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borjam

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Posts posted by borjam

  1. 2 hours ago, Fred Salles said:

    @Borjam I do not see the 

    Lectrosonics SNA600a As a wide band. unless I misunderstood, it is a dipole with an ajustable center frequency. So it allows to use it with a « wide range » of receivers but once set it is limited to the band around the chosen frequency, like a normal dipole.

     

    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. On 3/10/2024 at 12:40 PM, ramallo said:

    I guess it depends on whether the 1/2 dipole is at its correct distance. The advantage that I see in the Botwie is that it is suitable for multiple frequencies at the same time and you forget about it, but at the cost of losing gain. But also according to those at Betso it has an SWR of 1.2:1 (I think it is too good ) against the 2:1 (Fair) of, for example, the Lectrosonic SNA600a. Much more efficient the Betso

     

    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. On 3/9/2024 at 5:29 PM, Indeliblesound said:

    I was referring to the wideband whips you see more in HAM/amateur radio applications and tune to 400-900mhz. But giving this second though maybe the antenna is optimized for middle of that range?

     

    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) .

     

  4. 2 hours ago, The Documentary Sound Guy said:

    Huh, I could have sworn Arri was French.  I stand corrected.

    Aaton is French, they are in Grenoble. Arri is German. 

     

    That said, being both in the EU old nationalities no longer matter much.

  5. 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.

     

  6. 8 minutes ago, The Documentary Sound Guy said:

    So ... I think this is probably bad news for the way we currently operate.  How much intermodulation or noise floor does a 6MHz channel create?  How much wasted bandwidth will there be in the 600MHz UHF spectrum if people start using 6MHz channels to transmit three or four active tracks using technology capable of transmitting 18?

     

     

    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.

     

  7. 8 hours ago, The Documentary Sound Guy said:

    I once ran into an issue where I unknowingly had a bunch of wires directly in front of the diversity fin (they were in a wall), which knocked out reception quite effectively.  This wouldn't have happened in a split setup where the antenna were physically distant from each other.

     

    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. 

    8 hours ago, Dave Pullmer said:

    Nice to hear your perspectives. I’ve been combing through my set up, thinking of what I could improve, and that was one area I was thinking about. Was curious if using 2 passive fins would buy me any gains, but it seems like that would be negligible or minimal at best.

     

    I love the simplicity of the d-fin, though I have been thinking it could be nice to have 1 active antenna in case I need to go longer than my maximum 50ft run.

    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!

     

    8 hours ago, Dave Pullmer said:

    One other thing I have been thinking of is filters - I have read a few diversity fin users say they’ve benefited greatly from adding passive filters to their set up (RF Venue, or PWS). The mixers I’ve talked to have added 470-608 filters and said it has improved their range noticeably. Would this potentially be because the filters have a steeper cut off on both ends of the spectrum than the antenna? I’m always a bit surprised to hear of these gains when the filters people are implementing are quite wideband already (470-608).

    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.  

     

     

  8. 44 minutes ago, Constantin said:

    While you are making valid points I am curious why you think that 32-bit float of all things would negate the need for mixing? 

     

    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.

     

    28 minutes ago, Constantin said:

    As I understand it the converters themselves don’t need dynamic range greater than 24 bits, as they basically shift the reference point around to accommodate louder sounds. So the range stays the same, but the 0dBfs moves around. 
    Still the converters do need to be able to facilitate this

    I always thought the Cantar did have dual ADCs. But Aaton has never been very open about their specs

     

    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.

     

     

  9. 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)

  10. 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.

     

  11. On 12/25/2023 at 9:48 AM, Fred Salles said:

    Thanks for the info. But I hope it will not translate into further development of DTT on the 470-694 band! It already took over the 700 band almost entirely in most countries and it bleeds drastically over the 600 in some. 

    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! :P

     

     

  12. 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

     

     

  13. 56 minutes ago, Olle Sjostrom said:

    OK but here's a weird one. This is actually a TV show that use LDCs for its primary sound, so it's basically a good looking video podcast, with actual camera operators and such, not like a Joe Rogan type deal. It's a Swedish show. I just think it's weird that they choose to have the mics like that. It's almost uncanny valley. I mean I like the sound of it, it sounds great, but there's a big disconnect with what I'm used to seeing as a TV viewer.

     

    I guess they want to give it a podcaster/youtuber "vibe". Large microphones are trendy, look at how many youtubers use a Shure SM7B!

     

  14. 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.

     

     

    s-l1600.jpg

  15. 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.

     

  16. 5 hours ago, RadoStefanov said:

    Everytime it was not chip based but hardware port loosing connection problem.

    I am on a show now with USBC/TB4 port to Nic adapter and it has not been an issue. 

    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.

     

     

  17. 14 hours ago, RadoStefanov said:

    I had a few instances with thunderbolt 2 adapter disconnecting. 

    If it is ever my choice I would do a mac mini with actual integrated NIC  

    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).

     

     

  18. 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. 

  19. On 10/1/2023 at 6:00 PM, Ontariosound said:

    The Nanoshield was discontinued for a few reasons.  And the current Windjammers do not block the wind as well as the ones from years ago.  Yay.

    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

  20. 5 hours ago, JonG said:

     

    if you have been reading this forum you’d know that transmitters that record simultaneously are illegal in the US because Zaxcom holds the patent, so only they can do both in the US. If you want to get around those restrictions you’ll have to purchase outside this country. 

     

     

    Actually Deity licensed several patents from Zaxcom, so they can record and transmit without legal trouble.

     

     

  21. 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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