# EM9191 Throughput with 2/1 Antenna

**URL:** <https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365>\
**Category:** AirLink Routers\
**Created:** [November 16, 2022, 1:10pm UTC](https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365 "2022-11-16T13:10:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![himgupta](https://avatars.discourse-cdn.com/v4/letter/h/9de053/32.png) [@himgupta](https://forum.sierrawireless.com/u/himgupta)\
**Post date:** [November 16, 2022, 1:10pm UTC](https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365/1 "2022-11-16T13:10:45Z")

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Hello,

Is it recommended to use 2 ( Main and Aux) or 1 (Main) Antenna with EM9191 Module ?  
What will the loss in functionality and data throughput with 2 or 1 Antenna.

Thanks  
Himanshu

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**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [November 16, 2022, 1:25pm UTC](https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365/2 "2022-11-16T13:25:31Z")

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did you check the antenna RF technology support table in PTS?

 ![image](https://us1.discourse-cdn.com/flex025/uploads/sierrawireless/original/2X/b/b40901be4094cf06e7f7df095a4aaee197998891.png)

I think you must need to have Main antenna for TX.  
You might also need AUX for GNSS.

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**Author:** ![himgupta](https://avatars.discourse-cdn.com/v4/letter/h/9de053/32.png) [@himgupta](https://forum.sierrawireless.com/u/himgupta)\
**Post date:** [November 16, 2022, 5:14pm UTC](https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365/3 "2022-11-16T17:14:15Z")

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Hello,

Thanks for response, Yes I have checked the RF technology support tab.  
What will be the degradation in throughput without MIMO1 and MIMO2 antenna ?

Thanks

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<div class="post-metadata">

**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [November 17, 2022, 1:01am UTC](https://forum.sierrawireless.com/t/em9191-throughput-with-2-1-antenna/28365/4 "2022-11-17T01:01:59Z")

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Some ENDC combination does not need these two antennas.  
(e.g. If the downlink frequency is below 1G Hz, it is considered to be low band which will only use Main and AUX antenna.)  
But for the actual degradation, you might need to do a real test to measure