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RF EXPLORER WSUB1G vs lectro internal freq scan


alidav
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has anyone tested and used the rf explorer WSUB1G and compared with the ucr 411 freq scan, specially when working with bag with several wireless mics from differents blocks and frequencies range i need a a wider rf scan, from block 24 to block 29 (included some sennheiser for camera hops in range b. 
Does it worth the money ? 
 

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Here's a pic of what the same window looks like (block 21) on the explorer and SRb. Main advantages to explorer is you can adjust the noise floor/threshold to see more detail on Y-axis, and you can set it to average the readings over up to 28 iterations of the sweep, helpful for finding intermittent or spurious interference!

IMG_20200110_222135.jpg

I will let you know how the RTL-SDR works out, one advantage I see is you can tune the channels in FM and actually listen, which might help nail down the source of interference.

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I have a couple different versions of the RF Explorer.  Personally I've found that the center of frequencies that appear in it's "scan" can be off by as much as 5Mhz.  For that reason I don't trust the specific frequency numbers that it displays.  However it is helpful for showing "relative" frequencies especially when you see two on top of each other, but only one is coming from you!  I'd rather trust the scan on the Lectro receiver, in spite of the limited info that it provides.

 

Tom

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Hi there,

 

RF Explorer internal frequency is correct in range of +/-2Khz if calibrated. The reason you may see up to 5MHz deviation is not due to frequency accuracy, but screen resolution. To understand how the screen becomes a limitation in your measurement is important to get the best out of the instrument:

  • RF Explorer has 112 pixels to represent horizontal spectrum. Therefore, if you select a frequency span of, say, 1MHz, you get 1,000KHz/112=8.9KHz resolution per screen point. If you select a frequency span of 100MHz the resolution now becomes 100,0000KHz/112=892KHz, etc.
  • For best results in normal operation, you should use a large span to start, say 30MHz in the picture above, to locate point of interests. Then move to narrow span to get higher resolution frequency read.
  • If you need to read frequency with higher resolution, click ENTER once to enter Advanced Mode, then use RIGHT key to reduce span and, therefore, increase resolution. Or use FREQUENCY MENU to select a new center frequency of your choice, and a smaller span value.
  • It also becomes very useful to pre-record your frequencies of interest with large and narrow spans, using Presets, so a single click can help you navigate through your frequencies of interest using high and low resolution as needed. For more details www.rf-explorer.com/preset

Hope this helps

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9 hours ago, LoganSound said:

Here's a pic of what the same window looks like (block 21) on the explorer and SRb. Main advantages to explorer is you can adjust the noise floor/threshold to see more detail on Y-axis, and you can set it to average the readings over up to 28 iterations of the sweep, helpful for finding intermittent or spurious interference!

IMG_20200110_222135.jpg

I will let you know how the RTL-SDR works out, one advantage I see is you can tune the channels in FM and actually listen, which might help nail down the source of interference.

Ive got a sdr nooelec used with android smartphone app. Ive Heard the app Touchstone pro would work with and sdr usb dongle but they have Never  answered. The limit of the sdr dongle is the 2Mhz visualization.

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11 hours ago, RF Explorer Team said:

Hi there,

 

RF Explorer internal frequency is correct in range of +/-2Khz if calibrated. The reason you may see up to 5MHz deviation is not due to frequency accuracy, but screen resolution. To understand how the screen becomes a limitation in your measurement is important to get the best out of the instrument:

  • RF Explorer has 112 pixels to represent horizontal spectrum. Therefore, if you select a frequency span of, say, 1MHz, you get 1,000KHz/112=8.9KHz resolution per screen point. If you select a frequency span of 100MHz the resolution now becomes 100,0000KHz/112=892KHz, etc.
  • For best results in normal operation, you should use a large span to start, say 30MHz in the picture above, to locate point of interests. Then move to narrow span to get higher resolution frequency read.
  • If you need to read frequency with higher resolution, click ENTER once to enter Advanced Mode, then use RIGHT key to reduce span and, therefore, increase resolution. Or use FREQUENCY MENU to select a new center frequency of your choice, and a smaller span value.
  • It also becomes very useful to pre-record your frequencies of interest with large and narrow spans, using Presets, so a single click can help you navigate through your frequencies of interest using high and low resolution as needed. For more details www.rf-explorer.com/preset

