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borjam

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Everything posted by borjam

  1. It's a really clever design, the dipole arms are wide which increases bandwidth. Wider than a typical dipole anyway. I think Larry explained it somewhere.
  2. You are right about the distance: A misunderstanding on my part. When comparing a half wave dipole to a wideband bowtie antenna I assumed the half wave dipole was a builtin antenna in a receiver. My silly mistake By the way, the Lectrosonics SNA600a with its thick elements is a kind of a wideband antenna. A similar trick to the Nadenenko dipole you could see on many trawlers. That said: antennas can get detuned by stuff placed inside the near field (roughly 1 wavelength) and I wonder whether a wide band botwie can be a bit more "lenient" in that aspect. If someone can lend me one I can give it a try with the VNA (By the way I edited my previous post about amateurs using multi-narrow-band antennas instead of wide band ones). For some reason it got eaten (or I hit send before finishing it).
  3. Yes but better tuned. And if you can place it so that stuff is outside the near field it will work better.
  4. Amateur radio antennas are not usually wide band. Some are multi band as in “supporting several narrow bands” which is radically different. So you can find antennas that work on 144 - 146 MHz and 430 - 440 MHz but for, say 300 MHz they won´t be well matched. For example, at embassies and military installations you can see huge log periodic antennas (the equivalent of the shark fin) while hams use multi band Yagis. For an amateur the wide band antenna covering, say, 3 - 30 MHz is overkill when you really need to cover narrow segments at around 3.5, 5, 7, 10, 12, 14, 18, 21, 24 and 28 MHz. The bands of interest are on average 200 KHz wide (except the 28 MHz band, 1.7 MHz) .
  5. Just saw it on Slashdot. Press release linked. https://www.nikon.com/company/news/2024/0307_01.html
  6. Aaton is French, they are in Grenoble. Arri is German. That said, being both in the EU old nationalities no longer matter much.
  7. Who knows. Someone might just buy the brand and sell whatever stuff using it, or, if the new owners want to keep the current products they will need the engineering staff. In the late 90's I was designing multi track voice recorders (clunky stuff for call centers). We were a group of four people inside a larger company focusing on cable infrastructure and networking. The company went bankrupt and it was acquired by new owners. The new owners weren't interested on the development group I was part of and an interested party approached the new owners in order to acquire our business. Before approaching them, the interested party contacted each of us in order to know what we expected, what we wanted, ie, in order to make sure that they acquired a team and not just a bunch of source code, schematics and a brand name. They even asked our opinion on the location to set up the new premises, which new staff we needed, if any, etc. Sadly the new owners asked for too much money and the operation was aborted. So several months later I just left the company (I was the architect of the system and I had developed the most complex part of the software) and the value of the operation became zero. So, who knows. Not all "corporate" types are stupid.
  8. Actually, maybe it's not so bad, quite the contrary. Advanced modulation techniques can be more "gentle" as far as I know. Intermodulation is especially nasty with analog transmission that relies on continuous carriers. That said, my brother tried transmitting Dante over a 60 GHz wireless link (full duplex 1 Gbps, 0.5 ms delay, or course perfect line of sight) and it worked like a charm.
  9. Metallic objects within the antenna near field and they will disturb the antenna radiation pattern and/or detune it. Bear in mind that some directional antennas (Yagi-Uda for example) are created by adding additional elements which are not electrically connected to the dipole. Of course their lengths and distances are important. The simple rule of thumb is, avoid stuff at a distance of one wavelength. But be careful with the bandwidth of the active antenna amplifier. An antenna is rather poor as a band pass filter and LPDA antennas have a huge bandwidth, that is their most interesting property! As I said, an antenna is not a filter . And wide band filters are more prone to interference. A strong signal outside your frequencies of interest can make the amplifier distort or even get into blocking. Also, avoid excess gain. If you want to compensate for losses in your distribution system, say, a passive antenna distributor, adjust if possible the active antenna gain to compensate for that loss. No more. If the amplifier is not adjustable you can try an attenuator at the amplifier input.
  10. I was browsing the second hand inventory of a well known Spanish rental company (Ovide) and I stumbled upon a second hand HS-P82 including a RF82 control surface. Both for €890. https://www.ovide.com/segunda-mano/ Note that I am not affiliated to them, just thought someone might be interested.
