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VHF antenna height question
Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika |
Mika wrote:
Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika The "line of sight" at 3 metres would be about 7-8 miles. Is that enough? |
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RG-8 to the masthead is pretty much a standard rig for masthead antennas and
if the connectors are well done the signal loss is acceptable. The benefit of the additional height far and away overrides any signal loss. Try to make the antenna cable in a single run from the masthead to the back of the radio - no through-deck connectors. If you don't want to run cable of that diameter, don't try for the masthead because the loss in the smaller cable over a run of that length would be pretty bad. Tom Dacon " Mika" wrote in message ... Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika |
On Tue, 16 Aug 2005 13:47:27 -0400, Larry wrote:
( Mika) wrote in : Need to install a new VHF antenna to a sailboat. Put a 1/2 wave antenna as high as you can get it. 2000 meters is great! but the top of the tallest mast will do just fine. When you're screaming for help in a sinking boat, you can never have an antenna that's too high! The altitude of the mast antenna more than makes up for the length of the cabling losses. With a 25W Icom and 1/2 wavelength Metz whip at 55 ft on the other end of 30 meters of RG-58/U coax, Lionheart can call the US Coast Guard station way out of sight of land. but never, never, never ever use rg 58 cable. it's not shielded properly. it has high loss. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
On Tue, 16 Aug 2005 14:57:34 -0700, "Tom Dacon"
wrote: RG-8 to the masthead is pretty much a standard rig for masthead antennas and if the connectors are well done the signal loss is acceptable. The benefit of the additional height far and away overrides any signal loss. Try to make the antenna cable in a single run from the masthead to the back of the radio - no through-deck connectors. If you don't want to run cable of that diameter, don't try for the masthead because the loss in the smaller cable over a run of that length would be pretty bad. agreed. some folks have recommended rg 58 which has all the bad characteristics and none of the good ones of proper coax. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be, i would be great for use on boats for both HF and VHF. Has anyone used it? |
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"Larry" wrote in message ... (Bob) wrote in : but never, never, never ever use rg 58 cable. it's not shielded properly. it has high loss. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field Hogwash. There's RG-58 in every boat I work on and it works just fine....all the way out to the radio horizon....which, of course, is the limit of comms on VHF. At 50' if 2 watts makes it up there, it's full quieting at 10 miles. Besides, I can't imagine running hardline through those little holes to the masthead....(c; -- Larry I would agree that RG58 is very common. Its cheap and easy to run. Probably gives acceptable performance on most boats. I recently replaced mine with a single run of RG213 from masthead to radio. Didn't think I could pull RG8 up the plastic pipe inside my mast and the RG213 was recommended by a local communications shop so that's the way I went. Sitting at the top of my mast I was getting pretty tired pulling up 50 feet of 213. That stuff gets heavy. RG8 would be worse. |
I have just seen a range of low-loss thin ad flexible 50 ohm coax - aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be, i would be great for use on boats for both HF and VHF. Has anyone used it? Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than RG-213 (?). As an installer and repairman, we used foam dielectric coax once in a while for cell phone antennas because of UHF loss problems. It isn't as durable as RG-213 (the standard for most installations around salt water, as it crushes and flattens easier than solid dielectric. There were some brands of foam dielectric coax that absorbed moisture that degrades coax very quickly. RG-58 is ok for short runs of 25 watt VHF, but in tall masts, it just doesn't cut it. Also, it is a little light weight for 100 watt plus HF installations. The obvious weak link in most masthead installations is in the PL-259 coax connector installation. There are not many out there who can do a proper, watertight soldering job up at the top of a wavering, windy masthead. Been there, done that, was not always proud of my work. Old Chief Lynn, W7LTQ, PG-13-20604 |
Lynn Coffelt wrote:
