Wireless transmitter
 

Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Rob

Wireless transmitter
 

In article om,
Rob wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?

--
*If a thing is worth doing, wouldn't it have been done already?

Dave Plowman London SW
To e-mail, change noise into sound.

Wireless transmitter
 

On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Rob

Wireless transmitter
 

On Sat, 05 May 2012 08:44:27 +0100, Rob wrote:

On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Rob

There is nothing intrinsically wrong with it, but it does have one
disadvantage in real-world use. That is that it has no robust way to
combat data lost through interference. When you send real data over
WiFi it goes at high speed and lost info gets re-transmitted. With
this system, what is lost is gone for good, and you get a glitch
instead.

When it is running well, it should be capable of good sound quality.
In a city, with lots of local WiFi systems in use, this is unlikely to
be the case.

d

Wireless transmitter
 

In article m, Rob
wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

From the 'reviews' it looks like the specific device is prone to cross
interference because it uses the same band as other equipment, and falls
over if you expect to get the signal though a wall.

Impossible to say much about sound quality since there seems to be no
detail at all on modulation methods, and lossy data compression, etc. Nor
any relevant test results or serious listening.

"Intrinsically" a radio link can work fine. But you would not be buying an
"intrinsic" concept. You'd be buying an implimentation that might be great
or might be rubbish.

Personally, I'm quite happy to use cables. They work nicely.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Wireless transmitter
 

In article m,
Rob wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Radio links can of course work perfectly well under good conditions. But
many of these sort of things don't work well in practice. Other devices
interfering with the signal or that signal not being powerful enough to go
through walls etc.

All you can really do is try it and see if it works, as so much depends on
local conditions. And hope Maplin will refund if it doesn't suit.

--
*Give me ambiguity or give me something else.

Dave Plowman London SW
To e-mail, change noise into sound.

Wireless transmitter
 

In article m, Rob
scribeth thus
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Rob

It I suspect works on 2.4 Ghz which is now becoming very crowded with
the explosion in wi-fi. I 'd expect it to work well in the absence of
any interfering signals, but these places are now very few and far
between..

A lot of wireless problems are simply caused by congestion of the
available spectrum allocated to it.

Also signal attenuation is quite high in some domestic environments

It may well work fine today but tomorrow when next door start using
their new wi-fi point all the time and perhaps the one across the
way?....

Use wire if you can, a lot more reliable;)..
--
Tony Sayer

Wireless transmitter
 

Don Pearce wrote...

When it is running well, it should be capable of good sound quality.

Out of interest, how do those devices work, are they sending the raw
audio data stream over the radio link to the DAC in the receiver or is
there some conversion to another format in the transmitter before being
broadcast?


--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/

Wireless transmitter
 

On Sat, 5 May 2012 13:07:57 +0100, UnsteadyKen
wrote:


Don Pearce wrote...

When it is running well, it should be capable of good sound quality.

Out of interest, how do those devices work, are they sending the raw
audio data stream over the radio link to the DAC in the receiver or is
there some conversion to another format in the transmitter before being
broadcast?

It sends a kind of broadcast stream, which is decoded by a DAC in the
receiver. I don't know what the over-air transmitted format is - it
may well be proprietary.

d

Wireless transmitter
 

"Rob" wrote in message
eb.com...
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at all
times. Some of the best systems base the SQ evaluation on an ultrasonic
subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

What you're showing me seems to be a toy, not a professional tool. How these
comments impact you depends on your goals for performance.

Wireless transmitter
 

In article , Arny Krueger
scribeth thus

"Rob" wrote in message
web.com...
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at all
times. Some of the best systems base the SQ evaluation on an ultrasonic
subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

Well there is but in that part of the spectrum over here 2.4 Ghz, there
are a lot of devices using that now which the limiting factor!..

We had a digital link once that used 2.4 G over some miles but after
some time that started cutting out simply due to interferer's...

Full AES/EBU digital it was too..

What you're showing me seems to be a toy, not a professional tool. How these
comments impact you depends on your goals for performance.



