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Technical Topics => SDR - Software Defined Radio => Topic started by: K5KNT on April 06, 2018, 0015 UTC

Title: Online SDRs: Is it possible to find the Center Frequency?
Post by: K5KNT on April 06, 2018, 0015 UTC

A few questions regarding online SDRs and the Center Frequency:

Is knowing the center frequency necessary or important?

If so, is it possible to determine the center frequency?

If yes, how would this be accomplished?

Thanks,

K5KNT

Title: Re: Online SDRs: Is it possible to find the Center Frequency?
Post by: KaySeeks on April 07, 2018, 0041 UTC

The center frequency of the signal you are receiving?

Title: Re: Online SDRs: Is it possible to find the Center Frequency?
Post by: K5KNT on April 07, 2018, 0108 UTC

I"m not sure. In Appendix B of the Harvester User manual it says:

Quote

Determine the centre frequency of your receiver. This is particularly important
when receiving OOK or FSK signals and enabled [sic] you to accurately establish the
correct transmitter frequency.

I'm not actually using this software, but I found the User Manual interesting.

Title: Re: Online SDRs: Is it possible to find the Center Frequency?
Post by: Josh on April 07, 2018, 1745 UTC

In that case they refer to the cf, or center of intelligence of the given signal. If the mark of a 1000hz shift fsk sig is at 22.490 and the space is at 22.491. the cf is 22.490.5.
For a cw sig, if using a sdr, just look at the carrier and note the freq at the peak it occupies. For a non sdr rig you either add or subtract the beat note from the dial freq to get the cf, depending on if your bfo is above or below the cw.

Title: Re: Online SDRs: Is it possible to find the Center Frequency?
Post by: K5KNT on April 07, 2018, 1833 UTC

Thank you.  :)