20090929.ba v04_n289.bam.20090929 >From ???@??? Tue Sep 29 05:32:28 2009 -0500 Date: Tue, 29 Sep 2009 04:31:43 CST From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4289 Message-Id: <20090929103144.C9EDCD58BC@srvr1.theporch.com> BOATANCHORS Digest 4289 Topics covered in this issue include: 1) Fasten your seatbelts - ARRL by John Sehring 2) Re: Fasten your seatbelts - ARRL by "Sandy" 3) Re: Fasten your seatbelts - ARRL by Ralph Parker 4) Re: Fasten your seatbelts - ARRL by "David Stinson" 5) Re: Fasten your seatbelts - ARRL by "Robert Lawson" 6) Re:fasten your seatbelts-ARRL by "PHIL" 7) Re:fasten your seatbelts-ARRL by "PHIL" 8) RE: Fasten your seatbelts - ARRL by "Ed Zeranski" 9) reply - ARRL narrowband vs AMers by "jim evans" 10) Re: Fasten your seatbelts - ARRL by "Arden Allen" 11) Re: Fasten your seatbelts - ARRL by "Arden Allen" 12) Re: Fasten your seatbelts - ARRL by "Robert Lawson" 13) Re: Fasten your seatbelts - ARRL by "Robert Lawson" 14) Re: Fasten your seatbelts - ARRL by "Sandy" 15) Re: Fasten your seatbelts - ARRL by "David Stinson" ---------------------------------------------------------------------- Message-ID: <254488.68134.qm@web45612.mail.sp1.yahoo.com> Date: Sun, 27 Sep 2009 17:09:50 -0700 (PDT) From: John Sehring Subject: Fasten your seatbelts - ARRL To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii I think it's silly to go to even narrower FM signals. We were forced to leave +-15 kHz behind a few decades ago. IMO +-5 kHz FM is just adequate for current use. The developer of practical FM, Howard Armstrong, in his genius realized that WIDEBAND FM was the key to its successful use. (FM broadcasting uses +-75 kHz deviation.) Narrower FM means much less power winds up in the sidebands; the latter convey the intelligence(??) in the signal. It is analogous to having about 40% maximum modulation depth on an AM system. You can see this by looking at FM sideband theory. You also lose more & more of the FM advantages: Capture ratio & AM rejection (nothing personal meant here!), ultimate signal to noise ratio, distortion at low CNR's, get sloppier squelch action. Lest you disbelieve this, the new, even-narrower +-2.5 kHz FM systems need to use "companding" audio processing to get SNR's back to useable levels! This does not work well at low SNR's. IMO, this is NOT progress. And for all the talk about all repeater pairs being filled, ha! Just listen to repeaters anywhere, even in vy built up places, e.g. New York City: there's a deafening silence! All are evidently texting, twittering, and yakking on cell phones. I challenge someone to program a PC tied to a scanner to log actual on-times for all the repeaters in an area. This was done in NYC in the mid-70's; I was very surprised at the results: very low utilization! Could this be a genuine non-problem? A solution in search of a (non-existent) problem? Pepper the ARRL with comments, they're supposed to be listening. --John WB0EQ ------------------------------ Message-ID: <238B479AEC8145A1ADC94DC292D93C6A@gateway> From: "Sandy" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 11:25:58 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit For some strange reason, all the older "modes" are being modified so that they will perform "not as well" or so that they will take up less "spectrum space" You will notice at the same time, "digital modes" seem to be promoted that take up MORE space and spread a plethora of hash and interference to the "older modes" ("Older modes" being conventional Morse (CW), FM and narrow-band FM, Amplitude modulation. Notice aeronautical VHF/UHF radio continues to hang on to "AM". There must be a reason. (It's simple and it works?) Everyone seems to be hopping onto the "digital" bandwagon. Going digital requires more stuff that can "go wrong" and more complication of gear without necessarily giving much greater "advantages". Maybe I remember the "old days" when no "interface" was required bewteen the amateur operator and the radio being operated. No "black box" encoders/decoders that made the gibberish/noise being transmitted intelligible to the "operator". What happens next to FM? A digital "replacement"? Why a digital replacement for SSB? Why is it necessary....REALLY? Out of all the "digital" stuff (discountng manual CW) around, the