[NSRCA-discussion] Speaking of 2.4GHz

Ed Alt ed_alt at hotmail.com
Sun Mar 2 14:55:52 AKST 2008


The range of devices like these is usually the length of your runway or less.  Of these, only Bluetooth devices are ill behaved WRT use of bandwidth.  They usually reach about 25 feet.  Yawn...    Don't worry about this stuff.
 
Ed


Date: Sun, 2 Mar 2008 13:53:26 -0500From: atwoodm at paragon-inc.comTo: nsrca-discussion at lists.nsrca.orgSubject: Re: [NSRCA-discussion] Speaking of 2.4GHz
Pretty much all of your standard wireless routers use 2.4ghz.   802.11b and 802.11g (virtually all of the wireless traffic) is 2.4ghz as are bluetooth devices.  Bluetooth uses FHSS though where 802.11b/g  use direct sequencing (DSSS) I believe...could be wrong on that last part, but I know they all use 2.4ghz.-MOn 3/2/08 1:23 PM, "Del Rykert" <drykert2 at rochester.rr.com> wrote:
I thought many wireless devices were using the 2.4 GHz in homes and computer stuff. ?       Del
----- Original Message -----  From:  Randall Bearden <mailto:rbearden56 at bellsouth.net>   To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>   Sent: Sunday, March 02, 2008 9:13 AM Subject: Re: [NSRCA-discussion] Speaking  of 2.4GHz On 3/1/08 1:49 AM, "John Pavlick" <jpavlick at idseng.com>  wrote:
Yeah, how many  people experienced the bug in the early Spektrum stuff? We didn't hear too  much about that one. The best part is they addressed it and used their  resources to solve the problem quickly. Futaba is going through their  teething pains now. NOTHING is perfect. It is in your best interest to use  ANY new technology with extra caution until it develops a proven track  record. I would be a little "extra" apprehensive about the XPS stuff only  because it's not backed by large company like Futaba, JR or Airtronics.  Small companies tend to have a harder time solving problems similar to the  ones that we've seen with the Spektrum and Futaba systems.John  Pavlickhttp://www.idseng.comFrom: Ed Alt <mailto:ed_alt at hotmail.com>   
To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>    Sent: Saturday, March 01, 2008 12:15   AM Subject: Re: [NSRCA-discussion] Speaking   of 2.4GHz Spektrum is going to come out with  Telemetry for airborne  radios.  They've had it for years in  their ground radios, so they have a  handle on it.  I also like  the fact that their lead engineer who started  the entire Spektrum  line with Horizon came from Cypress Semiconductor, the  chip vendor  for the Spektrum stuff.  Futaba has a great base of  experience  with Spread Spectrum.  Their teething pains seem to have more   to do with re-packaging their existing technology in a scramble to  play  catch-up with Spektrum.   Every radio has  problems here  and there, as we've seen over the years with 72 mHz  gear, so when I hear that  something just totally died in a few  isolated cases, it does not alarm  me.  However, "the big 3"  have proven that they deliver good products  overall and will address  problems that do exist.  XPS on the other hand  has made some  questionable claims and really has no solution to provide path   diversity for the receiver.  If you look at Futaba and also  Airtronics  full range SS receivers, they get path diversity from  placing each antenna at  the end of thin coax leads that allow them  to each have a unique RF  environment, much like Spektrum  accomplishes with actual receivers at the end  of data leads that  feed a central unit.   If it was me  trying to use  XPS, I would spend a couple of years test flying it in stuff I  could  afford to lose, same as I did with Spektrum when it first came  out.   I wounded a foamy with a AR6100 receiver that had an  early  firmware bug, which Horizon acknowledged and fixed. It had nothing   to do with radio reception; it was the one that would slap down  elevator  and stay there.  Nice!  Since then, all of my  foamy kills  have been directly traceable to my  thumbs. Ed  