--
Tony Sayer

Wireless transmitter
 

"Arny Krueger"
"Rob"
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at
all times. Some of the best systems base the SQ evaluation on an
ultrasonic subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.


** OTOH - modern digital communication is almost wholly of the " spread
spectrum " kind and has few if any of the issues that have long plagued
analogue FM systems used by the vast majority of radio mics.


Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

** Frequency hopping does away with that need.

A single spread spectrum device uses as much bandwidth as the tuneable
frequency range typical, low powered FM audio transmitter.

What you're showing me seems to be a toy, not a professional tool.

** Agreed, but not for the spurious reasons you mention.



..... Phil

Wireless transmitter
 

On 05/05/2012 10:28, Dave Plowman (News) wrote:
In aweb.com,
wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Radio links can of course work perfectly well under good conditions. But
many of these sort of things don't work well in practice. Other devices
interfering with the signal or that signal not being powerful enough to go
through walls etc.

All you can really do is try it and see if it works, as so much depends on
local conditions. And hope Maplin will refund if it doesn't suit.


It could be a convenient method (for me) of attaching the proper stereo
to the TV system. I'd thought perhaps the technology had actually
'locked down' into something that worked - apparently not then, just yet.

Rob

Wireless transmitter
 

On 05/05/2012 10:52, tony sayer wrote:
In aweb.com, Rob
scribeth thus
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

Rob

It I suspect works on 2.4 Ghz which is now becoming very crowded with
the explosion in wi-fi. I 'd expect it to work well in the absence of
any interfering signals, but these places are now very few and far
between..

A lot of wireless problems are simply caused by congestion of the
available spectrum allocated to it.

Also signal attenuation is quite high in some domestic environments

It may well work fine today but tomorrow when next door start using
their new wi-fi point all the time and perhaps the one across the
way?....


Ah right, seems like a bother.

Use wire if you can, a lot more reliable;)..

Indeed, know where you are!

Rob

Wireless transmitter
 

On 05/05/2012 09:42, Jim Lesurf wrote:
In aweb.com, Rob
wrote:
On 04/05/2012 23:45, Dave Plowman (News) wrote:
In raweb.com,
wrote:
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

Have you read the reviews at the bottom of the page?


Yes - they seem to mention reliability. Any comments on the concept in
terms of audio? Or is the concept intrinsically unreliable?

From the 'reviews' it looks like the specific device is prone to cross
interference because it uses the same band as other equipment, and falls
over if you expect to get the signal though a wall.

Impossible to say much about sound quality since there seems to be no
detail at all on modulation methods, and lossy data compression, etc. Nor
any relevant test results or serious listening.

"Intrinsically" a radio link can work fine. But you would not be buying an
"intrinsic" concept. You'd be buying an implimentation that might be great
or might be rubbish.


Quite - I'd hardly list and quantify the variables that affect me, and
therefore define the parameters of implementation. It'd take a while,
but thanks for pointing it out.

Personally, I'm quite happy to use cables. They work nicely.


Goodo. Strikes me this sort of technology has a place for multi-source
and speaker setups, though.

Rob

Wireless transmitter
 

On 06/05/2012 12:52, Arny Krueger wrote:
wrote in message
eb.com...
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered to
be substandard unless they implement a true diversity reception system.
This means two independent receiving antennas, two independent receivers,
and a detection and logic system that picks the best received signal at all
times. Some of the best systems base the SQ evaluation on an ultrasonic
subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

What you're showing me seems to be a toy, not a professional tool. How these
comments impact you depends on your goals for performance.


I'd be looking for 'as good as wire'.

Rob

Wireless transmitter
 

In article om, Rob
wrote:

It could be a convenient method (for me) of attaching the proper stereo
to the TV system. I'd thought perhaps the technology had actually
'locked down' into something that worked - apparently not then, just yet.

The problem isn't simply a matter of 'technology' as such. It is the
situation:

The problem is that the band/channel being used is also already widely used
for various purposes in a way that includes no 'plan' of who can transmit
how much power from which places. So cross interference becomes a certainty
as the density of users rises. That then at least will degrade the
reliability for any individual user, and either cause pauses or dropouts,
or lower bandwidth to an unacceptable level.