only digital mode I have been VERY impressed with, and is easy to do (provided you have a computer....this means more electronic junk to carry around!) is PSK. It is confined to a few khz of space on each band and you can delve thru very many QSO's going on in this extremely narrow space (provided some idiot isn't running a huge amount of power which has a tendency to ruin things for everyone. Witness in the past the old 432 Mhz "uplink" 144 Mhz "downlink" Oscar when some blockhead runs too much power and kills all the weak uplink signals for everyone else!) Hopefully, we will have some technically and practically competant people looking at these proposals. Most of the FCC commissioners now seem to NOT be technically competant. We have witnessed the incompetance via the BPL fiasco, which some people seem still are promoting even as I type. My 2 cents worth. 73, Sandy W5TVW ----- Original Message ----- From: "John Sehring" To: "Old Tube Radios" Sent: Sunday, September 27, 2009 7:09 PM Subject: Fasten your seatbelts - ARRL >I think it's silly to go to even narrower FM signals. We were forced to >leave +-15 kHz behind a few decades ago. IMO +-5 kHz FM is just adequate >for current use. > > The developer of practical FM, Howard Armstrong, in his genius realized > that WIDEBAND FM was the key to its successful use. (FM broadcasting uses > +-75 kHz deviation.) > > Narrower FM means much less power winds up in the sidebands; the latter > convey the intelligence(??) in the signal. It is analogous to having > about 40% maximum modulation depth on an AM system. You can see this by > looking at FM sideband theory. > > You also lose more & more of the FM advantages: Capture ratio & AM > rejection (nothing personal meant here!), ultimate signal to noise ratio, > distortion at low CNR's, get sloppier squelch action. > > Lest you disbelieve this, the new, even-narrower +-2.5 kHz FM systems need > to use "companding" audio processing to get SNR's back to useable levels! > This does not work well at low SNR's. IMO, this is NOT progress. > > And for all the talk about all repeater pairs being filled, ha! Just > listen to repeaters anywhere, even in vy built up places, e.g. New York > City: there's a deafening silence! All are evidently texting, > twittering, and yakking on cell phones. > > I challenge someone to program a PC tied to a scanner to log actual > on-times for all the repeaters in an area. This was done in NYC in the > mid-70's; I was very surprised at the results: very low utilization! > > Could this be a genuine non-problem? A solution in search of a > (non-existent) problem? > > Pepper the ARRL with comments, they're supposed to be listening. > > --John WB0EQ > > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.409 / Virus Database: 270.13.113/2399 - Release Date: 09/27/09 17:52:00 ------------------------------ Date: Mon, 28 Sep 2009 10:18:15 -0700 From: Ralph Parker Subject: Re: Fasten your seatbelts - ARRL To: Old Tube Radios Message-id: <3.0.6.32.20090928101815.00bfb178@pop3.dccnet.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7BIT >For some strange reason, all the older "modes" are being modified... >..."digital modes" seem to be promoted that take up MORE space and spread >a plethora of hash and interference to the "older modes"... Amen to that, brother! As I favour CW (NOT a digital mode, IMHO - doesn't need a computer), I am becoming increasingly insensed with the intrusion of digital modes into 'my' bands (mostly the 40m CW portion). Why weren't they put in quieter ends of the bands (1.89 mhz, 7.09, 14.09, etc.) instead of .07 and .08, mixed in with the 'traditional' modes, and what can be more traditional than CW? This is what doing away with the Morse requirement is doing for us. Sorry, I've gotta go lie down for a minute - I'm getting too angry. I'll be dead soon, and it won't matter - and THEN they'll be sorry! VE7XF ------------------------------ Message-ID: <6F2B5DE963EC467F9B915FD914279E89@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 12:46:51 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit ----- Original Message ----- From: "Sandy" Subject: Re: Fasten your seatbelts - ARRL > Notice aeronautical VHF/UHF radio continues to hang on to "AM". There > must be a reason. (It's simple and it works?) It's