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Radio mic - remote aerials

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Anonymous
August 16, 2005 9:49:01 AM

Archived from groups: rec.audio.pro (More info?)

Dear all,

We've recently built a TV Control & Recording room at the rear of our
main church hall. I said before it was built that we would likely have
dropout problems on the radio mic receiver as there would be a couple
of walls (for sound deadening) between the transmitter and the
receiver. Following my return from a leave of absence from the team,
I'm discovering that we are having occasional dropout problems.

Some of it we can control by the position of the transmitter on the
pastor's belt however, I'm thinking that if we install remote aerials
on the receiver, lifting the aerials up above the control room, that
should help matters.

It's my intention to try running some coaxial cable from the BNC
connectors on the rear of the receiver to the top of the guardrail for
the tech area (graphics & lighting) above the control room. I'll then
attach the standard aerials to the end of the coaxial cabling.

Can anyone foresee likely problems with this? The distance from
transmitter - aerial will be similar to what we had before the control
room was built. Should I move the remote coaxial ends further apart
than the BNC connectors on the rear of the transmitter? Would this help
reduce further the risk of dropout?

I have thought that I may need to purchase the plate type of antennas
(directional?) to get this to work instead of using the standard
aerials that are on the receiver.

Your thoughts/experience would be appreciated.

Cheers,

glasgowsoundman
Anonymous
August 16, 2005 10:49:45 AM

Archived from groups: rec.audio.pro (More info?)

"glasgowsoundman" wrote ...
> It's my intention to try running some coaxial cable from the BNC
> connectors on the rear of the receiver to the top of the guardrail for
> the tech area (graphics & lighting) above the control room. I'll then
> attach the standard aerials to the end of the coaxial cabling.
>
> Can anyone foresee likely problems with this? The distance from
> transmitter - aerial will be similar to what we had before the control
> room was built. Should I move the remote coaxial ends further apart
> than the BNC connectors on the rear of the transmitter? Would this
> help
> reduce further the risk of dropout?
>
> I have thought that I may need to purchase the plate type of antennas
> (directional?) to get this to work instead of using the standard
> aerials that are on the receiver.

Yes, you can use directional antennas which have some gain.
Several vendors of wireless mics also sell antennas with
amplifiers built-in to increase their sensitivity.

However, note that just moving the antenna substitutes the
loss through the cable for the loss through the air/walls.
Far more reliable to move the whole receiver up to the
stage close to the transmitter. Use an existing mic line to
carry the audio output back to the mixing desk.
Anonymous
August 16, 2005 11:26:13 AM

Archived from groups: rec.audio.pro (More info?)

I know that moving the receiver would be a big help. I'm not sure how
easy it would be with our current setup. I'll have a think about how we
could do it.

Thanks.
Related resources
Anonymous
August 16, 2005 11:34:31 PM

Archived from groups: rec.audio.pro (More info?)

"glasgowsoundman" wrote...
>I know that moving the receiver would be a big help. I'm not sure how
> easy it would be with our current setup. I'll have a think about how
> we
> could do it.

Unless you are very careful, you could lose more RF
through a long antenna cable than you are losing through
the air/wall. Moving the receiver closer to the transmitter
is usually a more reliable solution.
Anonymous
August 17, 2005 12:57:05 AM

Archived from groups: rec.audio.pro (More info?)

Richard Crowley wrote:

> "glasgowsoundman" wrote...
> >I know that moving the receiver would be a big help. I'm not sure how
> > easy it would be with our current setup. I'll have a think about how
> > we
> > could do it.
>
> Unless you are very careful, you could lose more RF
> through a long antenna cable than you are losing through
> the air/wall. Moving the receiver closer to the transmitter
> is usually a more reliable solution.

This is why it's important that if you do
use a longer cable for the antennae (or some
combination of improvements that include
transmission line) that it be good quality
low-loss line that's correctly rated for
the frequency in use and of the correct
impedance.

rd
Anonymous
August 17, 2005 4:28:09 AM

Archived from groups: rec.audio.pro (More info?)

"Richard Crowley"
> "glasgowsoundman"
> Yes, you can use directional antennas which have some gain.
> Several vendors of wireless mics also sell antennas with
> amplifiers built-in to increase their sensitivity.
>


** An RF amp at the antenna is there to overcome losses in the connecting
cable -it will not actually improve matters compared to an antenna mounted
on the receiver.


> However, note that just moving the antenna substitutes the
> loss through the cable for the loss through the air/walls.
> Far more reliable to move the whole receiver up to the
> stage close to the transmitter. Use an existing mic line to
> carry the audio output back to the mixing desk.


