Low message rate with Pro Stick


#1

Hello all,
Since getting the Pro stick, i’ve noticed the message count / sec is much lower than the other sdr dvb sticks

The first day I got the Pro Stick I got extremely great results for the first hour or two, and then after it has been downhill.

I decided to get the Filter for the prostick thinking this will improve things however it is still the same

Right now :
Aircraft (total): 24 Messages: 44.6/sec
(with positions): 15 History: 2862 positions

I believe previously I could easily get 100+/sec or even 200 msgs / sec

Is there something I’m doing wrong ?


#2

Double check the antenna connection and the range you are seeing aircraft.
I definitely saw a major improvement when I added the FA Pro Stick.

Do you have a filter? Without one, you may need to reduce the gain.
Here is how to do it
flightaware.com/adsb/prostick/setup/
Even with a really good filter, I needed to reduce my gain a little.
I depends on how much RF interference there is in the area.
Singapore is a congested city, so I expect that there will be a lot of interference.


#3

Yeap I have the filter!
Still stumps me. I can even get aircraft some 100+nm away. but the message rates are so low. rarely exceeding 60 msgs/sec. Is this normal?


#4

Where do you get the rate data? I can check and see what mine is to compare to see if what you’re getting is normal or not.


#5

I see that your aircraft numbers went down, but your position reports when up, a few weeks ago.
Your stats are great. Better than the flight feeder in the area. You have the most position reports and are second in aircraft.
What type of antenna are you using?

@Solidjake,
dump1090-mutability gives realtime aircraft with and without positions and messages per second.
(I am in a really busy area. 3 major airports within 15NM(4 if you include a GA airport). Even with the antenna inside the attic, I peak at 1100-1200 messages per second. One unit, with antenna 3ft off the ground, gets up to 600 msg per sec)).


#6

I am using this antenna :
ebay.com.sg/itm/2-5dbi-ADS-B … SwI-BWOWnH

I’m surprised that even with 30 aircraft around me, I still get about 40-50 msgs / sec


#7

I have a few of these in my basement setup.
Ensure that the mcx connector is firmly plug into the mcx/sma adapter.
I (and others) found that these antennas are finicky and a slight movement alters their effectiveness.
Do you have a good groundplane base? I know someone did some testing, however, I can’t find the thread.

This thread has info on optimising gain
ads-b-flight-tracking-f21/gain-adjustment-t37172.html
The script will give you an idea if you are way off.


#8

There is no ground plane base as it is on a non metal surface. Would this be a problem you reckon ?

Then again doesn’t explain why previous receivers worked fine… Hmmm

I could try to put it on a metal disk


#9

You might take a look at this thread on antennas:
ads-b-flight-tracking-f21/trial-run-results-for-four-sizes-of-ground-planes-t37344.html


#10

Have you tried putting back the old dongle?
If it is still significantly then you need to work in it. If not, then no issue.


#11

Sure the metal disk/sheet/can helps a lot. I conducted an experiment last week to compare different sizes of ground plane. Found mag mount when placed over a metallic can/disk/sheet of 70mm dia or more, improves a lot. Please see details here:

Trial Run Results for Four Sizes of Ground Planes

This antenna is useless. I have conducted an experiment last week to find the best mag mount antenna. I found that the stock whip (which came with generic black dongle), when chopped to 52 mm length, gets optimum prformance.
Please see details here:

Trial Run Results for Three Types of Whip Antennas

.


#12

Where do you measure the 52mm from ?
Is it from the base of the antenna ? or is it measured with the antenna unscrewed from the base


#13

I agree with the others on a better grounding plane.

I see that on the “My ADS-B” page in the log I have the following info coming from my pi

[2016-05-28 09:44 EDT] mlat(901): Receiver: 520.0 msg/s received 8.7kB/s from receiver
[2016-05-28 09:29 EDT] mlat(901): Receiver: 479.9 msg/s received 8.0kB/s from receiver
[2016-05-28 09:14 EDT] mlat(901): Receiver: 480.7 msg/s received 7.9kB/s from receiver