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SSB Antennas
Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded
the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? |
SSB Antennas
In article ,
"Vito" wrote: Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? Most noncommercial boaters do not have the expertiese to understand, let alone install, what you are describing. Most commercial vessels have enough Mast Height to accommodate a "Total Antenna Length" of 75 ft so that common autotuners can resonate the system to 2182 Khz. On SOLAS Required Vessels MF and HF Antenna Systems are designed to be resonate on all the specific SOLAS Required Frequencies and are TESTED and Logged once a year by Licensed Marine Radio Tech's. Bruce in alaska -- add a 2 before @ |
SSB Antennas
Not familiar with a Marine Radio Tech License? I have a GROL
with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista "Bruce in Alaska" wrote in message ... In article , "Vito" wrote: Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? Most noncommercial boaters do not have the expertiese to understand, let alone install, what you are describing. Most commercial vessels have enough Mast Height to accommodate a "Total Antenna Length" of 75 ft so that common autotuners can resonate the system to 2182 Khz. On SOLAS Required Vessels MF and HF Antenna Systems are designed to be resonate on all the specific SOLAS Required Frequencies and are TESTED and Logged once a year by Licensed Marine Radio Tech's. Bruce in alaska -- add a 2 before @ |
SSB Antennas
On Thu, 29 Jan 2004 16:16:41 -0500, "Doug Dotson"
wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista You got it, Doug. Did you have 1st Phone before the shame of the GROL was thrust upon you? I keep my 1st Phone with Radar in a frame over my desk. I keep my GROL in the back of the file cabinet so noone can see I have a CB license...(c; You had to KNOW something to pass the 1st Phone, not just memorize the test questions handed to you on a silver platter......It meant something. I added GMDSS maintainer and operator, but that was just a rote memorizer test any fool who can read could pass, like the GROL..... I actually cheated on the GMDSS tests. I'm a Dale Carnegie graduate. DC teaches you how to memorize a whole magazine by associating each page with a visualization. It was the most important thing I got out of the course. One - Run Two - Zoo Three - Tree Four - Door Five - Hive Six - Sticks Seven - Heaven Eight - Grate Nine - Wine Ten - Den I can still hear my instructor harping the first 100 visualizations on us...(c; It's how I remembered the answers to the question bank, which is easy after you memorize the ad on page 49 of National Review for DC class. Larry W4CSC Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! |
SSB Antennas
I found that learning the underlying theory was alot easier than
memorizing the test bank. Good way to learn things as well. My father has a 1st Phone. He's probably almost as old as you ;) Unfortunately, they no longer issue the nice certificate to frame and hang on the wall. Just the same wallet sized license as the ham license. DOug, k3qt s/v Callista "Larry W4CSC" wrote in message ... On Thu, 29 Jan 2004 16:16:41 -0500, "Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista You got it, Doug. Did you have 1st Phone before the shame of the GROL was thrust upon you? I keep my 1st Phone with Radar in a frame over my desk. I keep my GROL in the back of the file cabinet so noone can see I have a CB license...(c; You had to KNOW something to pass the 1st Phone, not just memorize the test questions handed to you on a silver platter......It meant something. I added GMDSS maintainer and operator, but that was just a rote memorizer test any fool who can read could pass, like the GROL..... I actually cheated on the GMDSS tests. I'm a Dale Carnegie graduate. DC teaches you how to memorize a whole magazine by associating each page with a visualization. It was the most important thing I got out of the course. One - Run Two - Zoo Three - Tree Four - Door Five - Hive Six - Sticks Seven - Heaven Eight - Grate Nine - Wine Ten - Den I can still hear my instructor harping the first 100 visualizations on us...(c; It's how I remembered the answers to the question bank, which is easy after you memorize the ad on page 49 of National Review for DC class. Larry W4CSC Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! |
SSB Antennas
On Thu, 29 Jan 2004 21:27:10 -0500, "Doug Dotson"
wrote: I found that learning the underlying theory was alot easier than memorizing the test bank. Good way to learn things as well. My father has a 1st Phone. He's probably almost as old as you ;) Unfortunately, they no longer issue the nice certificate to frame and hang on the wall. Just the same wallet sized license as the ham license. DOug, k3qt s/v Callista A small GROL is easier to hide than a large one.....(c; Larry W4CSC Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! |
SSB Antennas
I guess as we grow older the fact that some of our past
accomplishments are deemed obsolete is hard to accept. "Larry W4CSC" wrote in message ... On Thu, 29 Jan 2004 21:27:10 -0500, "Doug Dotson" wrote: I found that learning the underlying theory was alot easier than memorizing the test bank. Good way to learn things as well. My father has a 1st Phone. He's probably almost as old as you ;) Unfortunately, they no longer issue the nice certificate to frame and hang on the wall. Just the same wallet sized license as the ham license. DOug, k3qt s/v Callista A small GROL is easier to hide than a large one.....(c; Larry W4CSC Is it just me or did the US and UK just capture 1/3 of the world's sweetest oil supply? What idiot wants to GIVE IT BACK?!! |
SSB Antennas
On Thu, 29 Jan 2004 23:16:29 -0500, "Doug Dotson"