** This would be the preferred and cheaper solution.



........... Phil
Anonymous
August 17, 2005 8:38:34 AM

Archived from groups: rec.audio.pro (More info?)

Many thanks to all for comments. Quick trial last night was useful, now
I need the go ahead to use better quality materials and then a decision
can be made, by others, as to whether to stick with coaxial or go for
proper antennas.

Thanks again,

glasgowsoundman
Anonymous
August 17, 2005 4:45:11 PM

Archived from groups: rec.audio.pro (More info?)

"Richard Crowley"
> "glasgowsoundman" wrote...
>>I know that moving the receiver would be a big help. I'm not sure how
>> easy it would be with our current setup. I'll have a think about how we
>> could do it.
>
> Unless you are very careful, you could lose more RF
> through a long antenna cable than you are losing through
> the air/wall. Moving the receiver closer to the transmitter
> is usually a more reliable solution.


** This reminds me of the time I got two Vega VHF radio mic systems with
the *usual* complaint that they has both lost range and were suffering drop
outs.

Distance from receivers to stage area was stated to be less than 20 metres
with a clear line of sight - the units were installed in a "bio box" high
above the dance floor.

Further inquiries produced the rest of the story - the so called "bio box"
was made from all steel framework and was surrounded in steel mesh.

A PERFECT Faraday cage !!!!!




............ Phil
Anonymous
August 18, 2005 6:35:45 AM

Archived from groups: rec.audio.pro (More info?)

Radio mic frequencies are: Handheld 863.900MHz and Tie 859.400MHz. We
have used these mics for some time with no intermodulation problems.
We've had no problems with other signals being picked up on these
frequencies. Systems are both Sennheiser G1. One is ew100, one is
ew500.

The current antennae are attached to the receiver with BNC connectors.
I was simply going to put suitable BNC connectors on each end of the
coax in order to easily swap between the current setup and the proposed
setup during testing.

The long cables on the antennae won't get the antennae any closer to
the transmitter but will get them past a wall and way above the heads
of the congregation.

Thanks,

glasgowsoundman
Anonymous
August 18, 2005 7:56:19 AM

Archived from groups: rec.audio.pro (More info?)

glasgowsoundman wrote:

> Radio mic frequencies are: Handheld 863.900MHz and Tie 859.400MHz. We
> have used these mics for some time with no intermodulation problems.
> We've had no problems with other signals being picked up on these
> frequencies. Systems are both Sennheiser G1. One is ew100, one is
> ew500.
>
> The current antennae are attached to the receiver with BNC connectors.
> I was simply going to put suitable BNC connectors on each end of the
> coax in order to easily swap between the current setup and the proposed
> setup during testing.
>
> The long cables on the antennae won't get the antennae any closer to
> the transmitter but will get them past a wall and way above the heads
> of the congregation.

RG58 is not suitable for these high frequencies.
I suggest springing for some decent UHF feedline
to make your efforts worthwhile and keeping the
run as short as possible. Also take care making
the terminations to assure clean connections and
avoid kinks, etc.

good luck
rd
Anonymous
August 18, 2005 9:42:35 AM

Archived from groups: rec.audio.pro (More info?)

rd,

What would you regard as "decent UHF feedline"? Is there any standard
reference coding in a similar way to RG58 for a type of coaxial cable?

Regards,

glasgowsoundman
Anonymous
August 18, 2005 11:04:34 AM

Archived from groups: rec.audio.pro (More info?)

TM,

Thanks for that information. Very helpful. I'm not trying to trump the
laws of physics, just trying to find the most cost-effective way of
improving the situation I've got.

Thanks again,

glasgowsoundman
Anonymous
August 18, 2005 5:20:53 PM

Archived from groups: rec.audio.pro (More info?)

PMFJI, but a little time spent in review of the following
might be time well spent:

http://www.locationsound.com/proaudio/ls/tips/techtips1...

and

http://www.locationsound.com/proaudio/ls/tips/techtips1...

and

http://www.locationsound.com/proaudio/ls/tips/techtips1...


You don't have to believe a word they say, but they pretty
much know their stuff (and they are nice folks to talk to,
as well). And the manufacturers of the equipment will
usually be quite helpful in providing specifics for getting
the best results. That's been my experience, at least.

What I find most puzzling about wireless is not the
technology or equipment, but the resistance of the people
wanting to use the technology to accept the basics of how it
works. Unreasonable expectations always seem to trump the
laws of physics. Amazing.

