FlightAware Discussions

Connecting Antenna via Coax Already In House

I am a novice in this hobby. I know practically nothing. But these forums have proven to me that there’s a great deal of expertise out there, so hear me out on this one…

Due to my inexperience the idea that follows may be ludicrously hilarious in its naivety, but here goes nothing…

My house had a satellite mounted on the roof, that I removed a couple years ago due to an approaching hurricane. I don’t use satellite service, so the dish was an eye sore. The mounting bracket is still there. If I could find another dish assembly (and I’m sure there are plenty out there), I could put a new mast onto this bracket and mount an ADS-B antenna to it. This would be the highest area I could mount an antenna without adding new holes in the roof.

The exterior cable box that runs into my house is only connected to one of the four existing lines that run into the house. All of these lines are RG6. In my house are 5 cable outlets: 1 in each of the 3 bedrooms and 1 in the living room, and one in the laundry room. (The internet line runs into my laundry room which is in the center of my house. From there, I have a switch hardwired to RJ45 ports in all bedrooms, plus a wifi router). I’m pretty sure that two of the cable ports are connected by a splitter, because they share opposite sides of the same wall.

My hypothesis is that the 3 unconnected lines run to the bedrooms.

If this is true, I want to ask:

  1. Would it be feasible to connect RG6 to the ADS-B antenna and run it into one of these lines to ultimately connect to the Pi in a bedroom?

    • There would only be two connections, one at the box and the other at the wall.
    • Would there be too much impedance (too long of line) for this to be feasible?
  2. Would an inline amplifier put at the antenna help resolve the issue of impedance?

  3. Is this unrealistic and just a pipe dream?

Thanks for any expertise! Cheers!

It’s not an unrealistic idea - I think you can get it working but as you guessed, you’ll need an amplifier. There are many helpful people in this forum that can provide amp recommendations (my setup doesn’t use one).

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I found this amplifier on Amazon. One of the reviewers said he used it exactly for this application along with a line injector, but that was dated in 2016. I am using the Pro Plus dongle. I wonder if a line injector would still be needed.

I use a 150 ft (45 meter) long coaxial TV cable between my antenna and my receiver. I have a LNA with ADSB filtering at the antenna - you can power the LNA via the same cable, via a so-called “bias tee”.

Some USB receivers can power the LNA from their internal 5V power, with a specific software command.
This is my LNA, 5V powered: https://www.rtl-sdr.com/new-product-rtl-sdr-blog-1090-mhz-ads-b-lna/
Amazon link: https://www.amazon.com/Performance-Triple-Amplifier-RTL-SDR-Blog/dp/B078TBG4H8/
You would need those coax adapters too: https://www.amazon.com/RFAdapter-Coaxial-Connector-Adapter-RTL-SDR/dp/B07WWNYHXM/
That linked LNA is not weather proof, I used a small box (7"x7") from HomeDepot. Both cable holes are on bottom of it.

It’s really a great solution for your location.

Yes, with a satellite amplifier, you need to feed dc 12v to 18v power through coax

OR

+

What kind of amplifier would you recommend?

Satellite amplifiers are cheap and good for 1090 MHz when used with Satellite coax (RG6). I have myself used a Satellite amplifier + 50 ft. RG6 coax successfully for 2 years during 2013 to 2015. At that time no dedicated 1090 Mhz amplifiers were available.

Currently dedicated amplifier for 1090 MHz are available, for example RTL-SDR Blog Triple Filter LNA, but wont fit RG6 coax without F to SMA adapters. Almost all currently available 1090 MHz amplifiers have SMA connector, while RG6 uses F-connectors. To fit these to RG6 you will need to buy SMA-male to F-female adapters.

Some dongles like “Flightaware ProStick Plus” have built-in amplifier. With this dongle, you dont need to arrange external power for the amplifier. It gets powered from RPi through the USB port in which it is plugged-in.

However for long runs of coax, it is much better to have amplifier closer to Antenna than to have it at the receiver. Ideal location of amplifier is immediately below the antenna, provided you can arrange to protect it from weather (rain, snow, sunlight etc). None of the currently available amplifier (Satellite or dedicated 1090 MHz) are currently rated for direct outdoor installation. Those who install these outdoor/roof top use water proof enclosures.

Would it be possible to wrap the amplifier with self fusing tape to protect it from the weather? If so, would the link to the amplifier above be ok to use with an antenna?

I never faced this situation as I live in an apartment and my antenna is indoor near a large window. However I remember people posting about protecting the amplifier by wrapping amplifier in self-fusing tape.

I also remember people posting about successfully using the Satellite amplifier you have linked in your above post. The one I used was RCA D903

CLICK ON IMAGE TO SEE LARGER SIZE

I’m using a Flightaware ProStick Plus, a $20 Nooelec LaNA Barebones - Wideband Ultra Low-Noise Amplifier, a Flightaware 1090 MHz filter and a FA antenna . The setup works better than my previous one with a RTL-SDR Blog Triple Filter LNA and a Nooelec NESDR Smartee. I like the Nooelec LNA because it can be powered by USB. There is no need to use a bias-T enabled stick or purchase a special bias-T power injector. I use a leftover wall wart USB power supply.

