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borjam

Wondering: any word on 60 GHz wireless microphones?

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Hi :)

 

Just wondering. I have been trying (with great success) a 60 GHz data link. It's equivalent to digging a trench and laying a fibre across the street and it

provides 1 Gbps full duplex, no packet drops even.

 

Apart from its small wavelength (5 mm, which means it can have trouble even crossing a window) it has a really big advantage: Oxygen absorption.

That limits the maximum usable distance (Oxygen absorption adds an extra attenuation of 15 dB/Km) but proides an enormous advantage: An

almost guaranteed interference free band. 

 

For now it's being considered as the candidate to be the next WiFi (which would need an access point inside each room but, again,

would suffer no interferences from the neighbors) and being used for high speed data links. 

 

Just curious, seems like an ideal system. Moreover with the small wavelength it's well suited to advanced antenna

techniques such as beamforming. The system I am trying now is even cheap. A pair of units capable of linking 1 Gbps

at 100 - 200 m is just $200.

 

 

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1 hour ago, borjam said:

 seems like an ideal system.

 

Does it? 

 

1 hour ago, borjam said:

small wavelength (5 mm, which means it can have trouble even crossing a window)

 

1 hour ago, borjam said:

it has a really big advantage: Oxygen absorption.

That limits the maximum usable distance (Oxygen absorption adds an extra attenuation of 15 dB/Km) 

 

That sounds like a dis-advantage to me. I heard the useable range is 10m, but only if there is absolutely nothing between the two devices. 

 

1 hour ago, borjam said:

but proides an enormous advantage: An

almost guaranteed interference free band. 

 

That would be an advantage, but: 

 

1 hour ago, borjam said:

For now it's being considered as the candidate to be the next WiFi 

 

There‘s that interference again. 

 

Considering the effort Zaxcom users have to invest to get even 2.4 GHz gear to work effectively, I‘m not holding my breath. 

Range is one of our most crucial issues, I don’t need a technology that can only achieve 10m - if everything works as it should. 

And then there is power. I bet these devices need a fair amount of more power to achieve even their 10m range compared to lower frequency bands

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60GHz is literally off our radar (no pun intended). I just searched the FCC website for information on that band and found virtually nothing.  If we aren't authorized to be there, we aren't going to spend engineering time on it.   Heck, we still looking at 5Ghz and 7Ghz and scratching our heads...........

 

edit - just looked at the FCC allocations - 59.3GHz to 64Ghz is allocated to "fixed inter-satellite" and "mobile radio-location" use.   

 

Edited by Gordonmoore1
additional information

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I am really interested in the 1-10Hz spectrum.  No Uber radios on it yet.

 

Is antenna size a problem for anyone?

 

D.

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8 hours ago, Constantin said:

 

That sounds like a dis-advantage to me. I heard the useable range is 10m, but only if there is absolutely nothing between the two devices. 

 

I have a working link. It's short, 20 m, but it supports 1 Gbps in full duplex. No packet drops, as I said. The equipment I am using is capable of 

sustaining that to 100, even 200 m unless there is a heavy hail storm or rain.

 

Yes, my link is short, I had to reduce power to avoid overloading the receiver.

 

8 hours ago, Constantin said:

 

 

There‘s that interference again. 

 

The thing is, the high atmospheric attenuation together with the small wavelength really reduces that interference. I could run another link across the same street and my link wouldn't notice.

 

8 hours ago, Constantin said:

 

Considering the effort Zaxcom users have to invest to get even 2.4 GHz gear to work effectively, I‘m not holding my breath. 

Range is one of our most crucial issues, I don’t need a technology that can only achieve 10m - if everything works as it should. 

And then there is power. I bet these devices need a fair amount of more power to achieve even their 10m range compared to lower frequency bands

 

I think you could achieve around 100 m without much problem. Human bodies absorb a lot, of course, but beamforming antennas exploit reflections on multiple surfaces. 

 

I don't have power consumption data and in my case it's distorted by the core CPU they need to be able to move 1 Gbps of traffic. Anyway, the power supply is not larger than the older 2.4 and 5 GHz equipment I used. It could be challenging for a small belt clipped wireless transmitter, right. I don't have figures for the current consumption of the RF part. A good aspect of this band, however, is that given the huge bandwidth available you don't need an elaborate coding scheme, which reduces the processing power needed. My link is using QPSK, not even QAM. 

