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TOPIC: S3 signal without Antenna

Signal without Antenna 03 Aug 2022 16:29 #1

  • XV9BPO
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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
Please do not email me and ask for help I no longer will be part of this, If I could delete /remove my profile I would do so.
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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

  • XV9BPO
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Thanks to both of you for your answers
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