Complete Electronics Outfit - Caliber 40

[witzgall]

Originally Posted by CAELESTIS

Go with the Vesper splitter. You need the antenna height with the mast mount.

X2. I used an AIS antenna mounted to our bimini , and I found that too low. In 1-4 foot seas, we could see ships 12 miles out. Bigger than that, and the distance started dropping, just when we needed to see these ships on AIS!

Chris

[LJH]

Originally Posted by CAELESTIS

Go with the Vesper splitter. You need the antenna height with the mast mount.

Originally Posted by witzgall

X2. I used an AIS antenna mounted to our bimini , and I found that too low. In 1-4 foot seas, we could see ships 12 miles out. Bigger than that, and the distance started dropping, just when we needed to see these ships on AIS!

Chris

Agreed, I have a mast mount and have had difficulty receiving class B targets with bimini mounted antennas. Sometime as close as 2 miles in rough seas. If you want others to see and avoid you, higher is better.

[DotDun]

Originally Posted by witzgall

X2. I used an AIS antenna mounted to our bimini , and I found that too low. In 1-4 foot seas, we could see ships 12 miles out. Bigger than that, and the distance started dropping, just when we needed to see these ships on AIS!

Chris

Can I ask what navigational value you find in seeing ships 12 miles out?

Just curious.

[DDabs]

Well in my case, I think since I'll be having a really nice antenna and coax cable going to the masthead, I might as well use that with the splitter for the AIS as well. Also one less thing to clutter up the arch and shade the solar panels.

[LJH]

Originally Posted by DotDun

Can I ask what navigational value you find in seeing ships 12 miles out?

Just curious.

It is not just the value of seeing them 12 miles out, but the value of them seeing you. With my mast mounted antenna, I regularly pickup class A targets when the TCPA is well over an hour. I have seen merchant ships adjust their course 45 minutes prior to CPA to ensure that they have a 2 mile CPA from my sailing vessel. With a big picture and early warning there are fewer surprises for everyone.

[DotDun]

Originally Posted by LJH

It is not just the value of seeing them 12 miles out, but the value of them seeing you. With my mast mounted antenna, I regularly pickup class A targets when the TCPA is well over an hour. I have seen merchant ships adjust their course 45 minutes prior to CPA to ensure that they have a 2 mile CPA from my sailing vessel. With a big picture and early warning there are fewer surprises for everyone.

With the variability of private vessels, I won't put any credence in TCPA more than 15-20 minutes. I find it interesting if professionals do.

[DDabs]

Quick update of my list:

https://docs.google.com/spreadsheet/...VE&usp=sharing

As of now I'm still trying to complete a good backstay antenna setup for the SSB and think of anything else that I may need. I am also thinking that with all of the lights/antenna being mounted on the masthead, I am better off pulling it out during the refit.

[ka4wja]

I have BOTH, a stern pole mounted VHF antenna, AND a Vesper SP-160 splitter/relay on my masthead VHF antenna....
And, I can use either for my Class B AIS transponder....

{I sailed for 6 years and 12,000+ miles offshore with only a stand-alone AIS receiver, before adding my current Class B AIS transponder w/ Vesper WatchMate 650 display, about 2 years ago....so I have experience with AIS rec-only as well as an AIS transponder on-board....with both a masthead antenna (65' high) and a stern-pole mounted antenna (9' - 10' high)....}

So, perhaps I can add some input and some caution...

Originally Posted by DDabs

Well in my case, I think since I'll be having a really nice antenna and coax cable going to the masthead, I might as well use that with the splitter for the AIS as well. Also one less thing to clutter up the arch and shade the solar panels.

I do NOT recommend any other "splitter"/relay than the Vesper SP-160....
1) Yes, there is some loss (approx. < 1db) thru the SP-160 for VHF, but I accept this combined with my LMR-240 / LMR-400 cabling loss, is less than most have in their masthead VHF antenna system.....and while it is another part that can fail, it's "failure mode" is VHF-straight-thru, so your primary VHF is always connected to the antenna....(and I have a bypass/coupler connector at the ready, should it be needed)....
And, I have the stern-pole mounted VHF antenna rigged/wired so I can use it for the AIS antenna in coastal areas and/or in good weather....(or use this as a spare primary VHF antenna, as well...)

2) Understand all of the above, and make your decisions accordingly...

3) Do NOT worry about the shading of a SS whip, on solar panels...
(my Wi-Fi antenna causes a bigger issue, and even it doesn't adversely effect my solar array output...)
See photos of my stern-pole mounted whip...








Here's a fairly detailed article I wrote about my AIS systems...
AIS Transponder




I hope this helps...

John
s/v Annie Laurie

[ka4wja]

Dot,
In my case, it's not so much the necessity for increased range, but rather the ability for other vessels to see my Class B AIS signal when in a heavy seaway...

