Is it worthwhile to add an LNA?


#1

Hello,

My setup consists of FlightAware Pro Plus (Blue), FA 1090 Mhz Filter, FA 1090 Mhz antenna, LMR400 cable, Raspberry Pi Zero W. I was on the fence about adding the filter or not since the blue dongle allegedly has a built-in filter, however I’ve experienced better results also using the filter and found it worthwhile. Now I am considering adding an LNA. I’m looking at a SMAKN LNA from Amazon:

amazon.com/SMAKN-Ultra-low- … +noise+lna

Anyone using this LNA (or any LNA in general) that can anecdote their experience and improvement? My antenna is ~50’ AGL on my apartment balcony. I’m seeing decent reception from the East, however I would really like to get it above the roofline to get more omnidirectional reception. It’s on the building wall blocking the W/NW, plus the terrain has a hill in that direction. Eventually, however, I’ll get it above the roofline. Until then, I’d like to see what type of improvements an LNA may add in all the other directions. From my background (SATCOM and Microwave Troposcatter in the Air Force), I’m assuming the best place to have the LNA would be directly connected to the antenna versus having it between my filter and receiver (dongle)?

I’ve experimented with different gain values using rtlsdr-gain and just leaving it at -10 for AGC was optimal.

Thanks!


#2

If most of your planes are captured at 200 mile, then maybe you will get an improvement. If they are at 100 mile, then you already are getting all of them - planes follow lanes, are not placed randomly on air.
Of course the only place you could put the amp is at the antenna, to compensate for the filter and cable loss (without increasing the noise).
Your best bet is raising the antenna above roofline, if is allowed by your HOA.


#3

Yeah, most are passing a VOR ~30 miles away, however there is quite a bit of traffic to my SE going in and out of Pittsburg (~200 miles) that I’m thinking an LNA may improve. My landlord said she’d have no problem with me getting it over the roof. Perhaps even on the roof. I’ve helped out with them in the past (setting up CCTV cameras), so they are cool with me. :grinning:


#4

I added a LNA4ALL and it improved my system no end.
lna4all.blogspot.co.uk/

You can run it with a Bias-T feed to simplify powering it.

Nigel.