 

As for 2.4 GHz, the band is too polluted. When I first tried wireless systems on 2.4 GHz the band was empty. You could achieve 100 - 200 m from laptop to laptop without an access point even. Now I detect around 100 wireless networks in the small street where I live.

 

5 GHz is better (walls add more attenuation) but it can be a problem with weather radars. 

 

7 hours ago, Gordonmoore1 said:

60GHz is literally off our radar (no pun intended). I just searched the FCC website for information on that band and found virtually nothing.  If we aren't authorized to be there, we aren't going to spend engineering time on it.   Heck, we still looking at 5Ghz and 7Ghz and scratching our heads...........

 

edit - just looked at the FCC allocations - 59.3GHz to 64Ghz is allocated to "fixed inter-satellite" and "mobile radio-location" use.   

 

https://transition.fcc.gov/oet/spectrum/table/fcctable.pdf

 

Page 61: 59.3 - 64 GHz. RF Devices (Part 15) and ISM equipment (Part 18). According to note 5.138 the 61 - 61.5 GHz band is designated for ISM devices. 

 

You can already use the equipment I am trying. It was approved in the USA some months ago.

https://fccid.io/TV7WAPG60AD

 

Caveat, I am Spanish, I'm not that familiar with the US regulations but I guess "Part 15" covers wireless microphones. 

 

 

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Part 15 does cover SOME lower power (50mW or less) wireless microphones.  Part 15 is an emissions rule governing the spectral behavior of the products.  But the emissions rule doesn't govern permitted use.  From the very same chart you cited, the USE is "fixed inter-satellite" and "mobile radio location" use.  The product you point to is a router - whether it's use is permitted in the US for this purpose I can't say.  I can say that we sure don't have any indications from the FCC that a wireless microphone would be allowed in this spectrum.   A router is a "fixed" location device - a wireless mic is not.  

 

Part 15 is also used for just about every consumer product out there and certifies only that the product will not cause damaging interference for other devices.  TV's, electric shavers with a digital display, LED light bulbs -  (anything that is a non-linear device) - need Part 15 certification.     There are lots of RF devices (microwave ovens for example) but not all RF devices can be used in all parts of the spectrum.  That falls under the USE part of the charts.

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1 hour ago, Gordonmoore1 said:

Part 15 does cover SOME lower power (50mW or less) wireless microphones.  Part 15 is an emissions rule governing the spectral behavior of the products. 

 

Understood. Sorry, I am not famiilar with the FCC regulations and I've seen so many mentions to Part 15 I assumed it covered intended usage. Although I have found this reference:

 

https://docs.fcc.gov/public/attachments/FCC-13-112A1_Rcd.pdf

 

In particular, paragraph 4 says "Any type of unlicensed operation within the 60 GHz band is permitted under these rules, with the exception of operation onboard aircraft or a satellite".

 

The airborne restrictions make sense because airborne transmissions might disrupt inter satellite communications. 

 

1 hour ago, Gordonmoore1 said:

But the emissions rule doesn't govern permitted use.  From the very same chart you cited, the USE is "fixed inter-satellite" and "mobile radio location" use. 

 

 

Hmm sorry to point it out but I don't think it's "fixed inter-satellite" nor "mobile radio location". I think it is "Fixed", "Inter-satellite", "mobile" and "radio location". The equipment I am testing is intended for fixed data links, for instance. 

 

Anyway, I was just curious. From my experience so far it seems to be promising for many applications. Especially with the possibility of a very high spectrum reuse and very little interference. It also encourages the usage of very narrow beam antennas, which would reduce interference further. My units, for example, use beam forming arrays with 36 elements. The antenna assembly is a small 20 mm x 20 mm square.

 

Let's see how it develops, I heard about the new 802.11ad wireless networks several years ago and I only could test some equipment this year. 

 

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I don't know a lot about these things but pretty much everything you mentioned so far seems to make this actually *unsuitable* for location sound wireless work.

 

to me the most promising new technology seems to be the new digital systems which sends data in synchronised nano second pulses, allowing for a tremendous amount of units in the same spectrum (forgot who got the first system out, I think it was a rack unit though)   

 

chris

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Much of that technology has been in place in many military systems since the 70's.  Your cell phone shares some of this technology also.

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Chris, I believe you're referring to Alteros (Audio Technica) and their 6.5GHz TDMA technology.  I agree it is an incredibly promising tech.  It seems perfectly suited for newsrooms and other small stage areas where the transceivers can circle the set.  24 channels over one frequency.  Incredible.

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