wrote: I guess as we grow older the fact that some of our past accomplishments are deemed obsolete is hard to accept. A real 1st Phone license, now expired, will get you a job at any broadcast station with an opening. It's a badge of accomplishment and knowledge that had to be worked for. Licenses aren't required, any more, at broadcast stations. FCC threatened to not renew station licenses of broadcasters who didn't have the required number of black transmitter operators, many years back. Broadcasters pointed out that the number of black operators was miniscule because of the 1st and 2nd Class license requirements. They simply weren't available. So, in typical politically-correct government fashion, FCC reduced the test to GROL and tried again. Failing to license the required black licensees of the much-simpler testing, FCC eliminated the license and testing requirements for broadcast transmitter operators to try to get the numbers up. It still hasn't worked and FCC stopped threatening the broadcasters soon after. "Griff", a black engineer at WCSC-TV, gets offers every month from stations not in compliance. He'll never be out of a job. Being black AND competent is a very valuable asset, indeed. The only thing the GROL is useful for, now, is marine and aviation radio. The only reason it's still in existence is the ITU requires it. Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
Yes the top hat would help out on 2 and 4 mhz frequencies. Problem is
where to put it where it is not in the way. A loading coil on the stay would also help out but it would work even better if it was up high nearer to the top of the stay. Problem is that usually only one antenna is available for all bands on a boat. At the higher frequencies that loading coil would act as a choke and effectively disconnect the upper portion of the antenna. Which may not be all that bad if there is sufficient length below the coil for the higher frequencies. The other problem that you may run into is that the auto tuner may not like the impedance it sees. Most auto tuners do not like to see a resonant antenna near 50 ohms. But on 2 mhz it would probably help a lot. Regards Gary On Thu, 29 Jan 2004 12:20:07 -0500, "Vito" wrote: Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? |
SSB Antennas
Funny, it is my impression that the reason that a licensed
engineer is no longer required at broadcast stations is that the transmitters are pretty much automated and self controlled by their computer. At least the one I am aware of is. I believe it is connected via the net to a control center that monitors many transmitters and dispatches licensed techs if any anomalies are detected. I got my GROL etc specifically to work with marine systems so it was worth it in my case. I have no interest in comercial broadcast stations. Doug, k3qt s/v Callista "Larry W4CSC" wrote in message ... On Thu, 29 Jan 2004 23:16:29 -0500, "Doug Dotson" wrote: I guess as we grow older the fact that some of our past accomplishments are deemed obsolete is hard to accept. A real 1st Phone license, now expired, will get you a job at any broadcast station with an opening. It's a badge of accomplishment and knowledge that had to be worked for. Licenses aren't required, any more, at broadcast stations. FCC threatened to not renew station licenses of broadcasters who didn't have the required number of black transmitter operators, many years back. Broadcasters pointed out that the number of black operators was miniscule because of the 1st and 2nd Class license requirements. They simply weren't available. So, in typical politically-correct government fashion, FCC reduced the test to GROL and tried again. Failing to license the required black licensees of the much-simpler testing, FCC eliminated the license and testing requirements for broadcast transmitter operators to try to get the numbers up. It still hasn't worked and FCC stopped threatening the broadcasters soon after. "Griff", a black engineer at WCSC-TV, gets offers every month from stations not in compliance. He'll never be out of a job. Being black AND competent is a very valuable asset, indeed. The only thing the GROL is useful for, now, is marine and aviation radio. The only reason it's still in existence is the ITU requires it. Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
In article ,
"Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista Licensed Marine Radio Tech is a person who has an FCC GROL/w RADAR/GMDSS-M and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels. The SOLAS Requires that Title III Part II, and title III Part I Vessels be inspected on an annual basis and that inspection by a Licensed Marine Radio Tech, be logged in the Vessel Station Log and a renewed SOLAS Certificate be Issued and Posted for Public Inspection. In the passed, these inspections were done by FCC Field Agents, and the SOLAS Certificates, Bridge to Bridge RadioTelephone Certificates, were issued by the FCC Field Agents, on completion of the inspection. A similar inspection of Title IIi Part IIi Vessels needs to be completed every 5 years for those class vessels, and is done, now, through the same method. Bruce in alaska -- add a 2 before @ |
SSB Antennas
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SSB Antennas
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SSB Antennas
In article ,
"Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. Knowledgable Tech's recomeended but not even required. That's why I got out of the Broadcast Business 35 years ago. To many Carneigie, and Elkins, First Phone's showing up, and getting OTJ Training on my license as Chief Engineer. There's no such thing as an Automated 50,000 Watt AM Transmitter. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. Bruce in alaska -- add a 2 before @ |
SSB Antennas
On Fri, 30 Jan 2004 21:07:52 GMT, Bruce in Alaska
wrote: In article , (Larry W4CSC) wrote: The only thing the GROL is useful for, now, is marine and aviation radio. The only reason it's still in existence is the ITU requires it. Larry W4CSC Yep, every CB nut with a screwdriver can now fiddle with any Land Mobile Radio, Broadcast Transmitter, Microwave System, and Public Safety Radio System, in the country. And folks wonder why interference complaints are doubleing every three years. Just follow the money.....(c; Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
"Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. I misstated my thought. I mean't "qualified techs" since a license is no longer required. The question was as to the reason that a license is no longer required. Larry seems to suggest that it is because very few blacks are able to get a 1st Phone. My recollection is that it is because detailed technical knowledge is not required to safely and legally operate a transmitter these days. There's no such thing as an Automated 50,000 Watt AM Transmitter. Maybe up in Alaska. But I'm pretty sure that is not the case in general. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. My years in the process control industry make me pretty confident that the computer can sense and react to pretty much anything unusual faster than the most skilled engineer/tech. Not to say that an on-site person is not an asset because once the computer has either shut things down or reduced power to save the transmitter, someone has to diagnose and fixed the problem. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. A good SCADA system should have sensed the impending problem and may have been able to save the day. But, as you say, some failures are so sudden that there is no way out. Bruce in alaska -- add a 2 before @ |
SSB Antennas
"Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista Licensed Marine Radio Tech is a person who has an FCC GROL/w RADAR/GMDSS-M and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels. Then I guess I R 1. But what is the second part of your statement? The part that reads "and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels"? What is this license? Who issues it? The SOLAS Requires that Title III Part II, and title III Part I Vessels be inspected on an annual basis and that inspection by a Licensed Marine Radio Tech, be logged in the Vessel Station Log and a renewed SOLAS Certificate be Issued and Posted for Public Inspection. In the passed, these inspections were done by FCC Field Agents, and the SOLAS Certificates, Bridge to Bridge RadioTelephone Certificates, were issued by the FCC Field Agents, on completion of the inspection. A similar inspection of Title IIi Part IIi Vessels needs to be completed every 5 years for those class vessels, and is done, now, through the same method. I remember all the mumbo-jumbo from the GMDSS license. So is the GMDSS/M license what makes one all of these fancy titles or is there some other authority that grants these lofty titles. Bruce in alaska -- add a 2 before @ |
SSB Antennas
On Fri, 30 Jan 2004 00:43:14 GMT, Larry W4CSC wrote:
On Thu, 29 Jan 2004 16:16:41 -0500, "Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista You got it, Doug. Did you have 1st Phone before the shame of the GROL was thrust upon you? I keep my 1st Phone with Radar in a frame over my desk. I keep my GROL in the back of the file cabinet so noone can see I have a CB license...(c; You had to KNOW something to pass the 1st Phone, not just memorize the test questions handed to you on a silver platter......It meant something. I had a 1st as well, but frankly thought the 2d was a good deal harder. If nothing else, it was a lot longer! I recall the 1st was 50 questions (and it seems like it was mostly law) and the 2d was 200 questions. I passed them both, but I recall spending a long time on the 2d. Never did the GMDSS/M or radar. I thought that after the FCC went to General Commercial that NABER or someone like that handled endorsements for a while, but then they gave that up. Do you remember what happened to that stuff? -- Larry W1HJF email is rapp at lmr dot com |
SSB Antennas
Er, ah, Bruce? There are no "finals" any more. The 50KW transmitter
is just a switching power supply from Harris.....take a look at: http://www.geocities.com/aaron_white/inside.html It's all done by that big board switching the modules on and off at the audio rate, in sequence. See those two little powertab transistors on the copper heat sink? THOSE ARE THE FINALS! If a module fails, the computer simply bypasses it and uses another module (there are spares) until someone shows up at the transmitter to look for the failure lights. They don't even shut down the transmitter to swap them out, any more. Hot swaps just like a computer...(c; The two PC boards on the door are the "modulator", the drivers for the modules creating the RF. It's so efficient it's cooled with small FANS! To produce a 50,000 watt carrier, it requires only 55,000 watts of AC power from the power company, not the 120KW we were accustomed to. No massive filament power, no blood-red plates being cooled with water, no cooling pond. The RF modules (there are 144 of them in a Harris DX-50, 50KW transmitter) look like: http://www.geocities.com/aaron_white/dxmod.html Some are 100W, 500W, 1KW, 2KW. The audio is simply converted into how many modules run at this instant in time. The modules, themselves are switching on and off at the carrier rate. The output filter takes out the 3rd harmonic caused by the square wave switching up. Nothing analog to make heat. It's a RF synthesized sinewave just like your boat inverter. You'll be glad to know from the Harris out it's still RF....(c; Here's the ATU at WFAN: http://www.geocities.com/aaron_white/atu1.html 75KW dummy load: http://www.geocities.com/aaron_white/load.html 50KW isn't what it used to be...(sigh). http://www.geocities.com/aaron_white/maintx.html The modulator and final are inside the right doors. The other end is the power supply. Kinda a non-event unless the RF output flashes over, which my friends in broadcasting says is also a non-event for the digital transmitter. It simply clears it, resets and tries again. If it continues to flash over, the transmitter comes up in low power (10KW) until the techies show up..... The computer that operates the transmitter is in that rack to the left of the Harris at WFAN. The whole thing is in a corner of the transmitter shack which is mostly taken up by the darkened old 50KW monster you're thinking about. Tom Ray, Director of Engineering over at WOR in NYC, sent me some cool pictures of their IBOC Digital AM experiments on their Harris DX-50. If you listen to WOR or WLW's IBOC on a regular AM radio you hear a faint hissing sound that is the digital subcarriers. The two stations, 10 Khz apart, are experimenting with interference caused by the IBOC carriers. Most interesting.....AM that sounds like mono-FM but at great distances. On Fri, 30 Jan 2004 21:20:46 GMT, Bruce in Alaska wrote: In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. Knowledgable Tech's recomeended but not even required. That's why I got out of the Broadcast Business 35 years ago. To many Carneigie, and Elkins, First Phone's showing up, and getting OTJ Training on my license as Chief Engineer. There's no such thing as an Automated 50,000 Watt AM Transmitter. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. Bruce in alaska -- add a 2 before @ Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
