Re: Can the TinySA measure DAB signals?
tinySA can discriminate as far as the RBW allows. Be sure that the 3KHz RBW is selected, as in the figure?
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No, but we do have HD Radio here. 73 -Jim NU0C On Tue, 19 Oct 2021 21:57:03 -0400 "Mike C." <mg@...> wrote: Interesting subject, this DAB signal. We don't have it here in the US,
look what we have for leadership.
Mike C.
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Re: Schematics for MAX2870
I suggest you use MAX2871, which is an improved version of MAX2870, you can refer to this project.
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Re: Schematics for MAX2870
Yeah, I read the spec sheet but what I'm looking for are some
instructions or users and their comments regarding the ebay item.
Mike C.
On 10/19/2021 10:34 PM, Ray Anderson
wrote:
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How about:
Ray WB6TPU
On Oct 19, 2021, at 6:29 PM, Mike C.
<mg@...> wrote:
?Hi Guys,
Has anybody come up with package information like
schematics on the MAX2870? i.e. ebayism # 363099163574
Mike C.
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Re: Schematics for MAX2870
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Show quoted text
On Oct 19, 2021, at 6:29 PM, Mike C. <mg@...> wrote:
?Hi Guys,
Has anybody come up with package information like schematics on the MAX2870? i.e. ebayism # 363099163574
Mike C.
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Interesting subject, this DAB signal. We don't have it here in the US, look what we have for leadership.
Mike C.
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Hi Guys,
Has anybody come up with package information like schematics on the MAX2870? i.e. ebayism # 363099163574
Mike C.
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Re: Can the TinySA measure DAB signals?
Be aware the tinySA is feeling the total power (summed power) at the mixer and not just the peak power at one single frequency so if the bandwidth is wide you have to reduce power further than the automatic attenuation will do. Start by ensuring the peak of the input is below -40dBm (after the internal attenuator) and see if that makes a difference versus -55dBm or -25dBm
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For more info on the tinySA go to https://tinysa.org/wiki/
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Re: Can the TinySA measure DAB signals?
I don't know how you're generating your OFDM signal, but try looking at it on the TinySA BEFORE you feed it into your transmitter amplifier chain, see how it compares. If your transmitter chain is compressing (non-linearity) your Tx signal in any way then that will reduces it's quality very quickly, no matter how strong it is when it reaches any receivers.
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Re: Can the TinySA measure DAB signals?
Yours looks clean enough, though there must be something a bit wrong somewhere if 100W's only gets you short distances.
The thing about OFDM is that it requires very linear transmitters, the PAPR (peak to average power ratio) is unfortunately very high, the peaks of the RF carrier are very much higher than the average power, it requires quite a high dynamic range to see the side lobes so not to compress the RF peaks - an OFDM spectrum might look nice and flat but the RF envelope.is far from it, the more OFDM sub carriers you have the higher the PAPR.
Maybe you're right, maybe the TinySA doesn't have the required dynamic range t o show the side lobes ?
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Re: Can the TinySA measure DAB signals?
[url=https://ibb.co/Qfz4YC1][img]https://i.ibb.co/W6qLBPY/DAB-10-W-20-15-10-30d-Batt.png[/img][/url]
[url=https://ibb.co/Tt1cFNk][img]https://i.ibb.co/ZxSdkbV/DAB-40-W-20-15-10-30-10d-Batt.png[/img][/url]
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Re: Can the TinySA measure DAB signals?
Hi Mr OneOfEleven,
I am experimenting with a DAB modulator and (DVB-T) power amplifier, and am quite sure that my signal is currently not OK. ( 40W of 100W output power hardly makes a difference, like 200 meters range)
I expected to see (large) shoulders, as i don't have a spectrum mask filter
Screenshot 1: 20dB+20Db+30Db+10Db hardware attenuator, en 10Db on the Tiny. Output power at that moment was 40W
Screenshot 2: 20dB+20Db+30Db+10Db hardware attenuator. Output power at that moment is 10W
I agree that local DAB broadcasters have a very clean signal - but i'm living near a transmitter site, and do not see any shoulders.
From what i've heard, you need a very good spectrum analyzer to see them - but i'm not sure...
