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Hey all,
Here's the posish: we have a whole lot of sennheiser wireless kit
running around (microphones) in our church hall. We have a whole lot of
base stations, most of which operate in the same range of frequency.
Now, we have a little recording studio on the side where we record
verious things during meetings - in order to avoid the complicated
wiring, we have been using some of our 'spare' diversity recievers to
pick up the signal running from the wireless tie, hand and headmics.
The problem is that every time we buy new mics its kind of pot luck as
to the frequency range we will get. Is there anyone who makes diversity
recievers that have a wide UHF range so we could buy a whole load and
not worry about the transmitter range? Any thoughts?

M

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Phil Allison
 
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Hey all,
Here's the posish: we have a whole lot of sennheiser wireless kit
running around (microphones) in our church hall. We have a whole lot of
base stations, most of which operate in the same range of frequency.
Now, we have a little recording studio on the side where we record
verious things during meetings - in order to avoid the complicated
wiring, we have been using some of our 'spare' diversity recievers to
pick up the signal running from the wireless tie, hand and headmics.
The problem is that every time we buy new mics its kind of pot luck as
to the frequency range we will get. Is there anyone who makes diversity
recievers that have a wide UHF range so we could buy a whole load and
not worry about the transmitter range?




** I seriously doubt you will find any UHF *mic* receives where the
frequency range is wider than a few percent of the centre frequency. This
is a result of the RF stages having to work without frequency tuning over
the whole range the receiver is capable of.

For example, an 840 MHz Sennheiser receiver might operate over a 32 MHz
range or about 3.7 %.



......... Phil




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Phil Allison wrote:

** I seriously doubt you will find any UHF *mic* receives where the
frequency range is wider than a few percent of the centre frequency. This
is a result of the RF stages having to work without frequency tuning over
the whole range the receiver is capable of.

For example, an 840 MHz Sennheiser receiver might operate over a 32 MHz
range or about 3.7 %.


Ah ok. Whats the ideal then? Using radio scanners or trying to make
sure that all our equipment operates in the 3.7% range?

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Phil Allison
 
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Phil Allison wrote:

** I seriously doubt you will find any UHF *mic* receives where the
frequency range is wider than a few percent of the centre frequency.
This
is a result of the RF stages having to work without frequency tuning over
the whole range the receiver is capable of.

For example, an 840 MHz Sennheiser receiver might operate over a 32 MHz
range or about 3.7 %.


Ah ok. Whats the ideal then?



** Radio mics are always a compromise.

The IDEAL is a length of nice mic cable !!!


Using radio scanners or trying to make
sure that all our equipment operates in the 3.7% range?



** Scanners are neither capable of high quality sound nor "diversity"
operation - they are very handy for sussing out the local radio
environment however.

As you WILL need one UHF mic receiver for EACH and EVERY mic, there is no
need nor advantage in a single model.



......... Phil




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Chewy Papadopoulous
 
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There is research going on right now into digital radio mics, although
it is having problems because the data needs to be compressed to fit
the radio channels, and currently the latency is unacceptable for use
in live performances.

d


Not really so. Check out DB Technologies' digital wireless systems. I
have one; great sound; no latency problem. I have a set, myself. It's
awesome.

Chewy
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Don Pearce
 
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On Thu, 18 May 2006 08:34:21 GMT, Chewy Papadopoulous
wrote:



There is research going on right now into digital radio mics, although
it is having problems because the data needs to be compressed to fit
the radio channels, and currently the latency is unacceptable for use
in live performances.

d


Not really so. Check out DB Technologies' digital wireless systems. I
have one; great sound; no latency problem. I have a set, myself. It's
awesome.

Chewy


This is one of those products that works in the unlicensed ISM bands,
and does not conform to the narrow channels that will be available for
licensed systems. This means that it doesn't have the same degree of
compression. Unfortunately this product is going to be subject to the
vagaries of interference from WiFi and microwave ovens.

d

--
Pearce Consulting
http://www.pearce.uk.com
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Phil Allison wrote:

As you WILL need one UHF mic receiver for EACH and EVERY mic, there is no
need nor advantage in a single model.


yep point taken about the scanners...My issue with baser stations is
that at the moment we need 2 base stations for every mic and they both
have to be in the right freq range for the mic. ideally it would be
cool to be able to buy a fully tuneable diversity reciever that
operates between say 630 Mhz to 960 Mhz and just buy a whole load of
those.

M

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we are using sennheiser ew 100 G2 boxes... whats the range like on
those akgs?


M
Geoff@home wrote:


Many manufactures make wireless mic systems that can have many channels
operating in the same band. Such performances depends on the selectivity of
the receiver, and is what costs more.

