Topics

measuring ?

militaryoperator
 

OK. I'll ask here. 




Hi Ben,
 
Here’s the place to ask: https://www.sdr-radio.com/Support .
 
Simon Brown, G4ELI
 

Subject: Re: v12 and measurements
 
Simon. 
 
I hope you do not mind a direct question. 
 
Using v.12 on my laptop. Regarding the dbm measurement scale. Is this a true indication of the difference at the i/p to the sdr set or is it dependant on the sdr being used? 
 
I trying to measure at 2.4GHz with Lime Mini, v.12 and win10 (brand new spec pc)
 
So, if the difference on the scale when I insert a small amp in line is from -75dbm to -60dbm, is it actually 15dbm difference at the ant socket of the Lime Mini?
 
Regards, Ben 

Allan Isaacs
 

Hi Ben

I find that the dBm readings are very unreliable if you use too much gain.

You can check this by inserting an attenuator into the antenna lead. I use a  switchable attenuator that provides 0dB to 100dB.

With my Andrus for example changing the gain setting in the console from -30dB to -24dB works fine increasing a typical signal reading by 6dB, but continuing to -12dB and then 0dB does not alter the dBm reading from that seen at -24dB.

To prevent overloading add a suitable attenuator then add your amplifier and you should see the right increase in dBm.

If your amp provides 15dB then you should see an increase from -75dBm to -60dBm but only if the Lime front end is not overloaded.

73 Allan G3PIY


From: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] On Behalf Of militaryoperator via Groups.Io
Sent: 11 September 2019 20:23
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] measuring ?

 

OK. I'll ask here. 

 

 

 

 

Hi Ben,

 

Here’s the place to ask: https://www.sdr-radio.com/Support .

 

Simon Brown, G4ELI

 


Subject: Re: v12 and measurements

 

Simon. 

 

I hope you do not mind a direct question. 

 

Using v.12 on my laptop. Regarding the dbm measurement scale. Is this a true indication of the difference at the i/p to the sdr set or is it dependant on the sdr being used? 

 

I trying to measure at 2.4GHz with Lime Mini, v.12 and win10 (brand new spec pc)

 

So, if the difference on the scale when I insert a small amp in line is from -75dbm to -60dbm, is it actually 15dbm difference at the ant socket of the Lime Mini?

 

Regards, Ben 

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