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#1
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
On Tue, 24 Nov 2009 18:29:14 -0500, "Flying Pig"
wrote: This is only one of several places this discussion is happening, and I get constant reference to both positive and negatives on 400, 8x, 58, 142, 9913, and a few others... 400 is too big, too heavy and too inflexible. I think you know that. I've also heard bad things about water intrusion but I have used it successfully on our boat for short runs to WiFi antennas which operate at *much* higher frequencies than marine VHF (max about 162 MHz). 8x is highly susceptible to water intrusion. 58 is cheap junk suitable only for short runs in non-critical applications. 142 (MIL spec variety) I like and have had good experience in the past, no need to belabor those points. Have you heard any negatives other than price? 9913 I have no experience with but I'm pretty sure it does not have teflon insulation or silver plated conductors. Here's a brief comparison from a respected source: http://www.amsat.org/amsat/articles/...-net/coax.html They don't mention 142 for some reason, perhaps because of price or availability but I don't know. I'm trying to understand your issue with the Metz antenna that required extra connectors. I've had several Metz over the years and don't recall having that problem. I believe the Metx comes with a small "L" shaped bracket that mounts to the side on the mast, and the female connector on the bottom of the coil goes through the top of the "L" and is held in place with a thin lock nut. The top of your coax should be terminated with a male PL-259 connector that hooks right up with the Metz female connector protruding through the "L" bracket. Make sure that top connection is well taped and sealed. I like to use several layers of self-sticking silicone tape topped off with more layers of white vinyl rigging tape to provide UV protection. What am I missing ? |
#2
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
"Wayne.B" wrote in message
... .... 400 is too big, too heavy and too inflexible. I think you know that. I've also heard bad things about water intrusion but I have used it successfully on our boat for short runs to WiFi antennas which operate at *much* higher frequencies than marine VHF (max about 162 MHz). 8x is highly susceptible to water intrusion. 58 is cheap junk suitable only for short runs in non-critical applications. 142 (MIL spec variety) I like and have had good experience in the past, no need to belabor those points. Have you heard any negatives other than price? 9913 I have no experience with but I'm pretty sure it does not have teflon insulation or silver plated conductors. Here's a brief comparison from a respected source: http://www.amsat.org/amsat/articles/...-net/coax.html They don't mention 142 for some reason, perhaps because of price or availability but I don't know. I'm trying to understand your issue with the Metz antenna that required extra connectors. I've had several Metz over the years and don't recall having that problem. I believe the Metx comes with a small "L" shaped bracket that mounts to the side on the mast, and the female connector on the bottom of the coil goes through the top of the "L" and is held in place with a thin lock nut. The top of your coax should be terminated with a male PL-259 connector that hooks right up with the Metz female connector protruding through the "L" bracket. Make sure that top connection is well taped and sealed. I like to use several layers of self-sticking silicone tape topped off with more layers of white vinyl rigging tape to provide UV protection. What am I missing ? Hi, Wayne, Follow the link in the anomaly thread, and you'll see why. It wouldn't fit on the bracket... Thanks for the detail on coax... L8R Skip -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog "You are never given a wish without also being given the power to make it come true. You may have to work for it however." (and) "There is no such thing as a problem without a gift for you in its hand (Richard Bach) |
#3
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
On Wed, 25 Nov 2009 08:09:23 -0500, "Flying Pig"
wrote: Follow the link in the anomaly thread, and you'll see why. It wouldn't fit on the bracket... OK, based on the following picture, I think I see the problem. It looks like the coil on the bottom of the Metz was interfering with the upright portion of your aluminum angle bracket, requiring you to space it higher? http://img16.imageshack.us/img16/892...tzbracket3.jpg You are incurring at least 1 db of extra loss as a result of that connector stack (0.5 db per extra connection), and that's assuming that no moisture has gotten in, and the connectors are all top shelf. 1+ db is a lot of loss, about equal to an 80 ft run of good quality coax. It looks like the solution is to trim away some small portion of the outer end of the angle bracket as indicated in the cross-hatching so that the Metz can be mounted flush the way it was intended. That would eliminate both adapters that you have now. While you're doing all that you might want to retighten the nut under the red shrink tubing that holds the whip in place. They sometimes loosen up over time and let the whip get away. It happened to us about 20 years ago on a cruise to Maine. The good news was that while up the mast fixing the Metz, I spotted a pod of whales on the horizon and they put on quite a show for us. |