I have just seen a range of low-loss thin ad flexible 50 ohm coax - aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be, i would be great for use on boats for both HF and VHF. Has anyone used it? Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than RG-213 (?). As an installer and repairman, we used foam dielectric coax once in a while for cell phone antennas because of UHF loss problems. It isn't as durable as RG-213 (the standard for most installations around salt water, as it crushes and flattens easier than solid dielectric. There were some brands of foam dielectric coax that absorbed moisture that degrades coax very quickly. RG-58 is ok for short runs of 25 watt VHF, but in tall masts, it just doesn't cut it. Also, it is a little light weight for 100 watt plus HF installations. The obvious weak link in most masthead installations is in the PL-259 coax connector installation. There are not many out there who can do a proper, watertight soldering job up at the top of a wavering, windy masthead. Been there, done that, was not always proud of my work. Old Chief Lynn, W7LTQ, PG-13-20604 Hay, chief, did ya ever think to push the wire down the mast using a messenger to guide it, like the old wire being replaced, or a fish line? that way, you leave the end with the on deck pre installed connector on it at the top and outside the mast with a drip loop*, while you cut to length and terminate the bottom end below decks, or at the mast base, an easy job, or at least not so awkward as at the top of a wobbly mast, which you heel a bit to guide the messenger. (Damn! dropped the flux, again;-) Is the soldering iron plugged in?) I once climbed to the top of a big fir to cut off the top for a Christmas tree, but dropped the axe after I got up there. Had to go down and up three times all together, once just to get my arms, which fell off next! If you were a masthead radio tech, and not proud of your work, you would have done it again, unless it was your own life at risk. Cobbler's shoes? Dija ever go up just to unscrew, remove and then rescrew the connector, then wait for a radio check after pulling gently on the feeder? It could benefit from doing it once every year. How long do hams spend sending? Rael hams use code, light duty cycle, to set up fax, etc, with old contacts. Or do they want full duplex stereo video to remote studios, at 450 megs using meteor scatter at days' ends, with gigantic yagis doublesteered at the masthead? I saw one like that, once, on a 40 foot ketch in green lapstrake on Grand Lake. Mil RG58 is good enough for most, cheap, light. Communications is our most valuable resource. *Note: A typical drip loop style exit from the mast head would cause compression of the dielectric. Soft cable with long heights hanging should be clamped above the exit hole, sealed with caulk, double clamped or wirehung to the mast, properly sized and torqued, No drip loop, unless needed to meet the antenna mount. Masts should be able to drain at the heel anyway. Matching coils should be below the masthead, 2"-3" away from the mast. Tilting the antenna a little to avoid instrumentation is ok, though it may affect directivity at extremes. Terry K -Yeah, yeah, we *can* build monster cables. -SofDevCo- |
Hay, chief, did ya ever think to push the wire down the mast using a
messenger to guide it, like the old wire being replaced, or a fish line? that way, you leave the end with the on deck pre installed connector on it at the top and outside the mast with a drip loop*, while you cut to length and terminate the bottom end below decks, or at the mast base, an easy job, or at least not so awkward as at the top of a wobbly mast, which you heel a bit to guide the messenger. (Damn! dropped the flux, again;-) Is the soldering iron plugged in?) I once climbed to the top of a big fir to cut off the top for a Christmas tree, but dropped the axe after I got up there. Had to go down and up three times all together, once just to get my arms, which fell off next! If you were a masthead radio tech, and not proud of your work, you would have done it again, unless it was your own life at risk. Cobbler's shoes? Dija ever go up just to unscrew, remove and then rescrew the connector, then wait for a radio check after pulling gently on the feeder? It could benefit from doing it once every year. How long do hams spend sending? Rael hams use code, light duty cycle, to set up fax, etc, with old contacts. Or do they want full duplex stereo video to remote studios, at 450 megs using meteor scatter at days' ends, with gigantic yagis doublesteered at the masthead? I saw one like that, once, on a 40 foot ketch in green lapstrake on Grand Lake. Mil RG58 is good enough for most, cheap, light. Communications is our most valuable resource. *Note: A typical drip loop style exit from the mast head would cause compression of the dielectric. Soft cable with long heights hanging should be clamped above the exit hole, sealed with caulk, double clamped or wirehung to the mast, properly sized and torqued, No drip loop, unless needed to meet the antenna mount. Masts should be able to drain at the heel anyway. Matching coils should be below the masthead, 2"-3" away from the mast. Tilting the antenna a little to avoid instrumentation is ok, though it may affect directivity at extremes. Terry K -Yeah, yeah, we *can* build monster cables. -SofDevCo- Hey, Terry! I like it, I like it! Can tell you've been there! Yes, when customers wanted to put the cable in themselves, (Glee!) I would sometimes help them figger a suitable length, and put one connector on in the nice warm shop, advising them to put the cable in, top down, and call me for the bottom connector. When you told of the tree, I initially knew you were bragging about the size of your Christmas tree. Upon closer inspection, I now know that you only used the top! The duty cycle on my 10 meter CW rig is way less than a thousandth of a percent. Usually giving it 8 to 10 months to cool down between contacts. However if one chose some of the FSK modes (I don't, personally), and had a little less than perfect SWR (and 100 watts or so) One can melt or soften current nodes in RG-58. Contributing, one would assume to Global Warming. Old Chief Lynn |