  11. At least some Sky programming has been made available on HBO. But maybe it will land on Sky Showtime? Confusing times! Have you watched this one? It is now available on Spanish TV, I guess it will be on others as well. https://www.pbs.org/wnet/nature/about-attenboroughs-wonder-song/28798/
  12. My post was rather poorly worded. I wrote on the iPad which is not exactly pleasant When I said "mixing" I meant "using files from different sources in your workflow", not mixing as in audio mixing. So well, it's obvious that if your other sources use 32 bit FP audio files it is more convenient to avoid conversions. From that point of view, even if they use a single converter it makes sense to generate floating point files. It just simplifies your workflow. Again, my poor writing I said "32 bit capable architecture" meaning dual converters with different gain or whatever. There are several approaches used by different manufacturers. I wonder about that as well. One problem with how 32 bit floating point has been marketed is, it looks like they suggest a full 32 bit dynamic range which is insane. The truth is, the dual ADC converter will add enough dynamic range so that you can really relax about gain settings. But do not expect it to record at a nuclear blast zero and not clip! A cost advantage is that you can implement the limiters in the digital domain. Indeed, seems they are not very open about their specs. And actually I guess it would be pretty easy for Zaxcom with their neverclip architecture to implement floating point files. Just they do not like the marketing and irrational expectations about it at all. I remember many years ago (1990 maybe) I attended a course on DSP programming based on the Motorola DSP56000. Being a fixed point processor you had to be careful with your calculations because, well, fixed point mathematically "clips" as well. The DSP96000 was different, based on floating point, so you could somewhat relax about that. Your data came from 24 bit converters at most of course.
  13. Anyway, does it have a 32 bit capable converter architecture? I mean, does it have converters capable of delivering a dynamic range greater than 24 bit? Or is it just the capability to save files in 32 bit floating point format so that you can freely mix them in post with other 32 bit sources without conversions? It says "32 bit float audio file format". So it must be just the file format (I have only seen Aaton Cantar recorders in photos, just wondering)
  14. The standard lyres included with the Blimp 2 are too soft. I had to replace mine in order to support a mile long NTG8 because of the weight. In my case I got "82 shore" lyres, which are the stiffest as far as I know. Due to the way lyres are fitted to the boom I had to add a couple of plastic spacers in order to place the microphone at the right position.
  15. I don't think so. If only, better modulation schemes should be developed. And bear in mind that broadcasters are also avid PMSE users, so they would be shooting themselves on the foot. I am pretty sure they know that their spectrum allowance can only shrink. So if broadcast usage within those bands expands, spectrum availability for PMSE will shrink. We'll see what happens in 2030 anyway. There is pressure to phase out free broadcast with the excuse that there is programming available on the Internet. I saw a report that PMSE usage is growing in some countries, curiously. So, when in doubt, lav everyone and everything in order to raise statistics and make a better case for the next review! Or go 192 KHz sampling with redundant coding!
  16. Seems there will be a respite until 2031 in Region 1 at least (Europe, Africa, Middle East and others). The 470 - 694 MHz retains broadcast as a primary user, keeps PMSE (program making and special events, wireless microphones and similar applications in regulatory-speak) as secondary, and while some countries might authorize some mobile activity it would be on a secondary basis if at all. One of the key points of the opinions supporting broadcast and PMSE was regulatory stability, and it seems the next review is scheduled for 2031. So, some peace of mind for now I guess. EBU seems to be happy. https://tech.ebu.ch/news/2023/12/ebu-position-reflected-in-wrc-23-decision-on-uhf-band
  17. I guess they want to give it a podcaster/youtuber "vibe". Large microphones are trendy, look at how many youtubers use a Shure SM7B!
  18. As far as I know (I own two units of the previous generation) the newest units (UTX-40, etc) offer some additional options: - A "gain" mode in the microphone attenuation menu - An occupancy sensor mode to prevent ultrasound from sensors hitting the microphones and affecting the compander - A digital shoe interface for Sony cameras Always check the frequencies you intend to use. Do a scan to make sure they are free. If you run into problems and you don't have a spectrum analyzer do a scan on a different channel group. And if not using RF Explorer or frequency coordination software, at the very least Sony offers advice for frequency usage depending on the number of channels you want. Check the frequency list for the relevant models (it's more or less the same for the latest UWP-D or the previous generation), paying attention to the "Grouping for multi-channel system" sections. https://pro.sony/ue_US/support-resources/utx-b40/manual Also, somewhere else in this forum @Atanas posted a firmware download to add the sensor occupancy immunity to the compander (advantages of digital domain implementation) but I haven't tried it. My units were purchased second hand and I am trying to get an answer from Sony about this beta firmware. And, last but not least: knowing that the included mics are really poor I ordered two second hand ECM77-BMP microphones from eBay. Surprise, they have a ferrite clamp installed close to the jack. Is this a hint that these transceivers might be susceptible to RF interference received through the microphone connector? As far as I know these ferrite clamps are installed by Sony themselves.
