Chotu’s Advanced Standing Rigging Thread (lots of pics)

[LakeSuperior]

Originally Posted by team karst

What you haven’t seen is the VSWR and horiz antenna pattern from such installs.

Side mounted vhf installs on towers exist, but usually with a wavelength or so of air space.

Physics majors learn this stuff in E&M. Translating to the real world a parallel install next to the mast would or should raise questions.

[Chotu]

Originally Posted by team karst

What you haven’t seen is the VSWR and horiz antenna pattern from such installs.

Side mounted vhf installs on towers exist, but usually with a wavelength or so of air space.

I mean, I’m not an electrical engineer but I am a physicist. So yeah. I knew there would be a lot of signal degradation in one direction.

I don’t understand why the Rigger would have bought this to begin with that’s what I’m so frustrated at. Plus the fact that it’s been raining and I’m losing days and it’s really hot. No different than Florida. Lol I might as well just be in Florida

i’m just losing too many days here and I have a finite window to get this done and it's almost up.

No car, no resources. Just public transportation.

and what’s really frustrating is this thing had an angle bracket on it for mounting a VHF. But the shady rigger insisted on not using it and buying this setup instead

[Chotu]

Originally Posted by rslifkin

If the antenna is close to the top of the mast, just get an extension mast to space the antenna up from the mount so it's above the mast. They come in 6 inch, 1 foot, 2 foot, and 4 foot lengths. If you're concerned about the extra load on the mount, add an upper support bracket at the top of the mast to brace the antenna.

There's no technical reason you can't use a "powerboat" antenna on a sailboat or vice versa. It's just a matter of what is commonly used on each (and is typically easy to install).

This is a reasonable approach. Unfortunately, it's no faster than a different antenna, but it is less wasteful

[Chotu]

Shakespeare 6500-wb also seems to be a side mount. (See attached)


engineering question. I could probably figure it out if I wasn’t outside doing this all right now in ridiculous heat and humidity and sun.

Given that this is a larger 4 foot or 3 foot antenna, and the typical ones on the mast head are these tiny little wire ones, why couldn’t I just stick it up above the mast as much as the smaller ones?

wouldn’t that work to give me the same range as the smaller ones on one side of the boat and a much larger range on the other side where it is reflected off the mast?

The smaller wire masthead antennas have a certain length based on the vhf wavelength. Isn't that all I need sticking up?

Like a 38" portion above the masthead which is the half wavelength of the vhf wave?

[rslifkin]

Originally Posted by Chotu

This is a reasonable approach. Unfortunately, it's no faster than a different antenna, but it is less wasteful

I was thinking that it gives you another option for something you might be able to find locally vs having to order and wait.

Originally Posted by Chotu

Shakespeare 6500-wb also seems to be a side mount. (See attached)


engineering question. I could probably figure it out if I wasn’t outside doing this all right now in ridiculous heat and humidity and sun.

Given that this is a larger 4 foot or 3 foot antenna, and the typical ones on the mast head are these tiny little wire ones, why couldn’t I just stick it up above the masa as much as the smaller ones?

wouldn’t that work to give me the same range as the smaller ones on one side of the boat and a much larger range on the other side where it is reflected off the mast?

The smaller wire masthead antennas have a certain length based on the vhf wavelength. Isn't that all I need sticking up?

Like a 38" portion above the masthead which is the half wavelength of the vhf wave?

You'd want the whole antenna above the masthead, as the exact length of the radiating elements, etc. depends on the design of the antenna. But once it's above the masthead, it'll work like any other antenna of equivalent gain regardless of whether it's the same design or not.

[Chotu]

Originally Posted by rslifkin

I was thinking that it gives you another option for something you might be able to find locally vs having to order and wait.




You'd want the whole antenna above the masthead, as the exact length of the radiating elements, etc. depends on the design of the antenna. But once it's above the masthead, it'll work like any other antenna of equivalent gain regardless of whether it's the same design or not.

Ok. Cool.

unfortunately there is nothing local. I am here by boat. No car. No marine resources nearby.

so I’m wondering if I can use what I have. And just get it above the mast. I’m sure I can rig something up. I’m going to look at that first since it’s fastest

[team karst]

This works for the vast majority of masthead installs.
Amazon has transport! This one has the AIS compromise too. Metz, Digital, all made the base loaded whip design. Like curb feelers when bridge is too short. [emoji847]

[Chotu]

so, to play it safe I just moved everything up. It would have been really nice to have a little sleeve for that side mount stainless steel bracket I could have made it vertical and just screwed it right to the top. But I don’t have a sleeve. I don’t have a car. I don’t have any resources.

might as well be fixing this thing in Barbados.

So, I just moved at all upward so that the antenna is above the top of the mass. It works.

Only problem is now my screws are too short to reach on the horizontal stabilizer piece. Getting pretty pissed off today actually

Lost almost 3 days here in a row. First transportation took six hours to get back on Saturday. Second, yesterday was pouring rain at a different level. And today everything just sucks.

Who wants to buy a boat? Lol

Joking.

[neilpride]

Look on the bright side, you are alive and you can enjoy things that others can't.

Boats, sometimes you have difficult days and others the stars align.

[Chotu]

what really sucks is now the screws won’t reach and I can’t get 316 stainless anywhere in the size I need..

Doesn't exist on Amazon.

No stores nearby that carry 316

Maybe I'll use 304?

I might as well be in Bonaire trying to do this at this point.

[Chotu]

Originally Posted by neilpride

Look on the bright side, you are alive and you can enjoy things that others can't.

Boats, sometimes you have difficult days and others the stars align.

True, it’s just a particularly frustrating day. That’s all.

but, I don’t know if it’s like enjoying things that others can’t. This is just the lifestyle I chose. I could do something different if I wanted to. But for some reason I keep sticking with this. Through all the suck.

[neilpride]

304 do the trick until you find 316. Tef gel ....

[team karst]

Boltdepot did a very quick turn on my last order. Out of boston area.

[rslifkin]

Especially up at the masthead where there's a lot less salt spray, 304 will do fine for now. Swap them out later when you get a chance if you're concerned, but they'll last quite a while before they show more than slight cosmetic corrosion.

[Chotu]

yes. Been using boat depot for like 10 years now. Every bolt on the boat came from there. Great place.

not entirely cost-effective to overnight ship two bolts.

Got help from the marina. Got some 316 coming tomorrow