Originally Posted by DotDun

Can I ask what navigational value you find in seeing ships 12 miles out?

Since the Class B transponder only transmits your position data every 30 seconds (compared to Class A of every 2 to 10 seconds), this can mean that many of your transmission packets might not get thru if your low-mounted antenna is blocked by waves, If you're in a heavy seaway, and you're down in a trough as your AIS sends out your transmission, over and over again....this can mean that the other vessels out there may not get many of your packets, and may not see you as a CPA threat until your are fairly close...

And, unfortunately heavy seas can also mean poorer visibility, so if you've got a Class B AIS transponder, and you're in a heavy sea, you may wish to use a higher antenna (such as your masthead VHF antenna) in order to increase the possibility of your Class B signal being recognized as far out as possible...



I hope this helps...

John
s/v Annie Laurie

[DotDun]

Originally Posted by ka4wja

Dot,
In my case, it's not so much the necessity for increased range, but rather the ability for other vessels to see my Class B AIS signal when in a heavy seaway...Since the Class B transponder only transmits your position data every 30 seconds (compared to Class A of every 2 to 10 seconds), this can mean that many of your transmission packets might not get thru if your low-mounted antenna is blocked by waves, If you're in a heavy seaway, and you're down in a trough as your AIS sends out your transmission, over and over again....this can mean that the other vessels out there may not get many of your packets, and may not see you as a CPA threat until your are fairly close...

And, unfortunately heavy seas can also mean poorer visibility, so if you've got a Class B AIS transponder, and you're in a heavy sea, you may wish to use a higher antenna (such as your masthead VHF antenna) in order to increase the possibility of your Class B signal being recognized as far out as possible...



I hope this helps...

John
s/v Annie Laurie

It would be interesting to review the discussions of the original AIS designers when they decided on the lower-power class B specifications. I would like to believe they considered these scenarios.

I find my stern mounted antenna adequate. I find a lot of the discussions for the need to be at the top of the mast more marketing hype than fact. I don't refute your scenario, but would considerate it very unlikely that one would be in the bottom of a trough exactly on 30 second intervals.

As you state, one should not jeopardize the VHF comms service for the sake of getting AIS to the top of the mast. You've obviously found a solution that's reasonable to you. It comes down to how many $$ one is willing to spend in order to gain functionality that has a very, very low probability of need. I would like for the unsuspecting CF readers to be aware that AIS on the stern rail works, and will cover, IMO, 99+% of their AIS needs.

I've considered an X switch, just never pulled the trigger (yet).

[DDabs]

So how easy is it to switch the AIS from the masthead antenna to a stern mounted antenna? Is it just a matter of unplugging and plugging in a different cable to the transceiver?

How does this sound:
-Shakespeare 5400-XTM Little Giant on masthead
-Ancor RG-213 coax
-Vesper VHF/AIS splitter
-Shakespeare 5250-AIS Skinny Mini on arch

The AIS whip for the arch comes with RG-58 cable, is this efficient or should I keep everything the same type of cable and run RG-213 there as well? After reading your blog and seeing the photos, you're right about the solar shading, doesn't look like it's going to be a problem. Also, I couldn't understand after reading your blog which VHF antenna you primarily use, the masthead or the stern mount? Another stupid question: if an antenna is called an AIS antenna, I am to assume that it can also be used as a VHF antenna correct?

[ka4wja]

David,
1) Yes, this is what I have rigged...

Originally Posted by DDabs

So how easy is it to switch the AIS from the masthead antenna to a stern mounted antenna? Is it just a matter of unplugging and plugging in a different cable to the transceiver?

In my case, it is just that easy....no switches to worry about, just "plug 'n play"...






2) I avoided the "which antenna is best" argument (i.e. discussion), as I didn't feel like a fight... (and still don't...)
But, in a nut shell...
Assuming the antennas are all properly designed/constructed, a "half-wave" antenna is a "half-wave" antenna, whether end-fed or center fed...
Sorry to say those are facts...but many will argue them, so I'll not go further...
(and please take note that even the center-fed "VHF-dipole antennas" are "coaxial dipoles", which work well, but usually have decoupling devices at their feed, just like the matching devices on the end-fed antennas...so no real difference in antenna gains/loss...)

So, having said that....
It comes down to two major things...
a) what is your mast height / do you need a bendable antenna on the masthead (as I DO, with my 64' high mast)
b) can you buy an antenna that has an SO-239 connector on it, so you can use your own cable as desired...(again, this is a yes for me...)

I chose the Shakespeare 3' SS whip antenna with the SO-239 connector at its base, for BOTH my masthead and my stern-pole mounted antennas...
It is the Shakespeare 5215....(actually have the 5215 at the masthead and a 5215-AIS on the stern....the SAME antenna, except the "AIS" is 1" shorter...)
5215-AIS Squatty Body® | Shakespeare Electronic Products Group

Sorry about the old photos...