Terry Spragg wrote in
: Rael hams use code Yeah....Pactor code, Amtor code, Packet code, PSK31 code, Baudot code....(c; REAL hams use digital modes. -- Larry |
Rael hams use code Yeah....Pactor code, Amtor code, Packet code, PSK31 code, Baudot code....(c; REAL hams use digital modes. -- Larry Ah heck! And here I thought CW was the granddaddy of digital. Lynn |
"Lynn Coffelt" wrote in
: Ah heck! And here I thought CW was the granddaddy of digital. Lynn I have some old friends, even friends who operated CW on subs in WW2, who've just become enthralled with PSK31 digital mode. If your transceiver has VOX, you don't even need any interface box expense. A 10K pot to control drive from the soundcard to the mic jack is plenty. Hookup is almost too easy. I use Winwarbler, which can copy three simultaneous stations on slightly different frequencies. PSK is SUPERIOR to the finest CW station. It will copy a DX PSK station so far into the noise you can't even tell there are tones in the noise, much less copy Morse from it if he were sending in Morse. PSK stations, to reduce interference in the 3Khz bandwidth the gentlemen's agreement puts them on at 14.070, usually use only 10 or 20 watts of power, even on the other side of the planet. It's uncanny that a cheap little soundcard can pull those tones out of the noise with such accuracy. Ham radio hasn't done much "inventing" in the past 30 years, but PSK is a ham radio invention that should be enjoyed by all. Tune your HF to 14.070 SSB and listen for tiny warbling tones. Plug the headphone jack into the LINE IN on your computer and run the Winwarbler software you get from: http://www.qsl.net/winwarbler/ Point your mouse at any little trace in the waterfall display and click on it. Winwarbler starts decoding instantly in the current window. Click the next window and pick another signal trace. It's that easy...(c; Instructions for use and installation are on the webpage. Simply amazing mode of RTTY comms between stations, with the simplest of equipment. Pick a trace you can hardly make out in the display and click on it...watch it type...(c; -- Larry |
Ah heck! And here I thought CW was the granddaddy of digital. Lynn I have some old friends, even friends who operated CW on subs in WW2, who've just become enthralled with PSK31 digital mode. If your transceiver has VOX, you don't even need any interface box expense. A 10K pot to control drive from the soundcard to the mic jack is plenty. Hookup is almost too easy. I use Winwarbler, which can copy three simultaneous stations on slightly different frequencies. PSK is SUPERIOR to the finest CW station. It will copy a DX PSK station so far into the noise you can't even tell there are tones in the noise, much less copy Morse from it if he were sending in Morse. PSK stations, to reduce interference in the 3Khz bandwidth the gentlemen's agreement puts them on at 14.070, usually use only 10 or 20 watts of power, even on the other side of the planet. It's uncanny that a cheap little soundcard can pull those tones out of the noise with such accuracy. Ham radio hasn't done much "inventing" in the past 30 years, but PSK is a ham radio invention that should be enjoyed by all. Tune your HF to 14.070 SSB and listen for tiny warbling tones. Plug the headphone jack into the LINE IN on your computer and run the Winwarbler software you get from: http://www.qsl.net/winwarbler/ Point your mouse at any little trace in the waterfall display and click on it. Winwarbler starts decoding instantly in the current window. Click the next window and pick another signal trace. It's that easy...(c; Instructions for use and installation are on the webpage. Simply amazing mode of RTTY comms between stations, with the simplest of equipment. Pick a trace you can hardly make out in the display and click on it...watch it type...(c; -- Larry Larry, thanks, I've always wanted a simple way to look at PSK31, and have read a little. Your explanation of how to get started sounds like something even I can do. I do have a couple of pretty hot computer's that I assembled and run right here next to a fairly good HF receiver. I'm going to give it a listen. Unfortunately, transceiver is not something in the inventory, but have been lurking for a good deal on a used. Low power works, no doubt with advanced forms of digital, better than we ever did with CW, but you know 10 or 15 watts into a 6V6 or 6L6 worked the world every winter on 40. Friends (not me) copied down in the dirt and heterodyne jungle. The human ear and brain are darned near as sharp as the digital processing developments used in the later "automatic" Loran C receivers. Stop Lynn, while you're still ahead. Old Chief Lynn |
