[Repeater-Builder] Radiating leaky cables and repeaters

2009-02-18 Thread kabjik777
Dear all,
I am a student currently researching on radiating  leaky coaxial cables.
I do understand that in long tunnels where radiating leaky coaxial
cables are used, repeaters are placed at various points of the cable.

I want to know what is the average distance between the repeaters.
I will be glad if somone tell me or share a link with information as
regards to this.

I will also like to know the acceptable signal degradation per km?
for example is it 15dB/km or  13dB/km?

Thanks in advance.
Bansoboy.



Re: [Repeater-Builder] Radiating leaky cables and repeaters

2009-02-18 Thread Doug Bade
That would depend on the frequency. All coaxial cables including 
radiax type cables have specific attenuation loss figures per 100 
feet published...You need to determine the initial power, the amount 
of loss allowed before re-amplifying, then the amplifier gain added 
and losses to the next hop. The other parameter is how much energy 
you need outside the cable for how far as this will determine the 
initial launch power needed.

It is all a mathematical balance based on needed signal and loss in 
cable vs gain of the amps... I do not think there is one answer

Cable diameters are also chosen based on acceptable loss per mile/km.

These are all engineering choices, not cast in stone..

Doug
KD8B

At 08:08 AM 2/16/2009, you wrote:

Dear all,
I am a student currently researching on radiating leaky coaxial cables.
I do understand that in long tunnels where radiating leaky coaxial
cables are used, repeaters are placed at various points of the cable.

I want to know what is the average distance between the repeaters.
I will be glad if somone tell me or share a link with information as
regards to this.

I will also like to know the acceptable signal degradation per km?
for example is it 15dB/km or 13dB/km?

Thanks in advance.
Bansoboy.





Re: [Repeater-Builder] Radiating leaky cables and repeaters

2009-02-18 Thread wd8chl
kabjik777 wrote:
 Dear all,
 I am a student currently researching on radiating  leaky coaxial cables.
 I do understand that in long tunnels where radiating leaky coaxial
 cables are used, repeaters are placed at various points of the cable.
 
 I want to know what is the average distance between the repeaters.
 I will be glad if somone tell me or share a link with information as
 regards to this.
 
 I will also like to know the acceptable signal degradation per km?
 for example is it 15dB/km or  13dB/km?
 
 Thanks in advance.
 Bansoboy.

A couple of good places to look up info:
http://www.rfsolutions.com/jdco.htm
http://www.txrx.com/
http://www.emrcorp.com/





Re: [Repeater-Builder] Radiating leaky cables and repeaters

2009-02-18 Thread Wesley Bazell
Hi

A number of years ago, I installed Leaky Coax Cable in an Jail in Manatee Co in 
Fla. 800 Trunking System. Portables could not make it out. I used one Repeater 
which covered the Entire Jail.Sq Feet?
There is an Site you might get Info on AFL Telecommunications

Wesley AB8KD
  - Original Message - 
  From: wd8chl 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, February 18, 2009 10:13 AM
  Subject: Re: [Repeater-Builder] Radiating leaky cables and repeaters


  kabjik777 wrote:
   Dear all,
   I am a student currently researching on radiating leaky coaxial cables.
   I do understand that in long tunnels where radiating leaky coaxial
   cables are used, repeaters are placed at various points of the cable.
   
   I want to know what is the average distance between the repeaters.
   I will be glad if somone tell me or share a link with information as
   regards to this.
   
   I will also like to know the acceptable signal degradation per km?
   for example is it 15dB/km or 13dB/km?
   
   Thanks in advance.
   Bansoboy.

  A couple of good places to look up info:
  http://www.rfsolutions.com/jdco.htm
  http://www.txrx.com/
  http://www.emrcorp.com/