Re: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit
Adding up the bell labs recommendation is 3300 KHz plus 3300 KHz or 6.6 KHZ total. Just because you roll off the 0 to 300 range doesn't make the signal narrower bandwidth. So 6KHz is narrower and 7 KHz is more normaL. Of Course, AM transmitters do not have 2.7 or 3.1 KHz filters to limit bandwidth as on SSB transmitters. So 7 to 8 KHz is normal AM transmission bandwidth. Of course the ARRL would not be agreeing to the 6 KHZ suggested by the international organization because the Directors have told us so. Those using clipping circuits should have an audio filter following the clipper to reduce the clipping "noise" not needed for communications. I find that most of the broad signals I hear on "modern" solid state receivers is generated with in the receiver in the noise limiters and other limiting circuits as I don't copy the same broadness of the signal on my 75S3. The Amers got kicked in the pants with the 1500 watt peak power limit probably due to the same faulty technical understanding by those making the decisions. Like having a Extra Class license these days doesn't mean you have an understanding of theory and applications, an engineering degree today doesn't either. With AM the average power due to voice characteristics is only about 20 to 30 percent of the total output power of the amplifier added to the carrier. Not 4 times the carrier output which is only on peaks.So a 375 watt carrier on average is only 490 to 500 watts output. What would be effective perhaps is to limit the audio bandwidth with filters, use compression of 10 to 20 percent and boost the averge output in the final or with a driver then amplifing with a linear that can boost the signal to a higher average output. Or use a properly adjusted controlled carrier modulated driver for the linear so the resting carrier is say 125 to 150 watts and on average will put out 450 to 500 watts and sound like it is much more power. Don W4BWS - Original Message - From: "D. Chester" <[EMAIL PROTECTED]> To: Sent: Thursday, April 17, 2008 1:22 PM Subject: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit On p. 64 of the May issue, the anonymous writer of the monthly Q-A "Workbench" column in QST entitled "The Doctor is In", responds to a report by the coordinator of the ARRL OO program regarding "wide AM signals with bandwidths of up to 30 kHz on 75 m." SNIP He briefly explains the relationship between signal bandwidth and the frequency response of the audio that modulates SSB and AM transmitters, then states that Bell Labs concluded many years ago that high quality voice transmission (toll quality in telco terminology) can be carried over a 300-3300 Hz frequency response, but that "This worked better for the grey-haired Bell scientists who were likely to have lost some of their high frequency hearing". He goes on to allege that an AM signal occupies "a bit more spectrum" than two SSB signals, based on the notion that there is no need to transmit audio frequency components of the voice that fall below 300 Hz, and that the "usual approach" with SSB is to transmit frequencies from 300 to 2700 Hz. He then cites §97.307 of the FCC rules that states "No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice." Since voice is what is being transmitted, he suggests that the rules require AM to occupy a bandwidth of "no more than about 6 kHz. __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Harris AM-80 AM modulation monitor manual needed
Does anyone out there have a copy of the Harris AM modulation monitor manual available for copy or download? I have a AM-80 and it is need of repair! Thanks for the bandwidth, Frank, W9FM __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit
I just don't get it. It has been many years since I have seen a crowded band but who knows what the next sun spot cycle may bring! Beside's Don, I have checked your bandwidth many times and found you to be very close to the so called desired width of +/- 3300 Hz. I can't say with any accuracy of course, but I have twisted the knob on the XTAL filter to a narrow width, not very comfortable with CW even, and found your shots to be very few and far between and weak out beyond 3.5KHZ. Not that they are not occasionally there but another signal similar to yours could easily be copied with a carrier just 5KHZ higher or lower than yours just by using the phasing control a little. What is it that makes certain folks so hateful? Let's talk about hate. I hate those head lights with the extended blue range. One glance at one of those and I see spots. What have I got to do, get a windshield with a high end filter that rolls off the blues? I think there could be a song in there somewhere. "Dem Headlites Dat Gime Da Blues" John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of D. Chester Sent: Thursday, April 17, 2008 1:22 PM To: amradio@mailman.qth.net Subject: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit On p. 64 of the May issue, the anonymous writer of the monthly Q-A "Workbench" column in QST entitled "The Doctor is In", responds to a report by the coordinator of the ARRL OO program regarding "wide AM signals with bandwidths of up to 30 kHz on 75 m." He briefly explains the relationship between signal bandwidth and the frequency response of the audio that modulates SSB and AM transmitters, then states that Bell Labs concluded many years ago that high quality voice transmission (toll quality in telco terminology) can be carried over a 300-3300 Hz frequency response, but that "This worked better for the grey-haired Bell scientists who were likely to have lost some of their high frequency hearing". He goes on to allege that an AM signal occupies "a bit more spectrum" than two SSB signals, based on the notion that there is no need to transmit audio frequency components of the voice that fall below 300 Hz, and that the "usual approach" with SSB is to transmit frequencies from 300 to 2700 Hz. He then cites §97.307 of the FCC rules that states "No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice." Since voice is what is being transmitted, he suggests that the rules require AM to occupy a bandwidth of "no more than about 6 kHz". __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit
