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Author Topic: IEM and Radio Mic frequency allocation in UK band GB  (Read 4093 times)

Guy Morris

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IEM and Radio Mic frequency allocation in UK band GB
« on: September 28, 2016, 01:04:50 PM »

Hi
Not seen anything on this subject over the net so to PSW!

I use multiple Sennheiser G3 systems and also their SR300 IEM units, both systems reside in their own specific racks
and all have the correct distribution amps and directional antennas and racks are used well separated from each other by a minimum 2m.
Belt packs are also housed in foil trays when active and standing by, Hand held are kept separate too.

Recently I have been getting more bands asking for both radio mics and IEMs  so taking the count up to 20 channels at times.
I have always kept to the listed bank frequencies to avoid IM but noticed that the banks on the radio mic receivers do not match those of the IEM transmitters. I have put a call into Sennheiser UK to ask for advice and the Sennheiser frequency planner I downloaded is old (G2 systems) so gave up with that!
Sennheiser advise that you should always never mix bank frequencies but fail to explain what you do about the differently configured IEM banks!

As an example:  G3 Bank 20 Radio Mic Frequency     SR300 Bank 20 IEM Frequency
                                                     607.525          607.100
                                                     609.075          609.200
                                                     611.825          611.00
To date I have only experienced a couple of issues but I need to get some plan on how best to co-ordinate frequencies that work well across the RX mics and the IEMs avoiding any IM it seems a bit of a Russian roulette situation, is there a rule of thumb for frequency separation I can utilise? 

I am aware of the free Ch 38 frequencies but usually go for co-ordinated ones when in crowded RF areas so purchasing a duff frequency is not cost effective either!

Maybe I'm missing something with this, it is not clear if for example all frequencies in Bank 20 on both the radio mics and IEM systems have all been pre selected to be IM free in Bank 20 across both systems?
Your advice will be very welcome!

Thanks
Guy

« Last Edit: September 28, 2016, 01:12:17 PM by Guy Morris »
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Mac Kerr

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #1 on: September 28, 2016, 01:18:39 PM »

Recently I have been getting more bands asking for both radio mics and IEMs  so taking the count up to 20 channels at times.
I have always kept to the listed bank frequencies to avoid IM but noticed that the banks on the radio mic receivers do not match those of the IEM transmitters. I have put a call into Sennheiser UK to ask for advice and the Sennheiser frequency planner I downloaded is old (G2 systems) so gave up with that! Sennheiser advise that you should always never mix bank frequencies but fail to explain what you do about the differently configured IEM banks!

As an example:  G3 Bank 20 Radio Mic Frequency     SR300 Bank 20 IEM Frequency
                                                     607.525          607.100
                                                     609.075          609.200
                                                     611.825          611.00
To date I have only experienced a couple of issues but I need to get some plan on how best to co-ordinate frequencies that work well across the RX mics and the IEMs avoiding any IM it seems a bit of a Russian roulette situation, is there a rule of thumb for frequency separation I can utilise? 

Once you go outside the manufacturer's preset "groups", which you do as soon as you add a second kind of system, you need to use software that will do the IM calculations for you. Sennheiser has free software called "Wireless Systems Manager", Shure has "Wireless Workbench". There are also paid packages from Professional Wireless Systems and RF Venue.

Mac
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Pete Erskine

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #2 on: September 28, 2016, 08:35:20 PM »

Hi
Not seen anything on this subject over the net so to PSW!

Maybe I'm missing something with this, it is not clear if for example all frequencies in Bank 20 on both the radio mics and IEM systems have all been pre selected to be IM free in Bank 20 across both systems?
Your advice will be very welcome!

On the Bestaudio.com website there are several videos showing coordination methods with Shure Wireless workbench (which will also do Sennheiser) and using IAS from Professional wireless, which is not free.

There is also a book on the process of coordination which is free.

What city are you in and what is the list of your wireless equipment and bands?
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Ike Zimbel

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #3 on: September 28, 2016, 09:38:01 PM »


Maybe I'm missing something with this, it is not clear if for example all frequencies in Bank 20 on both the radio mics and IEM systems have all been pre selected to be IM free in Bank 20 across both systems?
Your advice will be very welcome!