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"Lynn Coffelt" wrote in message ... Hay, chief, did ya ever think to push the wire down the mast using a messenger to guide it, like the old wire being replaced, or a fish line? that way, you leave the end with the on deck pre installed connector on it at the top and outside the mast with a drip loop*, while you cut to length and terminate the bottom end below decks, or at the mast base, an easy job, or at least not so awkward as at the top of a wobbly mast, which you heel a bit to guide the messenger. (Damn! dropped the flux, again;-) Is the soldering iron plugged in?) I once climbed to the top of a big fir to cut off the top for a Christmas tree, but dropped the axe after I got up there. Had to go down and up three times all together, once just to get my arms, which fell off next! If you were a masthead radio tech, and not proud of your work, you would have done it again, unless it was your own life at risk. Cobbler's shoes? Dija ever go up just to unscrew, remove and then rescrew the connector, then wait for a radio check after pulling gently on the feeder? It could benefit from doing it once every year. How long do hams spend sending? Rael hams use code, light duty cycle, to set up fax, etc, with old contacts. Or do they want full duplex stereo video to remote studios, at 450 megs using meteor scatter at days' ends, with gigantic yagis doublesteered at the masthead? I saw one like that, once, on a 40 foot ketch in green lapstrake on Grand Lake. Mil RG58 is good enough for most, cheap, light. Communications is our most valuable resource. *Note: A typical drip loop style exit from the mast head would cause compression of the dielectric. Soft cable with long heights hanging should be clamped above the exit hole, sealed with caulk, double clamped or wirehung to the mast, properly sized and torqued, No drip loop, unless needed to meet the antenna mount. Masts should be able to drain at the heel anyway. Matching coils should be below the masthead, 2"-3" away from the mast. Tilting the antenna a little to avoid instrumentation is ok, though it may affect directivity at extremes. Terry K -Yeah, yeah, we *can* build monster cables. -SofDevCo- Hey, Terry! I like it, I like it! Can tell you've been there! Yes, when customers wanted to put the cable in themselves, (Glee!) I would sometimes help them figger a suitable length, and put one connector on in the nice warm shop, advising them to put the cable in, top down, and call me for the bottom connector. When you told of the tree, I initially knew you were bragging about the size of your Christmas tree. Upon closer inspection, I now know that you only used the top! The duty cycle on my 10 meter CW rig is way less than a thousandth of a percent. Usually giving it 8 to 10 months to cool down between contacts. However if one chose some of the FSK modes (I don't, personally), and had a little less than perfect SWR (and 100 watts or so) One can melt or soften current nodes in RG-58. Contributing, one would assume to Global Warming. Old Chief Lynn So far no one has mentioned RAG-8X, which I see more of on boats these days than RAG-58. A second thing, what ever coax you use, use a stranded center conductor for marine use. I have repaired way to many fractured solid wire RAG-58 cables, broken right at or just beyond the PL259. I learned the pull it from the top with the connector already installed trick years ago doing type N connectors on RAG-8 or 213/214 for airport VHF radio antennas. I also learned to have a few adapters in my pocket before going on the roof/tower as you never knew what gender of N connectors the antenna stub might have. Also, please note that RAG-8 was dropped from the MilSpec books years ago and RAG-213 replaced it or the even better shielded RAG-214. Most of the RAG-8 you find available now says type RAG-8, not with a suffix, etc., to indicate a jacket or dielectric or solid or stranded wire. Radio Shack has been pawning junk off on unsuspecting citizens band ops for years, calling it type RAG-8. Since the standard has been deleted, they can get away with it. If you are going beyond RAG-8X (size of RAG-59), go with at least RAG-213 or the even better Belden cable. By the way, there is a type N connector around now that is just about the same as a PL-259, solder the center pin and shield there same way, with no more rubber gasket and compression nuts, etc. 73 Doug K7ABX "real radios glow in the dark!" Smoke signals and drum beats preceded CW as a digital mode! |
"Doug" wrote in
nk.net: RAG-58 What's RAG?? I've never seen that designation before. Is it like RG- 58A/U? -- Larry |
On Wed, 17 Aug 2005 08:23:22 -0400, Larry wrote:
