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Post by mark on Oct 25, 2019 3:51:36 GMT
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Post by Boomer on Oct 25, 2019 5:03:23 GMT
Radio people on the SpectrumWell, it looks nice, just how cute it is, but I haven't tried mini spectrum analyzers so far, no. Carl Blare has one that he's been blogging about, and it connects to the PC screen's display, and it looks useful as far as I can see, checking out wi-fi signals. I like that they can see up into the gigahertz, but I'd also want to have something that could do down to 10 khz as well and do the AM band, and test LED bulbs and power supplies for the lowest EMI. A spectrum analyzer will work on the FM band, as long as it could cover up to, for example 500 mhz, so it can see harmonics, has a low enough noise floor, and an ability to zoom in frequency-wise and see close to the carrier for spurs. A cheapie USB SDR dongle can work as a basic spectrum analyzer also. www.rtl-sdr.com/about-rtl-sdr/www.rtl-sdr.com/rtl-sdr-used-as-a-spectrum-analyzer/That's used on a Beaglebone mini computer, like the KiwiSDRs use already. See if any of this helps. Boomer
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Rich
Full Member
RF Systems Engr (retired)
Posts: 112
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Post by Rich on Oct 25, 2019 8:57:42 GMT
... Would this tell me if my transmitter is causing interference on any other bands or frequencies? Observation: it doesn’t include a receive antenna with a known pattern/gain across its operating range. Therefore it can’t accurately measure the absolute value of the field intensity or power of signals arriving at that receive antenna. |
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Post by Admin on Oct 25, 2019 14:24:18 GMT
But: It may show the relative relationship of a fundamental to harmonics and spurs. Check to see if a user manual is available which may give some info on how to use the instrument for that type of analysis. j3.rf-explorer.com/downloads/#doc |
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Post by mark on Oct 25, 2019 15:35:39 GMT
Boomer,
It goes from 50 kLz so it should cover from below the AM band too. A good idea to see the manual first.
Thanks guys for help. Out of all of them this is affordable! A good point about how sensitive it is.
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Post by mark on Oct 25, 2019 18:12:41 GMT
I saw a video on you tube showing this model and it showing the FM band and all the FM stations on the screen being received on each frequency and the bandwidth of each etc. I can buy on Amazon Canada and if not good I can return!
I may try and see what I get. Seems if I jump to other frequency ranges I would see if my transmitter is getting into anything else and If I don't like or can't understand it I can send back for refund in 30 days. This could also show if overmodulating it seems too, from the video demo.
Thanks for helping.
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Post by station8 on Oct 25, 2019 18:29:35 GMT
Howdy y'all:
This is my suggestion and what i seen in real world test.
1) Make sure spectrum analyzer goes higer then 960 Mhz ( 4 or 5 ghz range ).
Why i seen transmitters splatter higher than that frequency range!.
2) Make sure your sectrum analyzer can do direct hook up as well antenna receiving!,
Why is to check that you don't have other frequency mixing and blending or
Interference from other source when you use antenna on the transmitter as spectrum analyzer!.
Also if you live near cell tower like i do the cell towers will give you in nightmare of
Interference on am and fm i went through this where i live now!.
The Interference on cell tower keeps changing watch for it, hint hint.
If you see bad interference i would recommend very highly to stop transmitting immediately
And beef up your rf filter on your transmitter i i ve gone throught first hand!.
Glad to help have fun with the hobby
Station 8
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Rich
Full Member
RF Systems Engr (retired)
Posts: 112
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Post by Rich on Oct 26, 2019 10:09:51 GMT
But: It may show the relative relationship of a fundamental to harmonics and spurs. ... A few things to consider...
Still not accurately for relative measurements, though, for received signals that are more than a few percent different than the frequency of the transmitter being tested, because the gain and pattern of the receive antenna included with that spectrum analyzer are unknown at harmonic frequencies of the transmit system under test.
Also unknown are the effects of the physical environment at the test site, which will change the pattern of the receive antenna used to sample the incoming signals.
Even if all that was known, all spectrum analyzers are susceptible to being overdriven by strong local signals — which produce harmonics and mixing products within the analyzer, itself. They look exactly like "real" signals that arrived at the receive antenna, leading to invalid conclusions from the test results. |
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Post by mark on Oct 26, 2019 15:42:09 GMT
Rich said: "Even if all that was known, all spectrum analyzers are susceptible to being overdriven by strong local signals — which produce harmonics and mixing products within the analyzer, itself. They look exactly like "real" signals that arrived at the receive antenna, leading to invalid conclusions from the test results."
Something to consider.....false positives. Still debating, haven't got this yet. What Rich seems to be noting is don't hold the analyzer right by the antenna or at least go to another room or outside.
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Post by Admin on Oct 27, 2019 4:01:32 GMT
Fortunately this analyzer offers an attenuator which allows direct connection rather than from an antenna.
See the link I posted which lists accessories for this unit. Perhaps you'll have comment as to how they may help with measurements.
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Post by mark on Oct 27, 2019 4:54:06 GMT
Transmitter/s don't have an external antenna connection like a BNC,UHF, or SMA etc. to connect to the analyzer directly with coax to the SMA connector. The Decade MS-100 has telescoping antenna directly attached to the transmitter and so does the other I use, the Waio/Cardiotheater.
The only way is airwaves reception.
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