Thanks for the clarification Larry. I was pretty sure that modern
transmitter technology wasn't something I had in a dream. I was up in Fairbanks a couple years ago and I suspect that keeping the finals cool isn't much of a problem there :) My father was the engineer for a UHF station back in the late 50's. He told stories of having to run out and get bottles of Nitrogen to keep the finals going. Life is much simpler now. Doug, k3qt s/v Callista "Larry W4CSC" wrote in message ... Er, ah, Bruce? There are no "finals" any more. The 50KW transmitter is just a switching power supply from Harris.....take a look at: http://www.geocities.com/aaron_white/inside.html It's all done by that big board switching the modules on and off at the audio rate, in sequence. See those two little powertab transistors on the copper heat sink? THOSE ARE THE FINALS! If a module fails, the computer simply bypasses it and uses another module (there are spares) until someone shows up at the transmitter to look for the failure lights. They don't even shut down the transmitter to swap them out, any more. Hot swaps just like a computer...(c; The two PC boards on the door are the "modulator", the drivers for the modules creating the RF. It's so efficient it's cooled with small FANS! To produce a 50,000 watt carrier, it requires only 55,000 watts of AC power from the power company, not the 120KW we were accustomed to. No massive filament power, no blood-red plates being cooled with water, no cooling pond. The RF modules (there are 144 of them in a Harris DX-50, 50KW transmitter) look like: http://www.geocities.com/aaron_white/dxmod.html Some are 100W, 500W, 1KW, 2KW. The audio is simply converted into how many modules run at this instant in time. The modules, themselves are switching on and off at the carrier rate. The output filter takes out the 3rd harmonic caused by the square wave switching up. Nothing analog to make heat. It's a RF synthesized sinewave just like your boat inverter. You'll be glad to know from the Harris out it's still RF....(c; Here's the ATU at WFAN: http://www.geocities.com/aaron_white/atu1.html 75KW dummy load: http://www.geocities.com/aaron_white/load.html 50KW isn't what it used to be...(sigh). http://www.geocities.com/aaron_white/maintx.html The modulator and final are inside the right doors. The other end is the power supply. Kinda a non-event unless the RF output flashes over, which my friends in broadcasting says is also a non-event for the digital transmitter. It simply clears it, resets and tries again. If it continues to flash over, the transmitter comes up in low power (10KW) until the techies show up..... The computer that operates the transmitter is in that rack to the left of the Harris at WFAN. The whole thing is in a corner of the transmitter shack which is mostly taken up by the darkened old 50KW monster you're thinking about. Tom Ray, Director of Engineering over at WOR in NYC, sent me some cool pictures of their IBOC Digital AM experiments on their Harris DX-50. If you listen to WOR or WLW's IBOC on a regular AM radio you hear a faint hissing sound that is the digital subcarriers. The two stations, 10 Khz apart, are experimenting with interference caused by the IBOC carriers. Most interesting.....AM that sounds like mono-FM but at great distances. On Fri, 30 Jan 2004 21:20:46 GMT, Bruce in Alaska wrote: In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. Knowledgable Tech's recomeended but not even required. That's why I got out of the Broadcast Business 35 years ago. To many Carneigie, and Elkins, First Phone's showing up, and getting OTJ Training on my license as Chief Engineer. There's no such thing as an Automated 50,000 Watt AM Transmitter. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. Bruce in alaska -- add a 2 before @ Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
The nitrogen was for the transmission line.
Regards Gary On Fri, 30 Jan 2004 22:03:22 -0500, "Doug Dotson" wrote: Thanks for the clarification Larry. I was pretty sure that modern transmitter technology wasn't something I had in a dream. I was up in Fairbanks a couple years ago and I suspect that keeping the finals cool isn't much of a problem there :) My father was the engineer for a UHF station back in the late 50's. He told stories of having to run out and get bottles of Nitrogen to keep the finals going. Life is much simpler now. Doug, k3qt s/v Callista "Larry W4CSC" wrote in message ... Er, ah, Bruce? There are no "finals" any more. The 50KW transmitter is just a switching power supply from Harris.....take a look at: http://www.geocities.com/aaron_white/inside.html It's all done by that big board switching the modules on and off at the audio rate, in sequence. See those two little powertab transistors on the copper heat sink? THOSE ARE THE FINALS! If a module fails, the computer simply bypasses it and uses another module (there are spares) until someone shows up at the transmitter to look for the failure lights. They don't even shut down the transmitter to swap them out, any more. Hot swaps just like a computer...