Where can I get a proper FM transmitter?

[eug k]

hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.


thanks

 

[Phil Allison]

"eug k"

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

** A transmitter of that sort of power on the FM band requires the user to
have a broadcasting licence.

Better think of a solution that's not illegal - like IR.





............. Phil

 

[Russ]

eug k wrote:

hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

I think systems like induction loops are the more usual solution to this
kind of application.

Russ.

 

[Bill Bailley]

"eug k" <wired_au@change-this-to-ho.tmail.com> wrote in message
news:ch8bld$11$1@bunyip.cc.uq.edu.au...

hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.


thanks

You may want to check on the exact legality of this, but I venture to
suggest that if you are just a teeny tad over the permitted power, you will
almost certainly get away with it for occasional use.

My suggestion. Go here http://www1.jaycar.com.au/ and search for kit KC
5341. This is a PLL locked micropower transmitter that can be set to any of
8 different frequencies in the FM band. It will not drift off channel. As it
is, this device may well do exactly enough for your purpose if centrally
located in the hall. If it doesn't quite manage, a small FM radio
distribution amplifier of 10 to 15 db gain to amplify the output should be
all you need.
Purists will say that you should use a band pass filter after the amplifier,
and they are not wrong. However, if there is some space around the venue
then a few little RF spurs they will normally not bother anyone. Stress on
the word little.

You may well get away with this project for Au$100 or so.

JustMe.

 

[Phil Allison]

"Alf Beta" <a@b.com> wrote in message news:ch8obd$nl8$1@enyo.uwa.edu.au...

Phil Allison <philallison@tpg.com.au> wrote:

"eug k"

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.



You can probably wire a hall with jacks and purchase 600 headphones for
about 300-400.

** Huh ???

Headphones for a few cents a pair ???




........... Phil

 

[Phil Allison]

"Bill Bailley"

"eug k"

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.



You may want to check on the exact legality of this, but I venture to
suggest that if you are just a teeny tad over the permitted power, you
will
almost certainly get away with it for occasional use.

** The legal, unlicensed power on the 88-108 MHz FM band is 10 uW -
yes microwatts.

The Fordray unit is 10 watts - only 1 million times over !!

Using VHF FM indoors is full of problems - the signal will drop out
massively at different spots all over the room. People's bodies will shade
a low power VHF signal and ruin the sound quality.

Commercial radio mics use the diversity principle - either with multiple
antennas or twin receivers to get reliable reception - and that is with 50
mW transmitters on 150 - 220 MHz or else UHF.

Low powered AM ( using a big loop to radiate the signal, possibly on 455
kHz) has a far better chance of working - assuming that each audience
member has a portable AM receiver and headphones.




............ Phil

 

[Alf Beta]

Phil Allison <philallison@tpg.com.au> wrote:

"eug k"

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.


** A transmitter of that sort of power on the FM band requires the user to
have a broadcasting licence.

Better think of a solution that's not illegal - like IR.





............ Phil

You can probably wire a hall with jacks and purchase 600 headphones for
about 300-400. But I'd doubt you'll find a wireless solution for that
price. My church did a hall about half that size for just over $200 but
then again it was one of the congergation that pitched in free labour and
probably some free stuff too.

Are you sure those cheap radio mikes aren't powerful enough? I must say a
fm bug I built at an engineering camp some 5-6 years ago had increadible
range. I was halfway down the block and it was still audible and that
would've been about 50m away. The device was broadcasting at a freqency
well away from commercial station tho, so interference from those much
more powerful transmitters were not much of a problem. I'm no expert on RF
electronics but IIRC the length of the antenna matters when it comes to
reception and transmission. The length of the antenna on the fm bug went
from my finger tips to my chest, so I would guess it was about 80cm long.

I think I'll stop rambling here.

--

Wing Wong.
Webpage: http://wing.ucc.asn.au

 

[Ken Taylor]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2pqailFnsejeU1@uni-berlin.de...

"Alf Beta" <a@b.com> wrote in message news:ch8obd$nl8$1@enyo.uwa.edu.au...
Phil Allison <philallison@tpg.com.au> wrote:

"eug k"

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.



You can probably wire a hall with jacks and purchase 600 headphones for
about 300-400.


** Huh ???

Headphones for a few cents a pair ???




.......... Phil


Not to mention cable.....

Ken

 

[Phil Allison]

"Alf Beta"

Phil Allison


** Huh ???

Headphones for a few cents a pair ???

.......... Phil


You're probably right, it sounds a little low if you look at it that way.
the guy must've paid some out of the kind of his
heart and for the church. Religion does that to some.