Try AKG WMS400 or better still WMS4000 series. Or the equivalent from many
other solid manufacturers.




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Phil Allison
 
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oups.com...


** Beware - Google Groper


As you WILL need one UHF mic receiver for EACH and EVERY mic, there is no
need nor advantage in a single model.


yep point taken about the scanners...My issue with baser stations is
that at the moment we need 2 base stations for every mic and they both
have to be in the right freq range for the mic. ideally it would be
cool to be able to buy a fully tuneable diversity reciever that
operates between say 630 Mhz to 960 Mhz and just buy a whole load of
those.




** I seriously doubt you will find any UHF *mic* receives where the
frequency range is wider than a few percent of the centre frequency.


Is it Ground Hog day yet ?????




....... Phil


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Phil Allison
 
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"Anahata"

My Sennheiser EW100 G2 receiver has 1440 available frequencies in 8 banks
of which at least one is user-tunable (the others are preset). How does
that not give you enough frequencies?



** No where NEAR covers the whole UHF band.

Sennheiser dishonestly consider steps of a mere 25 kHz to be new
"frequencies"'.

At that rate, the UHF band has 36,000 steps or more.

Crapology.




........ Phil



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Geoff@home wrote:


I've only ever tested out to 50m (metres, not miles) and never missed a
beat. Reinforced concrete building with aluminium window frames to outside
was worst case (workshop !).


Er, i meant frequency range, sorry.

M

still good to know



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Scott Dorsey
 
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wrote:
Here's the posish: we have a whole lot of sennheiser wireless kit
running around (microphones) in our church hall. We have a whole lot of
base stations, most of which operate in the same range of frequency.
Now, we have a little recording studio on the side where we record
verious things during meetings - in order to avoid the complicated
wiring, we have been using some of our 'spare' diversity recievers to
pick up the signal running from the wireless tie, hand and headmics.
The problem is that every time we buy new mics its kind of pot luck as
to the frequency range we will get. Is there anyone who makes diversity
recievers that have a wide UHF range so we could buy a whole load and
not worry about the transmitter range? Any thoughts?


Some thoughts:
1. The wider the range possible, the wider the receiver front end has to
be and the wider the transmitter final amplifier has to be. This means
the greater the possibility of interference issues. So you really want
to avoid having to use stuff with too wide a range.

2. You need to stop buying things randomly. When you buy new mikes, you
need to order the range you want. You need to sit down, list out
everything you have right now, and use the calculator on the Sennheiser
website (or a desk calculator) and calculate out all the second and
third order intercepts so you know what frequencies you can use and
which ones you cannot.

3. If you do not have a plan for frequency allocation, and you do not follow
that plan, disaster will eventually result.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Scott Dorsey
 
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Don Pearce wrote:

There is research going on right now into digital radio mics, although
it is having problems because the data needs to be compressed to fit
the radio channels, and currently the latency is unacceptable for use
in live performances.


I dunno, I have used the Zaxcom and it works pretty well.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Scott Dorsey wrote:

Some thoughts:
1. The wider the range possible, the wider the receiver front end has to
be and the wider the transmitter final amplifier has to be. This means
the greater the possibility of interference issues. So you really want
to avoid having to use stuff with too wide a range.


Ok understood


2. You need to stop buying things randomly. When you buy new mikes, you
need to order the range you want. You need to sit down, list out
everything you have right now, and use the calculator on the Sennheiser
website (or a desk calculator) and calculate out all the second and
third order intercepts so you know what frequencies you can use and
which ones you cannot.


I agree, am working with their sound crew on this note (organisation)
What do you mean by 2nd and 3rd order intercepts?


3. If you do not have a plan for frequency allocation, and you do not follow
that plan, disaster will eventually result.


Ok, makes sense..thanks

M

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wrote:

What do you mean by 2nd and 3rd order intercepts?


When allocating wireless, there are a few things to be aware of:

1) External interference - go to the FCC web site and obtain a list of
all UHF radio transmissions in your area. Be especially aware of DTV
transmitters, and those that are listed as coming online in the next
year or two. It's possible to sneak in with an analog TV station, but
DTV is spread-spectrum and will be more problematic if you're in the
same frequency range.

Optimally, if you have a frequency analyzer available, you can use that
to find open ranges in your wireless spectrum. These are pretty
expensive, and you need to know what you're doing. If you don't already
have one, the FCC database should be fine.

2) Frequency spacing - as Phil said, the Sennheiser EW units allow you
to tune at increments of 25kHz. It's probably not a good idea to put
two systems that close to each other. I don't know the IF filter
topology in a Senn receiver, but especially in the lower end units
(e.g. EW100) I don't imagine that they have an incredibly narrow band
pass. This means that if you have two transmitters operating that close
to each other, they will produce noise in the others' output.

