From: Doug McLaren [EMAIL PROTECTED]
Of course it's a real phenomenon. The technical term is `desense'.
http://users3.ev1.net/~medcalf/ztx/desense.html
It's also called the near-far problem.
Imagine trying to hear a whisper across a crowded room. Nearby louder voices
drowned out the
@airage.com
Subject: Re: [RCSE] Re: TX RF output? Long!
From: Doug McLaren [EMAIL PROTECTED]
Of course it's a real phenomenon. The technical term is `desense'.
http://users3.ev1.net/~medcalf/ztx/desense.html
It's also called the near-far problem.
Imagine trying to hear a whisper across
Hmm. Of course this is true when all are speaking in the same
frequency range. But how about if all the other conversations are
being held above 20khz or below 20hz??
Does sheer power on other frequencies swamp the front end of a
receiver? Shouldn't we see more evidence of this at the
] Re: TX RF output? Long!
From: Doug McLaren [EMAIL PROTECTED]
Of course it's a real phenomenon. The technical term is `desense'.
http://users3.ev1.net/~medcalf/ztx/desense.html
It's also called the near-far problem.
Imagine trying to hear a whisper across a crowded room
A PCM signal is no better than PPM. The only benefit would have been if the
PCM Rx went into fail safe. Obviously could have been quite helpful. If it
did go into failsafe.
Bill Swingle
Janesville, CA
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On Fri, Mar 10, 2006 at 11:08:42AM -0500, Rick Eckel wrote:
| Hmm. Of course this is true when all are speaking in the same
| frequency range. But how about if all the other conversations are
| being held above 20khz or below 20hz??
Yes, whispered voices aren't the best analogy, as they
From: Rick Eckel [EMAIL PROTECTED]
But how about if all the other conversations are
being held above 20khz or below 20hz??
Does sheer power on other frequencies swamp the front end of a
receiver? Shouldn't we see more evidence of this at the launch area?
===
Up or
Imagine trying to hear a whisper across a crowded room. Nearby louder
voices drowned out the one familiar voice you are trying to hear. All
radio receivers face the same issues. (Jon Stone)
This is where the magic of the newer receivers comes into play. Like any
other radio they also have a
As it would have Bill...if indeed a PCMm RX was employed, as the communications
protocol would have been different (except in the unlikely case the offending
TX was identical and on the same frequency). A PCM RX would immediately have
gone into hold, and then would have either returned to
From: Doug McLaren [EMAIL PROTECTED]
For desense to occur, the signals don't even have to be in the same
band. For example, in my car the FM radio (88-108 MHz) signal gets
noticibly quieter when I transmit on my 144 MHZ ham radio.
Same thing happens in my
I hope you're right. Wasn't always like that, and I suspect with park
flyers, or any such single conversion (ugh! and yes, I've heard there
are other solutions than dual conversion) receivers it still isn't. Back
in 1990 or so, I conscientiously got a 1991 system on channel 20. I
could shoot
From: [EMAIL PROTECTED]The above is of course only a guess...Yep. Perhaps some of the engineers in the group could provide some factual info.
: [RCSE] Re: TX RF
output? and urban legends
From: [EMAIL PROTECTED]
The above is of course only a guess...Yep. Perhaps
some of the engineers in the group could provide some factual
info.
Actually Tony, what I stated are actual...heaven forbid...facts, as I prefer to
speak from a position of first-hand knowledge and experience rather than
hearsay.
The anecdotal evidence put forth by John D. is a great real-world indicator of
how prevelant this problem can be.
I have personally
- Original Message
From: [EMAIL PROTECTED]
Cc: Soaring@airage.com
Actually Tony, what I stated are actual...heaven forbid...facts, as I prefer to
speak from a position of first-hand knowledge and experience rather than
hearsay.
==
Yep. The guesswork Gordy was referring
Ok, great thread and to some degree, educational. While I have absolutely no
technical background on this subject, I have been the victim of a very
expensive and unavoidable, on my part, shoot down. I basically considered it
a swamping incident, another term for you experts to butcher. This
- Original Message
From: EXT-McCleave, Howard R [EMAIL PROTECTED]
I was flying at about 50 feet of altitude along the tree line at the west end
of the field when the plane did an immediate vertical dive into the ground with
no possibility of recovery. When I walked out to get the
On Thu, Mar 09, 2006 at 10:28:37AM -0600, EXT-McCleave, Howard R wrote:
! What do you think experts, is swamping a real phenomenon or did
| he have a lousy TX?? Plane's gone but I would still be interested to
| know what y'all think.
Of course it's a real phenomenon. The technical term is
What a novel and smart suggestion. Makes one wonder how many TX's out
there have never experienced a tune-up...
They don't have any moving parts. Older radios may have parts like
descrete coils (sometimes with slugs) that can can change their size
slightly over time (mechanical, maybe due to
Message-
From: Martin Usher [mailto:[EMAIL PROTECTED]
Sent: Wednesday, March 08, 2006 4:01 PM
To: soaring@airage.com
Subject: Re: [RCSE] Re: TX RF output?]
What a novel and smart suggestion. Makes one wonder how many TX's out
there have never experienced a tune-up...
They don't have any moving
You might consider asking a repair depot about how many TX's come in
that are indeed emanating into adjacent channels.
Secondly, RX's have interfered with each other in dual installations
causing a loss of range, which on some installations has been severe.
Using isolation techniques, the
Actually without being as smart as some of you I can still disagree with
this.
Most radios do get out of alignment. I have been on the receiving end
of splatter. A tuneup couldn't hurt.
Receivers do emit RF. An ESL member has come up with a way of tracking a
receiver based on its emission. He
the receiving end of splatter.
This is mostly just that .splatter, not RF but
conversation.
OurRX's have ahuge problem...they are sooo selective
they barely listen to their own frequencies, so the idea of them being bothered
by some sort of close emission from a grey tuned TX, while
What a novel and smart suggestion. Makes one wonder how many TX's out
there have never experienced a tune-up...
John Diniz wrote:
Food for thought. With all the talk about batteries and redundancy in the terms
of saving your expensive RC model I wonder how many people are concerned about
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