Testing FA Antenna


#1

I got interesting problem and wondering if there is a way to test and verify my new FA ADS-B antenna is working?

When I plug that antenna in to my FA+ receiver, I seem to not be able to track much if any traffic. However if I plug say a scanner antenna directly in to the receiver, I start getting traffic updates when I check out my live RPi tracking page. The FA antenna is on the roof as well and I would think I should be getting lots of updates from one outside vs inside. So I am wondering if I got a defective antenna. Thoughts?


#2

99% chance you have an issue with your cabling. Check if you have SMA vs SMA-RP connectors. RP would be incorrect.


#3

DIFFERENCE BETWEEN SMA AND RP-SMA

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TEMPORARY WORKAROUND
The SMA-male has center pin. The reverse SMA (RP-SMA) male does not have a center pin, it has a hole. The center wire connection is open because of missing pin. A temporary workaround is to cut a short piece of center wire of coax and insert in hole of RP-SMA male. This piece of wire will act as the missing pin, and connection will be established.
.

RP-SMA Worksround


#4

Yeah I verified that is not the case. I had this cable custom made and double checked no shorts. My connectors look like the sma.


#5

Are you using a filter?


#6

Not using an external filter. Just the flightaware plus blue receiver with it built in.


#7

Unless you live out in the country, suggest you get the FA filter.


#8

AGREED

Locations with lot of RF noise (Cell phone & other communications signals), do require an external filter both with ProStick (orange) and ProStick+(blue).

I live in a high rise building in an urban area, with lot of Cell Phone antennas on roof top of my building, as well as on roof top of many surrounding buildings.

My setup does not have an external amplifier, as the ProStic/ProStick+ have an integral amplifier. Adding a FA filter to both ProStick (orange) AND ProStick+ (blue) did improve performance. Here is result of a test I conducted last year. Gain setting was constant throughout the test:

Pro_Stick_Plus_Needs_External_Filter


#9

Well I will get a filter anyway. I don’t think this is the problem but a filter wont hurt even if the FA+ receiver already has one built in. Keep in mind I can plug a rubber duck scanner antenna directly in to the FA receiver and I get tons of traffic as is.

So here is what I am seeing now. If I barely thread my SMA cable on to the FA receiver, I will start to see messages increment on the live tracker. If I continue to thread the sma cable on more, it just stops. Even when I am receiving messages, at best I get about a 40 miles distance with my rooftop FA antenna. My antenna sits above the house peaks so I was expecting a bit more from this which is why I think the antenna or cable connector is messed up.

Is there any continuity check I can do with the FA 1090 antenna?


#10

The FA antenna test requires a signal generator at 1090MHz (the ADS-B frequency) and comparing the return signal from the antenna. The test equipment cost much more than the antenna.

40 miles range is like any random wire antenna range. You can literally place any bare wire on the end of the coax and should see something this far every so often. It doesn’t require much to pick up a signal that far.

Good tuned antennas will pick up both range AND message count. If you are only getting range but no message rates comparable to the range there is something wrong with your antenna or cables or something.

If you look on your ADSB stats page it will have a section near the bottom called “nearby sites”. It will list nearby sites and their plane count (this correlates very well with range) and message count.
https://flightaware.com/adsb/stats/user/deltaleader71#stats-69282
It is showing your site at 217 planes and 7600 message count in the last day.

This site is a few miles away and is a good comparison.
https://flightaware.com/adsb/stats/user/guidero
637 planes and 136,973 messages

Yea, something is not working. Hard to tell what is it at this point.


#11

The FA high gain (6 dB) antenna picks much more cell phone signals than a low gain rubber ducky picks.
As a result, FA antenna gives poor results without a filter, while rubber ducky gives good result without filter.

I have experienced this phenomenon with a low gain 1/4 wave (Spider) antenna. Please see below the test graph from last year:


#12

@deltaleader71

To determine what Interfering RF Signals are picked by your FA Antenna, use the method described in the thread “Do I Need A Filter?”
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#13

After further troubleshooting this problem. I think it is a bad SMA connector. My test was simply to connect the receiver center hole to the sma connector center pin on the coax using a piece of copper. When I did this, the live feed lit up with messages out past 125miles. So I am thinking the SMA connector is messed up.

I just need to figure out how I am going to get this fixed now. I did also order a filter and will install that as well.


#14

This seems a typo. The receiver sma has a center hole, not a pin.

The coax center is a pin if correct type (sma-male), and a hole if wrong type (rp-sma)


#15

Correct, sorry…it’s a center hole. So copper in center hole to the center pin on the coax is what I did…