OT: Aircraft radio FM

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OT: Aircraft radio FM

Ken G Kopp
I suppose the argument about no heterodyne with FM can be
made, BUT ...

AM aircraft radio has been around since the end of spark and
steadily growing world-wide since that time.  It was solidly in
place -long- before FM was a gleam in Armstrong's eye.  It
remains that the staggering cost of conversion to FM is the
real reason it continues today.

73!

K0PP
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Re: OT: Aircraft radio FM

w5tvw
NO!  I wondered about that for YEARS, even when I was working in avionics!
The REAL reason for using AM instead of FM is the "FM capture effect".  A
slightly stronger signal on the channel will "takeover" the channel.  You
can't hear weaker signals thru it like AM.  This was the real reason for
sticking with AM for aviation.....SAFETY in emergencies or "distress"
conditions.

Besides the usual 108-135 or so Mhz for AM aeronautical, the UHF (225-400
Mhz) the military uses is also still AM.

I think Aeronautical AM will be around for many more years IF some dumb ass
"non engineer" decides AM is "Obsolete" and screws things up.  Seeing the
present "bright" political appointees nothing would surprise me!

73 TO ALL,

Sandy W5TVW

-----Original Message-----
From: Ken G Kopp
Sent: Tuesday, July 16, 2013 3:54 PM
To: [hidden email] ; [hidden email]
Subject: [Elecraft] OT: Aircraft radio FM

I suppose the argument about no heterodyne with FM can be
made, BUT ...

AM aircraft radio has been around since the end of spark and
steadily growing world-wide since that time.  It was solidly in
place -long- before FM was a gleam in Armstrong's eye.  It
remains that the staggering cost of conversion to FM is the
real reason it continues today.

73!

K0PP
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No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.3349 / Virus Database: 3204/6495 - Release Date: 07/16/13

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Re: OT: Aircraft radio FM

daleputnam
And... what would the improvement be for FM over AM? What  would it be
for ?? Other than making every aircraft change over... (follow the money) and the side
by side systems in each control point...  what would improve? Range?... not really...
quality of audio? not really.. what then? someone's ego.. ??
or best of all.. lining someone's pocket.??
 


Have a great day,
 
 
--...   ...--
Dale - WC7S in Wy
 
 

 

> From: [hidden email]
> To: [hidden email]; [hidden email]; [hidden email]
> Date: Tue, 16 Jul 2013 16:27:26 -0500
> Subject: Re: [Elecraft] OT: Aircraft radio FM
>
> NO!  I wondered about that for YEARS, even when I was working in avionics!
> The REAL reason for using AM instead of FM is the "FM capture effect".  A
> slightly stronger signal on the channel will "takeover" the channel.  You
> can't hear weaker signals thru it like AM.  This was the real reason for
> sticking with AM for aviation.....SAFETY in emergencies or "distress"
> conditions.
>
> Besides the usual 108-135 or so Mhz for AM aeronautical, the UHF (225-400
> Mhz) the military uses is also still AM.
>
> I think Aeronautical AM will be around for many more years IF some dumb ass
> "non engineer" decides AM is "Obsolete" and screws things up.  Seeing the
> present "bright" political appointees nothing would surprise me!
>
> 73 TO ALL,
>
> Sandy W5TVW
>
> -----Original Message-----
> From: Ken G Kopp
> Sent: Tuesday, July 16, 2013 3:54 PM
> To: [hidden email] ; [hidden email]
> Subject: [Elecraft] OT: Aircraft radio FM
>
> I suppose the argument about no heterodyne with FM can be
> made, BUT ...
>
> AM aircraft radio has been around since the end of spark and
> steadily growing world-wide since that time.  It was solidly in
> place -long- before FM was a gleam in Armstrong's eye.  It
> remains that the staggering cost of conversion to FM is the
> real reason it continues today.
>
> 73!
>
> K0PP
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.3349 / Virus Database: 3204/6495 - Release Date: 07/16/13
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
     
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Re: OT: Aircraft radio FM

Mike Morrow-3
In reply to this post by Ken G Kopp
Ken wrote:

> AM aircraft radio has been around since the end of spark and
> steadily growing world-wide since that time.  It was solidly in
> place -long- before FM was a gleam in Armstrong's eye.

Er...I'm not sure how that supports an argument that transition
to FM was *at any point and time* considered *by any responsible
party* to have characteristics that were more desirable than AM
for aircraft communications.

