# Lothar's TL;DR on SDR selection for AIS, ADS-B, UAT, ACARS, VDL2 and Sondes

**URL:** <https://community.airframes.io/t/lothars-tl-dr-on-sdr-selection-for-ais-ads-b-uat-acars-vdl2-and-sondes/150>\
**Category:** General\
**Created:** [January 22, 2024, 5:08am UTC](https://community.airframes.io/t/lothars-tl-dr-on-sdr-selection-for-ais-ads-b-uat-acars-vdl2-and-sondes/150 "2024-01-22T05:08:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Lothar\_ot\_Hill\_Peeps](https://community.airframes.io/letter_avatar_proxy/v4/letter/l/f17d59/32.png) [@Lothar\_ot\_Hill\_Peeps](https://community.airframes.io/u/Lothar_ot_Hill_Peeps)\
**Post date:** [January 22, 2024, 5:08am UTC](https://community.airframes.io/t/lothars-tl-dr-on-sdr-selection-for-ais-ads-b-uat-acars-vdl2-and-sondes/150/1 "2024-01-22T05:08:18Z")

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Since TBG wanted to pin this in the [Airframes.io](http://Airframes.io) Discord server, I thought I would post this updated version of my rant here.  
Lothar’s general advice is:

- AVOID ALL plastic cased SDRs.
- FAVOR any SDR that uses the SKY7510 LNA, as it is hands down the lowest NF of any common LNA chip.
- FAVOR SDRs with Genuine Taisaw SAW filters for 1090.
- FAVOR LNA\>filter over Filter\>LNA SDRs topology for 1090 SDRs (unless you are in a rough high RF environment, where you MUST use an unfiltered orange stick and a cavity filter.
- ADD heat coupling putty pads (NOT adhesive foam thermal heat sink attachment pads) between the underside of the SDR PCB and the metal case. I use Gelid Solutions GP-Extreme 2.0mm Thermal Pads, available at Amazon, DigiKey, Mouser etc.

Happy Feeding!

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**Author:** ![thebaldgeek](https://community.airframes.io/user_avatar/community.airframes.io/thebaldgeek/32/141_2.png) [@thebaldgeek](https://community.airframes.io/u/thebaldgeek)\
**Post date:** [January 25, 2024, 4:05am UTC](https://community.airframes.io/t/lothars-tl-dr-on-sdr-selection-for-ais-ads-b-uat-acars-vdl2-and-sondes/150/2 "2024-01-25T04:05:15Z")

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This is one of the most solid tl;dr’s for SDR’s (filter and LNA variety) ever!!  
Thanks so much.  
Going to be able to refer a bunch of people that ask this.  
Wish we could put it in a LLM (large language model) for AI to answer this FAQ!

Hope you don’t mind, I did a quick format edit of your post for readability.

Also, where do we get the putty pads (not adhesive foam) from? I feel that all the Pi heatsink kits come with foam, but am not sure what to google/amazon for the putty.