a safety issue, learned through experiance. AM does not have the "capture effect" of FM; if someone transmits at the same time as someone else, the controller will hear the beat note from the mixing of the two carriers and know someone else is trying to transmit. If the two signals do happen to be spot-on freq, he'll hear both calls. Also- if someone's mike is "stuck," blanketing the channel with a strong carrier, FM signals have little chance of being understood, while an AM signal does have a better-than-even chance. ------------------------------ Message-ID: From: "Robert Lawson" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 12:54:30 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit Sandy, it is my experience that the reason the VHF aircraft radios use the AM mode is so that heterodynes can be generated and easily heard if two stations are transmitting at the same time. There are times when driving around boring holes in the clouds that if a pilot misses important information it could really ruin their day. Believe me. 73 Robert W4RL ----- Original Message ----- From: "Sandy" To: "Old Tube Radios" Sent: Monday, September 28, 2009 11:25 AM Subject: Re: Fasten your seatbelts - ARRL > For some strange reason, all the older "modes" are being modified so that > they will perform "not as well" or so that they will take up less > "spectrum space" You will notice at the same time, "digital modes" seem > to be promoted that take up MORE space and spread a plethora of hash and > interference to the "older modes" ("Older modes" being conventional Morse > (CW), FM and narrow-band FM, Amplitude modulation. > > Notice aeronautical VHF/UHF radio continues to hang on to "AM". There > must be a reason. (It's simple and it works?) > > Everyone seems to be hopping onto the "digital" bandwagon. Going digital > requires more stuff that can "go wrong" and more complication of gear > without necessarily giving much greater "advantages". Maybe I remember > the "old days" when no "interface" was required bewteen the amateur > operator and the radio being operated. No "black box" encoders/decoders > that made the gibberish/noise being transmitted intelligible to the > "operator". > > What happens next to FM? A digital "replacement"? Why a digital > replacement for SSB? Why is it necessary....REALLY? Out of all the > "digital" stuff (discountng manual CW) around, the only digital mode I > have been VERY impressed with, and is easy to do (provided you have a > computer....this means more electronic junk to carry around!) is PSK. It > is confined to a few khz of space on each band and you can delve thru very > many QSO's going on in this extremely narrow space (provided some idiot > isn't running a huge amount of power which has a tendency to ruin things > for everyone. Witness in the past the old 432 Mhz "uplink" 144 Mhz > "downlink" Oscar when some blockhead runs too much power and kills all the > weak uplink signals for everyone else!) > > Hopefully, we will have some technically and practically competant people > looking at these proposals. Most of the FCC commissioners now seem to NOT > be technically competant. We have witnessed the incompetance via the BPL > fiasco, which some people seem still are promoting even as I type. > > My 2 cents worth. > > 73, > > Sandy W5TVW > ----- Original Message ----- > From: "John Sehring" > To: "Old Tube Radios" > Sent: Sunday, September 27, 2009 7:09 PM > Subject: Fasten your seatbelts - ARRL > > >>I think it's silly to go to even narrower FM signals. We were forced to >>leave +-15 kHz behind a few decades ago. IMO +-5 kHz FM is just adequate >>for current use. >> >> The developer of practical FM, Howard Armstrong, in his genius realized >> that WIDEBAND FM was the key to its successful use. (FM broadcasting >> uses +-75 kHz deviation.) >> >> Narrower FM means much less power winds up in the sidebands; the latter >> convey the intelligence(??) in the signal. It is analogous to having >> about 40% maximum modulation depth on an AM system. You can see this by >> looking at FM sideband theory. >> >> You also lose more & more of the FM advantages: Capture ratio & AM >> rejection (nothing personal meant here!), ultimate signal to noise ratio, >> distortion at low CNR's, get sloppier squelch action. >> >> Lest