In general, 'broadcasting' and general radio transmission is controlled in
ways designs to avoid cross interference. If someone wants to transmit,
they have to get permission which depends on an assessment of the impact on
other services. But here you end up with 'crowded party' problems - unless
you live well clear of 'competing' users.

FWIW for indoor 'line of sight' you might be better looking to some kind of
near-visible 'optical' system where the transmitter lights up the room in a
modulated way. At least that helps prevent interference from next door. But
of course that won't go though walls, and may be affected by shadowing. I
can't suggest any commercial system, though. Personally, I'm quite happy in
general to use 'wired' systems at home unless there is a specific need to
do otherwise.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Wireless transmitter
 

In article om,
Rob wrote:
I'd be looking for 'as good as wire'.

Well, all the mains sockets and lights in your house will have wires going
to them. So the option is to do the same with everything else. Of course
it depends on the design of your house as to how easy this is to do.

--
*Vegetarians taste great*

Dave Plowman London SW
To e-mail, change noise into sound.

Wireless transmitter
 

On 07/05/2012 10:42, Dave Plowman (News) wrote:
In raweb.com,
wrote:
I'd be looking for 'as good as wire'.

Well, all the mains sockets and lights in your house will have wires going
to them.

They will, yes.

So the option is to do the same with everything else.

Agreed.

Of course it depends on the design of your house as to how easy this is to do.

Yes, got that.

It'd be nice to have a wireless audio sender/receiver but by no means
necessary.

Rob

Wireless transmitter
 

In article m,
Rob wrote:
It'd be nice to have a wireless audio sender/receiver but by no means
necessary.

Well, try it and see. You may be lucky.

--
*Make it idiot-proof and someone will make a better idiot.

Dave Plowman London SW
To e-mail, change noise into sound.

Wireless transmitter
 

On 07/05/2012 08:45, Jim Lesurf wrote:
In raweb.com, Rob
wrote:

It could be a convenient method (for me) of attaching the proper stereo
to the TV system. I'd thought perhaps the technology had actually
'locked down' into something that worked - apparently not then, just yet.

The problem isn't simply a matter of 'technology' as such. It is the
situation:

The problem is that the band/channel being used is also already widely used
for various purposes in a way that includes no 'plan' of who can transmit
how much power from which places. So cross interference becomes a certainty
as the density of users rises. That then at least will degrade the
reliability for any individual user, and either cause pauses or dropouts,
or lower bandwidth to an unacceptable level.

In general, 'broadcasting' and general radio transmission is controlled in
ways designs to avoid cross interference. If someone wants to transmit,
they have to get permission which depends on an assessment of the impact on
other services. But here you end up with 'crowded party' problems - unless
you live well clear of 'competing' users.

FWIW for indoor 'line of sight' you might be better looking to some kind of
near-visible 'optical' system where the transmitter lights up the room in a
modulated way. At least that helps prevent interference from next door. But
of course that won't go though walls, and may be affected by shadowing. I
can't suggest any commercial system, though. Personally, I'm quite happy in
general to use 'wired' systems at home unless there is a specific need to
do otherwise.


OK - thanks for that. By 'technology' I simply meant a wireless method
of relaying sound. After all, radio and TV seem to manage quite well
over many miles. I just wondered if a domestic equivalent had been invented.

Rob

Wireless transmitter
 

On 07/05/2012 13:12, Dave Plowman (News) wrote:
In aweb.com,
wrote:
It'd be nice to have a wireless audio sender/receiver but by no means
necessary.

Well, try it and see. You may be lucky.


No, I think that until it gets better I'll leave it. Thanks anyway.

Rob

Wireless transmitter
 

"Phil Allison" wrote in message
...

"Arny Krueger"
"Rob"
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered
to be substandard unless they implement a true diversity reception
system. This means two independent receiving antennas, two independent
receivers, and a detection and logic system that picks the best received
signal at all times. Some of the best systems base the SQ evaluation on
an ultrasonic subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.

