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Old 01-07-2017, 04:25 PM   #41
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A good place to mount them is on your T-top, or bimini, if you have one. You need a rail ratchet mount. By mounting to the forward edge or side, whichever is more convenient, you can step around the console to raise or lower it.
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Old 01-07-2017, 07:32 PM   #42
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Originally Posted by Kamper View Post
A good place to mount them is on your T-top, or bimini, if you have one. You need a rail ratchet mount. By mounting to the forward edge or side, whichever is more convenient, you can step around the console to raise or lower it.
I have a bimini, but it needs to operate independently of the antenna. This is a side view of the boat. I've moved the ratchet to one of the bow rail verticles rather than the top rail so that it doesn't chafe the cover, but it is essentially in the same location as this pic.



The Bimini when elevated is about 4' shorter than the antenna. It clears most of the bridges, but not all of them. My goal is to be able to leave the bimini up nearly all the time, and operate the antenna independly of it. I'm sure I could spend more time coming up to the bridges, but don't want the inconvenience. I can also see my wife fussing if I have to crawl over her to get to an antenna on the port side and let it down every time we go under a bridge. Zero chance of her doing it.
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Old 01-08-2017, 11:47 AM   #43
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Originally Posted by autobaun70 View Post
I have a bimini, but it needs to operate independently of the antenna. This is a side view of the boat. I've moved the ratchet to one of the bow rail verticles rather than the top rail so that it doesn't chafe the cover, but it is essentially in the same location as this pic.



The Bimini when elevated is about 4' shorter than the antenna. It clears most of the bridges, but not all of them. My goal is to be able to leave the bimini up nearly all the time, and operate the antenna independly of it. I'm sure I could spend more time coming up to the bridges, but don't want the inconvenience. I can also see my wife fussing if I have to crawl over her to get to an antenna on the port side and let it down every time we go under a bridge. Zero chance of her doing it.

I would think when around bridges, meaning close to shore the antenna will work just fine left down for FM. Only raise it if going offshore?


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Old 01-08-2017, 11:54 AM   #44
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I would think when around bridges, meaning close to shore the antenna will work just fine left down for FM. Only raise it if going offshore?


Jim
This is for lake use. My coastal boating is very limited, and is typically only on the ICW, murels inlet, charleston harbor, and Edisto. I'll possibly occasionally go out near shore a bit, but very rarely.

The end of the lake we are on is right in the middle between 2 major markets, on the outskirts of both. FM Signal is garbage there, making the height necessary. I'm not concerned about momentarily loosing reception going under a bridge, just ease and convenience of doing so.

I tried several antennas on my old CC (roughly the same height off the water) including a dedicated rubber duck, wire in the console, etc. None worked well. Out of all the boats I frequent the only one that is decent is my brothers CC which has an antenna on top of the t-top. Downside being he has to take a longer route in several places because if bridge clearance, and there are some places he can't go at all. An 8' vhf rail mounted antenna on my boat will be roughly the same height as his antenna.
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Old 01-08-2017, 01:07 PM   #45
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Originally Posted by jfwireless View Post
I would think when around bridges, meaning close to shore the antenna will work just fine left down for FM. Only raise it if going offshore?


Jim
I believe that is the best answer you can get. FM broadcast antennas historically were all vertically-polarized (as is marine VHF), but when car manufacturers migrated from telescoping vertical antennas, to horizontal dipoles embedded in windshield glass, most stations changed from vertical to elliptical (or, circular) polarization, so most FM receivers perform as well (or, as poorly) with either vertical or horizontal antennas.

Some stations were mandated to remain vertically polarized, to minimize interference to nearby TV Chan. 6, however. Some car manufacturers have compromised by placing their embedded antennas at a 45° angle, hard to do in the windshield without becoming noticeable to driver, and generally not possible in rear window due to defroster heating elements.

Try Jim's suggestion, and I don't think you will notice a bit of difference, unless you are laying the antenna down on a metal roof.
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Old 01-08-2017, 01:21 PM   #46
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It won't be a problem in Norway much longer. Deciding what kind of FM antenna to use, with or without a splitter, that is.

http://www.theverge.com/2015/4/19/84...-fm-radio-2017

When will the USA follow suit?
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Old 01-08-2017, 02:09 PM   #47
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Australia has had DAB+ running side by side with their AM/FM broadcast stations since July 2009. The radio's themselves are the problem as they still are difficult to find, even now after 8 years.
Fusion introduced their Digital radio, but needs expensive receiver module MS-DAB100A to suit.
Going by the number of radio announcers who love the sound of their own voice, no one wants it anyway.So I suppose phasing out FM here is many years away.
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Old 01-08-2017, 02:14 PM   #48
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What about the installed-base of millions of analog FM receivers, particularly in vehicles? Do car makers even offer it as an option?

