FlightAware Discussions

RTL-SDR ADS-B LNA back in stock

Just a heads up.

I saw that the RTL-SDR ADS-B LNA is back in stock after it was sold out and gone due to one of the chips not being manufactured anymore. I don’t know how it’s back but if you want one go grab it now! Check out the RTL-SDR Store.

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What benefits does this one have over the filter we are given with the kit from Flight Aware?

It’s more practical for the use case of a receiver that doesn’t have an LNA and filter in it already. (FA pro sticks have amps, and the blue one has a filter too). Also, it’s powered by bias tee so, with a bias tee compatible receiver or add on bias tee, it can be mounted at the base of the antenna which is the best place to amplify your signal if you have a longer cable from receiver to antenna.

I’m using this LNA on my test station and it is quite good with the AirSpy receiver. It is more powerful than some other LNAs for amplification.

But for optimal value/performance per $ spent, the FA blue and orange pro sticks can’t be beat in my opinion.

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When you say “given with the kit”, I assumed you were running a FlightFeeder.

The common dongles sold as ADS-B recevers typically have a (SAW) filter and an amp built in.
Receivers sold as general purpose (broad band) receivers, benefit from a narrow filter/amp to get the best out of them.
The RTL-Blog ADS-B offering has five stages being three filters and two amplifiers. So, if it suits your site, it has the potential for blocking more noise while enhancing your weak signals.

In the same way that a ProStick+ or RardarBox is a step up on the generic receiver, this is the next step.

Apparently the new batch has SAW filters that aren’t as narrow-band. (maybe 20 MHz instead of 10 MHz wide, estimating wildly here)
Still a good bit of gear but not quite as good as before apparently.

I hope that isn’t the case mine is almost delivered.

I could be wrong (I often am) but I believe you would need a very specific noise/interference signal range use case to notice the difference?

Yeah probably…

I was thinking the same - by the time an extra 10MHz BW is causing you problems, you are firmly into " cavity" territory.
@wiedehopf, did you see any part numbers mentioned? It may be that BW was traded for Higher Q (or some other desirable characteristic).

It’s 30MHz TA1090EC.
https://www.taisaw.com/upload/product/TA1090EC%20_Rev.3.0_.pdf

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Back side of both LNAs

The old is on top,
New one on bottom.

No someone who got a new part showed me a spectrum scan for his older model and the new model, the difference was obvious.

Well you might just be that unlucky :wink:
5 dB attenuation of some interfering signal can sometimes make enough of a difference.

For the bulk of users i’d hope the performance is the same as the old one.

Superb first post!
Welcome.

Oh … errrr … um.

Without a doubt, the PCB shown by @j4d looks the same as it’s always looked - yes?
the " double amplified, triple filtered" LNA - yes?

So where is the third filter?
(and why has it taken me this long to notice?)

Second thing I noticed, there is a green power LED on the PCB

Drill a hole through the case, cover it in clear tape and you’ve got a nice tell-tail your bias-t is working.

Because the first filter is a high-pass filter not a SAW IIRC.

Got it - thanks.
I didn’t recognise the two inductors on the input (two stage LC filter)

I has been there from day one. I wonder why the LED, if not easily visible.

As for the BW change from 10 to 30 MHz, I’m not so ‘accepting’ about it. I think it’s bad news for most ‘urban’ users. Could the original part also have become eol’ed?

Can anyone post high resolution photo of old pcb, like @j4d has done for the new one? Thanks.

Thank you @ca249

In old version, the filters (SF9175) were 8 Mhz bandwidth

http://www.bjzxsf.net/UploadFile/Files/201410181426182020.pdf