** OTOH - modern digital communication is almost wholly of the " spread
spectrum " kind and has few if any of the issues that have long plagued
analogue FM systems used by the vast majority of radio mics.

Interesting that the sp,e pf the best 2.4 GHz spread-spectrum-based
equipment uses multiple antennas.

Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

** Frequency hopping does away with that need.

Not entirely.

A single spread spectrum device uses as much bandwidth as the tuneable
frequency range typical, low powered FM audio transmitter.

Right, but the efficiency of spread spectrum gear does decrease if some of
the frequencies that are hopped to are always useless due to a stable
interferring source.

I've been in situations where upwards of a dozen wifi devices operating on
the same channels had useful signal strength at the reception point, and an
additional dozen devices had measurable and/or marginal signal levels. This
lead to an observed situation where the desired access point delivered what
seemed to be acceptable signal levels but a useful connection could not be
maintained.

There are upwards of a dozen identifiable Wifi access points that can be
observed from within my home, some business-related, some clearly home
networks.

From wikipedia:

"Wi-Fi connections can be disrupted or the internet speed lowered by having
other devices in the same area. Many 2.4 GHz 802.11b and 802.11g
access-points default to the same channel on initial startup, contributing
to congestion on certain channels. Wi-Fi pollution, or an excessive number
of access points in the area, especially on the neighboring channel, can
prevent access and interfere with other devices' use of other access points,
caused by overlapping channels in the 802.11g/b spectrum, as well as with
decreased signal-to-noise ratio (SNR) between access points. This can become
a problem in high-density areas, such as large apartment complexes or office
buildings with many Wi-Fi access points.

What you're showing me seems to be a toy, not a professional tool.

** Agreed, but not for the spurious reasons you mention.

Not spurious, but based on a more intense operational environment than you
may be familiar with.

Wireless transmitter
 

In article , Arny
Krueger
wrote:



Right, but the efficiency of spread spectrum gear does decrease if some
of the frequencies that are hopped to are always useless due to a
stable interferring source.

Much the same effect can occur when two (or more) hopping systems try to
use the same band - unless you have a common strategy they can adopt/agree
to avoid each other as they do so. Indeed, when one hopping system
encounters another it can't simply chalk up "avoid slot N" as it can to
avoid clashes with a static transmission in a slot. So adaptive hopping can
actually work better against a static-slot interference than another
transmission that hops in a way it can't predict.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Wireless transmitter
 

In article om, Rob
wrote:
On 07/05/2012 08:45, Jim Lesurf wrote:
In raweb.com, Rob
wrote:

FWIW for indoor 'line of sight' you might be better looking to some
kind of near-visible 'optical' system where the transmitter lights up
the room in a modulated way. At least that helps prevent interference
from next door. But of course that won't go though walls, and may be
affected by shadowing. I can't suggest any commercial system, though.
Personally, I'm quite happy in general to use 'wired' systems at home
unless there is a specific need to do otherwise.


OK - thanks for that. By 'technology' I simply meant a wireless method
of relaying sound. After all, radio and TV seem to manage quite well
over many miles.

Only by adopting the agreements/permissions that help them avoid or
minimise interference in a shared channel.

I just wondered if a domestic equivalent had been
invented.

I'm not aware of one. It would require some form of license or permission
from a national (or international) authority and would limit how many
people in a given area could use the system. Cheap domestic systems tend to
rely on a mix of low power, luck, hopping or spreading, and people putting
up with what they get. Some pauses or drops of data rate may be fine for
general computer file transfers. But audio is intolerant of pauses that
cause breaks in the music, and too low a data rate will degrade the result.
So audio is a surprisingly demanding application (in general comms and
computing terms) because of its intolerance to short pauses or breaks.

The alternatives would be ones like the one I mentioned as they would not
cause interference from outside when in a closed room. FWIW I know people
have experimented with 60GHz and 94GHz systems for this precisely to get a
high bandwidth 'indoor' system that would not be affected by neighbours
also using the same system. 60GHz also has the 'advantage' of high air
attenuation so may not make it next door even if it gets out of an open
window! :-)

At present fast modulated IR LEDs are probably a better bet, but I have no
idea if anyone sells these as consumer kit.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Wireless transmitter
 

"Arny Krueger"
"Phil Allison"
"Arny Krueger"
"Rob"
Any opinions on this:

http://www.maplin.co.uk/wireless-pc-...smitter-104993

Would anything be lost over a cable?