(c; The two PC boards on the door are the "modulator", the drivers for the modules creating the RF. It's so efficient it's cooled with small FANS! To produce a 50,000 watt carrier, it requires only 55,000 watts of AC power from the power company, not the 120KW we were accustomed to. No massive filament power, no blood-red plates being cooled with water, no cooling pond. The RF modules (there are 144 of them in a Harris DX-50, 50KW transmitter) look like: http://www.geocities.com/aaron_white/dxmod.html Some are 100W, 500W, 1KW, 2KW. The audio is simply converted into how many modules run at this instant in time. The modules, themselves are switching on and off at the carrier rate. The output filter takes out the 3rd harmonic caused by the square wave switching up. Nothing analog to make heat. It's a RF synthesized sinewave just like your boat inverter. You'll be glad to know from the Harris out it's still RF....(c; Here's the ATU at WFAN: http://www.geocities.com/aaron_white/atu1.html 75KW dummy load: http://www.geocities.com/aaron_white/load.html 50KW isn't what it used to be...(sigh). http://www.geocities.com/aaron_white/maintx.html The modulator and final are inside the right doors. The other end is the power supply. Kinda a non-event unless the RF output flashes over, which my friends in broadcasting says is also a non-event for the digital transmitter. It simply clears it, resets and tries again. If it continues to flash over, the transmitter comes up in low power (10KW) until the techies show up..... The computer that operates the transmitter is in that rack to the left of the Harris at WFAN. The whole thing is in a corner of the transmitter shack which is mostly taken up by the darkened old 50KW monster you're thinking about. Tom Ray, Director of Engineering over at WOR in NYC, sent me some cool pictures of their IBOC Digital AM experiments on their Harris DX-50. If you listen to WOR or WLW's IBOC on a regular AM radio you hear a faint hissing sound that is the digital subcarriers. The two stations, 10 Khz apart, are experimenting with interference caused by the IBOC carriers. Most interesting.....AM that sounds like mono-FM but at great distances. On Fri, 30 Jan 2004 21:20:46 GMT, Bruce in Alaska wrote: In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. Knowledgable Tech's recomeended but not even required. That's why I got out of the Broadcast Business 35 years ago. To many Carneigie, and Elkins, First Phone's showing up, and getting OTJ Training on my license as Chief Engineer. There's no such thing as an Automated 50,000 Watt AM Transmitter. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. Bruce in alaska -- add a 2 before @ Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
Ok guys,, what's your comments on the 2m homebrew antenna? Anyone build one
and had a particular preference or reasons why one over the other? Thanks "Gary Schafer" wrote in message ... Yes the top hat would help out on 2 and 4 mhz frequencies. Problem is where to put it where it is not in the way. A loading coil on the stay would also help out but it would work even better if it was up high nearer to the top of the stay. Problem is that usually only one antenna is available for all bands on a boat. At the higher frequencies that loading coil would act as a choke and effectively disconnect the upper portion of the antenna. Which may not be all that bad if there is sufficient length below the coil for the higher frequencies. The other problem that you may run into is that the auto tuner may not like the impedance it sees. Most auto tuners do not like to see a resonant antenna near 50 ohms. But on 2 mhz it would probably help a lot. Regards Gary On Thu, 29 Jan 2004 12:20:07 -0500, "Vito" wrote: Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? |
SSB Antennas
On Sat, 31 Jan 2004 04:04:29 GMT, Gary Schafer
wrote: The nitrogen was for the transmission line. Regards Gary Channel 24, WTAT-TV, runs 180KW into nitrogen-pressurized, rigid transmission line. ERP is 5 megawatts at 1900 ft. It's the FOX affiliate, here. Exciting things happen when 180KW of 500 Mhz RF flashes over inside 6 1/2" hardline if the nitrogen goes away.......some of it involving $30,000 4-cavity klystrons taller than a man. It's not pretty..... I have some friends in Charleston running only 1000 watts on Channel 12 from a little solid state Taylor (English) transmitter at 380' broadcasting Telefutura and local Spanish programs. The whole TV station is about the size of your refridgerator...(c; They used to have a remote studio, of sorts, about 9 miles away linked with 10 watts on Channel 26 UHF pointed at the transmitter with a dish. The "custom" receiver for this TV station, down at the transmitter building shared with pagers, businessband, etc., was a genuine Panasonic VHS tape deck tuned to Channel 26. If things at the studio went awry, one only punched PLAY on the link receiver to get the canned spanish movie on the air. The VHS cart would give you 4 hours of canned programming to get whatever blew up fixed....hee hee. Low Power TV is a lot of fun. I work for them for nothing because they run on the bleeding edge of bankruptcy. That's why they don't have a "studio" any more. Something about "rent payments"....(c; Panasonic link receivers are $59 at Circuit City, if you need one for you broadcast station. Ask for Mike and tell him you want one like WJEA-TV uses....(c; Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
On Sat, 31 Jan 2004 01:41:00 GMT, Larry wrote:
I had a 1st as well, but frankly thought the 2d was a good deal harder. If nothing else, it was a lot longer! I recall the 1st was 50 questions (and it seems like it was mostly law) and the 2d was 200 questions. I passed them both, but I recall spending a long time on the 2d. Never did the GMDSS/M or radar. 2nd was MUCH harder. I was a 3rd for too long...(c; Go to the FCC website and download the tests for GMDSS operator and servicer. Local ham radio volunteer examiners are also volunteer commercial testers, now. Our commercial tester used to be the "Mud Duck" on CB running 10KW into twin Telrex beams at 80'......(big grin). Times change. I helped him pass his Advanced ham ticket. I thought that after the FCC went to General Commercial that NABER or someone like that handled endorsements for a while, but then they gave that up. Do you remember what happened to that stuff? I had all mine long before FCC stopped doing the testing. All the testing is now done with volunteer examiners, mostly the VEs that test for ham radio. Sea School has a GMDSS testing site, but you have to go to Florida to take it. It's not offered in our Sea School in Charleston. 73, DE W4CSC Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