(Bob) wrote in : but never, never, never ever use rg 58 cable. it's not shielded properly. it has high loss. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field Hogwash. There's RG-58 in every boat I work on and it works just fine.... it's unreliable. you may know boats. you don't know electronics rg 58 is poorly shielded. that makes it more susceptible to interference... although it's not a big issue for short runs (like on boats), its loss/ft is much higher than other cables. its diameter is not compatible with pl 259's which means many are installed wrong. Besides, I can't imagine running hardline through those little holes to the masthead....(c; try rg 213 or rg 8. much, much better. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
On Thu, 18 Aug 2005 12:44:36 -0300, Terry Spragg
wrote: Lynn Coffelt wrote: The obvious weak link in most masthead installations is in the PL-259 coax connector installation. There are not many out there who can do a proper, watertight soldering job up at the top of a wavering, windy masthead. Been there, done that, was not always proud of my work. Old Chief Lynn, W7LTQ, PG-13-20604 Hay, chief, did ya ever think to push the wire down the mast using a messenger to guide it, like the old wire being replaced, or a fish line? that way, you leave the end with the on deck pre installed connector on it at the top except what happens when this thing sits in the wind, and rocks with boat motion? the mechanical support for the cable/connector interface isn't there. hell, these fail on CB installs all the time (no ham i've never known ever used rg 58). . How long do hams spend sending? Rael hams use code, light duty cycle, rtty is light duty? it's 100% duty cycle at full power. Mil RG58 is good enough for most, cheap, light. Communications is our most valuable resource. it'll work. but i wouldnt bet my life on it. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
"Larry" wrote in message ... "Doug" wrote in nk.net: RAG-58 What's RAG?? I've never seen that designation before. Is it like RG- 58A/U? -- Larry Looks like the spell checker got me and converted RG to RAG...I must have hit the correct all button in error. RG is correct. 73 Doug |
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What's RAG?? I've never seen that designation before. Is it like RG- 58A/U? -- Larry Looks like the spell checker got me and converted RG to RAG...I must have hit the correct all button in error. RG is correct. 73 Doug Whew! Thought I'd missed another new product! Old Chief Lynn |
On Mon, 22 Aug 2005 20:00:40 GMT, Me wrote:
In article , (Bob) wrote: it's unreliable. you may know boats. you don't know electronics rg 58 is poorly shielded. that makes it more susceptible to interference... although it's not a big issue for short runs (like on boats), its loss/ft is much higher than other cables. its diameter is not compatible with pl 259's which means many are installed wrong. Hmmm, another flatlander, who thinks Marine Electronics is the same as Ham Radio...... ROFLMAO! do much radio work? RG-58 comes in a whole pile of different forms, of which, some are prefectly adequite for some specific Maritime uses. It is enherently just as reliable as any other coax type, when installed properly. and you're missing the point. There certainly are some forms of RG-58 that have poor shielding, but there are also some forms of RG-58 that provide for 100% shileding, as well. Better go back and look at a Beldon Catalog again...... kinda missed the total picture, didn't you? part of the reason thicker cables work with pl 259's is the fact that, installed properly, the jacket seats itself in the connector. this functions as a stress relief and stabilizes the connector. rg58 is too thin to take advantage of this. and, again, the thicker cable has a mechanical advantage when inserted into the connecter since vibration is reduced, thereby reducing stress. Run Length and Frequency certainly are part of the list of things that determine the suitability of any Coaxial Cable installation. Obviously, you have never hear of the UG-174U Adapter..... and what makes you think that a PL-259 is the "Be All, and End all" of Marine Radio connectors? Me who wonders where these guys come from...... ever been on a boat? how many pl259's are out there? how many of them have adapters? answer: almost none. as to the adapter, it's unreliable since the mechanical advantage is not present over the entire length of the jacket/connector interface. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
"Lynn Coffelt" wrote in message ... What's RAG?? I've never seen that designation before. Is it like RG- 58A/U? -- Larry Looks like the spell checker got me and converted RG to RAG...I must have hit the correct all button in error. RG is correct. 73 Doug Whew! Thought I'd missed another new product! Old Chief Lynn No it was a senility attack (or is it way too many years of RF radiation exposure?)! Doug K7ABX "real radios communicate with smoke signals!" |
Am I missing something here? Surely the RG-58 wouldn't be attached to a
PL-259 without a UG-175 reducing adapter, would it? Is it being said that even with the UG-175, there is insufficient strain relief? Thanks for the clarification. Chuck |
On Mon, 22 Aug 2005 23:45:06 GMT, chuck wrote:
Am I missing something here? Surely the RG-58 wouldn't be attached to a PL-259 without a UG-175 reducing adapter, would it? Is it being said that even with the UG-175, there is insufficient strain relief? in my opinion the answer is there is insufficient strain relief for critical applications. the jacket of thicker cables, such as rg 213, when inserted into the pl 259, provide quite a bit of support for the connector. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
