New guy here
So I’m running a Flightaware Pro Stick Plus and a 5.5 dBi no-name antenna on the roof. (looks like a copy of the Flightaware antenna) So the issue is that anything closer than 3-4 km drop out. I understand that this is a common problem, but some say it’s signal loss due to the donut effect, and some say it’s signal overload? (Un)fortunately, it’s only affecting the occational heli, but since i live in the middle of nowhere, it can take weeks between every time they are in the area, so I have to be pretty patient to tune this system… 
I’ve currently set the gain to 25, but not sure if it did anything, yet. Another thing worth mentioning is that I can’t reach out more than 50-100 nm anyway due to mountains in the distance, so in retrospect, both the receiver and the antenna was probably overkill for my application.
Any advice?
if budget allows replace the Pro Stick Plus with an AIrspy Mini…you’ll get more dynamic range (8 bit adc on the Pro Stick Plus versus 12 bit on the Airspy). this means you can turn up the gain to get those distant targets while not overloading the front end of your SDR (so you won’t have nearly as many overload related drop out issues)
Thanks for the tip, I will keep that option in mind.
you can also use the “Hey Whats That” app to find your maximum theoretical range (versus altitude). if you search this forum you’ll find some good instructions on how to use it…also search for postings from ABCD567 as i believe he has some good step by step stuff…also wiedehopf
Add this, you will see gain changes easily.
If you don’t care about max range or rather are limited, it will be simple to reduce the gain to a point where you don’t lose local traffic.
If you didn’t see the RSSI in your interface change, you did something wrong changing the gain.
For Beginners - How to Set / Change Gain
I was at a local airport yesterday with my ADS-B box and dialed my gain down to 14.4 so the business jets landing 500 feet away didn’t drop out. Their RSSI would peak around -1.8 @ 500 feet away.
Interesting. So what sort of max range did you get with this setting, and what antenna did you use?
Have you tried letting the gain auto range? Especially in a case where you only get near flyovers occasionally, it might be an advantage to let it auto range instead of going fixed gain?
You can also tell the difference from donut effect and oversaturation as they should have RSSI values at opposite ends of the range. Donuts get big negatives, oversaturation is small negative or positive numbers for RSSI.
No, I have not tried that, but I will put it on the list, Thanks!
Other than an airspy, you could also try a metal case for the dongle, to keep out some noise and possible signal overload.
https://www.rtl-sdr.com/product/spare-aluminum-metal-enclosure/
The rtl-sdr site had them at one time but have been out of stock for a while. I bought several a few years ago.
As @wiedehopf suggested, install his very useful graph package so you’ll see your range and aircraft signal strength details like this …
My antenna is a DIY 1/4-wave antenna like the ones in the picture below. I didn’t check the range on Sunday so I don’t know if a 14.4 gain would still pick-up aircraft at 100 miles. My guess is 30-50 miles.
Thanks again all! I’m actually waiting on a RTL-SDR that I will do some experimenting with, also have a DIY 1/4 antenna that I will try out. I will keep you guys updated, but it may take a few weeks before I have any good data
I checked the range today with gain @ 14.4 and it was only 20-25 miles. I’d recommend reducing your gain from 25 down to 20 to see if you now pick-up those close aircraft and still get coverage out to 50 miles.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.