# RTL LNA Power **URL:** \ **Category:** ADS-B Flight Tracking\ **Created:** [January 14, 2023, 11:10pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224 "2023-01-14T23:10:54Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Jonseyt23](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jonseyt23/32/125135_2.png) [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)\ **Post date:** [January 14, 2023, 11:10pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/1 "2023-01-14T23:10:54Z")
Question for @SoNic67 about external power on RTL 1090 LNA, I have seen 2 closed posts about externally powering the LNA, 1 with an LDO and 1 that looks like it has a USB lead directly soldered, now the question is where would I solder the 5v+ & 5v- to on the LNA to power from USB as I don’t know if anything else needs to be desoldered on it, I can handle the soldering job, I just can’t read pcb electronic diagrams. ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [January 14, 2023, 11:16pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/2 "2023-01-14T23:16:27Z")
You are referring the the RTLSDR Blog filter/amp? There is no -5V on USB, just 0V and +5V ![RTLSDR lna 2](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/4/7/47c7c61815c4580a0dd0fb01c395ee2d3bb7fdff.jpeg) ![RTLSDR lna 3](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/d/0/d0daab92a3f88fee3b7b727aa59b1ed1a02401d8.jpeg) ---
**Author:** ![Jonseyt23](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jonseyt23/32/125135_2.png) [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)\ **Post date:** [January 14, 2023, 11:47pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/3 "2023-01-14T23:47:04Z")
Hi @geckoVN these are the posts I’m referring to > [@RTL-SDR LNA mod](https://discussions.flightaware.com/t/rtl-sdr-lna-mod/68675): > > I don’t know if anyone is interested, but I’ll post this regardless. I have used for a while the RTL-SDR LNA. First was fed via Bias-T from my Airspy R2, but I didn’t feel “safe” in case of a short on the cable. Then I fed it with 4.5V via a Bias-T power injector. The power supply is a cheap wall wart, and I could not regulate the output voltage in stable and definite steps. 4.5V This is the LNA: [New Product: RTL-SDR Blog 1090 MHz ADS-B LNA](https://www.rtl-sdr.com/new-product-rtl-sdr-blog-1090-mhz-ads-b-lna/) Well, due to my long (and mismatched impedance with… And > [@Ran into a bad RTL-SDR filtered preamp](https://discussions.flightaware.com/t/ran-into-a-bad-rtl-sdr-filtered-preamp/76689): > > I’ve been struggling for some time now to get my second (test) feeder up and running. This feeder is a mirror image of my usual feeder with a Jetvision A3 antenna, Pi 4, Airspy mini, RTL-SDR filtered preamp and Sysmocom cavity filter. Everything works but I’m seeing less traffic as usual even if I use the same antenna as my main feeder. I’ve been swapping several items around in my quest to find the culprit and it turned out to be the RTL-SDR filtered LNA, an item I just received 2 weeks ago. … ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [January 14, 2023, 11:51pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/4 "2023-01-14T23:51:39Z")
Ok, just checking we were talking about the same thing. Just remove the 0 Ohm resistor or you’ll feed 5V back down the antenna feeder. Then use its pad for the 5V ---
**Author:** ![Jonseyt23](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jonseyt23/32/125135_2.png) [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)\ **Post date:** [January 15, 2023, 12:16am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/5 "2023-01-15T00:16:14Z")
It was this way I was looking at, as I can make out where the +5v goes as its the hole pad on the PCB. But just struggling to see where the 0v wire goes to and also it looks like the 0ohm resistor it bridged to the pad next to it but not sure, I just want to be 100% on what to do as I really don’t want to fry the LNA as I can’t afford to get a new one. ![Screenshot_20230114_225915_com.android.chrome](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/6/e/6e29bca8a9dfa4c4aa75d1e949f0305a2a4c25f0.jpeg) ---
**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\ **Post date:** [January 15, 2023, 12:29am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/6 "2023-01-15T00:29:37Z")
This post shows how I powered RTL-SDR Tripple Filtered LNA using a low cost bias-t and a low cost 5v dc PSU, both from Chinese sellers on ebay. > [@How to improve performance of whip antenna of DVB-T](https://discussions.flightaware.com/t/how-to-improve-performance-of-whip-antenna-of-dvb-t/17325/33): > > I have RTL-SDR Blog Tripple Filtered LNA and it improved reception considerably when I tested it. > > **NOTE:** The photos below show a bias-t and a 5V dc adaptor to power the “rtl-sdr tripple filtered lna”. > > ![20190901_230118](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/6/a/6a68ea0678f33391fe78b41a8e2fc4aed6b463e0.jpeg) ![20190909_124019](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/1/9/195036575757afc4a11e1c116cd7c5ad48e10c11.jpeg) ---
**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\ **Post date:** [January 15, 2023, 1:45am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/7 "2023-01-15T01:45:49Z")
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**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [January 15, 2023, 3:24am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/8 "2023-01-15T03:24:01Z")
> [@Jonseyt23](#): > > I can make out where the +5v goes as its the hole pad on the PCB. That shouldn’t work, but it looks like you have a different PCB revision. Did you add a solder bridge to the 0R resistor? What receiver are you using? As you have it, you’ll be sending 5V down the antenna cable to the receiver. ---
