just below the lightning arrestor. And while I was up there, I split the ground wire and grounded the mast as well.

Before I disconnected the lead, I pulled up SkyView on my phone just to see what I could see. Roughly 100 planes, 85 with position, and about 330 messages/second. Once I got everything plugged in, SkyView started to light up quickly, hitting 185 planes, 135 with position, and about 667 messages/second. Incredible.

So thank you to all of you who had those suggestions. That definitely made a huge difference.

What’s next? I’ll probably purchase another 5’ antenna mast and extend upwards another 5’. I think that still keeps me below the top of the trees but height is king. I also want to get into 978, so need to start musing about that, but maybe not till spring. Depends on the budget. :slight_smile:

IMG_7093 IMG_7095 IMG_7096

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