In the US, with transition to digital TV, subsidized converter boxes were available...sounds like it would be awkward to impossible to do in mobile receivers to switch to digital, however...would they be D/A converters, so digital stations could be received as virtual FM stations?
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Old 01-08-2017, 03:47 PM   #49
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My own comment re:polarization, jogged some youthful memories...those telescoping car radio antennas were always a problem with urban vandalism, as they provided quick access to a weapon, not as lethal as today's collapsible-batons, but still intimidating, often requiring a facial plastic-surgeon...the car makers responded with power-antennas, which retracted with either radio or ignition being turned off.

This obviously dates me, as they're only seen at classic-car meets nowadays, and I only owned one car with one, which proved very expensive to replace when its motor failed. But the first glass-embedded antennas were marginal, generally requiring a pre-amp stage in the receiver. Just some more trivia I seem to be a reservoir of.
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Old 01-08-2017, 06:40 PM   #50
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Trey,
I have 2 antennas and a splitter you are more than welcome to. Hit me up sometime for how I can get them to you.
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Old 01-08-2017, 11:26 PM   #51
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Why not install a 4ft fixed mount vhf infront of the windscreen and you the rail mount for a dedicated am/fm arial? That would put the vhf at the same height as your Bimini and you will only need to fold down one arial and still have the proforma Central of both aerials for each radio
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Old 01-09-2017, 05:34 AM   #52
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I see today in the news Norway is the first country to eliminate FM in favor of DAB

http://money.cnn.com/2017/01/06/tech...page_tech_pool

Jim
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Old 01-09-2017, 06:57 AM   #53
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Originally Posted by jonboy View Post
Trey,
I have 2 antennas and a splitter you are more than welcome to. Hit me up sometime for how I can get them to you.
Will do. You still have a 709 phone #?
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Old 01-10-2017, 05:42 PM   #54
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Sent you a PM
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Old 01-11-2017, 09:04 PM   #55
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Quote:
Originally Posted by Karl in NY View Post
...FM broadcast antennas historically were all vertically-polarized (as is marine VHF)...
Karl has this exactly WRONG. Anyone actually familiar with radio broadcasting knows that FM Broadcasting began with horizontal polarization. Compare at

http://www.astronwireless.com/topic-...larization.asp

where you will find:

Quote:
In the early days of FM radio in the 88-108 MHz spectrum, the radio stations broadcasted horizontal polarization. However, in the 1960's, FM radios became popular in automobiles which used vertical polarized receiving whip antennas. As a result, the FCC modified Part 73 of the rules and regulations to allow FM stations to broadcast RHC or elliptical polarization to improve reception to vertical receiving antennas as long as the horizontal component was dominant.
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Old 01-12-2017, 01:00 AM   #56
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Originally Posted by jhebert View Post
Karl has this exactly WRONG. Anyone actually familiar with radio broadcasting knows that FM Broadcasting began with horizontal polarization. Compare at

http://www.astronwireless.com/topic-...larization.asp

where you will find:
Guess your broadcast experience pre-dates mine by about 15 years...are you using a computer in a nursing home?

Once you enter a thread, I'm gone...you always insist on getting in the last word, a game I refuse to play anymore. No link to a vanity-press article on continuouswave.com, this time?

My last post here in this thread.
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Old 01-12-2017, 01:41 PM   #57
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Originally Posted by Karl in NY View Post
Guess your broadcast experience pre-dates mine by about 15 years...are you using a computer in a nursing home?

Once you enter a thread, I'm gone...you always insist on getting in the last word, a game I refuse to play anymore. No link to a vanity-press article on continuouswave.com, this time?

My last post here in this thread.
Me too, and that goes for two other wikiwankers here who sit back and pop out like a wet fart who take a general comment aimed at the OPs post and shoot themselves in the foot trying to outsmart someone with forty years practical experience. Wannabe kids in a sandpit.
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Old 01-12-2017, 02:23 PM   #58
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wikiwankers
Love it mate
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Old 01-12-2017, 03:10 PM   #59
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Love it mate
You restore my faith, thank you. Shouldn't be necessary. Apologies for being completely off topic but here's an example.... If I say traffic lights are green, argumentative nit picking purists would say I'm wrong, stating their red, and before you know it, were arguing over priority encoders controlling traffic light sequences for pedestrian and cyclists buttons, progressing to LED vs Halogen and incandescent globes ending up with operation of buried metal detecting inductive loops in the ground and ignoring the question "what color traffic light means go". No doubt I will be accused of doing just that in this post...I know, that's the point, I'm now past caring, this forum is the most unfriendly forum on the internet with cretins praising cretins for providing info derived from 30 seconds of internet searching and coming back as a troll.
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Old 01-13-2017, 08:01 AM   #60
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To further correct some misinformation given in this discussion, the height of the receiving antenna has a very significant effect on reception of FM Broadcast signals. In an engineering study published in a respected journal, it was noted that increasing the height of a receiving antenna used for FM Broadcast reception to 30 feet from 5-feet generally resulted in about an 8-dB increase in signal.

"In very smooth terrain there is nearly a direct relationship [of signal strength] with height...in areas with terrain roughness...there is even greater increases with the same height increase."

Reception over open seawater would be "smooth terrain." Receiving antenna height has a very significant effect on received signal strength.

http://www.americanradiohistory.com/...th-Edition.pdf
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