The characterization that AM was "solidly in place -long- before FM
was a gleam in Armstrong's eye" refers accurately only to the era
when aircraft communications were only on medium and high frequencies...
an era when long-range aircraft communications often still made use
of Morse CW (hence the FCC Element 7 exam for Aircraft Radiotelegraph
Endorsement, now discontinued).

The transition from MF/HF to VHF for aircraft communications received
its greatest push with the UK's pioneering use after 1940 of aircraft
AM command sets operating in the range of 100 to 156 MHz.  This sparked
the allied US military's transition from MF/HF command sets to VHF
command sets, one of the earliest being the Western Electric 233A set.
At this point, VHF FM could have been *very easily* adopted, had it not
been for its undesirable capture effect.

Aircraft VHF-AM was chosen long after FM had been developed.  The
decision to use AM was purposely made.  The adoption of aircraft VHF-AM
was NOT the result of constraints from earlier legacy technology.
All civil aviation eventually adopted the military standard of VHF-AM,
although up to the mid-1950s many private aircraft continued to use
MF/HF sets with receivers in the 200 to 400 kHz range and a transmitter
on 3105 (later 3023.5) kHz...still far from a universal commitment
to VHF-AM at that late date, had VHF-FM been a better choice.

Further, by 1945, the US military began exploring UHF for aircraft
comms.  These new sets had no reason to stick with AM, if FM were
superior.  But FM was not superior...or as good.  AM was chosen for
use in the military UHF aircraft band as well.

> It remains that the staggering cost of conversion to FM is the
> real reason it continues today.

That is a gratuitous assertion for which my decades of study in this
area finds no substantiation.

73,
Mike / KK5F
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Re: OT: Aircraft radio FM

Rich-2
Am I the only one wondering what has any of this got to do with Elecraft??

Can the moderators put an end to all of these OT posts and return it to a reflector for its purpose please?? Yes I know where the delete button is but the threads get longer and longer.

Nothing personal Mike, just picked your post to reply to.
Sent from my BlackBerry® wireless device

-----Original Message-----
From: Mike Morrow <[hidden email]>
Sender: [hidden email]
Date: Tue, 16 Jul 2013 18:02:36
To: <[hidden email]>; <[hidden email]>
Reply-To: Mike Morrow <[hidden email]>
Subject: Re: [Elecraft] OT: Aircraft radio FM

Ken wrote:

> AM aircraft radio has been around since the end of spark and
> steadily growing world-wide since that time.  It was solidly in
> place -long- before FM was a gleam in Armstrong's eye.

Er...I'm not sure how that supports an argument that transition
to FM was *at any point and time* considered *by any responsible
party* to have characteristics that were more desirable than AM
for aircraft communications.

The characterization that AM was "solidly in place -long- before FM
was a gleam in Armstrong's eye" refers accurately only to the era
when aircraft communications were only on medium and high frequencies...
an era when long-range aircraft communications often still made use
of Morse CW (hence the FCC Element 7 exam for Aircraft Radiotelegraph
Endorsement, now discontinued).

The transition from MF/HF to VHF for aircraft communications received
its greatest push with the UK's pioneering use after 1940 of aircraft
AM command sets operating in the range of 100 to 156 MHz.  This sparked
the allied US military's transition from MF/HF command sets to VHF
command sets, one of the earliest being the Western Electric 233A set.
At this point, VHF FM could have been *very easily* adopted, had it not
been for its undesirable capture effect.

Aircraft VHF-AM was chosen long after FM had been developed.  The
decision to use AM was purposely made.  The adoption of aircraft VHF-AM
was NOT the result of constraints from earlier legacy technology.
All civil aviation eventually adopted the military standard of VHF-AM,
although up to the mid-1950s many private aircraft continued to use
MF/HF sets with receivers in the 200 to 400 kHz range and a transmitter
on 3105 (later 3023.5) kHz...still far from a universal commitment
to VHF-AM at that late date, had VHF-FM been a better choice.

Further, by 1945, the US military began exploring UHF for aircraft
comms.  These new sets had no reason to stick with AM, if FM were
superior.  But FM was not superior...or as good.  AM was chosen for
use in the military UHF aircraft band as well.

> It remains that the staggering cost of conversion to FM is the
> real reason it continues today.

That is a gratuitous assertion for which my decades of study in this
area finds no substantiation.

73,
Mike / KK5F
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Re: OT: Aircraft radio FM

Phil Kane-2
In reply to this post by w5tvw
On 7/16/2013 2:27 PM, Sandy Blaize wrote:

> I think Aeronautical AM will be around for many more years IF some dumb
> ass "non engineer" decides AM is "Obsolete" and screws things up.
> Seeing the present "bright" political appointees nothing would surprise me!