** And having a VERY guilty conscience ......




........... Phil

 

[Bushy]

I have seen a modified flying doctor radio that had a small fan mounted over
the output valve to provide enough cooling. The radio was detuned to give an
output on the normal car radio band and a clip wire was attached to the
car's antenna for an outback drive-in.

Gave better quality sound than a run of old shitty speakers that had spent a
few weeks outside in the sun and rain, well, maybe not so much rain, but
more than enough sun!

It also stopped the idiots driving off with the speakers still attached to
the car.

Hope this helps,
Peter

 

[Alf Beta]

Phil Allison <philallison@tpg.com.au> wrote:

** Huh ???

Headphones for a few cents a pair ???

.......... Phil

You're probably right, it sounds a little low if you look at it that way.
the guy must've paid some out of the kind of his
heart and for the church. Religion does that to some.

--

Wing Wong.
Webpage: http://wing.ucc.asn.au

 

[eug k]

Phil Allison <philallison@tpg.com.au> wrote:

"eug k"

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.


** A transmitter of that sort of power on the FM band requires the user to
have a broadcasting licence.

Whoops, I thought if I used it indoors with a small antenna, it would be
OK. There are two models btw, the FMT2 which is 2 watts and the FMT10
which is 10 watts. I definitely don't need so much power, but it was the
only "production-quality" unit I could find. Drift, hiss, and weak signals
were the problems i've faced with cheap units.

Better think of a solution that's not illegal - like IR.

that's what we're using now, but needing line-of-sight limits where people
can sit. putting it at the front of the hall might be a bit too far away
for people at the back.


thanks

 

[eug k]

Alf Beta <a@b.com> wrote:

Phil Allison <philallison@tpg.com.au> wrote:

"eug k"

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

** A transmitter of that sort of power on the FM band requires the user to
have a broadcasting licence.

Better think of a solution that's not illegal - like IR.

You can probably wire a hall with jacks and purchase 600 headphones for
about 300-400. But I'd doubt you'll find a wireless solution for that
price. My church did a hall about half that size for just over $200 but
then again it was one of the congergation that pitched in free labour and
probably some free stuff too.

Won't be possible in my situation as the chairs aren't fixed - they get moved
when the hall needs to be used for something else. And who likes wires
anyway?

Are you sure those cheap radio mikes aren't powerful enough? I must say a
fm bug I built at an engineering camp some 5-6 years ago had increadible
range. I was halfway down the block and it was still audible and that
would've been about 50m away. The device was broadcasting at a freqency
well away from commercial station tho, so interference from those much
more powerful transmitters were not much of a problem. I'm no expert on RF
electronics but IIRC the length of the antenna matters when it comes to
reception and transmission. The length of the antenna on the fm bug went
from my finger tips to my chest, so I would guess it was about 80cm long.

The biggest problem i've faced with basic transmitters is that the freq
would drift, and there would be black spots here and there. I might check out
the Jaycar fm transmitter that Bill posted about, and look into the AM solution
that Phil and Russ mentioned.

thanks!

 

[eug k]

Russ <nomail@hotmail.com> wrote:

eug k wrote:
hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

I think systems like induction loops are the more usual solution to this
kind of application.

I would imagine a proper induction loop system would cost quite a bit,
including the receivers. With an FM system, people can bring their
own pocket radios if they preferred, which means lower cost for us.

 

[eug k]

Bill Bailley <JustMe@home> wrote:

"eug k" <wired_au@change-this-to-ho.tmail.com> wrote in message
news:ch8bld$11$1@bunyip.cc.uq.edu.au...
hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

You may want to check on the exact legality of this, but I venture to
suggest that if you are just a teeny tad over the permitted power, you will
almost certainly get away with it for occasional use.

It did cross my mind, but what i thought was, if i used a crap antenna
(like a piece of wet string maybe and stayed far away from commercial
freqs, it would be ok. It would only be used for maybe 1-2 hours a week
at the most.

My suggestion. Go here http://www1.jaycar.com.au/ and search for kit KC
5341. This is a PLL locked micropower transmitter that can be set to any of
8 different frequencies in the FM band. It will not drift off channel. As it
is, this device may well do exactly enough for your purpose if centrally
located in the hall. If it doesn't quite manage, a small FM radio
distribution amplifier of 10 to 15 db gain to amplify the output should be
all you need.

Hmm, have you tried it out? i'm a bit concerned about background hiss on
these cheaper units.

Purists will say that you should use a band pass filter after the amplifier,
and they are not wrong. However, if there is some space around the venue
then a few little RF spurs they will normally not bother anyone. Stress on
the word little.

You may well get away with this project for Au$100 or so.

