Re: [WISPA] 450' PoE 48v

2006-04-24 Thread Scott Reed




First, 450' is way too far for really reliable ethternet, if it is cat 5.

Voltage drops due to resistance in the wire.  Voltage = Current * Resistance.  Longer wire has more resistance.  You will need to increase the voltage of the power supply based on the current rating of the device(s) at the other end of the wire and the resistance of the wire you are using.


Scott Reed 


Owner 


NewWays 


Wireless Networking 


Network Design, Installation and Administration 


www.nwwnet.net 




-- Original Message 
---

From: Mark Nash [EMAIL PROTECTED] 


To: WISPA General List wireless@wispa.org 


Sent: Mon, 24 Apr 2006 11:25:08 -0700 


Subject: [WISPA] 450' PoE 48v 



 Hello...got a run of cat5 about 450' that is 

working but doesn't seem to be sufficiently powering the amplifier built into 

the antenna.  The device is a Terabeam EtherAnt-Turbo/LR (same as 

Proxim's Terastar EtherAnt/LR).  It works but SNR should be better.  

If I power the thing locally (25' of cat5) it works as it should, so I think it 

may be insufficient power.  


  

 It's got a 48v 0.4a power supply.  I know 
that 

it's far over spec for PoE...but specs were made up from engineers who have to 

play it safe for what they recommend.  So...any field answers to my 

dilemma?  Is more information 
needed?

  

 Perhaps a side question:  What drops over 

distance...volts or amps?  Please consider the non-electrically-experienced 

crowd.

  

 Thanks 
much.

 
 Mark Nash
 Network 

Engineer
 UnwiredOnline.Net
 350 Holly Street
 Junction 
City, OR 

97448
 http://www.uwol.net
 541-998-
 
541-998-5599 

fax

--- End of Original Message 
---






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Re: [WISPA] 450' PoE 48v

2006-04-24 Thread Mark Nash



Thanks, Scott. So, increased voltage is 
something to try.

And your comment on the cat5 being too far...it was 
considered initially but the ethernet interface on these units is a 10mb/half 
duplex interface. My experience tells me that I can reliably do 10mb/half 
duplex ethernetwith 500 feet of cat5...going back to my old Novell CNE 
days when 10BaseT was the next greatest thing, replacing Token Ring  
Arcnet.
Mark NashNetwork EngineerUnwiredOnline.Net350 
Holly StreetJunction City, OR 97448http://www.uwol.net541-998-541-998-5599 
fax

  - Original Message - 
  From: 
  Scott Reed 
  To: WISPA General List 
  Sent: Monday, April 24, 2006 11:54 
  AM
  Subject: Re: [WISPA] 450' PoE 48v
  First, 450' is way too far for really reliable 
  ethternet, if it is cat 5. Voltage drops due to resistance in the 
  wire. Voltage = Current * Resistance. Longer wire has more 
  resistance. You will need to increase the voltage of the power supply 
  based on the current rating of the device(s) at the other end of the wire and 
  the resistance of the wire you are using. Scott Reed Owner 
  NewWays Wireless Networking Network Design, Installation and 
  Administration www.nwwnet.net -- Original Message 
  --- From: "Mark Nash" [EMAIL PROTECTED] To: "WISPA 
  General List" wireless@wispa.org Sent: Mon, 24 Apr 2006 11:25:08 
  -0700 Subject: [WISPA] 450' PoE 48v  Hello...got a run of cat5 about 450' that is working but doesn't seem 
  to be sufficiently powering the amplifier built into the antenna. The 
  device is a TerabeamEtherAnt-Turbo/LR (same as Proxim's Terastar 
  EtherAnt/LR). It works but SNR should be better. If I power the 
  thing locally (25' of cat5) it works as it should, so I think it may be 
  insufficient power.It's got a 48v 0.4a power supply. I know that it's far over spec 
  for PoE...but specs were made up from engineers who have to play it safe for 
  what they recommend. So...any field answers to my dilemma? Is more 
  information needed?Perhaps a side question: What drops over distance...volts or 
  amps? Please consider the non-electrically-experienced crowd. 
 Thanks much.  
   Mark Nash  Network Engineer  UnwiredOnline.Net 
   350 Holly Street  Junction City, OR 97448  http://www.uwol.net  541-998- 
   541-998-5599 fax --- End of Original Message --- 
  
