# BiasT recommendation
**URL:** https://discussions.flightaware.com/t/biast-recommendation/82979
**Category:** ADS-B Flight Tracking
**Created:** [May 27, 2022, 5:56pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979 "2022-05-27T17:56:01Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)
#### Post date: [May 27, 2022, 5:56pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/1 "2022-05-27T17:56:01Z")
Hello, looking for BiasT recommendations as I want to install the uputronics LNA on a 15cm patch lead from my antenna but the RTL-SDR only outputs 4.5v and the LNA spec is 5-26v
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### Author:  [@tomvdhorst](https://discussions.flightaware.com/u/tomvdhorst)
#### Post date: [May 27, 2022, 6:23pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/2 "2022-05-27T18:23:13Z")
you could power it from a USB port ( if you are using a Raspberry Pi offcourse). Standard voltage for a USB port is 5 volts.
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### Author:  [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)
#### Post date: [May 27, 2022, 6:29pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/3 "2022-05-27T18:29:17Z")
It’s currently powered from a USB on my PI, but I want to install it as close to the antenna as I can but need a BiasT after dongle though.
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### Author:  [@tomvdhorst](https://discussions.flightaware.com/u/tomvdhorst)
#### Post date: [May 27, 2022, 7:42pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/4 "2022-05-27T19:42:24Z")
Ah my mistake, I thought you had only 15 cm between the Pi and the antenna but that’s the dongle and the antenna.
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### Author:  [@caius](https://discussions.flightaware.com/u/caius)
#### Post date: [May 27, 2022, 11:06pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/5 "2022-05-27T23:06:50Z")
I use one very similar to this: [Bias Tee 10MHz-6GHz Broadband Radio Frequency Microwave Coaxial Bias SoftwaBias 4894909151576 | eBay](https://www.ebay.co.uk/itm/194992593395?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=RL2JOgfaTJS&sssrc=2047675&ssuid=0vb_8KARSf-&widget_ver=artemis&media=COPY)
It’s a bit more expensive than when I bought it, but that seems par for the course these days. It works fine. You could also try the amp on the built in dongle bias-t. You might find the 0.5v difference isn’t significant enough to make a lot of difference.
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [May 28, 2022, 10:40am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/6 "2022-05-28T10:40:54Z")
> [@Jonseyt23](#):
>
> the LNA spec is 5-26v
The standard board doesn’t have the VReg for such a wide input. You need to add it yourself if you need it.
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### Author:  [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)
#### Post date: [May 28, 2022, 11:36am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/7 "2022-05-28T11:36:18Z")
I’m just going off what it says on the uputronics website and on the case itself, so I have to open it up and add something if I want to use bias T on it?
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### Author:  [@biekerc](https://discussions.flightaware.com/u/biekerc)
#### Post date: [May 28, 2022, 1:19pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/8 "2022-05-28T13:19:36Z")
„ March 2020 we have fitted improved SMA female connectors for antenna input and radio output to address the issue of the SMA barrels coming away. Also the **Bias Tee regulator kit** is now fitted as standard. At this time a ceramic filtered version of this unit is no longer available.“
From uputronics website, maybe that allows you to run the bias t voltages mentioned?
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [May 28, 2022, 1:45pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/9 "2022-05-28T13:45:12Z")
> [@biekerc](#):
>
> Bias Tee regulator kit
Good start.
Easier to just check the specification of the LNA:
[Uputronics](https://store.uputronics.com/index.php?route=product/product&path=59&product_id=50)
> A regulator is fitted as standard which means the bias-tee voltage input range is 5V to 26V. USB input is 5V.
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [May 28, 2022, 1:46pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/10 "2022-05-28T13:46:35Z")
> [@Jonseyt23](#):
>
> RTL-SDR only outputs 4.5v and the LNA spec is 5-26v
Have you tried?
Pretty sure it’ll just work.
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [May 28, 2022, 3:20pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/11 "2022-05-28T15:20:29Z")
Well spotted. I went to the data sheet and it still shows the PCB without the reg.
From the pic I’ve found, I can’t ID the amp chip, but it’s a fair assumption it’s not higher than 3.3V.
That allows 1.2V drop across the reg for a 4.5V input.
There is a very high probability that’ll work fine.
