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SDR for Frequency Deviation

Posted: Wed Nov 07, 2018 7:49 pm
by Scubadennis
Hello,

I just purchased an SDR to help with my Kantronics KPC-3+ modulation settings. I want to hook my radio RF directly to the SDR. I understand I need a RF Sampler. Does anyone make one for Ham bands? Is it possible to just use provided antenna to get accurate measurement from dummy load?

Re: SDR for Frequency Deviation

Posted: Tue Nov 13, 2018 3:25 pm
by Scubadennis
Any help on this?

Re: SDR for Frequency Deviation

Posted: Wed Nov 14, 2018 5:29 am
by rtlsdrblog
Why can't you just connect the RF output to an attenuator, then into the SDR?

Re: SDR for Frequency Deviation

Posted: Wed Nov 28, 2018 2:37 pm
by Scubadennis
Which attenuator? That is what I need do know.

Re: SDR for Frequency Deviation

Posted: Thu Nov 29, 2018 11:15 am
by rtlsdrblog
You need to find out what the output power of the TNC is, then use an attenuator to reduce it to something well below 10 dBm (10dBm is the max input power of the RTL-SDR).

But yes you could also just attach a dummy load to the TNC, and put the RTL-SDR with an antenna near it. That should pick up the small stray signal which should be enough to evaluate the output modulation of the TNC.