All I remember is that dad said he had to run out and get the
nitrogen to prevent the finals from melting down. Otherwise the the station would have to shut down. Doug, k3qt s/v Callista "Gary Schafer" wrote in message ... The nitrogen was for the transmission line. Regards Gary On Fri, 30 Jan 2004 22:03:22 -0500, "Doug Dotson" wrote: Thanks for the clarification Larry. I was pretty sure that modern transmitter technology wasn't something I had in a dream. I was up in Fairbanks a couple years ago and I suspect that keeping the finals cool isn't much of a problem there :) My father was the engineer for a UHF station back in the late 50's. He told stories of having to run out and get bottles of Nitrogen to keep the finals going. Life is much simpler now. Doug, k3qt s/v Callista "Larry W4CSC" wrote in message ... Er, ah, Bruce? There are no "finals" any more. The 50KW transmitter is just a switching power supply from Harris.....take a look at: http://www.geocities.com/aaron_white/inside.html It's all done by that big board switching the modules on and off at the audio rate, in sequence. See those two little powertab transistors on the copper heat sink? THOSE ARE THE FINALS! If a module fails, the computer simply bypasses it and uses another module (there are spares) until someone shows up at the transmitter to look for the failure lights. They don't even shut down the transmitter to swap them out, any more. Hot swaps just like a computer...(c; The two PC boards on the door are the "modulator", the drivers for the modules creating the RF. It's so efficient it's cooled with small FANS! To produce a 50,000 watt carrier, it requires only 55,000 watts of AC power from the power company, not the 120KW we were accustomed to. No massive filament power, no blood-red plates being cooled with water, no cooling pond. The RF modules (there are 144 of them in a Harris DX-50, 50KW transmitter) look like: http://www.geocities.com/aaron_white/dxmod.html Some are 100W, 500W, 1KW, 2KW. The audio is simply converted into how many modules run at this instant in time. The modules, themselves are switching on and off at the carrier rate. The output filter takes out the 3rd harmonic caused by the square wave switching up. Nothing analog to make heat. It's a RF synthesized sinewave just like your boat inverter. You'll be glad to know from the Harris out it's still RF....(c; Here's the ATU at WFAN: http://www.geocities.com/aaron_white/atu1.html 75KW dummy load: http://www.geocities.com/aaron_white/load.html 50KW isn't what it used to be...(sigh). http://www.geocities.com/aaron_white/maintx.html The modulator and final are inside the right doors. The other end is the power supply. Kinda a non-event unless the RF output flashes over, which my friends in broadcasting says is also a non-event for the digital transmitter. It simply clears it, resets and tries again. If it continues to flash over, the transmitter comes up in low power (10KW) until the techies show up..... The computer that operates the transmitter is in that rack to the left of the Harris at WFAN. The whole thing is in a corner of the transmitter shack which is mostly taken up by the darkened old 50KW monster you're thinking about. Tom Ray, Director of Engineering over at WOR in NYC, sent me some cool pictures of their IBOC Digital AM experiments on their Harris DX-50. If you listen to WOR or WLW's IBOC on a regular AM radio you hear a faint hissing sound that is the digital subcarriers. The two stations, 10 Khz apart, are experimenting with interference caused by the IBOC carriers. Most interesting.....AM that sounds like mono-FM but at great distances. On Fri, 30 Jan 2004 21:20:46 GMT, Bruce in Alaska wrote: In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. Knowledgable Tech's recomeended but not even required. That's why I got out of the Broadcast Business 35 years ago. To many Carneigie, and Elkins, First Phone's showing up, and getting OTJ Training on my license as Chief Engineer. There's no such thing as an Automated 50,000 Watt AM Transmitter. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. Bruce in alaska -- add a 2 before @ Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
That must be a recent change. I had to take my test at a
Sylvan Learning Center testing site. I registered as a VE but haven't been called upon to exersize it. I'm not currently active in a local club. Doug, k3qt s/v Callista "Larry W4CSC" wrote in message ... On Sat, 31 Jan 2004 01:41:00 GMT, Larry wrote: I had a 1st as well, but frankly thought the 2d was a good deal harder. If nothing else, it was a lot longer! I recall the 1st was 50 questions (and it seems like it was mostly law) and the 2d was 200 questions. I passed them both, but I recall spending a long time on the 2d. Never did the GMDSS/M or radar. 2nd was MUCH harder. I was a 3rd for too long...(c; Go to the FCC website and download the tests for GMDSS operator and servicer. Local ham radio volunteer examiners are also volunteer commercial testers, now. Our commercial tester used to be the "Mud Duck" on CB running 10KW into twin Telrex beams at 80'......(big grin). Times change. I helped him pass his Advanced ham ticket. I thought that after the FCC went to General Commercial that NABER or someone like that handled endorsements for a while, but then they gave that up. Do you remember what happened to that stuff? I had all mine long before FCC stopped doing the testing. All the testing is now done with volunteer examiners, mostly the VEs that test for ham radio. Sea School has a GMDSS testing site, but you have to go to Florida to take it. It's not offered in our Sea School in Charleston. 73, DE W4CSC Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
SSB Antennas
Last one I built was just a rod soldered into a SO-259 chassis mount