It would have to come from the ICAO through the ITU before the FCC would
consider it.

Digital TV and FM came about because of lobby pressure on The Congress
(money talks).  I can't foresee a lobby for Aeronautical AM.  Very few
technical "changes" start with staff recommendations.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Re: OT: Aircraft radio FM

w5tvw
Yes I read all about RCA screwing Edwin Armstrong on wideband FM.  David
Sarnoff had connections with the FCC to eliminate the old FM band (pre war)
and have the 88-108 region allotted  which made all of Armstrong's equipment
obsolete.  Also RCA claims to have "invented" a new wideband FM system to
work around Armstrong's patents.  Armstrong's wife finally managed to
finally win out over the manufacturer's and RCA in lawsuits long after
Armstrong jumped out of a hotel window in disgust and near broke from legal
costs.

I remember FM "heralded" after the war but nothing ever overcoming the AM
broadcasters until years later when all the principals were dead by then!  A
sad story of corporate greed and corruption.  (With the help of the FCC back
then, a lot of whose engineers got plum jobs with RCA!)

73,

Sandy W5TVW

-----Original Message-----
From: Phil Kane
Sent: Tuesday, July 16, 2013 6:21 PM
To: [hidden email]
Subject: Re: [Elecraft] OT: Aircraft radio FM

On 7/16/2013 2:27 PM, Sandy Blaize wrote:

> I think Aeronautical AM will be around for many more years IF some dumb
> ass "non engineer" decides AM is "Obsolete" and screws things up.
> Seeing the present "bright" political appointees nothing would surprise
> me!

It would have to come from the ICAO through the ITU before the FCC would
consider it.

Digital TV and FM came about because of lobby pressure on The Congress
(money talks).  I can't foresee a lobby for Aeronautical AM.  Very few
technical "changes" start with staff recommendations.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.3349 / Virus Database: 3204/6496 - Release Date: 07/16/13

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Re: OT: Aircraft radio FM

Tim Hague
In reply to this post by Rich-2
More interesting in the permanent  self congratulation you see on here when someone buys a rig!

Best regards, Tim Hague
Skype m0afj.Tim
Sent on my iPad


On 16 Jul 2013, at 23:11, "Rich" <[hidden email]> wrote:

> Am I the only one wondering what has any of this got to do with Elecraft??
>
> Can the moderators put an end to all of these OT posts and return it to a reflector for its purpose please?? Yes I know where the delete button is but the threads get longer and longer.
>
> Nothing personal Mike, just picked your post to reply to.
> Sent from my BlackBerry® wireless device
>
> -----Original Message-----
> From: Mike Morrow <[hidden email]>
> Sender: [hidden email]
> Date: Tue, 16 Jul 2013 18:02:36
> To: <[hidden email]>; <[hidden email]>
> Reply-To: Mike Morrow <[hidden email]>
> Subject: Re: [Elecraft] OT: Aircraft radio FM
>
> Ken wrote:
>
>> AM aircraft radio has been around since the end of spark and
>> steadily growing world-wide since that time.  It was solidly in
>> place -long- before FM was a gleam in Armstrong's eye.
>
> Er...I'm not sure how that supports an argument that transition
> to FM was *at any point and time* considered *by any responsible
> party* to have characteristics that were more desirable than AM
> for aircraft communications.
>
> The characterization that AM was "solidly in place -long- before FM
> was a gleam in Armstrong's eye" refers accurately only to the era
> when aircraft communications were only on medium and high frequencies...
> an era when long-range aircraft communications often still made use
> of Morse CW (hence the FCC Element 7 exam for Aircraft Radiotelegraph
> Endorsement, now discontinued).
>
> The transition from MF/HF to VHF for aircraft communications received
> its greatest push with the UK's pioneering use after 1940 of aircraft
> AM command sets operating in the range of 100 to 156 MHz.  This sparked
> the allied US military's transition from MF/HF command sets to VHF
> command sets, one of the earliest being the Western Electric 233A set.
> At this point, VHF FM could have been *very easily* adopted, had it not
> been for its undesirable capture effect.
>
> Aircraft VHF-AM was chosen long after FM had been developed.  The
> decision to use AM was purposely made.  The adoption of aircraft VHF-AM
> was NOT the result of constraints from earlier legacy technology.
> All civil aviation eventually adopted the military standard of VHF-AM,
> although up to the mid-1950s many private aircraft continued to use
> MF/HF sets with receivers in the 200 to 400 kHz range and a transmitter
> on 3105 (later 3023.5) kHz...still far from a universal commitment
> to VHF-AM at that late date, had VHF-FM been a better choice.
>
> Further, by 1945, the US military began exploring UHF for aircraft
> comms.  These new sets had no reason to stick with AM, if FM were
> superior.  But FM was not superior...or as good.  AM was chosen for
> use in the military UHF aircraft band as well.
>
>> It remains that the staggering cost of conversion to FM is the
>> real reason it continues today.
>
> That is a gratuitous assertion for which my decades of study in this
> area finds no substantiation.
>
> 73,
> Mike / KK5F
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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Hop
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Re: OT: Aircraft radio FM

