I picked up one of these Stratux 1090/978 splitter for my Piaware feeder and works very well and very impressed. I did not want to maintain a second antenna for UAT.
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6dB is quite a hit without an amp before it.
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What that black chip inside the red circle does? Is it a LNA? If it is LNA, how it is powered? As there is no powering arrangement, it is unlikely to be a LNA. Seems some sort of splitter.
Nothing mentioned in product specs on Amazon.
I think the black chip is the splitter itself. The is a passive deice – no LNA. As @geckoVN says, there is about 6-dB loss in this device. So if the device is directly connected to the antenna, you will have a 6-dB increase in noise figure.
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Yep - it’s the splitter.
This one is pretty similar
BTW, from an RF point of view, that is a horrible PCB.
The wide tracks are an attempt to maintain constant impedance but mashed it together into more of a blob.
The “vias” have been made using thermal isolating pads rather than “vias” from the library (they’d be quite inductive).
It’s obviously been laid out by a first timer.
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The seller is honest, as he clearly mentions “insertion loss (above 3 dB): 2.73 dB”.
Most sellers will tell only the “2.73 dB” part and omit the “above 3 dB” part.
This deceives most user who dont realize that in a splitter, the “3 dB” part is due to splitting power into two branches, each getting 1/2 power (i.e 3 dB loss). Internal attenuation of say 2.73 dB is in addition of this 3 dB. This makes total loss = 3+2.73=5.73 dB
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Also, I don’t like just having a bare board exposed like that – I would want it to be in a metal box.
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The best thing about that type of splitter is it won’t take up much space in your rubbish bin.
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If you read the post of @kc7hex (which I have quoted above), he says about this splitter: “works great”.
He does, but doesn’t say what he is comparing it to.
It might work fine for what he is trying to achieve, but doesn’t means it performs well in a technical sense.
RTL SDR’s are known for feeding a lot of noise back out their antenna socket - this is being added to the noise generated by the other radio.
The sudden impedance miss-match will cause all sorts of reflections and resonances.
Real splitters can be had cheap enough, so I’d put the $10 towards something a lot better.
($10 would probably buy you two TV splitters that would be better)
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Thank goodness this is just a hobby. I tried splitting the ordinary way with a T connector, then I used the splitter above with some improvement since the SDRs are now isolated. Not as good when I only ran the 1090 side. Now I put a NooElect LANA amp in front of the splitter and both sides really picked up the traffic. I knew of the insertion losses was going to be high but trying this against a standard V3 RTL-SDR at 978 and 1090 MHz on SDR# and the newest combination not only I am able to use one single antenna for both modes and get decent range on UAT. I don’t run a lab of sorts but mainly work trial and error. I do agree its not the greatest splitter nor am I trying to see this item but I think the next experiment is to make or find a simple metal case for it.
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Yeah, it’s just a hobby, but you can learn a lot from it. I know I have. I’ve learned some Linux and some networking, but would like to learn a lot more.
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Same here and for a few folks listed above, They gave me some great pointers in Linux and a few other topics.
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