NBS Tilt Over Mast Experiences

[VK2AAH]

Hi all,

I'm about to invest in one of Brian's (NBS) tilt over mast mounts to support a TET TE-34.

Now I've dealt with Brian before & no-one has to tell me how good a bloke he is. I know he is... But I'm not the most mechanically gifted individuals & am looking for tips and tricks others used when installing one of these.

Pipe suppliers? How to handle the 90 odd kg of pipe... etc...

I'm going to be mounting my old Dick Smith rotator- Brian assures me that the mount should work perfectly. I'll get the Yaesu thrust bearing locally...

All advice would be appreciated.

Cheers


Richard
VK2AAH

[VK3AV]

Some comments (I hope that you can visualise what I am describing) -

I had an issue getting pipe delivered as I live out of town a bit. Plenty would sell it to me, but not deliver. Finally a passing comment when at a local local industrial supplier (my source of bolts etc) was picked up and 8m cut from the 10m length on their rack. They delivered as well. So easy after months of frustration talking to other suppliers.

I ended up removing the ram to drop the arm section against the lower vertical tube so that two of us could pick up one end of the 8m tube and sit it into the tilted section. Then we lifted it at the opposite end and bounced it into the lower mount. I used a car trolley jack and some framing timber to lift the 8m tube a meter or so out from the pivot bolt to heck the tube into a position where I could reinsert the ram.

Installing the carriage and top cap onto the 8m tube was now a little harder as the top end was too far off the ground so I slid my box trailer under it, braced it with axle stands at the back and used the jockey wheel to stabilise the trailer. This gave me an elevated platform that made the rest far easier.

I found a plumbing clamp devise in a rural hardware store that I bolted to one of the edge holes on the carriage unit and screwed to it a small length to timber with notches cut in it so that I could cable tie the feedlines into the notches to sleep the cable loops in place. That is working fine.

The rotator and bearing were not an issue for me though I did take time to get the scaffold tube centered correctly. I also used anti-seize on all of the bolts/screws to make removal easier. One thing to remember is the clearance needed to lower the carriage once the antennas are installed. I have placed a marker on the rotator controller in a position that lets me lower the carriage without hitting antenna elements. I have VHF/UHF antennas on the mast so the element spacing makes things a little tight and I have bent an element or two when I did not get it positioned quite right.

I have found that the winding cable can slap against the pole when it is windy and is quite annoying at night etc. This happened when the carriage was fully lowered due to high winds. Now I wind it up a little from the fully lowered position to keep tension on the cable. That has stopped the noise.

That is about it.

My $0.02 worth.

Best of success with the set-up.

Regards
Bernard

[VK3ALZ]

Hello Richard

I installed one just recently.
Mine holds a hexbeam (which is a story in itself!)
I found an article online by VK3YY which had some very good hints and ideas.
https://vk3yy.wordpress.com/2015/11/03/ ... nnas-mast/

I too had the ram removed to install the RHS except there was four people to lift it in.
My local metal mechant was very helpful. Handed over the cash, and the next day it was in my driveway!
In reading the article by VK3YY I made sure my base was solid so that when I poured the concrete in it didn't move.
My boxing or concreting work wasn't the best but I used 32MPA stuff to make sure it's going to stay there!

When you lower or raise the mast be very careful. There isn't any counter weight so there is a hell of a lot of weight at your finger tips (so to speak) Also when you start to lower it, be carefull as its a bit fiddly to get started. Once it's all together it'll make sense!
I have removed my ram so that it isn't exposed to weather (as suggested by a couple of people). This was the easiest way to protect it from the elements. It's very simple to remove and replace.

I've posted a couple of pictures below.

73
Michael
VK3ALZ

[VK2AAH]

Thanks guys! That info is brilliant- just what I was after. Michael your photos were just what I was after...

The 8m of pipe is sorted- luckily living in Sydney Edcon Steel are not far away & they will deliver. All up the steel looks like costing around $200.

Heading down to pick it up in the next week but now I'm much more confident... thanks.

Cheers


Richard
VK2AAH

[VK1JA]

I found a plumbing clamp devise in a rural hardware store that I bolted to one of the edge holes on the carriage unit and screwed to it a small length to timber with notches cut in it so that I could cable tie the feedlines into the notches to sleep the cable loops in place. That is working fine.

Hi Bernard,

Thanks for the details and hints of your install, very helpful.

One thing that has been buzzing around my head is how to hold the coax cables to the carriage is such a manner that it doesn't damage them. If using a few runs of LDF4-50, the weight of the cables can add up fast!

Does the carriage have an option for a cable holder, or at least holes in the carriage that something can be mounted to?

Are you able to provide some close ups of the way you've secured the cables to the carriage? It'd be very useful to see how you've done it.