3) Intermodulation - this is what Scott is talking about when he
mentions "2nd and 3rd order intercepts" I believe (though I haven't
heard the term "intercept" before). Basically, there are going to be
some nonlinearities involved in your wireless system that create sum
and difference terms of the frequencies involved. If you have one
wireless TX at A=600MHz and another at B=700MHz, then you need to worry
about not putting anything at A+B=1300MHz or B-A=100MHz. These are the
2nd order intermod terms. In practical wirelessapplication, 2nd order
rarely is important -- you need to worry more about 3rd order. Namely,
2A-B = 500MHz and 2B-A = 800MHz. There are various calculator programs
available that will test a set of operating frequencies for intermod
problems.

If all of this seems like too much to handle, I recommend consulting
the provider of your wireless equipment. They should have staff on hand
who understand this and can provide you with an optimally configured
system.

Hope that helps
-Todd

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Chewy Papadopoulous
 
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Don Pearce wrote:


This is one of those products that works in the unlicensed ISM bands,
and does not conform to the narrow channels that will be available for
licensed systems. This means that it doesn't have the same degree of
compression. Unfortunately this product is going to be subject to the
vagaries of interference from WiFi and microwave ovens.

d

Fair enough. FWIW, it's worked great in a variety of applications for
me; who knows if I'm someday going to hear somebody's "audio chat"
hashing up a performance!

Chewy


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Geoff
 
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wrote:
Geoff@home wrote:


I've only ever tested out to 50m (metres, not miles) and never
missed a beat. Reinforced concrete building with aluminium window
frames to outside was worst case (workshop !).


Er, i meant frequency range, sorry


http://www.akg.com/products/powersla...uage,EN .html

http://www.akgfrequency.at/

SR 4000 Receiver
Bands MHz
650 - 680,
680 - 710,
720 - 750,
760 - 790,
790 - 820,
835 - 863
Carrier Frequencies: up to 1,200 per range

I'm sure all other major wireless mic manufacturers have similar setups.

geoff
( and yes, I do contract to an AKG distributor)


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Hal
 
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Hi everyone,
This may be a bit off topic but here goes:
I am a sax player and want to invest in a wireless in-ear monitoring system
for myself in the $800.00 to $1200.00 range. I am currently looking at a
used Sennheiser EW 300 IEM system for $600.00. Anyone have experience with
these? In my price range it seems like it's either the Shure or Sennheiser.

I am new to this group and am wondering if there are other groups I might
post in as well.
Regards,
Hal
"Scott Dorsey" wrote in message
...
wrote:
Here's the posish: we have a whole lot of sennheiser wireless kit
running around (microphones) in our church hall. We have a whole lot of
base stations, most of which operate in the same range of frequency.
Now, we have a little recording studio on the side where we record
verious things during meetings - in order to avoid the complicated
wiring, we have been using some of our 'spare' diversity recievers to
pick up the signal running from the wireless tie, hand and headmics.
The problem is that every time we buy new mics its kind of pot luck as
to the frequency range we will get. Is there anyone who makes diversity
recievers that have a wide UHF range so we could buy a whole load and
not worry about the transmitter range? Any thoughts?


Some thoughts:
1. The wider the range possible, the wider the receiver front end has to
be and the wider the transmitter final amplifier has to be. This means
the greater the possibility of interference issues. So you really want
to avoid having to use stuff with too wide a range.

2. You need to stop buying things randomly. When you buy new mikes, you
need to order the range you want. You need to sit down, list out
everything you have right now, and use the calculator on the Sennheiser
website (or a desk calculator) and calculate out all the second and
third order intercepts so you know what frequencies you can use and
which ones you cannot.

3. If you do not have a plan for frequency allocation, and you do not
follow
that plan, disaster will eventually result.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."



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Scott Dorsey
 
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Hal wrote:
Hi everyone,
This may be a bit off topic but here goes:
I am a sax player and want to invest in a wireless in-ear monitoring system
for myself in the $800.00 to $1200.00 range. I am currently looking at a
used Sennheiser EW 300 IEM system for $600.00. Anyone have experience with
these? In my price range it seems like it's either the Shure or Sennheiser.


Both are okay. Vega models turn up used in that range also.

The thing you need to worry about is frequency coordination. Get something
that will work over a range of channels, make sure those channels are usable
in your area and make sure they are going to stay usable. That means check
HDTV allocations; they're moving UHF TV stations around so channels that were
usable last week may not be okay in a year or two. The Sennheiser website has
some info on what's going to be a problem in various major US cities.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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