Sounds like error in specs.  
You know there is a difference.  

From: castarritt 
Sent: Tuesday, December 3, 2024 8:45 AM
To: AnimalFarm Microwave Users Group 
Subject: Re: [AFMUG] Optics light budget

If you read the datasheets, they say a "guaranteed optical link budget" of 10dB 
for the 20km, and 14dB for the 40km.

On Tue, Dec 3, 2024 at 7:50 AM Ken Hohhof <khoh...@kwom.com> wrote:

  Maybe shoot a question to FS, they seem pretty responsive.



  From: AF <af-boun...@af.afmug.com> On Behalf Of Adam Moffett
  Sent: Monday, December 2, 2024 11:44 PM
  To: AnimalFarm Microwave Users Group <af@af.afmug.com>
  Subject: Re: [AFMUG] Optics light budget



  That's definitely true, but that affects how the light budget is consumed not 
how much I start with.  They give me the same Tx power and Rx sensitivity 
regardless of which frequency I pick.




------------------------------------------------------------------------------

  From: AF <af-boun...@af.afmug.com> on behalf of Jim Bouse [Brazos WiFi] 
<j...@brazoswifi.com>
  Sent: Monday, December 2, 2024 10:04 PM
  To: AnimalFarm Microwave Users Group <af@af.afmug.com>
  Subject: Re: [AFMUG] Optics light budget 



  Different frequency light has different loss per km.



  Jim







  Sent via the Samsung Galaxy S22+ 5G, an AT&T 5G smartphone







  -------- Original message --------

  From: Adam Moffett <dmmoff...@gmail.com>

  Date: 12/2/24 9:02 PM (GMT-06:00)

  To: AnimalFarm Microwave Users Group <af@af.afmug.com>

  Subject: [AFMUG] Optics light budget



  Help me understand this:



  20km transceiver (SFP+ CWDM)

  https://www.fs.com/products/38707.html?now_cid=65

  Max Tx power +6dBm.  Rx sensitivity -14.4dBm.  So a power budget of 20.4dB



  40km transceiver (SFP+ CWDM

  https://www.fs.com/products/15385.html?now_cid=65

  Max Tx power +5dBm.  Rx sensitivity -15dBm.  So a power budget of 20dB.



  What am I missing?   These seem roughly equivalent.  What makes one of them 
more appropriate for the 40km distance?

  I looked at Precision OT as well.  Their 40km CWDM SFP+ has a power budget of 
about 20dB, and they don't even make a 20km one.  Could this be kind of like 
CPUs where the 20km ones are just 40's that didn't test well?  



  -Adam



  -- 
  AF mailing list
  AF@af.afmug.com
  http://af.afmug.com/mailman/listinfo/af_af.afmug.com



--------------------------------------------------------------------------------
-- 
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com
-- 
AF mailing list
AF@af.afmug.com
http://af.afmug.com/mailman/listinfo/af_af.afmug.com

Reply via email to