[NSRCA-discussion] Speaking of 2.4GHz

Sun Mar 2 09:23:20 AKST 2008

Re: [NSRCA-discussion] Speaking of 2.4GHzI thought many wireless devices were using the 2.4 GHz in homes and computer stuff. ?  

    Del
  ----- Original Message ----- 
  From: Randall Bearden 
  To: NSRCA Mailing List 
  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 Pavlick
    http://www.idseng.com

    From: 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

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      Date: Fri, 29 Feb 2008 14:17:06 -0800
      From:  edvwhite at sbcglobal.net
      To: nsrca-discussion at lists.nsrca.org
      Subject: Re:  [NSRCA-discussion] Speaking of 2.4GHz

      Ed,

      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.

      Ed

      Ed 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

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            Date: Fri, 29 Feb 2008 08:44:14 -0800
            From:  edvwhite at sbcglobal.net
            To:  nsrca-discussion at lists.nsrca.org
            Subject: [NSRCA-discussion] Speaking  of 2.4GHz

            Anybody have experience with the xtremelink  systems?

            http://www.xtremepowersystems.net/

            Ed

            Ken  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 Brice

                kevinbrice at earthlink.net  

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

                From: Spektrum Signal  [mailto:webmaster at spektrumrc.com] 
                Sent: Thursday,  February 28, 2008 10:00 AM
                To: kevin at wenzlerarchitects.com
                Subject:  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 61822
                Spektrum  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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