Thanks
Guy

Hi Guy,
Here's brief primer on frequency coordination (which is also on Pete's site):http://www.prosoundweb.com/article/avoiding_intermod_the_importance_of_wireless_frequency_coordination/

As Mac points out, as soon as you start using two different products, even from the same manufacturer, the Group/Bank thing goes by the wayside. If you are using all Sennheiser gear, you may as well start out with the free download of WSM (Sennheiser's coordination and management program) and see where it takes you. It will bypass the pre-programmed groups and find coordinated frequencies for all of your systems...at which point you will need to go into User groups to program the frequencies it provides you with.
Best,
Ike
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Daniel Levi

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #4 on: September 29, 2016, 05:23:32 AM »

I must point out ch38 is not free and requires a shared user licence, it's not expensive but it is required. I'm not quite sure if the licence held by the venue (if it has one) would cover you so that would need to be checked.

The only licence free spectrum is from 863-865 (I.e. A small amount of ch70), some uk units may cover ch68 as well but that spectrum has been sold for 4g and is no longer useable (it used to be the shared user spectrum).
Sent from my Lumia 625 using Tapatalk
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Guy Morris

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #5 on: October 04, 2016, 06:12:49 AM »

Hi Daniel
My error, in the way I described Ch 38 I meant there are limited frequencies there you can use without paying for the frequency itself and yes correct you do require a licence even for that. I have a licence and account  with Ofcom otherwise I cannot buy the co ordinated  frequencies.

I must point out ch38 is not free and requires a shared user licence, it's not expensive but it is required. I'm not quite sure if the licence held by the venue (if it has one) would cover you so that would need to be checked.

The only licence free spectrum is from 863-865 (I.e. A small amount of ch70), some uk units may cover ch68 as well but that spectrum has been sold for 4g and is no longer useable (it used to be the shared user spectrum).
Sent from my Lumia 625 using Tapatalk
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Guy Morris

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #6 on: October 04, 2016, 06:19:01 AM »

Hi Pete
Thanks for the reply.
I'm in London.  All kit is Sennheiser mics G3 and 5000 series with SR300 and 2050 IEM systems.Was not sure if the Shure WWB would suit the Sennheiser as I was told sometimes the manufactures alter how the tuning works. Will check out your links.
On the Bestaudio.com website there are several videos showing coordination methods with Shure Wireless workbench (which will also do Sennheiser) and using IAS from Professional wireless, which is not free.

There is also a book on the process of coordination which is free.

What city are you in and what is the list of your wireless equipment and bands?
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Guy Morris

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #7 on: October 04, 2016, 06:41:30 AM »

Hi Ike
Thanks for the confirmation regarding the compatibility of banks across both the  RX mics and IEMS I was not sure if Sennheiser had interleaved the frequencies contained withing each bank to work IM free with RX mics and IEMs per bank but you confirm that is not the case! Will check out your link to WSM

Hi Guy,
Here's brief primer on frequency coordination (which is also on Pete's site):http://www.prosoundweb.com/article/avoiding_intermod_the_importance_of_wireless_frequency_coordination/

As Mac points out, as soon as you start using two different products, even from the same manufacturer, the Group/Bank thing goes by the wayside. If you are using all Sennheiser gear, you may as well start out with the free download of WSM (Sennheiser's coordination and management program) and see where it takes you. It will bypass the pre-programmed groups and find coordinated frequencies for all of your systems...at which point you will need to go into User groups to program the frequencies it provides you with.
Best,
Ike
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Guy Morris

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Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #8 on: October 04, 2016, 06:43:52 AM »

Thanks Mac
Looks like I'm in the right direction now. I'm very careful on my RF but want to nail the frequency co-ordination on all systems a new learning curve!
Guy
Once you go outside the manufacturer's preset "groups", which you do as soon as you add a second kind of system, you need to use software that will do the IM calculations for you. Sennheiser has free software called "Wireless Systems Manager", Shure has "Wireless Workbench". There are also paid packages from Professional Wireless Systems and RF Venue.

Mac
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ProSoundWeb Community

Re: IEM and Radio Mic frequency allocation in UK band GB
« Reply #8 on: October 04, 2016, 06:43:52 AM »


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