Date: Fri, 29 Feb 2008 14:17:06 -0800From:   edvwhite at sbcglobal.netTo:  nsrca-discussion at lists.nsrca.orgSubject: Re:  [NSRCA-discussion]  Speaking of 2.4GHzEd,I've been digging into  (ie,  poking around RCU) for XPS issues and as is usually the case find mostly   secondhand and anecdotal problems along with a few really unhappy   people.  I also find a lot of happy XPS users.  I am  attracted to  the XPS because it offers the future possibility of  telemetry, something I  would like to play with.  Lastly on the  Spektrum, I've seen only a  handful of systems fly at our local  field.  I've also seen two crashes on  two different Spektrum  systems due to total loss of control, at close  range.  At least  one of those verified good battery voltage under load  after the  crash (the other one didn't check).  I know there are a   huge number of satisfied Spektrum users.  I know of two locally  who are  not quite so satisfied.  Neither ever did figure out  the reason for the  loss of control.  And with Futaba's recent  problem (which they have  fixed), well I think we all have to realize  there is no bulletproof  system.  Just looking to see if people  have had problems with the  XPS.EdEd Alt  <ed_alt at hotmail.com> wrote:    

With a proven solution from  Spektrum / JR and with Futaba introducing what  will undoubtedly  be a solid solution, why play with XPS?  I can't  think of  any advantage that it offers and it apparently has some issues to   dig into and understand.    Ed 
 

Date: Fri, 29 Feb 2008 08:44:14 -0800From:   edvwhite at sbcglobal.netTo:   nsrca-discussion at lists.nsrca.orgSubject:  [NSRCA-discussion] Speaking  of 2.4GHzAnybody have  experience with the xtremelink  systems?http://www.xtremepowersystems.net/EdKen   Thompson <kthompson at stx.rr.com> wrote:   That's pretty cool, thanks for  bringing this to  the list.  I saw this in the Flying Giants first  thing  this morning.----- Original Message  -----  From:  Kevin Brice <mailto:kevinbrice at earthlink.net>    To: nsrca-discussion at lists.nsrca.org    Sent: Thursday, February 28,   2008 11:25 AM Subject:  [NSRCA-discussion] The  Great 2.4GHz DSM  Giveaway   For those  on the 2.4  fence, this may encourage you to upgrade to   DSM.  I am  not  sure if the html graphics will show so here is the  link to  Spektrum’s Receiver Giveaway.  http://www.spektrumrc.com/giveaway/     Kevin Bricekevinbrice at earthlink.net        
 

  
From: Spektrum Signal  [mailto:webmaster at spektrumrc.com]  Sent: Thursday,  February 28, 2008 10:00  AMTo: kevin at wenzlerarchitects.comSubject:   The Great 2.4GHz DSM Giveaway     
Having trouble viewing this email? Click   here. <http://publications.horizonhobby.com/read/archive?id=1223&amp;e=kevin@wenzlerarchitects.com&amp;x=99e8f192>    

          
   


      
February  28, 2008   


               
   

   

   
  PLEASE  VISIT WWW.SPEKTRUMRC.COM/GIVEAWAY <http://publications.horizonhobby.com/t/322561/1056524/7046/0/>    FOR MORE INFORMATION  Copyright  © 2008  Horizon Hobby. All rights reserved.If  you no longer  wish to receive this newsletter,  you may unsubscribe <mailto:leave-322561-1056524.eb728df499487cb49c599c8dbafb4236 at publications.horizonhobby.com>  Please  send any questions, comments, or concerns to  webmaster at spektrumrc.com <mailto:webmaster at horizonhobby.com>  Mailing  Address: Horizon Hobby, Inc., 4105   Fieldstone Rd., Champaign, IL 61822Spektrum  is  used with permission from Bachmann  Industries,   Inc.     
     

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I am curious what “noise” from a house is detectable on a Spectrum   Analyzer tuned to a center frequency of 2.4 GHz?  Not even a  900 MHz wireless phone would even come close.  Microwave? No wrong  frequency, Wi Fi networks? No, wrong frequency.   Granted if you  tune the analyzer’s center frequency well beyond 2.4 you might be able to  see other signals or noise but the narrow bandwidth the 2.4 operates in  and the clean signal/noise ratio doesn’t lend itself to the idea of house  noise causing interference.  Also, unless you can narrow the display  bandwidth way down then you won’t see any frequency “hopping”.  The  shift is very close to the carrier and unless you know what to look for  then you can miss it.  

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