connector. Radials were bolted into the 4 mounting holes along with a mounting bracket. Worked good. Hardly worth doing homebrew for something so common these days. Doug, k3qt s/v Callista " Tuuk" wrote in message ... Ok guys,, what's your comments on the 2m homebrew antenna? Anyone build one and had a particular preference or reasons why one over the other? Thanks "Gary Schafer" wrote in message ... Yes the top hat would help out on 2 and 4 mhz frequencies. Problem is where to put it where it is not in the way. A loading coil on the stay would also help out but it would work even better if it was up high nearer to the top of the stay. Problem is that usually only one antenna is available for all bands on a boat. At the higher frequencies that loading coil would act as a choke and effectively disconnect the upper portion of the antenna. Which may not be all that bad if there is sufficient length below the coil for the higher frequencies. The other problem that you may run into is that the auto tuner may not like the impedance it sees. Most auto tuners do not like to see a resonant antenna near 50 ohms. But on 2 mhz it would probably help a lot. Regards Gary On Thu, 29 Jan 2004 12:20:07 -0500, "Vito" wrote: Tests of mobile antennae in the Amateur Radio 75 meter band (4MHz) yielded the following results: * Well-designed Bugcatcher or Screwdriver with top hat 0 dB reference * Bugcatcher or Screwdriver with no top hat -3 dB * Hustler or Outbacker -9 dB * Hamstick -12 dB * Whip with autotuner -14 dB This suggests that the common insulated-backstay-with-autotuner used on sailboats could be improved by adding a capacitive top hat immediately below the upper insulator and/or a tapped coil in parallel (ie around) the lower insulator to tune whatever length of antenna one can physically accomodate to resonate on or near the Marine frequencies of interest, such as 2182 MHz. Has anyone any experience doing so? |
SSB Antennas
In article ,
"Doug Dotson" wrote: "Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: and dispatches licensed techs Nope Doug, no License Required anymore. I misstated my thought. I mean't "qualified techs" since a license is no longer required. The question was as to the reason that a license is no longer required. Larry seems to suggest that it is because very few blacks are able to get a 1st Phone. My recollection is that it is because detailed technical knowledge is not required to safely and legally operate a transmitter these days. There's no such thing as an Automated 50,000 Watt AM Transmitter. Maybe up in Alaska. But I'm pretty sure that is not the case in general. When those puppy's decide to melt down, they do it in a hurry, and usually with lots of sparks and steam from the liquid cooling systems. My years in the process control industry make me pretty confident that the computer can sense and react to pretty much anything unusual faster than the most skilled engineer/tech. Not to say that an on-site person is not an asset because once the computer has either shut things down or reduced power to save the transmitter, someone has to diagnose and fixed the problem. Usually the finals are pulled at 50% of rated time, but nowdays with skimpy maintaince money, owners are pushing that out to 80% and catastophic failure is happen a lot more often. Reminds me of a very cold January Night when KRAB-FM's antenna took a hell of a wet snow load, and unbalanced the two 5Kw finals explosivly. I came around the corner and the DJ on duty was out in the street with a bunch of steaming holes in the snow where hot final Parts had melted down through the snow. Took the consulting engineer and I, 8 hours to rebuild the final cage (Lots of plumbing parts) and get it back on the air. A good SCADA system should have sensed the impending problem and may have been able to save the day. But, as you say, some failures are so sudden that there is no way out. Bruce in alaska -- add a 2 before @ Well I have now been updated on Broadcast Transmitters...... thanks Larry. It has been a few years since I inspected an AM Broadcast Station and the one's I did do were out in the small communities of alaska. I got out of the Broadcast Industry as an Engineer, many years ago, so it isn't to suprising that I am a bit out of date on the technology. Oh well, age gets us all eventually. Thank goodness Marine Radios are still using 1990 technology, cause I still have a bit of a handle on them. I also talked to my buddies at SEA, and they are just coming back into production on their SEA157 VHF Radio's and even a few of the SEA235 MF/HF Radio's. This is very good news for the thousands of folks who have SEA Products onboard. I also had a chance to talk to Mark Johnson of ShineMicro about AIS. He is really big into this new (to me) Position Reporting System now being mandated for ships of 65Ft in the US. Way cool stuff if you got the money, and still way cool when the ClassB stuff for Volitary Compliance comes out later this year. Bruce in alaska -- add a 2 before @ |
SSB Antennas
In article ,
"Doug Dotson" wrote: "Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista Licensed Marine Radio Tech is a person who has an FCC GROL/w RADAR/GMDSS-M and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels. Then I guess I R 1. But what is the second part of your statement? The part that reads "and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels"? What is this license? Who issues it? The SOLAS Requires that Title III Part II, and title III Part I Vessels be inspected on an annual basis and that inspection by a Licensed Marine Radio Tech, be logged in the Vessel Station Log and a renewed SOLAS Certificate be Issued and Posted for Public Inspection. In the passed, these inspections were done by FCC Field Agents, and the SOLAS Certificates, Bridge to Bridge RadioTelephone Certificates, were issued by the FCC Field Agents, on completion of the inspection. A similar inspection of Title IIi Part IIi Vessels needs to be completed every 5 years for those class vessels, and is done, now, through the same method. I remember all the mumbo-jumbo from the GMDSS license. So is the GMDSS/M license what makes one all of these fancy titles or is there some other authority that grants these lofty titles. Bruce in alaska -- add a 2 before @ Yep, your R one, and with this little slip of paper, you can now LEGALLY adjust Marine & Aircraft Radio Systems so as to make them compliant with Parts 80 & 87 of the FCC Rules and Regulations. Oh yea, you need an FAA Certificate if you mess with Aircraft systems in actual Aircraft, or you need someone who has an FAA Certificate to sign off on any work on Aircraft Radio's. All that said, there really isn't much to adjust anymore unless your working with some of the older MF/HF Radio's around. Mostly just setting the Master Osc. on frequency, and then setting the power output, and your done these days. Bruce in alaska -- add a 2 before @ |
