RSP2 Frequency is Incorrect - Why?

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ultravista

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I just bought a 2nd hand RSP 2 on eBay (from a ham).

With SDRUno, SDR#, and HDSDR, the frequency is off a bit compared to a known signal. For example, in SDRuno, my local Las Vegas NOAA frequency is 162.555.000 but the applications above don't 'center' with the signal @ 162.555.000 but 162.555.200 instead.

By 'center', I mean the peak of the signal in the application.

The issue is similar across every application, so I know it's not an offset problem with a single application.

For the record, my RTL-SDR v1.3 dongle tunes exactly on the right frequency.

What would cause the RSP 2 to tune incorrectly?

What are the last three digits and the frequency above, hertz? In other words, the RSP is off by 200 hertz?
 

jonwienke

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PLL-controlled radios have a reference crystal they use as a frequency reference. If that reference crystal is off-frequency, then every frequency generated by the PLL will be wrong by the same percentage.

The RTL-SDR dongle uses an extra-accurate TXCO frequency reference that is accurate to within one part per million, so the PPM adjustment in SDR# or other programs usually best left at zero.

The RSP2, evidently not so much. It could be why you got a deal on it.
 

mbott

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I just bought a 2nd hand RSP 2 on eBay (from a ham).

With SDRUno, SDR#, and HDSDR, the frequency is off a bit compared to a known signal. For example, in SDRuno, my local Las Vegas NOAA frequency is 162.555.000 but the applications above don't 'center' with the signal @ 162.555.000 but 162.555.200 instead.

<snip>
My local NWS is not exactly on the freq. they claim to be operating on. What is the difference on any of the WWV or CHU frequencies?

--
Mike
 

ultravista

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PLL-controlled radios have a reference crystal they use as a frequency reference. If that reference crystal is off-frequency, then every frequency generated by the PLL will be wrong by the same percentage.

The RTL-SDR dongle uses an extra-accurate TXCO frequency reference that is accurate to within one part per million, so the PPM adjustment in SDR# or other programs usually best left at zero.

The RSP2, evidently not so much. It could be why you got a deal on it.
I am surprised that a much more expensive piece of equipment is off-frequency compared to the $25 RTL-SDR. Yes NOAA 162.555.000 tunes in precisely at 162.555.200.
 

Your_account

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The RTL-SDR dongle uses an extra-accurate TXCO frequency reference that is accurate to within one part per million, so the PPM adjustment in SDR# or other programs usually best left at zero.
my dongle are between +/- 60ppm!!!
 
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