[NSRCA-discussion] RX choices

[J.Oddino]

Dean,

I have never heard anyone explain the Spectrum system in a manner that made sense. Sounds as though you might have some insight.  Can you point me to something to fill in the blanks?

Jim O 
  ----- Original Message ----- 
  From: Dean Pappas 
  To: NSRCA Mailing List 
  Sent: Friday, September 15, 2006 8:29 AM
  Subject: Re: [NSRCA-discussion] RX choices


  Even the latest Spektrum DSS system is just narrow-band FM!
  How that works is an even better story, especially because it involves Hedi Lamarr!
  later,
  Dean

  Dean Pappas 
  Sr. Design Engineer 
  Kodeos Communications 
  111 Corporate Blvd. 
  South Plainfield, N.J. 07080 
  (908) 222-7817 phone 
  (908) 222-2392 fax 
  d.pappas at kodeos.com 

    -----Original Message-----
    From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Bob Richards
    Sent: Friday, September 15, 2006 11:17 AM
    To: NSRCA Mailing List
    Subject: Re: [NSRCA-discussion] RX choices


    John,

    I'm not surprised the manufacturers keep the PCM information (like packet specification, operating parameters, etc) private.  For one, that information could be considered a trade secret and they would not want competitors to know about it. On the other hand, they might be worried that a competitor would examine the data and discover some flaw or limitation in the technology and then publicly announce this fact. Still, I'm surprised no one has reverse engineered the PCM data stream from either JR or Futaba (maybe someone has, I just don't know).

    I'll take some issue with what you have said regarding the technology not changing since the '50s. I believe the '50s saw super-regen systems? After that, there was (is) super-heterodyne systems. Then, dual conversion and narrow band systems, as well as FM instead of AM.  PCM was added (really nothing to do with the RF, just a data link added to the existing RF systems). I think the systems today are more reliable than in the 70s when I first started, and they are having to do this in a much more polluted RF environment.

    Still, I agree with you that, as a group (modelers in general), we have not done a good job demanding more from the manufacturers. For most, cost seems to be the big issue, but we don't look at cost in terms of the big picture, like "a cheap receiver will cost you a lot AFTER you buy it".  Those of us that are competitors do a better job demanding more, IMHO.

    Bob R.


    John Ferrell <johnferrell at earthlink.net> wrote:
      Although I fly Futaba I have a lot of respect for the JR receiver 
      technology. It is the only thing new in receiver design other than the 
      Futaba synthesized receiver since the early 1950's. The technology made the 
      change to solid state but that was not taking advantage of any new design.

      I can assure you that Ham radio receivers have made steady progress during 
      that time even as prices came down.

      The bigger problem is that we have no idea about the real specs on these 
      receivers. The maintenance information is held very close and parts even 
      closer. We have no idea how long it takes to cycle in and out of fail safe 
      let alone any control over it. In fact we have no real indicator of failure 
      thresholds. George Steiner has done a lot of work in this area such as his 
      "missing frames" detector but his work has been hampered by lack of 
      published specs by the manufactures with PCM.

      I had hopes of improvements when HiTec swallowed Multiplex but it seems to 
      me they have only used the acquisition to leverage their efforts to become 
      another Futaba/JR/Airtronix.

      We have not been demanding customers and we have put way too much faith in 
      letting the suppliers make decisions for us!
      John Ferrell W8CCW
      "My Competition is not my enemy"
      http://DixieNC.US

      ----- Original Message ----- 
      From: "Ed Alt" 
      To: 
      Sent: Thursday, September 14, 2006 5:02 PM
      Subject: Re: [NSRCA-discussion] RX choices


      >
      > Yep, I've been flying JR single conversion ABC&W sine the late 90's in 
      > quite
      > a number of different locations around the country and have never, not 
      > once
      > had the slightest indication of a problem. Lot's of time with ignition
      > systems too. Must be some other cheesy single conversion receiver?
      >
      > Ed
      >


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