NBS Tilt Over Mast Experiences

[VK6EI]

I purchased a mast off Brian last year after finally getting planning approval from our shire, has been a great investment and happily keeps my Force12 C4S and 2m/70cm vertical in place.

I picked up a 2.4m platform ladder and it is the perfect height for doing any antenna work with the carriage lowered and mast left in the vertical plane. Soon will be putting up a 3 element SteppIR 20m-6m.

Brilliant product from NBS and Brian was a pleasure to deal with.

73 de VK6EI.

Tim.

[VK1JA]

This may be a question for a new thread, but it relates to the NBS Mast so I'll try here first.

Planning has started on redesigning the back yard, and all going well with approvals, I'll be putting in a NBS Mast.

Where I'd like to install the mast is about 2m away from a double brick retaining wall that is ~1.4m high and I was wondering if this 2m is enough standoff from the retaining wall?

If you can picture it in your head, the floor level of the back of the house is 1.4m lower than the base of the mast (it steps UP 1.4m from the house to the base of the mast), the retaining wall is about 1.2m away from the house. So I'm wondering if the 2m of dirt (clay for VK1) between the retaining wall and the concrete for the mast support will be enough to support the mast - the mast will obviously tilt away from the house.

The hole for the mast support calls for a 2m hole, so the hole/concrete/support will extend below the lowest point of the retaining wall. If needed I could extend the hole down to 2.5m.

Do we have any engineers in the house?

[VK4TI]

Personally imho long as the hole is filled well and doesn't make a path for the retaining wall foundation to move there should be a problem , I assume the hole will be concrete reo filled and well braced ?

[VK1JA]

From what I can tell from pictures online, the mast support extends down into the hole, maybe 1.8 to 2m, so specs don't appear to call for the need of reo.

Thanks to VK3YY for this write up - https://vk3yy.wordpress.com/2015/11/03/ ... nnas-mast/

[VK3MEG]

Jason talk to brian i hit rock and my tower foundation is 1 m cubed remember that weighs around 2.3 tonne. so very substantial so there is more than 1 way to skin a cat.
my nbs tower has been up for nearly 3 years and with my antenna farm on top there has never been an issue even in 100 kph winds gusts.
cheers

[VK1JA]

G'day Steve,

Sounds good with your setup!

Looks like timing might be in my favor this time, I've arranged with Brian for us to stop in on our way from VK1 to GippsTech, it'll give me a change to chat to Brian and have a look at his new extendable mast that fits into the tilt over base he has.

P.S> 2.3 tonne, that's a big hunk of concrete

Cheers

[VK3MEG]

hey Jason pics of the extendable mast would be great

[VK2AAH]

G'day Steve,

Sounds good with your setup!

Looks like timing might be in my favor this time, I've arranged with Brian for us to stop in on our way from VK1 to GippsTech, it'll give me a change to chat to Brian and have a look at his new extendable mast that fits into the tilt over base he has.

P.S> 2.3 tonne, that's a big hunk of concrete

Cheers

Tell me about it... my concrete truck couldn't squeeze around the back to where my mast is... so I had to wheelbarrow the whole load of 32MPa into the hole before it set. After some months I swear my shoulders are still sore... but it was worth the pain. There is no way my mast is going to move.

Cheers


Richard
VK2AAH

[VK3MEG]

Tell me about it... my concrete truck couldn't squeeze around the back to where my mast is... so I had to wheelbarrow the whole load of 32MPa into the hole before it set. After some months I swear my shoulders are still sore... but it was worth the pain. There is no way my mast is going to move.

Cheers
Richard
VK2AAH

i'm thank full richard they sent small truck to my one ... just made it but still lots work and the 500mm deep rock i needed to dig out, i'm ever thanks full to my frend vk3faaj marcel for showing his elite jack hammer skills.

[VK2AAH]

I was lucky with the hole Steve... I had forgotten that there was an old absorption trench there so the backhoe hit a concrete lid, some bricks & then there was a cavity. Lucky it wasn't still in use... he hit a solid rock shelf at about 1800mm down so I wound up with a hole much wider than I needed but plenty deep. The base is sitting on the solid rock. I don't think mine is going to go anywhere... I'm very happy with my NBS- worth every cent & every aching muscle for the convenience it gives me. Being able to work on the antenna and rotator, being able to lower it when not in use... is brilliant... but I know I'm singing to the choir!

Cheers


Richard
VK2AAH

[VK1JA]

One thing I've been looking into recently is trying to find a suitable noise less hand brake winch that has the same capacity as the one that comes with the NBS mast (1500lb - 680kg).

One I found (link below for the BHW1200) looks good, but has not got the same load rating, and I would prefer to stick to the 1500lb specs (or higher).

http://www.pacifichoists.com.au/our-pro ... e-winches/

I like to lower the antennas when not in use, and raising them at 8am on a weekend makes a bit of noise in the middle of suburbia

Oh, a tip for other NBS owners, a 21mm socket on a cordless drill makes quick and easy work of raising and lowering the antennas

[VK3AV]

Mine has been in place since October 2015, is exposed to the weather and the dust that comes from living on a dirt road in a rural area and the brake winch makes no noise at all when winding. I also keep it wound down when not in use.

I do like the idea of using a socket and drill to raise and lower I would not have thought of that.

Regards
Bernard

[VK1JA]

Hi Bernard,

That's interesting that yours makes no noise at all.

I presume you are using the one that came with the NBS mast? There must've been a model change at some stage. Is there any make/model info printed on your winch?

Mine only makes the racket noise when lifting the antennas, it's 100% quite when lowering them.

Thanks

[VK3AV]

Jayson,

The model that came with my mast is a brake winch (orange coloured thing). You can see them here - https://www.nbsantennas.com.au/antennas-and-parts.html

I have just wound mine up a little and yes indeed you can hear the pawl clicking on the internal toothed gear. So no different to yours except that I don't a) tend to wind it up too often, b) do it at 8:00am and c) remember what it sounds like (it seems).

I really should turn the radios on more often...

Regards
Bernard

[VK1JA]

Just an update- I double checked the mounting hole measurements of the 'quiet' winch I linked above and sadly they are different to the holes on the nbs winch mount plate, so it's not a direct replacement - the quiet version seems to be the next size down compared to the one that comes with the nbs mast.

I'm not willing to re-drill the nbs mount plate as that will just weaken it.

Just to confirm, the winch that comes with the nbs mast is perfectly ok, I was just on the hunt for a quiet version of the winch. I'll continue to search around, but I haven't found anything as yet.