#4
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
----- Original Message -----
From: "Wayne.B" On Wed, 25 Nov 2009 08:09:23 -0500, "Flying Pig" wrote: Follow the link in the anomaly thread, and you'll see why. It wouldn't fit on the bracket... OK, based on the following picture, I think I see the problem. It looks like the coil on the bottom of the Metz was interfering with the upright portion of your aluminum angle bracket, requiring you to space it higher? http://img16.imageshack.us/img16/892...tzbracket3.jpg You are incurring at least 1 db of extra loss as a result of that connector stack (0.5 db per extra connection), and that's assuming that no moisture has gotten in, and the connectors are all top shelf. 1+ db is a lot of loss, about equal to an 80 ft run of good quality coax. It looks like the solution is to trim away some small portion of the outer end of the angle bracket as indicated in the cross-hatching so that the Metz can be mounted flush the way it was intended. That would eliminate both adapters that you have now. While you're doing all that you might want to retighten the nut under the red shrink tubing that holds the whip in place. They sometimes loosen up over time and let the whip get away. It happened to us about 20 years ago on a cruise to Maine. The good news was that while up the mast fixing the Metz, I spotted a pod of whales on the horizon and they put on quite a show for us. Hi, Wayne, and list, Thanks for the note - but the entire reason for the connector was that there aren't any threads on the Metz which would allow attachment to the bracket. As it is, the nut, which might be seen in one or more of the pix, on the original connector (it's the same, as far as I can tell, is a standard connector, one end in the base, and the other to the usual thin bracket), but which (the bottom nut) broke off when I was getting the down-and off the bracket, probably made the connector end too short to fully seat the ring from the cable. The way I have it installed allows plenty of room for the collar to screw on tightly without contacting the nut securing it to the bracket. Is there any reason to believe that this bulkhead mount connector is any different electrically from the "standard" connector which was supplied with the Metz (I have three - MMSI, AM/FM and this - and they all have what appears to be the same connector as part of the original antenna)? You'll note in the pic sequence that my original thought was to use the original antenna. Then I found that the bracket interfered, so cut away the offending part. It's not as big a cutaway as you have, but would have allowed the Metz to mount to the bracket. Then I found that the threads weren't long enough on the original connector to even get a nut on, let alone the cable, and thus the kludge. It's my presumption that I can do away with the double male under the antenna as currently installed, along with the Metz-supplied connector, using the bulkhead connector instead of the original, screwing the coil directly to it (the new longer connector). So, the question of the moment was whether I'm correct in that presumption... L8R Skip Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog "You are never given a wish without also being given the power to make it come true. You may have to work for it however." (and) "There is no such thing as a problem without a gift for you in its hand (Richard Bach) |
#5
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
On Wed, 25 Nov 2009 11:07:25 -0500, "Flying Pig"
wrote: It's my presumption that I can do away with the double male under the antenna as currently installed, along with the Metz-supplied connector, using the bulkhead connector instead of the original, screwing the coil directly to it (the new longer connector). So, the question of the moment was whether I'm correct in that presumption... There's something about your antenna that I don't understand. Does yours look like the follwing drawing: http://www.metzcommunication.com/ima...heetforweb.jpg That diagram clearly shows an SO-239 female connector with plenty of threads showing, which is how I remember it. Is yours different in some way? Is your coax terminated with a PL-259 male connector? That is what the Metz is expecting. http://www.universal-radio.com/CATAL...ts/plconn.html |