Hope this helps

I use mine in 'Max Hold' mode and run it while recording in the hope it'll pick up intermittent interference should it happen. Am I right in thinking a direct 'hit' on 1 of my freqs would present as an increase in amplitude of 1 of my existing 'spikes' (and therefore need to leave some headroom for this to show)? 

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18 hours ago, daniel said:

I use mine in 'Max Hold' mode and run it while recording in the hope it'll pick up intermittent interference should it happen. Am I right in thinking a direct 'hit' on 1 of my freqs would present as an increase in amplitude of 1 of my existing 'spikes' (and therefore need to leave some headroom for this to show)? 

 

Yes, an increase of amplitude in MaxHold mode may clearly indicate an interferer higher than your expected signal link at that specific frequency.

You can refresh MaxHold levels anytime using RETURN key.

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An advantage of using a SDR receiver, be it a cheap RTL or something more expensive like a SDRPlay (or Airspy) is that the SDR work as "real time spectrum analyzers" while the RF Explorer and others (like my Siglent SVA1000X) are classical sweeping analyzers.

 

The difference is: A sweeping analyzer is not monitoring the whole SPAN bandwidth simultaneously, but sweeping a receiver over the frequency range and sampling amplitudes. So there is a chance that a very quick burst may be missed. Of course if you leave it in peak hold mode and have it running for several minutes the detection probability will be high.

 

A real time analyzer, however, samples a whole chunk of spectrum (1 MHz or so for the RTL, 8 or 10 MHz or so for the SDRPlay and the Airspy) and calculates a Fourier transform, which means it is sampling the SPAN at once. So even really short bursts can be made visible.

 

But the disadvantages of using a SDR are too many. You need more equipment (computer), SPAN is limited unless you buy a really expensive one (10 MHz or less) and complexity skyrockets because you need SDR software running on the computer. And at least all of the SDR software I know is a royal p.i.t.a. so unusable in a demanding situation like a shot or stage where you need to focus 200% on everything else.

 

On the other hand, if anyone is considering a full RTA, it would be a huge overkill and the minimum prices are in the thousands of dollars. Such units are useful for people who design digital communications equipment, especially if doing bursty transmissions. 

 

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On 1/11/2020 at 1:33 PM, RF Explorer Team said:

Hi there,

 

RF Explorer internal frequency is correct in range of +/-2Khz if calibrated. The reason you may see up to 5MHz deviation is not due to frequency accuracy, but screen resolution. To understand how the screen becomes a limitation in your measurement is important to get the best out of the instrument:

  • RF Explorer has 112 pixels to represent horizontal spectrum. Therefore, if you select a frequency span of, say, 1MHz, you get 1,000KHz/112=8.9KHz resolution per screen point. If you select a frequency span of 100MHz the resolution now becomes 100,0000KHz/112=892KHz, etc.
  • For best results in normal operation, you should use a large span to start, say 30MHz in the picture above, to locate point of interests. Then move to narrow span to get higher resolution frequency read.
  • If you need to read frequency with higher resolution, click ENTER once to enter Advanced Mode, then use RIGHT key to reduce span and, therefore, increase resolution. Or use FREQUENCY MENU to select a new center frequency of your choice, and a smaller span value.
  • It also becomes very useful to pre-record your frequencies of interest with large and narrow spans, using Presets, so a single click can help you navigate through your frequencies of interest using high and low resolution as needed. For more details www.rf-explorer.com/preset

Hope this helps

Hi, ive just purchased an rf Explorer but i dont see any advanced menu option to get the span view setting. 

