Hoping to shed some light on the tinySA possibilities I created a wiki measurement example on IQ balance tuning in a single side band transmitter.

Sala,
I have an SDRPlay RSP2 that I have used as a spectrum analyzer with the RSP-Spectrum-Analyzer software.? ?I would say that it is good for checks below 40 MHz, so good for tight in spurs detection, and OK for harmonics up to 40 meters (I have not tested 30 meters, as no interest there).? When testing for 20-meter harmonics, I am getting a spur around 53 MHz that may be related to the USB clock.? The one thing that I do use it for that seems to work well is two-tone testing.? The RBW seems to be small enough to see both of the tones.

I have ordered the RSP1A to see if that unit has a better response above 40 MHz.? It also has a 14 bit DAC, as opposed to the 12 bit in the RSP2.

The above are my opinions based on my experiences so far.? Yours may be different.
73
Evan
AC9TU

The cheap msi.sdr rsp1 clone is not good.

These are definitely interesting and the price is not overly high.
Are SDRplay models good as general spectrum analyzers, Are there a lot of ghost lines and so on.

Tiny Sa and a SDR are good pair.
I think checking modulation close to carrier and checking spurs and harmonics are two different things. It is not IMO necessary to do both at same sweep.

That is the same? as what I see with my MSI.SDR SPR1 clone. But is soon as you apply an input signal the spurs start to explode

I have been experimenting with an MSi.SDR RSP1 clone from China for a short while and must admit I have only used it for relatively narrow span measurements. IMHO the RSP SA software has many nice features and is slick to use.

Attached is what the baseline looks like with a 1GHz span with no signal and terminated input and RBW of 500Hz. I have not done any calibration to match the software to this particular receiver. However this should illustrate the internal spurs without any signal input for this particular RSP1 clone.

It appears some switching takes place around 60 MHz and possibly a pre-amplifier is inserted at 420 MHz. I had the clock spur removal feature turned on which removed many spurs. There are significant spurs around 196 MHz and 401 MHz plus a few other low level spurs.

I suspect this software would work better with a genuine RSP1A that has more filtering. Unfortunately I don't have an RSP1A to make a comparison.?
?

I tried a cheap RSP1 Chinese clone with the RSP SA PC software.
It works very well for small RBW but when doing wider sweeps I saw many spurs and I was never sure if they where really there or where internally generated.
Is there in this group someone with experience with an RSP1?

Greetings,

? ? ? ? ? ? IMHO the major advantages offered by the tinyVNA concept are handheld portability and cost. The instrument concept is ideal for many portable field measurement needs. Professional field portable, battery powered spectrum analyzers are typically ten to a hundred times more expensive - well beyond the budget limitations of the majority of hobbyists.

? ? ? ? ? Usually the measurement of modulation components can be done conveniently?without the need for handheld portability. With modern day DSP technology using computer muscle power all that is needed for the measurement of modulation components is an inexpensive SDR receiver along with a PC running freeware such as HDSDR. A nice, quite low cost combination is SDRPlay's RSP1A receiver running under their free accessory RSP Spectrum Analyser PC software. That combination offers spectrum analysis that has a professional feel to it with frequency coverage from VLF to UHF. With the selection of a 20KHz span the RSP SA resolution bandwidth can be reduced to less than 1 Hz.

? ? ? ? ?But the relative downside of using an SDR receiver as an analyzer is that it needs to be tethered to a PC thus it does not offer a nearly as portable a concept as the tinySA. The tinySA appears to provide sufficiently narrow resolution bandwidth capability to separate most signals which IMHO should make it a good fit for many uses other than modulation component analysis.

Tom, VA7TA

Have a look at this post where I show the side band suppression measurement using a softrock RXTX and a tinySA

/g/HBTE/message/1126

I have been able to check side band suppression and carrier suppression by using a 2.5kHz tone as input. Of course this gives limited dynamic range but 40dB is possible for the opposite side band

On Mon, May 11, 2020 at 11:09 AM, <erik@...> wrote:

Can you explain what you mean with "going close to the carrier"?
Can you give a practical example?

==========================================================
Erik,
? ?I believe he means that if your lowest resolution bandwidth is much wider than the modulation frequency then the modulation cannot be resolved in the presence of a nearby carrier.? The modulation gets integrated into the carrier.? I've "missed" many signals because they were too close to a carrier and I didn't use a narrow enough resolution bandwidth and slow enough sweep time to resolve them.

?-Herb

Can you explain what you mean with "going close to the carrier"?
Can you give a practical example?

Thank you all. I have checked SDRs in the past and I thought that only a few or one could go very close to carrier.
Once again, thank you.

For your info, I have one SA from Aaronia Spectran something, but it wont go close enough. But it goes to 6GHz.

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OK, very good to know. Thank you for the information.

The tinySA uses a downconverter, selectable band pass filters and signal strength measurement all in one integrated device. As a consequence the output of the band pass filters stay's inside the device.
It is possible to demodulate AM till at most 2kHz bandwidth and with a small trick it is possible to demodulate FM. But it is impossible demodulate SSB or look inside the spectrum of a 2.7kHz wide SSB transmission as the smallest bandwidth? of the tinySA resolution filters is equal to the complete 2.7kHz SSB. As there are so? many options to use (web) SDR receivers to look at the spectrum I assumed that would not be a big problem. But none of the cheap SDR's can do a spur free fast scan of 0.1 to 350MHz to study harmonics content.

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Below is the reason that I took interest in the tinysa. I had hoped to see and demonstrate how modulation works in the HF and VHF bands. The old SA that I have now can barely do that.?

I concur: I have an RSP1A. I've used the "RSP Spectrum Analyzer" software (technically an FFT analyzer) with it on occasion ... it goes to 2GHz which is better than my ancient HP 8590A (nicknamed ole drifty).? I haven't used the optional DIY tracking generator yet.

Here is brief video on it:?

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I have one Airspy HF+ for HF and some VHF, one Softrock Ensemble for HF,? one Airspy R0 for V-UHF and a dozen or so RTL-SDR digital TV dongles repurposed for V-UHF receivers (very cheap, about $10).

As the software part (in fact the receiver, the mentioned hardware are only front ends), I mostly use SDR# for all of them, but I have other software such as SDR-Console, HDSDR, etc.

The bandwidths, demodulation modes and displays are all on the software part.

Regards,

Ignacio, EB4APL

Can you recommend one/a few which can do that? I have not found a SDR which could do that.
Leif