Just found the silicon chip article on the project, will have a read.
I probably should just pick one up and test it out, it's probably more
definite that way.

$49 sounds a lot for a kit seeing that ready-made products that (i'm
guessing) use the same IC go for $40ish.


thanks!

 

[eug k]

Phil Allison <philallison@tpg.com.au> wrote:

"Bill Bailley"

http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.



You may want to check on the exact legality of this, but I venture to
suggest that if you are just a teeny tad over the permitted power, you
will
almost certainly get away with it for occasional use.



** The legal, unlicensed power on the 88-108 MHz FM band is 10 uW -
yes microwatts.

Hmm, the article in silicon chip about the minimitter says 10mW? which
sounds a lot more usable than 10uW!


"In particular, the frequency of transmission must be within the 88-108MHz
band at a EIRP (Equivalent Isotropically Radiated Power) of 10mW and with
FM modulation no greater than 180kHz bandwidth. The transmission must not
be on the same frequency as a radio broadcasting station (or repeater or
translator station) operating within the licence area."

The Fordray unit is 10 watts - only 1 million times over !!

They actually have two models, a 2 watt and a 10 watt one. Fordray says
it is broadcast-quality, which was what attracted me. The last thing I want
to worry about is a drifting transmitter, or one that can't handle a
reasonable dynamic range, or one with excessive background hiss. I suppose
I get what I pay for, but who knows, there might be a lower-power version
somewhere out there for less money.

Using VHF FM indoors is full of problems - the signal will drop out
massively at different spots all over the room. People's bodies will shade
a low power VHF signal and ruin the sound quality.

yup, that's what i've found. What if I set up the micromitter high up on a wall
to minimize the effects of human bodies? Hm..

Low powered AM ( using a big loop to radiate the signal, possibly on 455
kHz) has a far better chance of working - assuming that each audience
member has a portable AM receiver and headphones.

I haven't listened to an AM radio for ages, what i'm concerned about is that
it'd pick up interference from other gear or wires or the lights or something.
sounds like it's worth checking out though.


thanks

 

[atec]

check in the ham groups , all you need is to surround the hall with a
multi strand induction loop , drive the loop with the audio out put from
a cheap transistor radio and the ear pieces should be simple hearing
aids.. google for more information , dead cheap and it works...

eug k wrote:

hi,

Does anyone know where I can get a proper FM transmitter? The only
one I've found is by Fordray, but it's a but pricey at $680. i'm
hoping to find one for around the $300-$450 mark. Range isn't very
important, it just needs to cover a hall that seats 600 people for
a translation system. Stability and clarity is important though.

This is the link to the fordray one:
http://www.fordray.com.au/Products/FMT2-10/fmt2-10.html

Perfect, but a bit over budget.

thanks

--
X-No-Archive: Yes

 

[Phil Allison]

"eug k"

Phil Allison


Better think of a solution that's not illegal - like IR.

that's what we're using now, but needing line-of-sight limits where people
can sit.

** What the hell does that mean ???

You said it was a hall - not a catacomb.



............. Phil

 

[Phil Allison]

"eug k" <

Phil Allison

** The legal, unlicensed power on the 88-108 MHz FM band is 10 uW -
yes microwatts.

Hmm, the article in silicon chip about the minimitter says 10mW?

** SC is not the damn regulatory authority - the 10 uW figure is a
misprint.

See :
http://www.aca.gov.au/aca_home/legislation/radcomm/class_licences/lipd.rtf


THE CORRECT FIGURE IS **10 MICROWATTS** !!!!!

The Fordray unit is 10 watts - only 1 million times over !!

They actually have two models, a 2 watt and a 10 watt one. Fordray says
it is broadcast-quality, which was what attracted me. The last thing I
want
to worry about is a drifting transmitter, or one that can't handle a
reasonable dynamic range, or one with excessive background hiss. I suppose
I get what I pay for, but who knows, there might be a lower-power version
somewhere out there for less money.

** With no licence using one of them is ** TOTALLY - FUCKING - ILLEGAL
** !!!!!!!!!!!!

How dare YOU expect honest people to advise you on doing an illegal
thing !!!

Low powered AM ( using a big loop to radiate the signal, possibly on
455
kHz) has a far better chance of working - assuming that each audience
member has a portable AM receiver and headphones.

I haven't listened to an AM radio for ages,

** You are a compete fuckwit - a complete fucking IDIOT !!!




............ Phil

 

[Phil Allison]

"Phil Allison"

** Correction:

** SC is not the damn regulatory authority - their 10 mW figure is a
stupid misprint.

See :

http://www.aca.gov.au/aca_home/legislation/radcomm/class_licences/lipd.rtf




......... Phil