  19. WRC-23 is ongoing (World Radio Conference) and it seems PMSE (programme making and special events) will tend to be protected. At least it is the European position. This is interesting: https://accesspartnership.com/access-alert-what-impact-might-wrc-23-have-on-the-content-and-events-industry/ Quoting: " A recent study from the European Commission showed that demand for PMSE spectrum was increasing in 50% of the EU Member States, with Spain showing the biggest increase at 20% a year[3]. " At least they are considering PMSE as an incumbent application that should be protected. And while they are considering a proposal for mobile service (beware, in radio regulation gobbledygook mobile service is _not_ cell phones, which are called "IMT" with IMT being the real threat to PMSE). It is interesting to note that, while broadcasting usage is decreasing in some countries, they are taking into account the growth in PMSE, ie, wireless microphones and associated applications). And https://www.itu.int/dms_pub/itu-r/oth/0A/0A/R0A0A0000150001PDFE.pdf Slide 14: "CEPT supports the continuation and development of the incumbent usage by PMSE (SAP/SAB) (in accordance with existing RR No. 5.296)." So maybe there is hope! Sometimes crazy proposals are made in World Radio Conferences only to be discarded. I remember the French put out a poorly written proposal to reassign the Amateur 144-146 MHz spectrum to aeronautical communications which was rejected. They are still insisting though, and the International Amateur Radio Union is still on guard. And, adding some more information, the Radio Spectrum Policy Group of the European Commission recommends "long term regulation stability" for PMSE and free to view television. I know I am talking about Europe (Region 1) but hope the US authorities get a clue. Who fights to protect the PMSE usage, anyway? Seems mostly broadcasting organizatios (such as EBU) but maybe other representatives of the entertainment (or sports) industry should participate somehow. A coalition of wireless equipment manufacturers and industry associations such as AMPS (MPAA even!) could help make a difference joining forces with the broadcasting associations.
  20. Interesting. What chipset does it use? In my experience Realteks are a big no-no, AX88179A chipset (or, I guess, similar) works although not as well as the Thunderbolt attached Broadcom.
  21. Ouch! There are several Thunderbolt to Ethernet adapters sold by Sonnet. I think the one sold as "AVB" has a Broadcom chip (well supported by Apple and others) would work as well without needing to chain dongles. But I haven't tried it. The Mac Mini option of course is the best option of course. The thing with Dante is, the protocol is not so complicated. But the market is littered with real networking junk which works well enough for the low end peecee market (or it doesn't work at all but unsuspecting customers don't know who is to blame).
  22. Last Summer I tried several USB-C to Ethernet interfaces with a Macbook Pro. I was going to do something rather straightforward, recording a concert (16 channels over Dante from the stage preamps). I only found one combination to really work as it should. The old Apple Thunderbolt GbE adapter chained to a Thunderbolt 4 to Thunderbolt 2 adapter. The rest were a mixed bag and some of them outright catastrophic.
  23. There is something called "institutional knowledge". Skills that are difficult to document that pass from generation to generation. If you break the cycle through a layoff or letting people retire without passing on that knowledge through apprenticeship you are toast. That happened, it's been said, to the French nuclear industry and it backfired spectacularly when building the Okiluoto reactor in Finland. https://www.power-eng.com/news/lessons-learned-from-olkiluoto-3-plant/#gref
  24. Actually Deity licensed several patents from Zaxcom, so they can record and transmit without legal trouble.
  25. borjam

    Rode mics

    I understand his frustration with overly enthusiastic marketing departments, but he doesn't seem to understand very well how digital audio works. Dynamic range (let's say, macrodynamics) is different from resolution. When he says his voice can be recorded with 8 bits I think he is talking about envelopes, range of amplitudes, not failthful audio recording. So much for 8 bit audio, even good old digital telephone audio used 12 bits! (Yes, non linear, A or µ law but it's still 12). Resolution is related to S/N ratio because low resolution means quantization noise. So when you record you aim to make a good use of the A/D dynamic range leaving some headroom to prevent clipping. Of course everyone here knows that there is a chain of elements with different dynamic ranges involved in audio recording. Air: Yes, it can become non linear for loud enough levels! (*) Microphone Preamp ADC. And turns out many beginners (for whom many Rode products are aimed!) tend to fail setting up recording levels and clip. So, what's wrong with making their lives easier? As for controlling all of the circumstances or not, well, it depends. For people shooting guerrilla style, or documentaries, or even doing nature recordings, all kinds of unpredictable stuff can happen! Imagine you are recording a distant bird (with lots of preamp gain!) and suddenly an interesting bird comes close and sings. So yes, it won't capture 32 bit audio. Fine. But it will be much more lenient with recording levels. So what's wrong? Youtube videos. UGH!
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