borjam

I wouldn't recommend at all to mix different digital wireless systems on ISM (Industrial, Scientific, Medic) bands. Each one of them may implement completely different spectrum arbitration/management features. And if I recall well, the Deity protocol might be somewhat of a bully, at least nudging (ahem!) WiFi networks to steer clear.

I know two sources that may design those filters. One of them is in Italy and the other one in Greece. The prices are from cheap to reasonable. The first one is a radio amateur in Greece who is selling some nice products. I am quite sure he would take custom orders and, besides, this area would be a promising market for him I think. While his products are more oriented to the diy amateur radio operator, I am sure he can supply finished products for end users. http://www.sv1afn.com The other one is in Italy. He is actually selling filters for professional applications. I have purchased a couple of filters from him and they certainly matched specifications. However, he is rather chaotic with delivery times and shipping. Otherwise the products I have tried are great. https://www.jghitechnology.com/gb/

Anything Ethernet based is so flexible. You can even use fiber instead of twisted pair. It’s much thinner and depending on the type of transceivers and fiber you use it can run for several Km while twisted pair is limited to 100 m.

The main difference between the two antenna types is bandwidth. Log-periodic antennas are useful over a much wider range of frequencies. That’s the reason, I imagine, why the so called shark fin antennas are so popular for radio mics.

I would say he is in Spain, gathering swift sounds for a sound background. (Several Spanish productions feature really conspicuous swift sounds, which is actually a nice detail because they are really loud in Spring and Summer)

Wow, just got an email from Sound Devices announcing firmware version 7 and an additional feature for the II Series: A Noise Assist plugin at $300. Previously it was MixAssist. So, I guess MixPres are doubling as an entry level hook for the Sound Devices "drug"

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

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.

No I didn't, as the kludge worked for me and I haven't had much time to go outdoors and recording this Spring 😕 I'll do it this week, after all being confined at home...

It's just reducing probability. Someone with mild symptoms can have some fever.

Oh I am really sorry! I only exchanged a message or two with him but it was clear to me how knowledgeable he was, how generous sharing his knowledge and what a gifted technical writer he was. My condolences.

The NeXT Cube I have at home has a 450 MB hard disk. That was a huge disk in the late 80's And I remember back in 1991 we ordered a couple of 750 MB disks from the USA. Large Maxtor drives weighting a ton, the interface was SCSI probably. I think they were $2500 each. At that time it was worth ordering directly from abroad, in Spain prices for this stuff could be 2x or even 3x.

At high sound pressure levels ultrasounds can produce audible sounds when colliding with objects. The transition between different mediums (air and a solid body) creates a non linear effect. For example, it is possible to beam an AM modulated towards a wall. The beam will be demodulated and the modulating signal will be heard like it originated from a spot on the wall. https://en.wikipedia.org/wiki/Sound_from_ultrasound I have seen it working, a friend was experimenting with this some time ago. I guess it will provoke a similar phenomenon on the microphone diaphragm.

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.

(I am not affiliated with them, just curious about the outcome!) Austrian Audio, the company created by former AKG staff "made redundant" when Samsung acquired Harman Group, has announced two headphone models. An over-the-ear (Hi-X55) and and on-ear (Hi-X50). https://austrian.audio/hi-x55/ https://austrian.audio/hi-x50/ The prices I've seen announced by the British distributor are 249 pounds for the Hi-X55 and 199 pounds for the Hi-X50. Both models feature detachable cables and they claim robust construction with metal hinges, etc.

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.

I'm glad it worked. Regarding the vanishing permissions, the advantage of operating systems with a Unix heritage is that very few paranormal phenomena occur, if any! So yes, it was trivial to predict that one Now, I'll check later what spell you need to make that change permanent. I am not familiar at all with Ubuntu, so I have to dig a bit. It will involve editing a configuration file. Do you feel comfortable doing that? It's a simple task but Unix text editors can be a bit daunting to inexperienced users! And no problem at all for the technical support thing. I'm happy to contribute to this forum. Besides, I guess it will be useful for other users. Turning an old, cheap computer into a large spectrum analyzer screen is great

Good. So you need to embrace serialism. Listening to good music never hurts, Or become a member of the “serial” group instead of “dialout”. I imagine the permissions were c r w - r w - - - - ? (that means the owner —root—and the owner group —serial— have read and write access to it) While I check which is the right command you can try something simple: sudo chmod a+rw /dev/ttyUSB0 if will ask for your password. If the system doesn’t complain you will have full access to the serial port as a regular user. So, if you launch the RF Explorer software it should work. Unfortunately these permissions will be gone once you reboot the system or unplug the RF Explorer. I’ll check how to add you to the serial group to make it permanent. (Linux distributions have lots of silly changes between versions).

So you are not a member of the dialout group. Not surprising, I found the syntax for that "adduser" command rather odd. What Linux distribution exactly have you installed? I will search for the relevant spell. As a worst case solution you can edit the group file yourself (it's a plain text file) and add your account. I forgot. Was the RF Explorer connected to the computer? The /dev directory contains device files. In order to access a device a file is created there. And for plug and play devices (such as USB ones) the file only exists when it's connected. So, if the RF Explorer was connected either the device was owned by a different group or it wasn't recognized in the first place. If it was connected, check the "tty" devices present in the /dev/directory ls -l /dev/tty* Check for /dev/ttyUSB to see if it exists. I think that's the correct name for the serial line. ls -l /dev/ttyUSB* (the USB has an asterisk at the end, maybe it's too small with this font)

I am not a Linux user (I have been using Unix since the late 80's though) and using "adduser" in that way looks odd to me. try this fgrep dialout /etc/group to check if your user has actually been added to the proper group. Otherwise the program won't have permission to open the device. A crude but easy to grasp way to find wether the RF Explorer is being detected and it's really available to the dialout group is cd /dev ls -l | fgrep dialout At least some device names starting by "tty" should appear. Post the output here. There is always a lot of uncertainty in Linux as developers suddenly decide to make breaking changes between versions. So, we need to know wether there is a valid driver present for the device (it appears as an old fashioned serial port), which permissions it has (the group name might be "dialup" instead of "dialout" and wether the device has really been assigned the proper permissions.

Can you post here que troublesome commands? Maybe I can help.

Maybe I am asking a very silly question, my apologies in advance. How do you guys perform a RF Explorer scan? Some digital transmission systems work with very short bursts, so a regular spectrum analyzer has a limited detection probability unless you leave the analyzer running for some minutes and set up so that it holds the peak levels. Otherwise you might miss the offending transmissions.

Brace for audiophile grade compost and plant pots coming!

I cound't wait, first thing I did right after I arrived home was watching it. It's a really awesome documentary. I love how the story is told and how it can connect with you even emotionally. It's a pity that sound work is so invisible compared to camera/cinematography work that grabs so much more attention in the form of books and documentaries. Yet it is so powerful. Now wish me luck, I am going to try to convince my 18 year old nephew to watch it.He is studying 3D design and it seems he would like to work on video games.

And the DVD just arrived today.