  
  

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Re: [WISPA] 450' PoE 48v

2006-04-24 Thread Scott Reed




The wireless physics discussion in another thread here applies as well. After 100 meters propogation delays can be an issue.  If it works, no problem, but be aware, I have seen things work for years and then it quits.

If you need the power calculations for your run, feel free to hit me offlist.

Scott Reed 


Owner 


NewWays 


Wireless Networking 


Network Design, Installation and Administration 


www.nwwnet.net 




-- Original Message 
---

From: Mark Nash [EMAIL PROTECTED] 


To: WISPA General List wireless@wispa.org 


Sent: Mon, 24 Apr 2006 12:02:58 -0700 


Subject: Re: [WISPA] 450' PoE 48v 



 Thanks, Scott.  So, increased voltage is 

something to 
try.

  

 And your comment on the cat5 being too far...it 
was 

considered initially but the ethernet interface on these units is a 10mb/half 

duplex interface.  My experience tells me that I can reliably do 10mb/half 

duplex ethernet with 500 feet of cat5...going back to my old Novell CNE 

days when 10BaseT was the next greatest thing, replacing Token Ring  

Arcnet.

 
 Mark Nash
 Network Engineer
 
UnwiredOnline.Net
 350 

Holly Street
 Junction City, OR 97448
 http://www.uwol.net
 541-998-
 
541-998-5599 

fax
 


  
 - Original Message - 

  
 From: 

  Scott Reed 

  
 To: WISPA General List 

  
 Sent: Monday, April 24, 2006 11:54 

  
AM
  
 Subject: Re: [WISPA] 450' PoE 
48v
  
 
 First, 450' is way too far for really reliable 

  ethternet, if it is cat 5. 
 
 Voltage drops due to resistance 
in the 

  wire.  Voltage = Current * Resistance.  Longer wire has more 

  resistance.  You will need to increase the voltage of the power supply 

  based on the current rating of the device(s) at the other end of the wire and 

  the resistance of the wire you are using. 
 
 Scott Reed 

 Owner 

  
 NewWays 
 Wireless Networking 
 Network Design, 
Installation and 

  Administration 
 www.nwwnet.net 
 
 -- Original 
Message 

  --- 
 From: Mark Nash [EMAIL PROTECTED] 
 To: 
WISPA 

  General List wireless@wispa.org 
 Sent: Mon, 24 Apr 2006 
11:25:08 

  -0700 
 Subject: [WISPA] 450' PoE 48v 
 
  Hello...got a run of cat5 about 450' that is working but doesn't seem 

  to be sufficiently powering the amplifier built into the antenna.  The 

  device is a Terabeam EtherAnt-Turbo/LR (same as Proxim's Terastar 

  EtherAnt/LR).  It works but SNR should be better.  If I power the 

  thing locally (25' of cat5) it works as it should, so I think it may be 

  insufficient power.  
    
  It's got a 48v 0.4a power supply.  I know that it's far over spec 

  for PoE...but specs were made up from engineers who have to play it safe for 

  what they recommend.  So...any field answers to my dilemma?  Is more 

  information needed? 
    
  Perhaps a side question:  What drops over distance...volts or 

  amps?  Please consider the non-electrically-experienced crowd. 

  
    
  Thanks much. 

  

  
  Mark Nash 
  Network Engineer 
  
UnwiredOnline.Net 

  
  350 Holly Street 
  Junction City, OR 97448 
 
 http://www.uwol.net 
  541-998- 

  
  541-998-5599 fax 
 --- End of Original Message 
--- 

  
 

  
 

  



  
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