In the world of professional audio, wireless connections are considered
to be substandard unless they implement a true diversity reception
system. This means two independent receiving antennas, two independent
receivers, and a detection and logic system that picks the best received
signal at all times. Some of the best systems base the SQ evaluation on
an ultrasonic subcarrier.

Also, the whole system if based on analog (e.g. FM) is surrounded by
companding which can elevate effective dynamic range from about 60 dB to
more like 100 dB.


** OTOH - modern digital communication is almost wholly of the " spread
spectrum " kind and has few if any of the issues that have long plagued
analogue FM systems used by the vast majority of radio mics.

Interesting that the sp,e pf the best 2.4 GHz spread-spectrum-based
equipment uses multiple antennas.

** Wanna try that again ???

Red fish on special today where you live Arny?


Finally, there should be some kind of frequency mobility so that
interference sources can be completely avoided.

** Frequency hopping does away with that need.

Not entirely.


** It eliminates signal drops out due to standing waves - which the ONLY
reason FM radio mics employ diversity receiving antennas.


A single spread spectrum device uses as much bandwidth as the tuneable
frequency range typical, low powered FM audio transmitter.

Right, but the efficiency of spread spectrum gear does decrease if some of
the frequencies that are hopped to are always useless due to a stable
interferring source.

** Another very smelly red fish.

Such interference will obviously affect **BOTH** antennas !!!


What you're showing me seems to be a toy, not a professional tool.

** Agreed, but not for the spurious reasons you mention.

Not spurious,

** Utterly WRONG in fact.

As bloody usual.


.... Phil

Wireless transmitter
 

In article ,
Phil Allison wrote:
** It eliminates signal drops out due to standing waves - which the
ONLY reason FM radio mics employ diversity receiving antennas.

You've obviously never used radio mics. Diversity reception can also be
used to vastly increase the coverage range. By using directional aerials
'pointing' in different directions.

--
*The only difference between a rut and a grave is the depth.

Dave Plowman London SW
To e-mail, change noise into sound.

Wireless transmitter
 

"Dave Plowman = Nutcase ****WIT **** "

Phil Allison

** It eliminates signal drops out due to standing waves - which the
ONLY reason FM radio mics employ diversity receiving antennas.


You've obviously never used radio mics.


** You are obviously a ****ing, anencephalic pommy ****.


Diversity reception can also be
used to vastly increase the coverage range.

** Pure idiocy.


By using directional aerials 'pointing' in different directions.


** Pure ****wit insanity.

Get cancer and die ASAP - you revolting, autism ****ED steaming pile of
excrement.



.... Phil

Wireless transmitter
 

"Jim Lesurf" wrote in message
...
In article , Arny
Krueger
wrote:



Right, but the efficiency of spread spectrum gear does decrease if some
of the frequencies that are hopped to are always useless due to a
stable interferring source.

Much the same effect can occur when two (or more) hopping systems try to
use the same band - unless you have a common strategy they can adopt/agree
to avoid each other as they do so.

As a rule wi-fi devices don't have adaptive strategies.

Indeed, when one hopping system
encounters another it can't simply chalk up "avoid slot N" as it can to
avoid clashes with a static transmission in a slot.

Wi fi frequency hopping strategies appear to be simplistic.

So adaptive hopping can
actually work better against a static-slot interference than another
transmission that hops in a way it can't predict.

Right. In some ways Wi Fi is like 10BT ethernet all over again. Its
simplistic strategies and low data rate lead to slow and unreliable
transmission rates due to contention, even when actual usage is relatively
low. Ethernet over wire was somewhat rejuvinated by two order-of-magnitude
increases in basic transmission rates.

Dave Plowman = NUTCASE TROLL
 

Dave Plowman ****ing NUTCASE TROLL


Well, all the mains sockets and lights in your house will have wires going
to them. So the option is to do the same with everything else. Of course
it depends on the design of your house as to how easy this is to do.