I just don't get it. It has been many years since I have seen a crowded band but who knows what the next sun spot cycle may bring! Beside's Don, I have checked your bandwidth many times and found you to be very close to the so called desired width of +/- 3300 Hz. I can't say with any accuracy of course, but I have twisted the knob on the XTAL filter to a narrow width, not very comfortable with CW even, and found your shots to be very few and far between and weak out beyond 3.5KHZ. Not that they are not occasionally there but another signal similar to yours could easily be copied with a carrier just 5KHZ higher or lower than yours just by using the phasing control a little. What is it that makes certain folks so hateful? Let's talk about hate. I hate those head lights with the extended blue range. One glance at one of those and I see spots. What have I got to do get a windshield with a high end filter that rolls off the blues? I think there could be a song in there somewhere. "Them Headlights That Gime da Blues" John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of D. Chester Sent: Thursday, April 17, 2008 1:22 PM To: amradio@mailman.qth.net Subject: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHzAM Bandwidth Limit On p. 64 of the May issue, the anonymous writer of the monthly Q-A "Workbench" column in QST entitled "The Doctor is In", responds to a report by the coordinator of the ARRL OO program regarding "wide AM signals with bandwidths of up to 30 kHz on 75 m." He briefly explains the relationship between signal bandwidth and the frequency response of the audio that modulates SSB and AM transmitters, then states that Bell Labs concluded many years ago that high quality voice transmission (toll quality in telco terminology) can be carried over a 300-3300 Hz frequency response, but that "This worked better for the grey-haired Bell scientists who were likely to have lost some of their high frequency hearing". He goes on to allege that an AM signal occupies "a bit more spectrum" than two SSB signals, based on the notion that there is no need to transmit audio frequency components of the voice that fall below 300 Hz, and that the "usual approach" with SSB is to transmit frequencies from 300 to 2700 Hz. He then cites §97.307 of the FCC rules that states "No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice." Since voice is what is being transmitted, he suggests that the rules require AM to occupy a bandwidth of "no more than about 6 kHz". __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Harris AM-80 AM modulation monitor manual needed
Does anyone out there have a copy of the Harris AM modulation monitor available for copy or download? I have a AM-80 and it is need of repair! Thanks for the bandwidth, Frank, W9FM __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] The QST Doctor
WB8IMY is his call.I think he is taking his cue from old Johnny Johnston, W3BE(ex-K3BNS) the AM-hater who is now retired from the FCC. Joe W4AAB - Original Message - From: "Mike Duke, K5XU" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" Sent: Thursday, April 17, 2008 4:52 PM Subject: [AMRadio] The QST Doctor While the ARRL will deny it, scuttlebutt has it that the Doctor is Steve Ford, the QST Editor. Mike Duke, K5XU American Council of Blind Radio Amateurs __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] The QST Doctor
While the ARRL will deny it, scuttlebutt has it that the Doctor is Steve Ford, the QST Editor. Mike Duke, K5XU American Council of Blind Radio Amateurs __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHz AM Bandwidth Limit
It says, "...for the information rate and emission type..." The emission type is AM and I see no bandwidth problem...what ever it is! It's an AMATEUR mode in a HOBBY service. Let's all have fun out there! Dino - K6RIX [EMAIL PROTECTED] - He then cites §97.307 of the FCC rules that states "No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice." Since voice is what is being transmitted, he suggests that the rules require AM to occupy a bandwidth of "no more than about 6 kHz". __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Anonymous QST Author suggests that Part 97 requires 6 kHz AM Bandwidth Limit
On p. 64 of the May issue, the anonymous writer of the monthly Q-A "Workbench" column in QST entitled "The Doctor is In", responds to a report by the coordinator of the ARRL OO program regarding "wide AM signals with bandwidths of up to 30 kHz on 75 m." He briefly explains the relationship between signal bandwidth and the frequency response of the audio that modulates SSB and AM transmitters, then states that Bell Labs concluded many years ago that high quality voice transmission (toll quality in telco terminology) can be carried over a 300-3300 Hz frequency response, but that "This worked better for the grey-haired Bell scientists who were likely to have lost some of their high frequency hearing". He goes on to allege that an AM signal occupies "a bit more spectrum" than two SSB signals, based on the notion that there is no need to transmit audio frequency components of the voice that fall below 300 Hz, and that the "usual approach" with SSB is to transmit frequencies from 300 to 2700 Hz. He then cites §97.307 of the FCC rules that states "No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice." Since voice is what is being transmitted, he suggests that the rules require AM to occupy a bandwidth of "no more than about 6 kHz". __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Re: Collins 20V 1KW AM TX
I can't practically have a 1200 pound 1KW AM Broadcast Transmitter here in CA. So, I am not moving the 20V from Texas to CA. I'm putting it up for sale for pick up in Dallas. The 20V is tuned to 75 meters. It has a Digital VFO mounted inside, a High Power internal TX/RX Antenna Relay, 12 VDC PTT circuitry, 12 VDC low voltage power supply for VFO and PTT circuits, a Collins 1KW RF Power meter instead of the RF Ammeter, a 20V-2 modulator chassis, a 20V-2 upgraded low voltage power supply and HV rectifier, a 20V-2 chain drive TUNE and LOAD Control, spare HV rectifier tubes, and a dolly to sit on. All it needs is a Line Level audio feed, antenna, and a receiver. It has been given a complete body shop make over and the paint and cabinet are perfect. I have $3700 in it. I also have a 212F-1 audio console I can be talked out of, if and ony if, you buy the 20V. You can see pictures at http://zilliox.net/20V Note: some people had to manually type this web address into their browser to see the pictures. You can contact me on my cellular: (214) 212-0979 or email. 73, Pete Zilliox, K5PZ/6 __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