Hop
In reply to this post by Rich-2
Hmm. I noticed but it doesn't bother me. Presumably all who post here are
either Elecraft owners or wannabees. I enjoy reading stuff from all those
old hams who are "been there, done that, wore out a dozen tee-shirts" types.
I am gonna join the Quarter Century Wireless Association (QWCA) this month,
Chapter 9 (Southwestern Ohio), just to be around some of those guys who meet
for lunch once a month. Many were born shortly after the turn of the
previous century and have plenty of history to share.

As for FM... gee, we are well into the 21st Century. If there was some
overwhelming demand for aeronautical FM I am sure someone could engineer a
chip that would eliminate the "capture effect" which, if I recall correctly,
is an artifact of discriminator and ratio detector design, not a given
because of the modulation mode. Maybe some sort of delayed auto-correlation
algorithm applied prior to the limiter or in lieu of it would allow weak
signals to be selected in preference to nearby strong signals, thereby
preventing the "capture effect." Ask Wayne. I don't see a limiter or a
discriminator or a ratio detector in my KX3 schematic, yet it does FM. You
can do almost anything with an SDR, except maybe brew coffee.

End thread?

74 de AC8NS
Hop


----- Original Message -----
From: "Rich" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, July 16, 2013 6:11 PM
Subject: Re: [Elecraft] OT: Aircraft radio FM


Am I the only one wondering what has any of this got to do with Elecraft??

Can the moderators put an end to all of these OT posts and return it to a
reflector for its purpose please?? Yes I know where the delete button is but
the threads get longer and longer.

Nothing personal Mike, just picked your post to reply to.
Sent from my BlackBerry® wireless device

-----Original Message-----
From: Mike Morrow <[hidden email]>
Sender: [hidden email]
Date: Tue, 16 Jul 2013 18:02:36
To: <[hidden email]>; <[hidden email]>
Reply-To: Mike Morrow <[hidden email]>
Subject: Re: [Elecraft] OT: Aircraft radio FM

Ken wrote:

> AM aircraft radio has been around since the end of spark and
> steadily growing world-wide since that time.  It was solidly in
> place -long- before FM was a gleam in Armstrong's eye.

Er...I'm not sure how that supports an argument that transition
to FM was *at any point and time* considered *by any responsible
party* to have characteristics that were more desirable than AM
for aircraft communications.

The characterization that AM was "solidly in place -long- before FM
was a gleam in Armstrong's eye" refers accurately only to the era
when aircraft communications were only on medium and high frequencies...
an era when long-range aircraft communications often still made use
of Morse CW (hence the FCC Element 7 exam for Aircraft Radiotelegraph
Endorsement, now discontinued).

The transition from MF/HF to VHF for aircraft communications received
its greatest push with the UK's pioneering use after 1940 of aircraft
AM command sets operating in the range of 100 to 156 MHz.  This sparked
the allied US military's transition from MF/HF command sets to VHF
command sets, one of the earliest being the Western Electric 233A set.
At this point, VHF FM could have been *very easily* adopted, had it not
been for its undesirable capture effect.

Aircraft VHF-AM was chosen long after FM had been developed.  The
decision to use AM was purposely made.  The adoption of aircraft VHF-AM
was NOT the result of constraints from earlier legacy technology.
All civil aviation eventually adopted the military standard of VHF-AM,
although up to the mid-1950s many private aircraft continued to use
MF/HF sets with receivers in the 200 to 400 kHz range and a transmitter
on 3105 (later 3023.5) kHz...still far from a universal commitment
to VHF-AM at that late date, had VHF-FM been a better choice.

Further, by 1945, the US military began exploring UHF for aircraft
comms.  These new sets had no reason to stick with AM, if FM were
superior.  But FM was not superior...or as good.  AM was chosen for
use in the military UHF aircraft band as well.

> It remains that the staggering cost of conversion to FM is the
> real reason it continues today.

That is a gratuitous assertion for which my decades of study in this
area finds no substantiation.

73,
Mike / KK5F
______________________________________________________________
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