 

 

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What is the level of the background rf energy to work safely?

For example I set 650 Mhz as my working frequency  on my wireless mic and Rf explorer get an average  rf background energy of -55 dbm,  what kind of problems can happens, what should be the rf background energy level to work without risk of dropping?

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On 1/19/2020 at 1:35 PM, alidav said:

Hi, ive just purchased an rf Explorer but i dont see any advanced menu option to get the span view setting. 

 

 

There's no menu option. You can switch the spectrum view between modes by pressing the [Return] key (user manual, page 17).

 

if you see SP (span, ie, the frequency range shown on screen), C (center frequency) and RBW on the bottom of the screen, you are in advanced mode. 

 

For example the screenshot shared by Michiel is in advanced mode.

 

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On 1/19/2020 at 4:20 PM, alidav said:

What is the level of the background rf energy to work safely?

For example I set 650 Mhz as my working frequency  on my wireless mic and Rf explorer get an average  rf background energy of -55 dbm,  what kind of problems can happens, what should be the rf background energy level to work without risk of dropping?

 

An noise floor or "rf background" of -55dBm is pretty high, you may get any sort of interference in such an environment.

 

What you are interested in measuring is not absolute but relative levels, that is, how much stronger is your received microphone signal from the noise floor. You should typically be about 20dB higher to play safe, assuming of course your RF Explorer is close to your microphone receiver station so you measure what your station will get.

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  • 3 months later...

 

On 1/14/2020 at 3:38 AM, borjam said:

But the disadvantages of using a SDR are too many. You need more equipment (computer), SPAN is limited unless you buy a really expensive one (10 MHz or less) and complexity skyrockets because you need SDR software running on the computer. And at least all of the SDR software I know is a royal p.i.t.a.

 

An Ebay vendor just sent me an RTL-SDR V3 instead of a dipole and did not want it back. So I played with it. While I found the instruction page to be a bit daunting, in actuality, reading through it and following the instructions, installation was easy. I didn't find the software to be a problem. It works well.

 

It's real drawback as borjam says is the limited span that is displayed. This one had a maximum display of 6 Mhz. It's easy to scroll up and down the spectrum, but I'd rather see 50 - 100 Mhz for an initial scan and then zoom in from there. It's ok. It does the job and you get to listen to whatever it is you see on the spectrum and record it. If someone is looking for a cheap solution to try for just a few bucks, it works.

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11 hours ago, Paul F said:

 

 

An Ebay vendor just sent me an RTL-SDR V3 instead of a dipole and did not want it back. So I played with it. While I found the instruction page to be a bit daunting, in actuality, reading through it and following the instructions, installation was easy. I didn't find the software to be a problem. It works well.

 

It's real drawback as borjam says is the limited span that is displayed. This one had a maximum display of 6 Mhz. It's easy to scroll up and down the spectrum, but I'd rather see 50 - 100 Mhz for an initial scan and then zoom in from there. It's ok. It does the job and you get to listen to whatever it is you see on the spectrum and record it. If someone is looking for a cheap solution to try for just a few bucks, it works.


What program are you using? And what OS? I had a hell of a time getting anything to work on Mac. Unfortunately I found that a lot of the SDR software out there is hopelessly buried in academic/programming nerd land and is pretty inaccessible without software compiling skills. Not as much for PC users though. All of the stuff for Mac I tried seemed pretty half baked and had me futzing around in the terminal doing god knows what to my old MacBook. 


Also - I’d be more inclined to buy an RF Explorer if the user interface was more intuitive and it had a nice modern looking screen. Sorry if that’s petty but that’s where I’m at lol. 

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Running Gqrx has pretty painless on a Mac for me. Can be downloaded here: https://github.com/csete/gqrx/releases/download/v2.11.5/Gqrx-2.11.5.dmg

 

Biggest issue for me is there's no practical way to scan; I found some scripts that I couldn't get to run due to incompatibilities with the OS version of some executable and I gave up. I did get it to work on Linux running on a virtual machine on my laptop, and decided this was too janky and if I really needed an RF scanner I'd buy an RF Explorer. I still enjoy futzing with the SDR, but doubt I'll ever use it on site.

