FlightAware Discussions

Advice on graphs

Hi ,i got my first station up 5 days ago.
Current setup is:
Pi3
Flightaware blue stick
about 5m of RG6 and a pepsican antenna (design from abcd567 , thank you) which is outside on a plastic pole about 10m AGL
At first i tried to make a coco but the results where poor,about 50nm range.With the pepsican i have peaks to 200nm.On the graphs i have a big number of Tracks with single messages,what would cause this and how to fix it if it can be fixed.
Also any pointers looking at my graphs?

Thank you

Today i got the flightaware dark blue filter,lets see if it gets tracks with only one signal nr down.



Added pictures without the filter and with the filter

Unfortunately the filter did not help with the single messages which is still massive ammount.

200 per hour isn’t an issue at all, that’s perfectly normal due to noise being detected as a message.
Anyhow as long as you don’t get a second message from the same number (icao hex) it will just be ignored.

I’ve considered more than once to remove that as people are without reason always talking about that.

1 Like

Thanks wiedehopf for for making it clear.

Please don’t. For me it is actually quite useful to get some insights.

Mind you, the graph is not such a good representation because MLAT numbers were very high this week.

@SithEmperor Have you tried increasing/lowering your gain?

I mean remove the red (single message) tracks only.
But i’ll leave it as is … there something to say about consistency in something like the graphs.
(even if i’ve changed stuff in the past especially in regards to signal.)

1 Like

Since you were asking for opinions/advice - I’d probably lean towards retiring the pepsi can antenna since it won’t live very long outdoors anyhow. If you don’t have the equipment to tune it, there is no telling how flat it’s VSWR curve is (you want steep in your area due to interference) and it may very well be sucking in all that interference you have at 950 and 810Mhz, hence the single message count. In short, it appears to me that it’s working harder than it needs to be working. You can spend a ton of money working your system around a 50 cent homemade antenna, or you can get something that’s been tested and working for many others and remove your heartburn.

1 Like

@ PA1NT I have played a little with the gain, currently at 48.Will try some more
@ Nitr0 Thanks for youre input.I think i will go with the Flightaware antenna next.

I’d suggest you have a look at Vinnant antenna’s, too.

Decent prizes, good performance and good quality (especially the P-series). The FE-1090P has a low price, small, but a good performer.

If an antenna is sold out, just contact them. The owner/builder is Stanislav Palo, very friendly guy.

2 Likes

Thanks for the info. I contacted Stanislav and his 5 db gain Col antenna is on its way to me. Really nice guy to deal with. He didnt have my country listed in the dropdown menu and after contacting him he fixed it fast.

1 Like

I just started to use graphs1090. I think the bright red color attracts curiosity. Dim it may reduce unqualified attention. Meanwhile, I do think the measure of single messages is useful on that plot for one more reason: it helps assess quality of station. For this purpose, can you make a ratio available between total of single messages and that of the green track, similar to the “Messages > 3 dBFS” ratio displayed in the legend of the message rate graph?

I get almost same sucking of interference with a professional (FA) antenna and DIY (V-Stub) antenna :wink:

Actually most antennas will suck the noise. Their frequency responce is not steep enough to reject close interference. That is why filter, even “Triple-filter” are needed

 

 

@Nitr0
Please see my January 2016 post quoted below.

This was when I received my FA antenna and replaced Pepsi Can Antenna (Cantenna) by it. I was shocked to see that the performance dropped drastically. I thought it is either defective N connector or defective FA antenna. Finally I discovered that FA antenna sucks a lot more noise than the Cantenna, and saturated the dongle, causing drastic drop in performance. I then purchased FA filter and after adding it, the performance of FA antenna jumped up dramatically.