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### Author:  [@LawrenceHill](https://discussions.flightaware.com/u/LawrenceHill)
#### Post date: [May 29, 2022, 9:28am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/12 "2022-05-29T09:28:46Z")
> [@geckoVN](#):
>
> I can’t ID the amp chip
The chip is a MiniCircuits PSA4-5043+
> **[PSA4-5043+.pdf](https://www.minicircuits.com/pdfs/PSA4-5043+.pdf)**
>
> 412.87 KB
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [May 29, 2022, 10:28am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/13 "2022-05-29T10:28:25Z")
> [@LawrenceHill](#):
>
> The chip is a MiniCircuits PSA4-5043+
Excellent - thanks.
The PSA4-5043+ only wants 3V, so there is a bit more headroom for the regulator.
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### Author:  [@emilybessen](https://discussions.flightaware.com/u/emilybessen)
#### Post date: [May 29, 2022, 11:33am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/14 "2022-05-29T11:33:24Z")
I have two units running using the uputronics LNA powered by the Nooelec NESDR SMArTee v2 SDR. Even though the SMArTee outputs 4.5v, it still powers the LNA without any issues. I have the LNA directly connected to the SMArTee via the SMA joiner. Almost 12 months now.
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### Author:  [@tech0](https://discussions.flightaware.com/u/tech0)
#### Post date: [May 29, 2022, 11:51am UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/15 "2022-05-29T11:51:34Z")
I switched to Nooelectric LNAs because they can be powered directly via USB or bias tee. Because they are broadband, it is best to put a narrow filter in front of them.
ant → filter → lna → receiver
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [May 30, 2022, 12:32pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/16 "2022-05-30T12:32:46Z")
> [@emilybessen](#):
>
> Even though the SMArTee outputs 4.5v, it still powers the LNA without any issues.
Good to know -thanks.
And welcome to the forum.
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### Author:  [@dmandrell](https://discussions.flightaware.com/u/dmandrell)
#### Post date: [June 5, 2022, 7:13pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/17 "2022-06-05T19:13:11Z")
> [@tech0](#):
>
> ant → filter → lna → receiver
I have had REALLY good luck with this arrangement. I put the filter and LNA right at the antenna.
A challenge I am facing right now is that all the LNAs I can find are not outdoor rated. I am starting the process of trying to waterproof one, but my first attempt with Gorilla Waterproof Patch & Seal Spray did not go as well as I had pictured in my head. Instead of spraying like a spray paint, it was more like a wasp spray.
Anyone making LNAs that can go outside on the tower right under the antenna?
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [June 5, 2022, 7:51pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/18 "2022-06-05T19:51:54Z")
they are expensive
[https://shop.kuhne-electronic.com/kuhne/en/shop/low-noise-amplifiers/KU+LNA+10902+A+TM++Selective+Low+Noise+Amplifier/?card=1813](https://shop.kuhne-electronic.com/kuhne/en/shop/low-noise-amplifiers/KU+LNA+10902+A+TM++Selective+Low+Noise+Amplifier/?card=1813)
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### Author:  [@dmandrell](https://discussions.flightaware.com/u/dmandrell)
#### Post date: [June 5, 2022, 8:19pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/19 "2022-06-05T20:19:37Z")
> [@wiedehopf](#):
>
> they are expensive
Wow, those are expensive! The funny thing is, when I setup my first outdoor antenna back in 2015, I used some random in-line satellite TV amp I had laying around with the giant brick power supply and it’s worked amazing and is still trucking away. I am terrified to touch it!
I have been doing testing in my attic with several antennas, filters, and amps because I want to setup a dual 1090/978 system. I have had a little free time to finish up some fiddling and testing, and the amp is my final piece at the moment.
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### Author:  [@tech0](https://discussions.flightaware.com/u/tech0)
#### Post date: [June 6, 2022, 9:28pm UTC](https://discussions.flightaware.com/t/biast-recommendation/82979/20 "2022-06-06T21:28:18Z")
Try using an inverted 2 liter beverage bottle. I’ve cut a bottle to fit a camera inside, then resealed the bottle with waterproof tape. The power/data cables exit through a wine bottle cork at the cap end. So far I’ve not had no moisture issues in the wet Florida environment.
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