** This stinking, know nothing arsehole is a 100% mentally retarded ****.

And Pommyland knows how to breed them by the million.

Killfile the vile scumbag, chase him off the NG.

Or I will.


.... Phil

Wireless transmitter
 

In article ,
Phil Allison wrote:
which the
ONLY reason FM radio mics employ diversity receiving antennas.


You've obviously never used radio mics.


** You are obviously a ****ing, anencephalic pommy ****.

And you don't understand the meaning of 'only'. So perhaps you'd learn
that before using even more words you don't understand, as above?


Diversity reception can also be
used to vastly increase the coverage range.

** Pure idiocy.



By using directional aerials 'pointing' in different directions.


** Pure ****wit insanity.


Must be lots of insane people I know then who are sound professionals.
It's a standard method outdoors. You could try it before showing you don't
know half as much as you think.

Get cancer and die ASAP - you revolting, autism ****ED steaming pile of
excrement.

Have you ever considered treatment?

--
*If vegetable oil comes from vegetables, where does baby oil come from? *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman = Criminal Psychopath
 

Dave Plowman = Criminal Psychopath ****


ONLY reason FM radio mics employ diversity receiving antennas.


You've obviously never used radio mics.


** You are obviously a ****ing, anencephalic pommy ****.

And you don't understand ..


** Why ****wit scumbags like you are allowed to breath.

There needs to be a law that permits vermin like you to be shot on sight.



Diversity reception can also be
used to vastly increase the coverage range.

** Pure idiocy.


By using directional aerials 'pointing' in different directions.


** Pure ****wit insanity.


Must be lots of insane people I know then who are sound professionals.

** Most of them are - but YOU are an extraordinary example.


It's a standard method outdoors.


** So only in a situation where DIVERSITY reception is not needed at all
!!!!!!!!!!!!!!

YOU CONTEXT SHIFTING AUTISTIC MORON !!!!!!!!!!!!!

Get cancer and ****ing die ASAP - you revolting, autism ****ED steaming
pile of
excrement.

Wireless transmitter
 

In article , Jim Lesurf
scribeth thus
In article om, Rob
wrote:
On 07/05/2012 08:45, Jim Lesurf wrote:
In raweb.com, Rob
wrote:

FWIW for indoor 'line of sight' you might be better looking to some
kind of near-visible 'optical' system where the transmitter lights up
the room in a modulated way. At least that helps prevent interference
from next door. But of course that won't go though walls, and may be
affected by shadowing. I can't suggest any commercial system, though.
Personally, I'm quite happy in general to use 'wired' systems at home
unless there is a specific need to do otherwise.


OK - thanks for that. By 'technology' I simply meant a wireless method
of relaying sound. After all, radio and TV seem to manage quite well
over many miles.

Only by adopting the agreements/permissions that help them avoid or
minimise interference in a shared channel.

I just wondered if a domestic equivalent had been
invented.

I'm not aware of one. It would require some form of license or permission
from a national (or international) authority and would limit how many
people in a given area could use the system. Cheap domestic systems tend to
rely on a mix of low power, luck, hopping or spreading, and people putting
up with what they get. Some pauses or drops of data rate may be fine for
general computer file transfers. But audio is intolerant of pauses that
cause breaks in the music, and too low a data rate will degrade the result.
So audio is a surprisingly demanding application (in general comms and
computing terms) because of its intolerance to short pauses or breaks.

The alternatives would be ones like the one I mentioned as they would not
cause interference from outside when in a closed room. FWIW I know people
have experimented with 60GHz and 94GHz systems for this precisely to get a
high bandwidth 'indoor' system that would not be affected by neighbours
also using the same system. 60GHz also has the 'advantage' of high air
attenuation so may not make it next door even if it gets out of an open
window! :-)

At present fast modulated IR LEDs are probably a better bet, but I have no
idea if anyone sells these as consumer kit.

Slainte,


You can try 5.8 Ghz but theres an Ofcom report around on their site
thats claiming it doesn't work as well indoors as what 2.4 G does
attenuation due to absorption being higher...