#6
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
Hi, Wayne, and list
"Wayne.B" wrote in message ... There's something about your antenna that I don't understand. Does yours look like the follwing drawing: http://www.metzcommunication.com/ima...heetforweb.jpg That diagram clearly shows an SO-239 female connector with plenty of threads showing, which is how I remember it. Is yours different in some way? http://www.justpickone.org/skip/gall...onics&start=88 and the next page have pix of the current Metz antenna. Apparently, they've changed their antennae, as the MMSI, AM/FM and this Metz I have all have the type of connector shown, which is a discontinous thread. The pix of my holding the still-mounted-to-original-bracket antenna show that it's not long enough to mount with a nut, thus the extended connector I used... Is your coax terminated with a PL-259 male connector? That is what the Metz is expecting. http://www.universal-radio.com/CATAL...ts/plconn.html Yes... L8R Skip -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog "You are never given a wish without also being given the power to make it come true. You may have to work for it however." (and) "There is no such thing as a problem without a gift for you in its hand (Richard Bach) |
#7
posted to rec.boats.cruising
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I hate to say it but there sure is a bunch of ignorance here concerning VHF antennas
On Wed, 25 Nov 2009 15:02:01 -0500, "Flying Pig"
wrote: That diagram clearly shows an SO-239 female connector with plenty of threads showing, which is how I remember it. Is yours different in some way? http://www.justpickone.org/skip/gall...onics&start=88 and the next page have pix of the current Metz antenna. Apparently, they've changed their antennae, as the MMSI, AM/FM and this Metz I have all have the type of connector shown, which is a discontinous thread. The pix of my holding the still-mounted-to-original-bracket antenna show that it's not long enough to mount with a nut, thus the extended connector I used... OK, I see what you mean. Apparently your angle bracket is too thick for the threads provided by Metz. There is a cheap and dirty solution to that kind of mounting problem involving Ty-Wraps and JB Weld that might just do the job if you're so inclined. I won't tell anyone as long as you don't look too closely at how my latest WiFi antenna is mounted at the top of our trawler mast. :-) |
#8
posted to rec.boats.cruising
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More On Skip's Antenna (was I hate to say it but ...)
Flying Pig wrote:
"Wayne.B" wrote in message ... ... 400 is too big, too heavy and too inflexible. I think you know that. I've also heard bad things about water intrusion but I have used it successfully on our boat for short runs to WiFi antennas which operate at *much* higher frequencies than marine VHF (max about 162 MHz). 8x is highly susceptible to water intrusion. 58 is cheap junk suitable only for short runs in non-critical applications. 142 (MIL spec variety) I like and have had good experience in the past, no need to belabor those points. Have you heard any negatives other than price? 9913 I have no experience with but I'm pretty sure it does not have teflon insulation or silver plated conductors. Here's a brief comparison from a respected source: http://www.amsat.org/amsat/articles/...-net/coax.html They don't mention 142 for some reason, perhaps because of price or availability but I don't know. I'm trying to understand your issue with the Metz antenna that required extra connectors. I've had several Metz over the years and don't recall having that problem. I believe the Metx comes with a small "L" shaped bracket that mounts to the side on the mast, and the female connector on the bottom of the coil goes through the top of the "L" and is held in place with a thin lock nut. The top of your coax should be terminated with a male PL-259 connector that hooks right up with the Metz female connector protruding through the "L" bracket. Make sure that top connection is well taped and sealed. I like to use several layers of self-sticking silicone tape topped off with more layers of white vinyl rigging tape to provide UV protection. What am I missing ? Hi, Wayne, Follow the link in the anomaly thread, and you'll see why. It wouldn't fit on the bracket... Thanks for the detail on coax... L8R Skip Looks like Skip is using a UG363 - adaptor. This is a UHF female to female and comes in various lengths from 1 to 12 inches see, for example http://www.universal-radio.com/CATALOG/parts/ug363.html His relevant pictures are 8291135 -6 -7 -9 He is constrained by mounting on a metal angle, flange up - the flange interfering with the antenna base. Not great practice but acceptable. Brian W |
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