Antenna recommendations

[PrivatelyJeff]

I’m putting together a raspberry pi based ADSB/UAT receiver system up in my house and am wondering if spending big bucks is worth it on antennas. The receiver equipment will be in a closet and I plan on sending to multiple tracking sites. There’s already good coverage over my area and my main area of interest is my local area to track public safety aircraft, which tries to obfuscate their info.

Is there anything to be gained by dropping big bucks on some of those 4.5 foot tall high gain antennas that go for $150 or can I go for the cheaper ones? It will be mounted to my house and the antenna will be at about 20-25 feet above ground level. I have no problem spending the big bucks, but I don’t also went to waste money if there’s nothing to be gained from going all out. I also have no interest building an antenna.

 

[mmckenna]

Remember that high gain antennas achieve their gain by smashing down the radiation pattern so most of it is pointed at the horizon.
Unless you are on top of the Sierra Nevada mountain, there's not really any reason to do that.
A lower gain antenna will have a better pattern for getting stuff that is closer in and above you.

I run an ADS-B site at work, and I'm using the cheap antenna they sent with it. It's about 18" tall. I regularly pull in aircraft from 270 miles out, sometimes more.

Put the money you'll save on the less expensive antenna into better coaxial cable. I'm running about 40 feet of LMR-600 on mine.

 

[mmckenna]

I'm a few miles in from the Pacific Ocean, and my antenna is right around 800 feet above sea level.
I'm getting hits off aircraft 280 miles out as of yesterday. I think my longest was somewhere around 320 miles.

 

[PrivatelyJeff]

Yeah, I’m buying the adsbexchange kit on amazon and it comes with some antennas I’m gonna start with. I may luck out with that, at least to start. If the receivers weren’t going to be in the dead center of my house in a wiring closet, I’d just get some basic antennas and put them near a window.

 

[vagrant]

Putting the antenna above your roofline will make a big difference versus in a window. A SAW filter and an amp will help, but can be added later and you can find combo versions of them. Also, a $40 ADS-B outdoor antenna is fine.

I am north of you and your feed will help between Fresno and Bakersfield. I use that $150 antenna so a $40 one will fill your area fine. No problem here with 250 miles, but when they get low, the earth gets in my way.

I am looking forward to your feed.

 

[PrivatelyJeff]

Putting the antenna above your roofline will make a big difference versus in a window. A SAW filter and an amp will help, but can be added later and you can find combo versions of them. Also, a $40 ADS-B outdoor antenna is fine.

I am north of you and your feed will help between Fresno and Bakersfield. I use that $150 antenna so a $40 one will fill your area fine. No problem here with 250 miles, but when they get low, the earth gets in my way.

I am looking forward to your feed.

IDK how much coverage my area has but it seems ok enough. I can usually pickup my counties airplane and EMS helicopters ok though there did seem to be a dead zone when the whole adsbexchange sale became public. If anything, I’ll just be adding in some redundancy for the lower altitude craft since the higher stuff will hit more/further off receivers. That’s also why I’m using UAT as well since I’m about a mile from my local general aviation airport.

 

[Ubbe]

Yeah, I’m buying the adsbexchange kit on amazon and it comes with some antennas I’m gonna start with.

It will be a big difference when using that 1090 filter that the SDR have as well as its amplifier. Not being able to have the amplifier at the antenna are not the optimum but better than no amplification at all. That adsbexchange kit seems to be a very affordable setup.

/Ubbe

 

[venom6733]

I ran a test about a year ago ago using the Flight Aware ADSB usb dongle,the Flight Aware Antenna for ADSB and the Flight Aware ADSB Filter. I didnt use any LNA on either test and my antenna is about 25 feet above the ground which is about 5 feet above my roofline.

I seem to have better results with the filter than without. The planes I pick up are as far as 200 miles away. Its not the best setup in the world by no means but It covers my area pretty good.

 

[vagrant]

@PrivatelyJeff - I need to add UAT, but not in a rush as the ADS-B gear for aircraft costs less, so…

Anyways, your feed will help. Internet problems, or whatever, will take systems offline and redundancy is good especially for MLAT. I easily catch the high altitude stuff, but everywhere needs help with low altitude.

@venom6733 - I had my filter/amp inline and along came a cell tower 100’ away years later. I never noticed a loss. As you noted, we are better off with one inline.

 

[venom6733]

- I had my filter/amp inline and along came a cell tower 100’ away years later. I never noticed a loss. As you noted, we are better off with one inline.

I live a mile from a 50kw FM station (which doesnt hurt 1090mhz too bad I think). In the pic I posted of the display listed as "no adsb filter" the signal at about 850mhz is a tower for a P25 Phase 1 system all the police and fire...etc use in my area and its about 3 miles away. Not sure the wattage but according to the FCC database it says 220.000 EVP