However we've got the band C 5.8G equipment's working fine over quite
some miles..


One link is doing 17.5 miles at a 10 Meg thruput;)...



Jim


--
Tony Sayer

Wireless transmitter
 

On Mon, 07 May 2012 17:03:36 +0100, Jim Lesurf wrote:

The alternatives would be ones like the one I mentioned as they would
not cause interference from outside when in a closed room. FWIW I know
people have experimented with 60GHz and 94GHz systems for this precisely
to get a high bandwidth 'indoor' system that would not be affected by
neighbours also using the same system. 60GHz also has the 'advantage' of
high air attenuation so may not make it next door even if it gets out of
an open window! :-)

Does it also keep you warm in winter? :-)

(I believe that 3mm waves have been used as a non-lethal weapon because
they can cause an intense burning pain.)

Wireless transmitter
 

In article , Chris
Isbell
wrote:
On Mon, 07 May 2012 17:03:36 +0100, Jim Lesurf wrote:

The alternatives would be ones like the one I mentioned as they would
not cause interference from outside when in a closed room. FWIW I know
people have experimented with 60GHz and 94GHz systems for this
precisely to get a high bandwidth 'indoor' system that would not be
affected by neighbours also using the same system. 60GHz also has the
'advantage' of high air attenuation so may not make it next door even
if it gets out of an open window! :-)

Does it also keep you warm in winter? :-)

Not at the power levels required for signal transfers across a room. You'd
probably need the order of a milliwatt for 'wi fi' types of applications in
a domestic room. Quite possibly much less.

Hesitate to say this, but I worked for decades with mm-wave beams in the
open lab at such levels - up to around 100 mW. And I don't *think* it has
done me any harm. }8-]

(I believe that 3mm waves have been used as a non-lethal weapon because
they can cause an intense burning pain.)

Yes. They have been experimented with for 'crowd dispersion'. But so far as
I know, the tests were decided to be rather poor in cost/effect terms.
Cheaper and simpler to beam from large 'electric fires' with big
collomating dishes! Powerful 95GHz sources are rather more expensive. And
easily defeated by tinfoil. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Wireless transmitter
 

tony sayer wrote:

One link is doing 17.5 miles at a 10 Meg thruput;)...


The last time I was an employee I worked on 24GHz links working over 20
miles or so. I've forgotten the bit rate but it equated to a bandwidth of
some 6MHz after downconversion. Diversity reception used vertical pairs of
dishes a few meters apart. Main source of deep fades was heavy rain.

Wireless transmitter
 

In article , TonyL
scribeth thus
tony sayer wrote:

One link is doing 17.5 miles at a 10 Meg thruput;)...


The last time I was an employee I worked on 24GHz links working over 20
miles or so. I've forgotten the bit rate but it equated to a bandwidth of
some 6MHz after downconversion. Diversity reception used vertical pairs of
dishes a few meters apart. Main source of deep fades was heavy rain.



I expect this will work over longer paths but as its a licence exempt ,well
sort of, its not doing that bad for terminals costing less then 100 quid each
end and just needs a CAT 5 cable to connect it with..;))..

--
Tony Sayer

Wireless transmitter
 

In article , TonyL
wrote:
tony sayer wrote:

One link is doing 17.5 miles at a 10 Meg thruput;)...


The last time I was an employee I worked on 24GHz links working over 20
miles or so. I've forgotten the bit rate but it equated to a bandwidth
of some 6MHz after downconversion. Diversity reception used vertical
pairs of dishes a few meters apart. Main source of deep fades was heavy
rain.

FWIW Work I did for the old Radcom agency involved us using a 100 mW
36GHz source (with a horn having a gain of about 26dBi) to run a
measurement link over 26 km. Worked OK even in heavy rain.

Mind you, the 'bandwidth' was tiny as we were doing interferometry with a
time-resolution of about 10 ms.

The main worry we had was when there was a wargame with Apache attack
copters along the coast and up the estuary. We wondered if they would
interpret our signal as an attempt at EW. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html