HTH


TM

glasgowsoundman wrote:
>
> What would you regard as "decent UHF feedline"? Is there any standard
> reference coding in a similar way to RG58 for a type of coaxial cable?
Anonymous
August 18, 2005 5:20:54 PM

Archived from groups: rec.audio.pro (More info?)

"T Maki" wrote ...
> What I find most puzzling about wireless is not the
> technology or equipment, but the resistance of the people
> wanting to use the technology to accept the basics of how it
> works. Unreasonable expectations always seem to trump the
> laws of physics. Amazing.

Oh, I don't think that effect is limited to wireless systems!
August 20, 2005 2:34:49 AM

Archived from groups: rec.audio.pro (More info?)

\

This depends on the type of Coax,, RG 8 or RG 58.

cheers the islander


On Tue, 16 Aug 2005 19:34:31 -0700, "Richard Crowley"
<rcrowley@xpr7t.net> wrote:

>"glasgowsoundman" wrote...
>>I know that moving the receiver would be a big help. I'm not sure how
>> easy it would be with our current setup. I'll have a think about how
>> we
>> could do it.
>
>Unless you are very careful, you could lose more RF
>through a long antenna cable than you are losing through
>the air/wall. Moving the receiver closer to the transmitter
>is usually a more reliable solution.
August 20, 2005 2:38:09 AM

Archived from groups: rec.audio.pro (More info?)

Whae type of directional... quad... yagi... is it a diversity
syetem...if you plan on yagi in a diversity system you will get more
problems with Rf phasing.

cheers
the islander



On Tue, 16 Aug 2005 06:49:45 -0700, "Richard Crowley"
<rcrowley@xpr7t.net> wrote:

>"glasgowsoundman" wrote ...
>> It's my intention to try running some coaxial cable from the BNC
>> connectors on the rear of the receiver to the top of the guardrail for
>> the tech area (graphics & lighting) above the control room. I'll then
>> attach the standard aerials to the end of the coaxial cabling.
>>
>> Can anyone foresee likely problems with this? The distance from
>> transmitter - aerial will be similar to what we had before the control
>> room was built. Should I move the remote coaxial ends further apart
>> than the BNC connectors on the rear of the transmitter? Would this
>> help
>> reduce further the risk of dropout?
>>
>> I have thought that I may need to purchase the plate type of antennas
>> (directional?) to get this to work instead of using the standard
>> aerials that are on the receiver.
>
>Yes, you can use directional antennas which have some gain.
>Several vendors of wireless mics also sell antennas with
>amplifiers built-in to increase their sensitivity.
>
>However, note that just moving the antenna substitutes the
>loss through the cable for the loss through the air/walls.
>Far more reliable to move the whole receiver up to the
>stage close to the transmitter. Use an existing mic line to
>carry the audio output back to the mixing desk.
August 20, 2005 2:53:17 AM

Archived from groups: rec.audio.pro (More info?)

From what I am reading here through all these... it is not a
diversity system... I know the Sennheiser systems fairly well... Used
them lots.. Plus you only need to go s short distance.. with the
coax... so RG 58 should work well even above 700 mHz it is only
minimal line loss. May I suggest a Yagi antenna made for the
frequency for each of the transmitter/receivers.. 3 pole ones will
likely do well. A ham operator can help you with design and maybe
even constructioin. they will be small at 800 megs

cheers
the islander



On 18 Aug 2005 07:04:34 -0700, "glasgowsoundman"
<glasgowsoundman@yahoo.co.uk> wrote:

>TM,
>
>Thanks for that information. Very helpful. I'm not trying to trump the
>laws of physics, just trying to find the most cost-effective way of
>improving the situation I've got.
>
>Thanks again,
>
>glasgowsoundman
August 20, 2005 2:53:37 AM

Archived from groups: rec.audio.pro (More info?)

what type of wireless mics.. and what receiving system... is it a
diversity receiver?

cheers
the islander

On 16 Aug 2005 05:49:01 -0700, "glasgowsoundman"
<glasgowsoundman@yahoo.co.uk> wrote:

