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<DIV><FONT face=Arial size=2>1950's communications receivers were dual
conversion but implemented in vacuum tubes. </FONT></DIV>
<DIV> </DIV>
<DIV>John Ferrell W8CCW<BR>"My Competition is not my
enemy"<BR><A href="http://DixieNC.US">http://DixieNC.US</A><BR></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bob@toprudder.com href="mailto:bob@toprudder.com">Bob Richards</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, September 15, 2006 11:16
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] RX
choices</DIV>
<DIV><BR></DIV>
<DIV>John,</DIV>
<DIV> </DIV>
<DIV>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).</DIV>
<DIV> </DIV>
<DIV>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.</DIV>
<DIV> </DIV>
<DIV>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.</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV><BR><BR><B><I>John Ferrell <johnferrell@earthlink.net></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Although
I fly Futaba I have a lot of respect for the JR receiver <BR>technology. It
is the only thing new in receiver design other than the <BR>Futaba
synthesized receiver since the early 1950's. The technology made the
<BR>change to solid state but that was not taking advantage of any new
design.<BR><BR>I can assure you that Ham radio receivers have made steady
progress during <BR>that time even as prices came down.<BR><BR>The bigger
problem is that we have no idea about the real specs on these <BR>receivers.
The maintenance information is held very close and parts even <BR>closer. We
have no idea how long it takes to cycle in and out of fail safe <BR>let
alone any control over it. In fact we have no real indicator of failure
<BR>thresholds. George Steiner has done a lot of work in this area such as
his <BR>"missing frames" detector but his work has been hampered by lack of
<BR>published specs by the manufactures with PCM.<BR><BR>I had hopes of
improvements when HiTec swallowed Multiplex but it seems to <BR>me they have
only used the acquisition to leverage their efforts to become <BR>another
Futaba/JR/Airtronix.<BR><BR>We have not been demanding customers and we have
put way too much faith in <BR>letting the suppliers make decisions for
us!<BR>John Ferrell W8CCW<BR>"My Competition is not my
enemy"<BR>http://DixieNC.US<BR><BR>----- Original Message ----- <BR>From:
"Ed Alt" <ED_ALT@HOTMAIL.COM><BR>To:
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>Sent: Thursday, September 14, 2006
5:02 PM<BR>Subject: Re: [NSRCA-discussion] RX
choices<BR><BR><BR>><BR>> Yep, I've been flying JR single conversion
ABC&W sine the late 90's in <BR>> quite<BR>> a number of different
locations around the country and have never, not <BR>> once<BR>> had
the slightest indication of a problem. Lot's of time with ignition<BR>>
systems too. Must be some other cheesy single conversion
receiver?<BR>><BR>>
Ed<BR>><BR><BR><BR>_______________________________________________<BR>NSRCA-discussion
mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<BR></BLOCKQUOTE><BR>
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