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What a different experience we are having. Printed on the dongle was the website to use. I went to the SDR-RTL.com. site and followed their instructions. When I first looked it over, I started rolling my eyes as it was going over all kinds of information. But when I actually stepped through it for the installation, it was simple and straightforward. It was like any other software installation - download, extract, install, and run it. There were no hiccups of any kind. There was no misleading or incorrect instructions. The software they recommended is SDR#. I'm using Windows 10.

 

I needed no help to get it working and detecting FM radio stations. It was all there. Yes, there is a lot of things that are on the left side of the screen that had me scratching my head. I didn't need to know about any of it. After playing with it, I did want to know more, so I read through the guides they provided and learned about all of the other stuff.

 

I didn't find scanning a problem. I was able to type in a frequency and then I could see a 6 Mhz span - limited for sure. But then I was able to scroll though the spectrum by dragging the mouse left or right. I clicked on a carrier and the AGC locked in on it, displayed the audio waveform, played the audio, and recorded the audio without me doing anything but clicking on the carrier and the FM demod button. 

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I understand that it's fun, but beware: All of the computer based SDR software I have tried is fiddly. And I own three more serious SDR units. You know better than me how expensive shooting time is :)

 

The worst problem with a RTL used as a test instrument is, however, dependability. These units don't have very good front end filtering, and in the presence of strong out of bands signals they might show ghosts that would not be a problem for properly filtered wireless equipment. 

 

So, using something like the RF Explorer is more dependable and predictable. RTLs are great for tasks such as software development tasks because being what is now called a "real time spectrum analyzer" you can observe very fast digital transmission bursts. 

 

Also, spectrum analyzers like the RF Explorer tend to have software options better suited for this task (like building a curve with maximum peaks) while SDR programs for computers are better suited for radio listening. There are some spectrum analyzer applications but, as I said, most of that software is not production ready.

 

If it works for you, great! But please be aware of its limitations. 

 

 

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On 1/14/2020 at 6:38 AM, borjam said:

An advantage of using a SDR receiver, be it a cheap RTL or something more expensive like a SDRPlay (or Airspy) is that the SDR work as "real time spectrum analyzers" while the RF Explorer and others (like my Siglent SVA1000X) are classical sweeping analyzers.

 

The cheap SDR dongles can be made to sweep as well by reducing the window size and performing FFTs on sequential, overlapping samples over the frequency range of interest. The open source rtl_power is part of the rtl_sdr driver package and does this very thing and is also the backend for many of the spectrum analyzer GUI applications. Maybe I'm wrong but I assumed RF Explorer behaves in the same way.

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2 hours ago, Derek H said:

I could never find a good GUI for rtl-power that worked with my older MacBook and wired nooelec brand sdr dongle 

 

Things are pretty bleak for mac. The only one I found a few years ago was RTLSDR Scanner and it works okay. Theoretically QSpectrumAnalazyer could be made to work and have better performance but I haven't bothered building it. It's just easier to run linux.

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On 5/27/2020 at 8:07 PM, Patrick Farrell said:

The cheap SDR dongles can be made to sweep as well by reducing the window size and performing FFTs on sequential, overlapping samples over the frequency range of interest. The open source rtl_power is part of the rtl_sdr driver package and does this very thing and is also the backend for many of the spectrum analyzer GUI applications. Maybe I'm wrong but I assumed RF Explorer behaves in the same way.

 

But a RTL dongle lacks the analog filters before the ADC present in a real spectrum analyzer. As far as I know RF Explorer is a ˝classic" spectrum analyzer with a mixer and a sweeping local oscillator. That configuration improves the dynamic range. No matter how good your digital domain filtering is, if the ADC gets overloaded, game over ;)

 

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