"Bob" wrote in message
... On Mon, 22 Aug 2005 23:45:06 GMT, chuck wrote: Am I missing something here? Surely the RG-58 wouldn't be attached to a PL-259 without a UG-175 reducing adapter, would it? Is it being said that even with the UG-175, there is insufficient strain relief? in my opinion the answer is there is insufficient strain relief for critical applications. the jacket of thicker cables, such as rg 213, when inserted into the pl 259, provide quite a bit of support for the connector. And what about the PL-259 which is specifically made for RG-58, without using an UG-175 adapter? Meindert |
On Tue, 23 Aug 2005 07:51:35 +0200, "Meindert Sprang"
wrote: "Bob" wrote in message .. . On Mon, 22 Aug 2005 23:45:06 GMT, chuck wrote: Am I missing something here? Surely the RG-58 wouldn't be attached to a PL-259 without a UG-175 reducing adapter, would it? Is it being said that even with the UG-175, there is insufficient strain relief? in my opinion the answer is there is insufficient strain relief for critical applications. the jacket of thicker cables, such as rg 213, when inserted into the pl 259, provide quite a bit of support for the connector. And what about the PL-259 which is specifically made for RG-58, without using an UG-175 adapter? i haven't seen one of those, but there are other factors which argue against rg 58 when there are superior cables out there. the loss factor is one...physics itself causes rg58 to be lossier than cables like rg213 or rg 8. although this is not a factor for a short run, depending on how long the run is, it could be an issue. also, thicker cables are going to be more mechanically sound than thinner cables. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
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On Tue, 23 Aug 2005 11:33:18 -0400, Gary Schafer
wrote: On Tue, 23 Aug 2005 10:44:14 GMT, (Bob) wrote: On Tue, 23 Aug 2005 07:51:35 +0200, "Meindert Sprang" wrote: i haven't seen one of those, but there are other factors which argue against rg 58 when there are superior cables out there. the loss factor is one...physics itself causes rg58 to be lossier than cables like rg213 or rg 8. although this is not a factor for a short run, depending on how long the run is, it could be an issue. also, thicker cables are going to be more mechanically sound than thinner cables. The type of connector has little to do with how well the cable holds up. You are supposed to provide support for the cable irrespective of the connector. The connector is not supposed to support the cable. The cable should be properly strapped down so the connector does not take any load. i agree. in a perfect world this would be true. but the fact is that a connector with rg 58 is less able to handle mechanical stress than one using a more robust cable. lots of boats have connectors attached improperly. As far as RG58 cable being no good, I suppose you might want to tell Motorola and many other radio manufacturers about that. They have for many years supplied that cable on their VHF and UHF mobile antenna installations. And by the way the PL259 was the standard connector for both too. as someone pointed out here, the marine environment is different than the land based one. for short runs not subject to stress rg 58, while obsolete, can work. but it's ridiculous to use when when other, superior cables are available. In marine VHF antenna applications you will be hard pressed to find any marine VHF antenna that comes with a length of cable pre attached that does not use RG58 type cable. agreed again. ease of installation, cost, etc. has alot to do with it. rg 58 generally costs a few cents a foot less than its competitors The size of a cable has little to do with its mechanical durability. There are small cables that are much more robust than larger cables. It all depends on how each is constructed. we're comparing apples to apples here. coax cables of the type rg 8/213/58 have basically similar constructions. the diameter of the cable DOES affect its mechanical stability when compared to cables of similar construction. The amount of shielding of coax cable is of little importance in most typical radio installations. disagree. with the increasing amount of electronics on boats nowadays, more shielding is better. Coax with 70 or 80% coverage verses 100% will not matter unless it is used in multicoupling or duplex systems where high isolation is important. Otherwise you will not be able to measure any difference in performance. again, disagree. many people report GPS, electronic compass, and computer problems when they key up their radios. of course some of this is overload from the antenna, etc. but more shielding on the cable reduces inteference to and from the radio. If running a cable for a VHF antenna up the mast of a sail boat I would opt for an RG8 type of cable over the RG58 type for the lower loss benefit. Other than that RG58 cable would be the choice for HF or VHF unless I happen to have some extra RG8 type cable handy at the time. rg 58 losses become significant even at 10 meter HF frequencies. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