3) Why "Ancor" RG-213???
Why not use Belden, Times, Commscope, or Davis??? (all of these are reputable/reliable cable manufacturers....I don't know where Ancor coax is made....it might be good, but I don't know....so, I'd recommend buying your cable from Texas Towers or DX Engineering....)
Texas Towers, Coaxial Cable Page
Texas Towers, Coax Jumpers Page

Coaxial Cable, Bulk - Free Shipping on Orders Over $99 at DX Engineering

Coaxial Cable Assemblies - Free Shipping on Orders Over $99 at DX Engineering



4) The Vesper SP-160 "splitter/"relay is good...
Just understand the limitations / losses involved, and make your decision accordingly....(which means I recommend compensating for the minor additional loss, by using as low-loss cable to your masthead antenna as practical, which is usually RG-213/u or LMR-240uf...but if you can fit and afford LMR-400uf or Davis Bury-Flex, that is what I recommend...)




5) All addressed above....but specifics here in red....

Originally Posted by DDabs

How does this sound:
-Shakespeare 5400-XTM Little Giant on masthead ??? (a good antenna, but no better than the 5215, and understand that it will NOT bend, if you need the clearance for bridges!)

-Ancor RG-213 coax ??? (Why not use a known-good, name-brand coax???)

-Vesper VHF/AIS splitter (okay, as long as you understand the negatives and compensate for them)

-Shakespeare 5250-AIS Skinny Mini on arch ??? (why not use the 5215-AIS ???)


The AIS whip for the arch comes with RG-58 cable, is this efficient or should I keep everything the same type of cable and run RG-213 there as well?
For VHF and UHF I always recommend low-loss cables (such as LMR-240, LMR-400, etc.) but at the very least RG-213...even for short runs...

{BTW, in 40 years of using low-loss foam dielectric cables, I've never had any moisture issues with the cables....connector issues on lots of various cables, but never moisture issues due to a low-loss foamed dielectric...oh, and further if you ever wondered what type of dielectric is in the bigger cables used on cellular towers, etc.....yep, it's foam dielectric cable...just weather-proof the connectors like you're supposed to, and no worries..)}


After reading your blog and seeing the photos, you're right about the solar shading, doesn't look like it's going to be a problem. Also, I couldn't understand after reading your blog which VHF antenna you primarily use, the masthead or the stern mount?
Not sure if you're asking me...as I don't have a blog (and I never will have one!!)....
But if you are asking me...
As of right now, my masthead antenna is shared between the primary VHF radio (Icom M-602) and my AIS transponder, using the Vesper SP-160 "splitter"/relay....(my stern-mounted antenna is my spare...)
I can change that arrangement in about 30 seconds, by swapping coaxes at the Nav Station....


Another stupid question: if an antenna is called an AIS antenna, I am to assume that it can also be used as a VHF antenna correct?
Yes, absolutely!!!

I hope this helps...

John
s/v Annie Laurie

[DDabs]

John, awesome, thank you SO much. By blog I meant your website, sorry.

My mast is right around 60'. I have read that it is 59', but other Caliber owners have said that theirs is 61'. If there isn't any much performance difference between a whip and a dipole, maybe I'll reconsider, but after reading the sticky on VHF antennas, I am partial to go with a fiberglass antenna.

For the masthead, if I use LMR-400UF, what type of connector will I need? Or does the LMR-400 just run from the VHF to the antenna?

Now all that's left is to figure out a solution for the SSB.

[ka4wja]

Goota make this quick...

Use Times connectors designed just for LMR-400....
But...
But much better to have a pro do it, so you know that it is done correctly....putting on these connectors takes practice...
Or, if you don't wish to spend the $$$ hiring a pro, buy pre-made cable assemblies...yes, the connectors make the installation a bit more problematic, but at least you'll know it works...

BTW, I would take a known-good / professionally installed connection on even RG-8x, over a piss-poor connector install on LMR-400 or even RG-213....'cause you know the former will still be working months/years dfrom now, when the latter may have failed within days...


Fair winds..


John
s/v Annie Laurie

P.S. Actually not my website....although most of the photos and articles there are mine, the website was out together by an owner of a sister-ship to my Annie Laurie, as he wanted everyone's projects/upgrades/etc. in one place....
C470 Projects by Boat Name

[DDabs]

John, all of the work on my boat is going to be professionally done at Sailcraft Services in Oriental, NC. I am going to participate as much as I can during the outfit to learn about how to do things myself, since all of this is new to me.

I am just trying to put together a list to have of what to order and I'm making sure I have all of the small things needed so there is no confusion once I start to have things installed.

I guess my question was, if I go with the LMR-400UF, I see the Shakespeare antennas come with an SO-239 connector. The coax has an option for a connector when I purchase it:

http://www.theantennafarm.com/catalo...84be774c8.html

Do I need to order the coax with a connector installed?