The problem however with these satellite amplifiers is that they are designed to be used at the IF frequency in a satellite receiving system. The signal level out of the LNB is relatively high and in such a system the LNB determines the overall system noise figure. The noise figure of the amplifier is then not really that important. Consequentially most of these amplifiers have a noise figure of about 5dB.
When you use an amplifier with such a poor noise figure with your ADS-B antenna it is equivalent to adding another 5dB of cable loss. This is the same as about 80ft of RG6 so, if your cable length is less than 80ft you would actually be better off not having the amplifier. Amplifiers designed specifically for ADS B use are low noise amplifiers. The noise figure is important.

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@LawrenceHill

Those days when Pro Stick and dedicated 1090 MHz amplifiers were not available, hobbyist were mostly using Satellite amplifier, and even with all the shortcoming you described, almost every one reported good enhancement by adding the Satellite amplifier. I myself am witness to this as I used 50 feet (15 m) RG6 coax from antenna in one room to the receiver in another room. My range was 50 nm without any amplifier. When I added a Satellite amplifier close to the antenna, my range jumped to nearly 300 nm and plane count jumped many-fold.

That said, definitely the dedicated 1090 MHz LNA give better performance than the Satellite amplifier as these use components with lower noise figure. I have myself discontinued use of Satellite amplifier after I purchased ProStick / Pro Stick Plus, and moved my Pi’s within few meters of the antenna thereby eliminating long (50 ft) coax length.

Yes, some sdr dongles are somewhat deaf and have a system noise figure of around 15dB. In this case, adding a 5dB noise figure pre-amp will be an improvement. However, if you are using a dongle with a noise figure of less than 5dB, then using a 5dB noise figure preamp will make things worse. It all hinges on the performance of your receiver. I believe the ProSticks are below 1dB NF so the 5dB amp would make things worse in this case.

This discussion has given me a lot of perspective. I am cautious to move forward though, as I’ll need to spend some money on supplies and equipment to get this set up right. I am cautious because I don’t know if the result will pay off in the end. Given the input generated on this thread, here was my initial plan:

  1. Satellite antenna mast for the roof bracket ($20)
  2. 100ft of RG6 cable to run to the cable box, cut and crimped to desired length, plus tools to test lines, cut and crimp ($45)
  3. Purchase one of Stanislan Palo’s ADS-B antennas with F mount for ease of connections (~$25)
  4. In line amplifier to connect to antenna ($20)
  5. Self fusing tape to weatherproof outdoor connections ($5)
  6. Power injector ($19)

About $135. It would be seriously disappointing to have everything hooked up only to see traffic less than what I am picking up now indoors, or worse, no traffic at all!

That’s what makes me nervous.

With satellite amplifier, I used Generic DVB-T (Black), one from NooElec, and other from eBay Chinese seller.

Your antenna seems ok, but as I have not used it, I invite those who used or know about it, to give their opinion / comment.

RG6 coax is also not bad, particulsrly if amplifier is installed near the antenna. However many members here are allergic to RG6 and recomend a costlier cable like LMR195 or LMR400.

The only thing which has options is the amplifier and its power supply arrangement.

With antenna outdoors and an amplifier, it will receive Cell/ Mobile and UHF TV signals. If at your location these are strong, then a high gain antenna installed outdoor may result in reduction in performance, unless you add a filter.

All this boils down to one thing: all this is trial and error.

Each location and setup is unique and results cannot be accurately predicted. Try and see results, if not satisfactory, make changes in hardware and hardware configuration and try again.

Also follow current trend of using custom 1090 mhz amplifier instead of satellite amplifier. I recommend RTL-SDR BLOG Triple Filtered LNA, a good performer at a reasonable price. With this amplifier, using RTL-SDR BLOG V3 dongle saves cost & headache of adding an external Bias-T as this dongle has a builtin Bias-T.

https://www.rtl-sdr.com/product/rtl-sdr-blog-ads-b-triple-filtered-lna-bias-tee-powered/

https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/

Now that I think about it, when I removed that dish, I didn’t remove the cable that ran from the dish to the house. I just checked it, and it appears to be dual RG6. It’s already cut to the the appropriate length. If this can be used to attach to the antenna instead, this would save me several steps, bring cost down and could likely make this project a possibility. Thoughts?

If the existing RG6 coax is intact, use it, why not?

Which antenna you are currently using? If not using any, make a DIY antenna such as Spider, and mount it on roof with temporary support, and connect to existing RG6 cable end at the roof. Do not add any amplifier. Connect room end of coax to your Dongle.

This way you can test with practically zero investment. Later you can go for further improvement by adding an amplifier and replacing Quick Spider by a commercial antenna.

QUICK SPIDER - No Soldering, No Connector

 

It worked! I have a cantenna that I made last week and hooked it up. There was some rust on the copper wire of the RG6, so I tried to brush it off with a wire brush. Wasn’t too successful. But even with that, I was able to pick up some traffic, albeit that it wasn’t too far out. The antenna was close to the ground though.

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Try to fix Cantenna or Spider on roof by some temporary support, and connect to the end of coax available at roof. You will need to fit F-male connector on end of coax at roof to connect to barel connector of Cantenna.

If you make Quick Spider, you can use a barel connector between the two F-male connectors fitted on coax end on roof and Quick Spider.