>Dear all,
>
>We've recently built a TV Control & Recording room at the rear of our
>main church hall. I said before it was built that we would likely have
>dropout problems on the radio mic receiver as there would be a couple
>of walls (for sound deadening) between the transmitter and the
>receiver. Following my return from a leave of absence from the team,
>I'm discovering that we are having occasional dropout problems.
>
>Some of it we can control by the position of the transmitter on the
>pastor's belt however, I'm thinking that if we install remote aerials
>on the receiver, lifting the aerials up above the control room, that
>should help matters.
>
>It's my intention to try running some coaxial cable from the BNC
>connectors on the rear of the receiver to the top of the guardrail for
>the tech area (graphics & lighting) above the control room. I'll then
>attach the standard aerials to the end of the coaxial cabling.
>
>Can anyone foresee likely problems with this? The distance from
>transmitter - aerial will be similar to what we had before the control
>room was built. Should I move the remote coaxial ends further apart
>than the BNC connectors on the rear of the transmitter? Would this help
>reduce further the risk of dropout?
>
>I have thought that I may need to purchase the plate type of antennas
>(directional?) to get this to work instead of using the standard
>aerials that are on the receiver.
>
>Your thoughts/experience would be appreciated.
>
>Cheers,
>
>glasgowsoundman
Anonymous
August 20, 2005 7:34:00 PM

Archived from groups: rec.audio.pro (More info?)

"Islander" = another top posting nut case
>
> Whae type of directional... quad... yagi... is it a diversity
> syetem...if you plan on yagi in a diversity system you will get more
> problems with Rf phasing.
>


** Nonsense .

Diversity receivers do not take any account of relative RF phase.




........... Phil
August 20, 2005 7:34:01 PM

Archived from groups: rec.audio.pro (More info?)

May I ask you a questioin Sir...

Is the distance between the antennas in a diversity system or in any
dual antenna system critical.... and why?

Have a nice day.

the islander





On Sat, 20 Aug 2005 15:34:00 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>
>"Islander" = another top posting nut case
>>
>> Whae type of directional... quad... yagi... is it a diversity
>> syetem...if you plan on yagi in a diversity system you will get more
>> problems with Rf phasing.
>>
>
>
>** Nonsense .
>
>Diversity receivers do not take any account of relative RF phase.
>
>
>
>
>.......... Phil
>
>
Anonymous
August 20, 2005 7:34:02 PM

Archived from groups: rec.audio.pro (More info?)

Islander <islander@island.com> wrote:


> >Diversity receivers do not take any account of relative RF phase

> Is the distance between the antennas in a diversity system or in any
> dual antenna system critical.... and why?

It is not absolutely critical, but the RF standing wave pattern in a
room will have peaks and troughs at half-wavelength spacing. If you
have the aerials about a quarter of a wavelength apart, they can't both
be in a null at the same time.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Anonymous
August 20, 2005 7:51:22 PM

Archived from groups: rec.audio.pro (More info?)

"Islander" = another top posting wanker

> From what I am reading here through all these... it is not a
> diversity system...


** Of course it is - dimwit.


I know the Sennheiser systems fairly well... Used
> them lots..


** With zero comprehension.

Usual for a half-witted radio ham.




............ Phil
August 20, 2005 7:51:23 PM

Archived from groups: rec.audio.pro (More info?)

Sigh.... I guess the islander is too old to know everything... and too
old to be nasty about it of others.

have a nice day.



On Sat, 20 Aug 2005 15:51:22 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>
>"Islander" = another top posting wanker
>
>> From what I am reading here through all these... it is not a
>> diversity system...
>
>
> ** Of course it is - dimwit.
>
>
> I know the Sennheiser systems fairly well... Used
>> them lots..
>
>
>** With zero comprehension.
>
> Usual for a half-witted radio ham.
>
>
>
>
>........... Phil
>
Anonymous
August 22, 2005 7:47:50 AM

Archived from groups: rec.audio.pro (More info?)

glasgowsoundman wrote:

> rd,
>
> What would you regard as "decent UHF feedline"? Is there any standard
> reference coding in a similar way to RG58 for a type of coaxial cable?

http://www.shure.com/support/technotes/app-remote-anten...

According to Shure:
Cable Length from Antenna to Receiver
Cable Type
Cable loss @ 800 MHz per 100 ft.

Up to 15 feet
RG-58C/U(Belden 8262 or similar)
18.5 dB per 100 ft.

Up to 25 feet
RG-8X/U(Belden 9258 or similar)
12 dB per 100 ft.

Up to 40 feet
RG-213/U (Belden 8267 or similar)
7 dB per 100 ft.

Up to 75 feet
RG-8/U(Belden 9913 or similar) for permanent installation only
3.9 dB per 100 ft.

There's also loss in the connectors so care
must be taken in assembly.

If the receiver is true diversity there should be
some indicator light that will show which receiver
is active. You can try replacing just one of the
inputs with a remote antenna and see if there's any
improvement. RG58 may be OK to get you just on the
other side of the wall, but you may have as good or
better results by placing the receiver on the other
side of the wall and feeding the audio through.

good luck
rd
!