FlightAware Discussions

TV cable acceptance?

Hello forum users,

I have the following:
1/ FlightAware Pro Stick Plus
2/ FlightAware 1090 MHz ADS-B Bandpass SMA Filter
3/ FlightAware 1090MHz ADS-B N-Type Antenna 26" - 5.5dBi

I am installing FlightAware Antenna on the roof. I am having several TV Antenna cables running down the house and was thinking of utilizing them.

1/ Would that be a good idea?
2/ Should I have Bandpass filter installed as well or it is an overkill with Pro Plus version?

I don’t know the quality of the reception in my area yet, but it is not a very congested urban area.

Thanks in advance,

Jeff

For the question regarding filter:

I bought the blue FA Filter as addon to my blue FA stick (pro plus) and it turned out that the performance did not increase with filter. So it always depends on your individual environment causing noise. Many might need it for better results, some (like me) not.

And for the cable it depends if antenna or satellite.
I was running my installation with a five meter extra shielded low loss sat cable without issues.

UHF television cable is not particularly high quality, used mainly at frequencies around 470 to 700 MHz. It’s very lossy at 1090 MHz.

Use a much higher quality cable to preserve signal levels.

Additionally, TV cable is usually 75 Ohm. I assume ADS-B receivers need 50 Ohm cable.

Using the wrong impedance cable increases the signal losses.

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What about RG6 coax used with Satellite Dish TV? Satellite TV channels are in GHz frequency range, and the RG6 coax is designed for this frequency band

 

The Generic DVB-T is designed for TV (Digital Video Broadcast - Terrestria), and as TV systems use 75 ohms antenna & coax, it has an input impedance of 75 ohms. The specialty dongles like ProStick and RadarStick have a LNA chip which is 50 ohms.

That said, the reflection of power caused by 75 to 50 impedance mismatch is significant when transmitting, as powers involved is in tens or hundreds of watts. In receiving senario, powers involved are mili or even micro Watts, and losses are easily compensated by front-end amplifier of the receiver.

The 50 to 75 ohm mismatch causes SWR to change from 1 to 1.5, and power loss of 0.177 dB only.

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Whether or not you need a (additional) filter is not a question anyone else can answer for you (except perhaps your next door neighbour).
As you already have the filter, try with and without for (say) 24 hours each and see how it performs.

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That works. I am operating this since i started my feeding journey and it always gave me best reception. Of course it should be high quality.

My main receiver is currently using a different cable bought from Jetvision because of the connector on the antenna.

While satellite TV works on, for example, 10.7 to 11.7 GHz and 11.7 to 12.75 GHz, the signal from the dish to the house has already been down-converted to a much lower frequency. The so-called “LNB” is a filter, amplifier and down-converter.

The output from the LNB usually spans 950MHz to 1950 MHz and 1100MHz to 2150 MHz. Any cable which performs well in this XapplicationX frequency range will be great for ADS-B reception at 1090 MHz (or 978 MHz for that matter).

That’s not always correct.

Dealing with an amplified signal vs a signal straight of the antenna makes a big difference in regards to what loss is acceptable.

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Install an amplifier/LNA immediately after antenna and before the start of the coax. This will make coax losses acceptable. An example using this technique is in the photo below. :slight_smile:

The white coax is RG6, length 50 feet from amplifier to generic DVB-T

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I have 150 feet of RG6 coax after the LNB and I think the results are fine.

But they’d be better with Hyperflex 10 :smiley:

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I got the idea.

 
I will now replace my
IMG_27072020_200525_(137_x_90_pixel)
 
by
IMG_27072020_200423_(54_x_90_pixel)

:wink:

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As said by @abcd567 Satellite TV cable is very good for 1090mhz operations, can be used also for VHF/UHF airband with very good results, on a par with far more expensive coaxial cables, economical too. See first section of this post in my blog site.

http://www.merseyradar.co.uk/airband-radio/home-made-coaxial-dipole-antenna-for-civil-airband/

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Nah, waveguide is the way to go.

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Waveguide is a bit on the large side for 27.5 cm.

No need for a tower and low loss. Win, win.

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