On Tue, 23 Aug 2005 18:24:32 GMT, Me wrote:
If you "haven't seen one of those", you need to get out more, as they have been around for years. I especially like Gary's post, as he covered the same items that I covered, only with better diction, and clarity. As I stated before, Marine Electronics is a different Ballgame, than your typical Ham Radio experience, and if you don't know, or can't see, the difference, then you really need to go "Buy a Clue", at ITT VOGTech.... see my response to gary. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
In article , "Doug" wrote:
"Larry" wrote in message ... "Doug" wrote in nk.net: RAG-58 What's RAG?? I've never seen that designation before. Is it like RG- 58A/U? -- Larry Looks like the spell checker got me and converted RG to RAG...I must have hit the correct all button in error. RG is correct. 73 Doug You just made everyone feel like an idiot for not knowing what you were talking about!! Had me going!! greg N6GS |
"Bob" wrote in message
... On Tue, 23 Aug 2005 11:33:18 -0400, Gary Schafer wrote: The amount of shielding of coax cable is of little importance in most typical radio installations. disagree. with the increasing amount of electronics on boats nowadays, more shielding is better. Theorethically yes. In practice, it doesn't matter that much. A shield works because it creates loops of current, opposite of that in the inner conductor which keeps the field in. A practical mesh size on for instance parabolic antenna's is 1/10 of the wavelength. This will yield a good field reflection. So on VHF, where the wavelength is about 6 ft, a mesh size of 7 inches would already shield. On many older FM radiostations, "coax" was was made by an inner conductor surrounded by a "screen" of many (say 20) outer conductors supported by metal rings. again, disagree. many people report GPS, electronic compass, and computer problems when they key up their radios. of course some of this is overload from the antenna, etc. but more shielding on the cable reduces inteference to and from the radio. This kind if interference is more likely caused by improper termination (standing waves), which causes currents to flow on the outside of the shield. Nothing to do with bad shielding. Meindert |
On Tue, 23 Aug 2005 16:04:06 -0400, Gary Schafer
wrote: On Tue, 23 Aug 2005 18:45:33 GMT, (Bob) wrote: i agree. in a perfect world this would be true. but the fact is that a connector with rg 58 is less able to handle mechanical stress than one using a more robust cable. lots of boats have connectors attached improperly. Lots of boats have a lot of things improperly attached. That is no evidence bigger is better unless you plan to swing from the cable. communications is one area where bigger is better, in this case. as someone pointed out here, the marine environment is different than the land based one. for short runs not subject to stress rg 58, while obsolete, can work. but it's ridiculous to use when when other, superior cables are available. Then I suppose all boat antennas should be fitted with hard line. Why would you even want to use RG8 type cable if bigger cable is available. I was refering here to your stance that RG58 was a poor cable for VHF and HF frequencies because of its loss. it's poor at HF (10 meters). it's very lossy at VHF. In marine VHF antenna applications you will be hard pressed to find any marine VHF antenna that comes with a length of cable pre attached that does not use RG58 type cable. agreed again. ease of installation, cost, etc. has alot to do with it. rg 58 generally costs a few cents a foot less than its competitors The fact is that it doesn't make any noticiable performance difference either electrical or mechanical. unless, of course, you want to HEAR what's being said on the radio. we're comparing apples to apples here. coax cables of the type rg 8/213/58 have basically similar constructions. the diameter of the cable DOES affect its mechanical stability when compared to cables of similar construction. Again, only if you plan to swing from the cable. As a matter of fact a smaller cable is much easier to keep stable than a larger one on a boat. disagree. it's generally a bad idea to flex wire. this leads to cold working of the material and premature failure. again, thicker is better. again, disagree. many people report GPS, electronic compass, and computer problems when they key up their radios. of course some of this is overload from the antenna, etc. but more shielding on the cable reduces inteference to and from the radio. You can bet that the problems are not from poor shielding of the coax cable. How much leakage do you think coax has anyway? Even poor coax. quite a bit. i used rg58 a bit for the connector between radio and amplifier. i had a computer right next to it. the hash was s5. replacement of this by rg 213 eliminated it completely. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
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