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TOPIC: Signal without Antenna

Signal without Antenna 03 Aug 2022 16:29 #1

Hi guys,

Just wondering.
Is it normal that even without antenna the signal does not go below S3 or around -111.7dbm ?
I am using ESDR3 0.12.1
Thanks for your help
Last Edit: 03 Aug 2022 16:30 by XV9BPO.
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Signal without Antenna 03 Aug 2022 18:53 #2

  • N8SDR
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XV9BPO wrote:
Hi guys,

Just wondering.
Is it normal that even without antenna the signal does not go below S3 or around -111.7dbm ?
I am using ESDR3 0.12.1
Thanks for your help

YES, a true direct sampling SDR will always have / show a noise figure

you notice if you engage the preamps the noise floor without antenna will decrease as well again this is correct

it is created from the components
73 Rick
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Signal without Antenna 03 Aug 2022 20:31 #3

  • W3FRG
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Hello,

Regarding the S5 S-Meter reading, one of the best explanations I've seen is on the Flex site.
Back before I upgraded to the Dx, my 6600M did this and I also asked the same question.

The explanation can be seen here:
community.flexradio.com/discussion/5523377/why-does-my-s-meter-read-s5-all-the-time

GL Tom W3FRG
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Signal without Antenna 03 Aug 2022 20:42 #4

Thanks to both of you for your answers
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