**Author:** ![Jonseyt23](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/jonseyt23/32/125135_2.png) [@Jonseyt23](https://discussions.flightaware.com/u/Jonseyt23)\ **Post date:** [January 15, 2023, 8:51am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/9 "2023-01-15T08:51:36Z")
I have not done anything yet to it, I want to be sure what I’m doing before even attempting it, that pic is not my LNA ---
**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\ **Post date:** [January 15, 2023, 10:09am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/10 "2023-01-15T10:09:06Z")
The safest way is to purchase a $4 Bias Tee from Ebay and use it, like I did. Using an external Bias Tee has advantage that there is no soldering to Amplifier pcb, hence there are no mistakes in soldering at wrong points of pcb of Amplifier. Also no soldering is needed to the pcb of Bias Tee, as dc 5V wires are connected to screw terminals. However one has to take care of following: (1) +ve & ground connection to be according to marking on screw terminal. (2) DC+RF marked SMA is connected to Amplifier OUT, and RF marked SMA is connected to dongle ---
**Author:** ![SoNic67](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/sonic67/32/119872_2.png) [@SoNic67](https://discussions.flightaware.com/u/SoNic67)\ **Post date:** [January 15, 2023, 5:32pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/11 "2023-01-15T17:32:24Z")
> [@abcd567](#): > > The safest way is to purchase a $4 Bias Tee from Ebay and use it, like I did. > > Using an external Bias Tee has advantage that there is no soldering to Amplifier pcb, hence there are no mistakes in soldering at wrong points of pcb of Amplifier. The issue is that the PCB accepts BIAS-T, but is not stabilized. For short coax cable runs it doesn’t matter, it is good as it is. For long coax cable runs, you will have an unknown DC voltage drop. Stabilizer IC allows to raise the voltage at Bias-T a bit, to compensate (like 7.5V). The circuit board has the space for a 5V stabilizer. ---
**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\ **Post date:** [January 15, 2023, 5:39pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/12 "2023-01-15T17:39:49Z")
> [@SoNic67](#): > > The circuit board has the space for a 5V stabilizer. I understand from your sentence that the stabilizer is _not_ provided, _only a space_ is provided so that user can add it if he wants, **and** he has enough knowledge and skill to do it. ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [January 15, 2023, 10:55pm UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/13 "2023-01-15T22:55:01Z")
Yes to each of those questions. - The OP says he has the soldering skills, so that’s covered. - The pic above show the pads where the LDO can be fitted - the link to @SoNic67 previous post shows the mod to reposition the 0R resistor for under C$3, you can buy practice boards if you are not confident > **[SMT SMD Component Welding Practice Board Soldering Training DTSAWWIXI~iy | eBay](https://www.ebay.com/itm/225307425757)** > > Find many great new & used options and get the best deals for SMT SMD Component Welding Practice Board Soldering Training DTSAWWIXI~iy at the best online prices at eBay! Free shipping for many products! ---
**Author:** ![abcd567](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/abcd567/32/113769_2.png) [@abcd567](https://discussions.flightaware.com/u/abcd567)\ **Post date:** [January 16, 2023, 12:43am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/14 "2023-01-16T00:43:39Z")
> [@geckoVN](#): > > Yes to each of those questions. Yes is true for @geckoVN, @SoNic67, @abcd567, @Jonseyt23, and many more users, but is definitely _NOT_ true for each and every user. My comments were for general hobbyists who do not posses enough knowledge and skills to do the job properly and safely. ---
**Author:** ![geckoVN](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/geckovn/32/136508_2.png) [@geckoVN](https://discussions.flightaware.com/u/geckoVN)\ **Post date:** [January 16, 2023, 1:37am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/15 "2023-01-16T01:37:32Z")
@Jonseyt23 asked the question and the answers are in the context of this thread. Anyone else is welcome read the comments and judge for themselves if they can make use of the information. Even if someone doesn’t have the skills/ equipment, many will know someone who would be willing to do the job for the price of a beer. Not all Bias-T’s are created equal. Some are suitable for HF, but not higher, so there is plenty of potential for distorting or attenuating the signal only because of poor/uninformed component selection. I understand your point and you are correct that not everyone is capable of carrying out this mod, but not every thread needs to be dumbed down to the level of the least capable, least equipped user who wouldn’t do the mod anyway. ---
**Author:** ![SoNic67](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/sonic67/32/119872_2.png) [@SoNic67](https://discussions.flightaware.com/u/SoNic67)\ **Post date:** [January 18, 2023, 12:06am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/16 "2023-01-18T00:06:54Z")
> [@abcd567](#): > > I understand from your sentence that the stabilizer is _not_ provided, _only a space_ is provided so that user can add it if he wants, **and** he has enough knowledge and skill to do it. Exactly. Might not even be needed, if the power supply is in the 5.2V range, and coax is short. Yes, I have a few “5V” packs that are labeled to output that. Amazon Kindle Fire for example. ![20230117_190438](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/6/7/67033d9cde6508f5bc92d36cebef17b38f9cf4f1.jpeg) But then… you almost ask why would you need a LNA. ---
**Author:** ![system](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/system/32/38558_2.png) [@system](https://discussions.flightaware.com/u/system)\ **Post date:** [January 18, 2024, 12:07am UTC](https://discussions.flightaware.com/t/rtl-lna-power/86224/17 "2024-01-18T00:07:45Z")
Closed on January 18, 2024, 12:07am UTC This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.