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Re: Can the TinySA measure DAB signals?
The local DAB braodcast transmissions are very clean, the side lobes are very low down. You might see them if you can feed a nice strong DAB signal into the TinySA, so long as you don't overload the it's front end.
This shows what various types of OFDM can achieve (filtered OFDM being the cleanest) ..
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Re: Can the TinySA measure DAB signals?
Such as here (live DAB radio in the UK) .. 
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Re: Can the TinySA measure DAB signals?
When you say shoulders, wonder what it is you're expecting to see ?
DAB uses OFDM modulation, so the signal will basically be very square indeed, ie vertical sides to it with an ideally flat top.
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Can the TinySA measure DAB signals?
Hi All,
Did some tried to measure a DAB signal already?
I did, and i'm getting the feeling that the TinySA is not accurate enough to measure the shoulders of this signal.
If this is the case - i fully understand since it has it's limitations... but now i'm not sure.
In my test setup i expected to see shoulders, but i don't see them
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Interesting video series on radio design using nanoVNA and tinySA
Found this youtube playlist on radio design that combines theory with practical implementation and measurement using the nanoVNA and tinySA Very good if you ever want to design something yourself!!!
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For more info on the tinySA go to https://tinysa.org/wiki/
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Dear tinySA team,
Working with the tinySA, I noticed 2 minor presentation enhancements ?that can improve the product¡¯s performance:
1.- When you work in dBm, if you use the MARKER in DELTA mode, the relative markers (or markers 2 & 3 in MEASURE /3dB WIDTH) correctly indicate dB, but if you are working in dBmV or dB?V, the relative markers continue to indicate dBmV or dB?V instead of dB.
2.- When measuring digital CATV or DTT systems in dBmV or dB?V, when selecting MEASURE / CHANNEL POWER, the units automatically change to dBm. Although it is simple to convert the measurements obtained to dBmV (adding +47) or to db?V (adding +107), it would be preferable to read the measurement in the units in which we were working originally.
For future FW versions if you think it is convenient to implement it.
Thank you for the tinySA,
ToniC
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James,
The TinySA has a minimum frequency of 100KHz (0.1MHz), much higher than the audio range(0 to 20KHz) that you express as your area of interest.? It is using RF devices that cannot go low enough in frequency to detect audio signals.? I got this from the specifications listed on the TinySA.org web page (wiki).
You would need an RF noise source to use the TinySA to characterize filters.? That is what Eric is describing in his video. You would do a similar process for the audio range, but, you need the equipment that can measure the audio frequency signal.
73
Evan
AC9TU
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Even
?
Just read this again.? You suggest getting a PC based Sato make measurements.? Couldn¡¯t I use my TinySA?
?
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From: [email protected] <[email protected]>
On Behalf Of Evan Hand
Sent: Thursday, October 14, 2021 4:14 PM
To: [email protected]
Subject: Re: [tinysa] Filters
?
On Tue, Oct 12, 2021 at 09:23 PM, James Belcher wrote:
It is not so much being interested in a particular freq, it has to do with improving my knowledge of analog circuitry.? I am wiz with digital and knowledgeable of basic analog, but I would like to know more.
?
I am working my way through the ¡°Art of Electronics¡±? books and the lab book that goes with it has me make basic filter and test it.? So I felt this would be a good time to learn these instruments since I have
never used them before.
James,
Here is an Audio noise source that runs on a PC.
You can feed that into your audio filter and then connect the output of the filter to the PC mic input and measure the spectra with an Audio Spectrum Analyzer on the PC like this free one:
There are many other audio spectrum analyzers to be found on the internet as well as other audio noise sources.??The above is free and simple.? You should understand the limits of your test instruments, in this case, both the noise source and the spectrum analyzer
are using the PC sound card with its limitations on frequency and flatness.? You should run a scan bypassing the filter, then connect the filter to see the differance.? You will also need to familiarize yourself with the controls of both pieces of software.
Again, just suggestions.? Also, thank you for the hint on the "Art of Electronics" books.? I have purchased them to use as a reference.?
73
Evan
AC9TU
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Jim Shorney
Mike C.
