[Gareth Magennis]

Hi,

I have an IEM system with a faulty receiver antenna. It is a screw in
flexible wire thing about 6cm long. Is it possible to substitute a length
of wire as a temporary fix til the new antenna arrives? I don't know how
these antennae are constructed - is it just a long coiled wire? Does it have
some termination on the end? What length would work?

The transmitting frequency is 860.900 MHz.



Cheers,



Gareth.

[Gareth Magennis]

Sorry, I was a bit preature on that one.



New question: I thought I had a faulty aeriel on an IEM receiver. I have
substituted a piece of wire 34.8cm long, since by my calculation of V = FL,
this is the wavelength of the transmitting frequency of 860.900 MHz.. The
receiver still has crap reception. I take it this should work as a good
aeriel?



Cheers,



Gareth.

[Don Pearce]

On Fri, 18 Jan 2008 13:21:41 -0000, "Gareth Magennis"
wrote:

Sorry, I was a bit preature on that one.



New question: I thought I had a faulty aeriel on an IEM receiver. I have
substituted a piece of wire 34.8cm long, since by my calculation of V = FL,
this is the wavelength of the transmitting frequency of 860.900 MHz.. The
receiver still has crap reception. I take it this should work as a good
aeriel?

Try halving that length - half wave is the normal aerial length. But
what about the location? Is this thing up in the clear where it is
likely to get a good signal? More to the point, has it just stopped
working, or is this the first time you have used it in this location?

d

--
Pearce Consulting
http://www.pearce.uk.com

[Gareth Magennis]

"Don Pearce" wrote in message
...
On Fri, 18 Jan 2008 13:21:41 -0000, "Gareth Magennis"
wrote:

Sorry, I was a bit preature on that one.



New question: I thought I had a faulty aeriel on an IEM receiver. I have
substituted a piece of wire 34.8cm long, since by my calculation of V =
FL,
this is the wavelength of the transmitting frequency of 860.900 MHz.. The
receiver still has crap reception. I take it this should work as a good
aeriel?

Try halving that length - half wave is the normal aerial length. But
what about the location? Is this thing up in the clear where it is
likely to get a good signal? More to the point, has it just stopped
working, or is this the first time you have used it in this location?



Just tried that, no good. The original aeriel is just a quarter length
piece of wire isn't it?

The location is my workshop and it loses reception after 2 metres. I have
another receiver which detects strong RF from the transmitter, and I've
taken this receiver apart and cleaned all the connections/ribbon cables etc,
so it looks like its goosed. Its a Sennheiser EW300. Going back to
Sennheiser.


Kind of thought I'd use the opportunity to learn about radios.


Thanks,


Gareth.

[Don Pearce]

On Fri, 18 Jan 2008 13:50:00 -0000, "Gareth Magennis"
wrote:


"Don Pearce" wrote in message
...
On Fri, 18 Jan 2008 13:21:41 -0000, "Gareth Magennis"
wrote:

Sorry, I was a bit preature on that one.



New question: I thought I had a faulty aeriel on an IEM receiver. I have
substituted a piece of wire 34.8cm long, since by my calculation of V =
FL,
this is the wavelength of the transmitting frequency of 860.900 MHz.. The
receiver still has crap reception. I take it this should work as a good
aeriel?

Try halving that length - half wave is the normal aerial length. But
what about the location? Is this thing up in the clear where it is
likely to get a good signal? More to the point, has it just stopped
working, or is this the first time you have used it in this location?



Just tried that, no good. The original aeriel is just a quarter length
piece of wire isn't it?


Quite right - stupid me. Half wave is for two bits of wire in opposite
directions.

The location is my workshop and it loses reception after 2 metres. I have
another receiver which detects strong RF from the transmitter, and I've
taken this receiver apart and cleaned all the connections/ribbon cables etc,
so it looks like its goosed. Its a Sennheiser EW300. Going back to
Sennheiser.


Sounds that way. Either that or you have some serious interference
locally on the same frequency.


Kind of thought I'd use the opportunity to learn about radios.

I think you have - the hard way.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Richard Crowley]

"Gareth Magennis" wrote ...
The location is my workshop and it loses reception
after 2 metres.

That doesn't really tell us much, does it?
Your workshop could be down in the basement or at the
bottom of a well for all we know. Mr. Pierce was refering
to whether the antenna is indoors or outdoors, how high
off the ground, what else (particularly metal) is around it,
etc. etc.

[Gareth Magennis]

"Richard Crowley" wrote in message
...
"Gareth Magennis" wrote ...
The location is my workshop and it loses reception after 2 metres.

That doesn't really tell us much, does it?
Your workshop could be down in the basement or at the bottom of a well for
all we know. Mr. Pierce was refering to whether the antenna is indoors or
outdoors, how high off the ground, what else (particularly metal) is
around it, etc. etc.


Erm, the transmitter is on my bench transmitting a tone, and the reciever is
in my hand losing reception 2 metres from the transmitter. I am repairing
it for someone who also finds that it loses reception 2 metres from the
transmitter while on stage.



Gareth.

[Bruce]

"Gareth Magennis" wrote in
:

Sorry, I was a bit preature on that one.



New question: I thought I had a faulty aeriel on an IEM receiver. I
have substituted a piece of wire 34.8cm long, since by my calculation
of V = FL, this is the wavelength of the transmitting frequency of
860.900 MHz.. The receiver still has crap reception. I take it this
should work as a good aeriel?



Cheers,



Gareth.



You're way off. In english measurements, the approximation for a 1/4 wave
antenna is 234/f(MHz) = feet. So for 860.9MHz the length would be 0.27 feet
or 3.26 inches, which is 1.28cm.

Is there a possibility of a new cell site having moved into your area, or
some other radio service in that band - especially digital.

[Don Pearce]

On Sat, 19 Jan 2008 16:17:48 GMT, Bruce wrote:

You're way off. In english measurements, the approximation for a 1/4 wave
antenna is 234/f(MHz) = feet. So for 860.9MHz the length would be 0.27 feet
or 3.26 inches, which is 1.28cm.

Make that 8.5cm. 1.28cm is about half an inch.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Bruce]

(Don Pearce) wrote in
:

On Sat, 19 Jan 2008 16:17:48 GMT, Bruce wrote:

You're way off. In english measurements, the approximation for a 1/4
wave antenna is 234/f(MHz) = feet. So for 860.9MHz the length would be
0.27 feet or 3.26 inches, which is 1.28cm.

Make that 8.5cm. 1.28cm is about half an inch.

d


Thanks...Must remind myself not to do math after a 4AM load-in....

[Don Pearce]

On Sun, 20 Jan 2008 12:19:46 GMT, Bruce wrote:

(Don Pearce) wrote in
:

On Sat, 19 Jan 2008 16:17:48 GMT, Bruce wrote:

You're way off. In english measurements, the approximation for a 1/4
wave antenna is 234/f(MHz) = feet. So for 860.9MHz the length would be
0.27 feet or 3.26 inches, which is 1.28cm.

Make that 8.5cm. 1.28cm is about half an inch.

d


Thanks...Must remind myself not to do math after a 4AM load-in....

Take my advice - let Google do your maths.

c / 886MHz / 4 in cm

will do the job nicely

d

--
Pearce Consulting
http://www.pearce.uk.com