you disbelieve this, the new, even-narrower +-2.5 kHz FM systems >> need to use "companding" audio processing to get SNR's back to useable >> levels! This does not work well at low SNR's. IMO, this is NOT progress. >> >> And for all the talk about all repeater pairs being filled, ha! Just >> listen to repeaters anywhere, even in vy built up places, e.g. New York >> City: there's a deafening silence! All are evidently texting, >> twittering, and yakking on cell phones. >> >> I challenge someone to program a PC tied to a scanner to log actual >> on-times for all the repeaters in an area. This was done in NYC in the >> mid-70's; I was very surprised at the results: very low utilization! >> >> Could this be a genuine non-problem? A solution in search of a >> (non-existent) problem? >> >> Pepper the ARRL with comments, they're supposed to be listening. >> >> --John WB0EQ >> >> >> >> > > > -------------------------------------------------------------------------------- > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.113/2399 - Release Date: > 09/27/09 17:52:00 > ------------------------------ Message-ID: <004701ca407e$78ed1220$749b67d0@philkq3u7bu4ay> From: "PHIL" To: Old Tube Radios Subject: Re:fasten your seatbelts-ARRL Date: Mon, 28 Sep 2009 15:58:45 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit I agree with you. But you have to make known to the ARRL your thoughts. I plan to Phil ____________________________________________________________ Best Weight Loss Program - Click Here! http://thirdpartyoffers.netzero.net/TGL2241/fc/BLSrjpYSwrDUdILZpbJCG5dLbl35N341DTSWAzFOipgo3wyCIQwOE6PA1CA/ ------------------------------ Message-ID: <000d01ca4080$0f373bb0$749b67d0@philkq3u7bu4ay> From: "PHIL" To: Old Tube Radios Subject: Re:fasten your seatbelts-ARRL Date: Mon, 28 Sep 2009 16:10:07 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit There, have just sent an e-mail to the ARRL about reducing FM bandwidth. You people should really do the same Phil ____________________________________________________________ Click here for great quotes from top international movers! http://thirdpartyoffers.netzero.net/TGL2241/fc/BLSrjpYZJC1rklSub6AdKfQhb1U8ebfBt0ZNjcTmQpyJw1tAcxvtAFg6ges/ ------------------------------ From: "Ed Zeranski" To: Old Tube Radios Subject: RE: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 16:41:05 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Subject: Re: Fasten your seatbelts - ARRL Notice aeronautical VHF/UHF radio continues to hang on to "AM". There must be a reason. (It's simple and it works?) They worried about FM 'capture'. 73 EdZ ------------------------------ Message-ID: From: "jim evans" To: Old Tube Radios Subject: reply - ARRL narrowband vs AMers Date: Mon, 28 Sep 2009 21:41:37 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit ----- Original Message ----- From: "Tom Frenaye" To: "jim evans" Cc: "k1twf" Sent: Monday, September 28, 2009 9:08 AM Subject: Re: Fw: BOATANCHORS digest 4288 - ARRL narrowband vs AMers > At 05:46 AM 9/28/2009, jim evans wrote: >>I thought you'd like to know what was posted for this in the Boatanchors >>reflector. > > Thanks Jim - > > It should be pretty obvious by the full text of the motion the board > passed that the intention is to deal with VHF+ FM, and not other modes (or > HF). > >>29. On motion of Mr. Sarratt, seconded by Mr. Frenaye, the following >>resolution was ADOPTED: >> >>WHEREAS, there is current substantial amateur radio movement, activity, >>and innovation in the digital narrowband area; and >> >>WHEREAS, the FCC has mandated that by 2013 commercial radio move to >>narrowband channels and Amateur Radio manufacturers normally follow >>commercial practices; and >> >>WHEREAS, the VHF/UHF Amateur Radio band plan currently uses 15 and 20 kHz >>FM channels; and >> >>WHEREAS, with the increasing use of narrowband across the country amateurs >>are placing and using narrowband equipment outside the repeater subband >>because there is no real place to fit the narrowband pairs; and >> >>WHEREAS, for ARRL to remain a respected leader in technology, we must be >>actively involved in innovative solutions to problems by bringing about a >>productive discussion on a technical paradigm shift; now >> >>THEREFORE, the President shall appoint a study committee