Poor performance with antenna plugged directly into ProStick+


#1

So I’ve been playing around with various combinations of setups to see which works best for me using the components I have to hand. I’ve just tried plugging my Nooelec 1090mhz ant directly into the ProStick+ and then connecting to the rpi via a very short (good quality) usb extender. Performance was terrible, as in 10% of the flights I used to get - you can see it clearly in my recent stats. I had been using a very cheap ebay 1m sma lead (that is as thin as an old fashioned shoe-lace) to connect to the ant and had assumed that direct connection would be better, but in this case I appear to be wrong. Have I done something wrong ? And what are your thoughts about the best way to connect the pi to the stick, and the stick to the ant ? I’d welcome any suggestions you may have.


#2

2


#3

if you have strong interference the prostick+ internal amplifier can be overloaded so a cable that reduces gain can actually be useful in certain cases.

also the usb extender may be of good quality but that is still no guarantee that it does not create problems/interference.

try it without the usb extender maybe? or are you talking usb cable (extender is an active component)


#4

Its just a short usb cable - 10cm at most. Its not an active extender, sorry if I used the wrong term. And the gain idea is one I will explore - I’ll play around with the gain settings as I am near the centre of a busy city with lots of interference.


#5

Are you sure that the cheap SMA cable is making contact with the prostick input? Could it be a reverse SMA adapter cable (check there is a pin on the plug that goes to the stick)?


#6

i mean the internal pre-amplifier can be overloaded by interference, you can’t fix that with the software gain setting. only by a weaker signal or filtering before the amplifier.
have you tried your previous setup with the same antenna position?


#8

Built by @TomMuc. Antrnna directly connected to dongle.


#9

I’ve tried several USB extension leads (including very short cables) and without fail, they all have a detrimental effect. Clipping a ferrite onto the cable (or using a commercial cable with molded ferrite) is even worse.


#10

Thanks for all the replies - I decided that directly connecting the stick to the ant was a bad idea due to the location (in a window, in direct sunlight) so I revised my setup again…

I got a tin can, drilled hole in the bottom and attached it to a new 50ohm coax extension cable with the supplied nut. I then plugged the ant into that and well, wow what can I say. The number of aircraft detected doubled from the day before, and the range has greatly increased, so thank you abcd567 for your pictorial response. I also tidied up the pi and prostick so everything is nice and neat.

The Antenna . The Pi (and pilot)

I’m really happy with the performance now, especially as the ant is indoors and in the middle of a city.


#11

Congratulations.
Glad to know you managed to not only to solve your problem, but also got substantial improvement.
Happy experimenting, DIY is fun.


#12

Next I want to a Led strip/ring so I can see the volume of traffic without needing a screen. I’m working on installing the led driver, just need to figure out how to get the value from the dashboard and feed it into the leds. Python probably, I need to do some reading.