I’ve made progress tonight. Using my Pi and my Cantenna, I was able to find which port was active in the house. Turns out the port in the room I wanted to put the Pi in was active. (What luck!) Then I connected the satellite RG6 to the cable box, and connected the Pi to the port in the wall. Surprisingly, I got some traffic on screen. Not much, but it’s there. I’m guessing an amplifier will be needed. But this is a good starting point. I’d like to see how this changes if I can get the cantenna to the roof.
One more “gocha” for the satellite amp is that it passes DC.
That is, the DC you feed up the coax to power it, also appears on the antenna port of the amp.
Careful antenna selection is required or the system won’t work.
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Insert a capacitor in ceneter wire of coax between amplifier and antenna, and it will block dc to reach antenna.
The left recycled tv splitter is a dc blocker
The right recycled tv splitter is dc power inserter
CLICK ON IMAGE TO SEE LARGER SIZE
Having just been through the calculations (for a different thread), what value capacitor would you recomend for minimum loss at 1090MHz?
I used 200 pF (see writeup on photo in my above post).
Reactance of 200pF at 1090MHz = 1/(2 x 3.14 x 1090 x 106 x 200 x 10-12) = 0.73 ohm
If you can find a “perfect” capacitor, that will be fine.
Do you want to try again using a datasheet for a product you can actually buy.
Mist are without proper specs. Only one found with specs.
Insertion loss @ 1 GHz = 0.3 dB
https://www.pasternack.com/dc-blocks-category.aspx
I would NOT waste the money on the satellite LNA, it might create huge problems if you have a cell tower close by! Any wideband LNA will do the same!
I don’t know why you don’t get the filtered ADS-B LNA that I linked above…
For weather proofing, after you wrap that with self fusing tape, you can cut the top of a plastic water/soda bottle and use that as supplementary rain proofing (the cut opening facing down of course).
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Seriously?
You are recommending someone spends $128 for a DC block so they can use a $5 amp?
https://www.pasternack.com/75-ohm-f-inner-dc-block-0.1-2-ghz-pe8240-p.aspx
My point was that the cap you used is not a perfect cap and probably has a self resonance below 1090MHz.
This morning, I did some additional testing. Using my indoor spider, which is currently how I run the setup, traffic message rates showed between 74-88 messages per second.
Since I worked out where the satellite coax is going in the house, I plugged directly into the wall and attached my cantenna to the end of the satellite RG6, stood out on my back porch and held the cantenna as high as I could, while looking at the map on my phone. Message rates dropped about 17%.
My current set up uses the Flight Aware Pro Stick Plus, which has the amp and filter built into the dongle. This has been a good experiment, but it seems if I want to take this further, the ADS-B LNA may be necessary. If that’s the case, how is power supplied to the LNA, if the LNA is wrapped up and attached to the connection end of the antenna? Is this where the power injector comes in?
Blockquote This has been a good experiment, but it seems if I want to take this further, the ADS-B LNA may be necessary. If that’s the case, how is power supplied to the LNA, if the LNA is wrapped up and attached to the connection end of the antenna? Is this where the power injector comes in?
Correct, the LNA is fed through the coax. DC is put on it by an power injector aka biaser (or a dongle with Bias-Tee)
edit:
A capacitor passes high frequencies and blocks low frequencies/DC
A coil passes low frequencies and DC but blocks higher frequencies.
So, if I am understanding this correctly, the LNA will be attached to the base of the antenna, and the bias tee will be inside the house with the power injector?
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Correct.
A few ft (<10 ft) of coax between antenna and LNA is ok though. Perhaps the LNA could be inside the exterior cable box?
On the photo of the bracket I spotted a cable box nearby. Is that the junction where the original cable from the dish ran to?
Bias tee:
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Yes. The cable box and the bracket are near each other, but greater than 10 feet. I’d say closer to 25 feet, plus the run to get it up to the roof.
[quote=“mwshell, post:30, topic:70444”] …if the LNA is wrapped up and attached to the connection end of the antenna?
[/quote]
Cut the top of a Pepsi bottle, and put it upside-down on top of the LNA. Snake the cables trough the bottom opening.
I did NOT recommend it.
I posted it in response to your query about insertion loss of DC Blocker. This one has a proper data sheet giving insertion loss figure. Most sellers do not provide insertion loss or capacitance figure.
Instead of using a custom 1090 MHz amplifier-filter combo recommended by me and many other members, if you have decided to use satellite amplifier, the sketch in this old (2015) thread shows how to feed power to a Satellite amplifier (I was using Satellite Amplifier at that time):
Help understanding the components between antenna and Pi
I’m leaning towards using the ADS-B LNA. I’ll just need to run it through an outdoor box. Since I also need the power injector, is this what is considered the bias tee?
YES.
Bias-T aka Power Inserter
https://www.amazon.com/Inserter-powering-subscriber-amplifiers-5-1002MHz/dp/B00D0UTKK8/
See here how the “Power Inserter” is connected
CLICK ON IMAGE TO SEE LARGER SIZE
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