for the purpose >>of research and to consider developing a plan to move the US amateur >>community to narrowband channel spacing. > > > 73 Tom > >>----- Original Message ----- From: "Old Tube Radios" >> >>To: "Old Tube Radios" >>Sent: Sunday, September 27, 2009 5:15 PM >>Subject: BOATANCHORS digest 4288 >> >> >>> BOATANCHORS Digest 4288 >> >>>Message-ID: <745323.70137.qm@web112616.mail.gq1.yahoo.com> >>>Date: Wed, 23 Sep 2009 19:53:06 -0700 (PDT) >>>From: "J.D. MacAulay, WQ8U" >>>Subject: Fasten your seatbelts - here we go for another ARRL ride >>>To: Old Tube Radios >>>MIME-Version: 1.0 >>>Content-Type: text/plain; charset=us-ascii >>> >>>The October 2009 QST magazine, page 64, reports the actions of the 2009 >>>second meeting of the ARRL Board. >>> >>>The Board approved the "establishment of a Study Committee to study, >>>research and consider developing a >>>PLAN TO MOVE THE US AMATEUR COMMUNITY TO NARROWBAND CHANNEL SPACING." >>>(Emphasis mine) >>> >>>One has to wonder who those folks really represent after their >>>performance with the frequency allocation by signal bandwidth push and >>>now this. >>> >>>Maybe all us AM Ops will be dead by the time their buracuracy gets >>>through all this process. - probably not though. >>> >>>Time to start writing to Newington? >>> >>>73 >>>Mac >>>WQ8U >>>Hillsborough, NC >>> >>>P.S. Don't forget the phone segment of the Classic Exchange "CX" is this >>>Sunday. >>>M >>> >>>snip> >> > > ===== > e-mail: k1ki@arrl.org ARRL New England Division Director > http://www.arrl.org/ > Tom Frenaye, K1KI, P O Box J, West Suffield CT 06093 Phone: 860-668-5444 > > > ------------------------------ Message-ID: <005601ca40aa$92da52c0$a99d480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 18:55:33 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > ....As I favour CW (NOT a digital mode, IMHO - doesn't need a computer), ...... I never thought of CW as being digital either. My fist has five digits, not two. Has anyone come up with a five state device yet? Arden Allen KB6NAX Adopt a shelter dog, save an innocent life, and make a friend forever =:-) ------------------------------ Message-ID: <005801ca40aa$94e7fd10$a99d480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 19:13:37 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > It's a safety issue, learned through experiance. .... FM also suffers from phase modulation by propeller reflections. Not a problem with wooden props ;-) Transoceanic HF aeronautical communications switched to SSB years ago. It's like having a bunch of controllers from around the world sitting in one room. They seldom all talk at once being very a very safety minded lot ;-) Arden Allen KB6NAX Adopt a shelter dog, save an innocent life, and make a friend forever =:-) ------------------------------ Message-ID: From: "Robert Lawson" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 21:39:52 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Oh yes CW is an original digital mode, and when done by hand (fist) it's encoding and decoding device is one of the miracles of this Universe. The human brain. Now for the matter of whether or not it is a 16, 32, or 64 bit device, I have no idea and I don't seek to know. I do know that it is precious to each and every one of us. For those of us who have had it become temporarily impaired or God forbid not temporarily, we know it is the most perfect 'computer' ever designed which strives to live through adapting. No man made computer can do that now or anytime in the future. Remember it built the computer I use today in writing this email. Robert W4RL Pensacola FL ----- Original Message ----- From: "Arden Allen" To: "Old Tube Radios" Sent: Monday, September 28, 2009 8:55 PM Subject: Re: Fasten your seatbelts - ARRL >> ....As I favour CW (NOT a digital mode, IMHO - doesn't need a computer), > ...... > > I never thought of CW as being digital either. My fist has five digits, > not > two. Has anyone come up with a five state device yet? > > Arden Allen > KB6NAX > > Adopt a shelter dog, > save an innocent life, > and make a friend forever =:-) > ------------------------------ Message-ID: From: "Robert Lawson" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 21:40:39 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Oh yes CW is an