Busted it...


Swapped out my yellow pro-stick and filter for the blue pro-stick yesterday, at the same time I moved the pro-stick to the base of the antenna to shorten the coax run. The cable is now probably only 10cm.

When I fired everything back up, results have been very disappointing. I have been doing gain surveys but can’t get close to the range performance I had. Could there be an issue with the pro-stock being so close to the antenna? Interference maybe?

Anything else I can try before I climb back on roof and pull the mast down again?


Setup looks a bit like this:


System(1) My Ras Pi and Filter+Orange ProStick are connected to FA 26" antenna (gain 6 dBi) by 4 ft RG6 coax, and doing excellent. When keeping every thing else same, I replaced Orange ProStick+Filter combo by Blue ProStic Plus, my message rate & aircraft count went down to 40%. After adding external filter, it went to level of Orange ProStic+Filter combo.

System (2) My Orange Pi PC and Filter+Orange ProStick are connected to Cantenna (gain 1.5 ~ 2 dBi) by 12 ft RG6 coax, and doing excellent. When keeping every thing else same, I replaced Orange ProStick+Filter combo by Blue ProStic Plus, it performed slightly better than Orange ProStic+Filter combo.

From above I concluded that high gain antenna results in picking lot of cell phone signal, short cable results in negligible attenuation, and a very strong signal is fed to rf preamplifier. Since the built-in filter is after the rf preamplifier, the cell phone signal is not removed at input, and overloads the front end RF pre amplifier. Adding filter before preamplifier chops off cell phone signals and overload of front end preamplifier is no more there.

I have now ordered two attenuators (3dB and 6 dB). Waiting for delivery from China, not less than a month :frowning: . Will try these to find if my opinion is right or wrong.


Hmmm OK, I might try and cram the filter in there, may have to rebuild the enclosure, not a major it’s just some pipe.

Also read about disconnecting the USB ground at the Prostick end as there is a very long shielded USB cable and apparatly the sheild picks up signals too.


Adding filter didn’t help, just went back up there and put the yellow stick back, all seems good now :confused:

  1. Did you put back Yellow Stick only, or Yellow Stick + Filter?
  2. What is the type and gain of your antenna?

  1. Back on yellow + filter
  2. 6 dBi colinear (ebay.com/itm/Omnidirectional … 3NOXaZFQcw)


I had same situation with 6 dBi FA 26" which is Wire Collinear, but adding filter restored things. I am surprised to hear trhat in your case adding filter did not help. I am now waiting for 3 dB & 6 dB attenuaters, will try these instead of filter.