SSB Antennas
Maybe someday I'll look into the FAA stuff. If ever I decide to get
current on my pilot's license I can fix my own radios! Doug, k3qt s/v Callista "Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: "Bruce in Alaska" wrote in message ... In article , "Doug Dotson" wrote: Not familiar with a Marine Radio Tech License? I have a GROL with radar Endorsement and a GMDSS/M, but I'm not aware that is what you are referring to. The NMEA has a certification process but that's not really a "license" per se. Doug, k3qt s/v Callista Licensed Marine Radio Tech is a person who has an FCC GROL/w RADAR/GMDSS-M and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels. Then I guess I R 1. But what is the second part of your statement? The part that reads "and is licensed to maintain Maritime Mobile Radio Service licensed systems aboard US flagged Vessels"? What is this license? Who issues it? The SOLAS Requires that Title III Part II, and title III Part I Vessels be inspected on an annual basis and that inspection by a Licensed Marine Radio Tech, be logged in the Vessel Station Log and a renewed SOLAS Certificate be Issued and Posted for Public Inspection. In the passed, these inspections were done by FCC Field Agents, and the SOLAS Certificates, Bridge to Bridge RadioTelephone Certificates, were issued by the FCC Field Agents, on completion of the inspection. A similar inspection of Title IIi Part IIi Vessels needs to be completed every 5 years for those class vessels, and is done, now, through the same method. I remember all the mumbo-jumbo from the GMDSS license. So is the GMDSS/M license what makes one all of these fancy titles or is there some other authority that grants these lofty titles. Bruce in alaska -- add a 2 before @ Yep, your R one, and with this little slip of paper, you can now LEGALLY adjust Marine & Aircraft Radio Systems so as to make them compliant with Parts 80 & 87 of the FCC Rules and Regulations. Oh yea, you need an FAA Certificate if you mess with Aircraft systems in actual Aircraft, or you need someone who has an FAA Certificate to sign off on any work on Aircraft Radio's. All that said, there really isn't much to adjust anymore unless your working with some of the older MF/HF Radio's around. Mostly just setting the Master Osc. on frequency, and then setting the power output, and your done these days. Bruce in alaska -- add a 2 before @ |
SSB Antennas
"Larry W4CSC" wrote about AIS / APRS:
Every boat should be on APRS on both HF and VHF through assigned VHF and HF channels. Every packet APRS station can be a repeater for ever other APRS station, far extending the range of the individual stations. Some stations are connected through the internet to the national APRS servers hams have setup, including www.findu.com. It's all voluntary, of course, in true ham radio tradition. For the marine application of APRS, visit Bob Bruninga, APRS' inventor, at the Naval Academy website: http://web.usna.navy.mil/~bruninga/aprs.html He tracks the Academy's boat fleet with APRS on them. I fixed one of the APRS stations on an Academy yacht when it was in Charleston a few years ago to put it back online with APRS on VHF and HF. It keeps our Midshipmen from being too lost...(c; Larry, are you aware of any "findu" type charts that are adaptable to APRS? Mapquest "maps" display a poor graphic when plotting a vehicle on long bridges like the type that interlace the Hampton Roads Va area. It's not that the position reported from GPS is inaccurate, but a graphic representation becomes muddled when bodies of water are shown by Mapquest. We're thinking the mapquest maps would accordingly be of little use in this area as a result, but have not actually tried the equipment from a boat yet. Jack Va Beach Va |
SSB Antennas
On Sun, 1 Feb 2004 12:42:55 -0500, "Jack Painter"
wrote: "Larry W4CSC" wrote about AIS / APRS: Every boat should be on APRS on both HF and VHF through assigned VHF and HF channels. Every packet APRS station can be a repeater for ever other APRS station, far extending the range of the individual stations. Some stations are connected through the internet to the national APRS servers hams have setup, including www.findu.com. It's all voluntary, of course, in true ham radio tradition. For the marine application of APRS, visit Bob Bruninga, APRS' inventor, at the Naval Academy website: http://web.usna.navy.mil/~bruninga/aprs.html He tracks the Academy's boat fleet with APRS on them. I fixed one of the APRS stations on an Academy yacht when it was in Charleston a few years ago to put it back online with APRS on VHF and HF. It keeps our Midshipmen from being too lost...(c; Larry, are you aware of any "findu" type charts that are adaptable to APRS? Mapquest "maps" display a poor graphic when plotting a vehicle on long bridges like the type that interlace the Hampton Roads Va area. It's not that the position reported from GPS is inaccurate, but a graphic representation becomes muddled when bodies of water are shown by Mapquest. We're thinking the mapquest maps would accordingly be of little use in this area as a result, but have not actually tried the equipment from a boat yet. Jack Va Beach Va Bob Bruninga, the Naval Academy inventor of APRS, has charts for APRS on the water..... Larry W4CSC No, no, Scotty! I said, "Beam me a wrench.", not a WENCH! Kirk Out..... |
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