original digital mode, and when done with the hand it's encoding and decoding device is one of the miracles of this Universe. The human brain. Now for the matter of whether or not it is a 16, 32, or 64 bit device, I have no idea and I don't seek to know. I do know that it is precious to each and every one of us. For those of us who have had it become temporarily impaired or God forbid not temporarily, we know it is the most perfect 'computer' ever designed which strives to live through adapting. No man made computer can do that now or anytime in the future. Remember it built the computer I use today in writing this email. Robert W4RL Pensacola FL ----- Original Message ----- From: "Arden Allen" To: "Old Tube Radios" Sent: Monday, September 28, 2009 8:55 PM Subject: Re: Fasten your seatbelts - ARRL >> ....As I favour CW (NOT a digital mode, IMHO - doesn't need a computer), > ...... > > I never thought of CW as being digital either. My fist has five digits, > not > two. Has anyone come up with a five state device yet? > > Arden Allen > KB6NAX > > Adopt a shelter dog, > save an innocent life, > and make a friend forever =:-) > ------------------------------ Message-ID: <4332D0A0A5404853A3A2EBC21F5BF955@gateway> From: "Sandy" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Mon, 28 Sep 2009 21:43:36 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit I was always told FM would add undesirable effects to aeronautical communication. The MAIN argument though is still: If it works, DON'T "FIX" IT! It is rather stupid to add complications to a system that is already satisfactory ad working well. Some "expert" I taked to one day many years ago, said the aeronautical folks were leary of "new" "Oh my gosh!" systems until they have been in service for a while and are thoroly tested and proven reliable. The "it's simple and it works" was the hallmark of why they kept AM for so long. 73, Sandy W5TVW ----- Original Message ----- From: "David Stinson" To: "Old Tube Radios" Sent: Monday, September 28, 2009 12:46 PM Subject: Re: Fasten your seatbelts - ARRL > > ----- Original Message ----- > From: "Sandy" > Subject: Re: Fasten your seatbelts - ARRL > > >> Notice aeronautical VHF/UHF radio continues to hang on to "AM". There >> must be a reason. (It's simple and it works?) > > It's a safety issue, learned through experiance. > AM does not have the "capture effect" of FM; if someone transmits at > the same time as someone else, the controller will hear the beat note > from the mixing of the two carriers and know someone else > is trying to transmit. If the two signals do happen to be spot-on freq, > he'll hear both calls. Also- if someone's mike is "stuck," blanketing > the channel with a strong carrier, FM signals have little chance of being > understood, while an AM signal does have a better-than-even chance. > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.409 / Virus Database: 270.13.113/2400 - Release Date: 09/28/09 05:51:00 ------------------------------ Message-ID: <1780371A05984001B223120399112BAE@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Re: Fasten your seatbelts - ARRL Date: Tue, 29 Sep 2009 05:31:18 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit ----- Original Message ----- From: "Sandy" Subject: Re: Fasten your seatbelts - ARRL > The "it's simple and it works" was the hallmark of why they kept AM for so > long. When someone reminds me of the latests "gee-whiz" bit of massively computer-or-network-dependant gadgetry, with its thousands of possible failure modes (every wire connection in the network, for instance), I remind them of my favorite line from my favorite fictional character, "Scotty," the miracle-working engineer of "Star Trek." It is a "guiding light" to me in matters technical: Star Fleet had just built the most technically advanced, "gee-whizzy" ship in history, and was going to chase our heros with it. Scotty got aboard and disabled this futuristic Titanic by removing a small handful of little parts. When asked by Dr. McCoy how he did it, Scotty gave the parts to the Doctor and said: "...from one surgeon to another. The more complicated they make the plumbing, the easier it is to stop-up the drain." 73 Dave S. ------------------------------ End of BOATANCHORS Digest 4289 ******************************