73

Jayson
VK1JA

[VK4TI]

"VK3ALZ"Hello Richard

I installed one just recently.
Mine holds a hexbeam (which is a story in itself!)
I found an article online by VK3YY which had some very good hints and ideas.
https://vk3yy.wordpress.com/2015/11/03/ ... nnas-mast/
snip


73
Michael
VK3ALZ
''

Useful information , what size is the rhs looks like 75mm (wall thickness?)
Ok so the hexbeam story ?
Tnx

[VK3LU]

Hi all,
This is a very interesting thread. I have been contemplating what to do if my existing mast has to go. Now I might have an answer.
One question: what are the dimensions of the hole to be bored in the ground?
Also, how far out from the mast base does the section below the pivot protrude when the mast is tilted over?

Cheers
Nev

[VK2AAH]

2000mm deep by 450mm square. 25Mpa concrete is specified.

The box steel section is 89mm x 89mm x 3mm. This normally comes in 8m lengths weighing 9kg/m. Edcon are delivering mine ($90... ouch!).

[VK3ALZ]

Hello everyone

I'm using FSJ4-50 on my two meter yagi.
I have some rope attached at two different points.
My thinking is that way it can move around as much as it needs when the antenna is turning but it isn't going to drop.
The added complication is the preamp.



73
Michael

[VK3LU]

Richard,
Thanks for the hole details.
Looking at different photos it would appear that the bottom section of the mast protrudes about 700mm when the mast is layed over.
That's not too bad a projection. It enables the mast to be located reasonably close to buildings.
Looking good.

Cheers
Nev

[VK2AAH]

Yes Nev I was thinking the same... I want to mount mine fairly close to a covered verandah and I was concerned about how close it could get... I'm on a pretty typical block that is deeper than it is wide so I want the mast to drop towards my back fence. I think it will work...

Cheers

Richard
VK2AAH

[VK3AV]

Richard,

The device that I used to hang the cables is here - http://www.abeytrade.com.au/product-cat ... xtensions/ it is the "Nut Clip Standoff Bracket". What I did is invert the bracket as shown and screwed a 100mm or so of timber to it with slots cut in one side. I had a rather too long bolt of the correct diameter and thread pitch so I used it to attach the bracket to one of the holes in the lower arm.

The distance from the pivot bolt to below the winch mount is 800mm.

I am running LDF4-50 underground to the base of the mast (plus more overground currently) this will ultimately run into a cabinet at knee height. From there up to the antennas it is LL400 to the 23cm yagi and RG213 to the 70cm/2m/6m yagi's.

Take care with your cable loop at the rotator. As the 6m Diamond antenna is fed at the front element, and the others at the back end, I failed to provide sufficient slack and it hooked the top of the mast during the Spring Field Day tearing apart the PL259 connect. Running repairs on the day got me back on air but you can see in the photo that it hooked again subsequently. Since then I have extended the cable and zip tied it to the boom more effectively. No issues during the Summer field Day.

I was going to put the hex beam on the NBS mast but it needs to be at the top and I wanted the 23cm yagi up there. Now I have a 'Plan B' for the hex mounting in the months ahead. (My carriage assembly is the one for mounting a HexBeam rather than yagi's). The scaffold tube holding the antennas is 3m in length.

I also remove the ram to reduce corrosion. I thought that I might be able to push the ram in as well but no way could I get it to move so it is wrapped in plastic and oiled a little. Actually that thing is heavy and takes some effort to lift up to re-attach when I need to drop the mast over. I would not want to drop it on my foot...

Regards
Bernard

[VK3MEG]

HI Richard congrats i have had my nbs tower up for 2 years or so.
i run a pretty big stack.
te 4-3 6.5m boom i did run it as a 5-3 8.2 m long boom

9 element lfa 2m 4.3m boom
4element 6m yagi ( diamond 2 element modded to 4
best to have 3 or 4 people when putting the gal rhs in its not easy.
i find it best to fit antenna once the tower is vertical. i use a crude pully system i can mount my antenna's my self with very minor help from the xyl. remember once vertical take the jack/pump off the tower dont let it get wet ..
i run a yaesu g1000dx rotator yaesu thrust bearing i make a nest of cables and tape together i have had no issue with tangling of cables.
my antennas and towers work most days lots of hf dx and even 2m and 6m
plan your assembly thoughly . mine was quick and painless. safety is your number one concern and my xyl always watches when i work in case i miss somthing.
always park your antenna in the postion you need to put it down in case of rotator failure ( i do this most of the time. ) mine is in a 1m x1m square block which is in rock from 500 deep . 100 + kph wind no problem with currnet set up with the 5 elmenet i lowered it as it was massive and flopped around. the tower does move but i'm not worried.
the best investment i have made. i still dream of a 14-20m tower but will never own one as i can sort my antennas with out needing to climb a tower or a scissor lift.
any other questions just ask

[VK4WDM]

I am running LDF4-50 underground to the base of the mast

Is it in some sort of pipe or just by itself?

73

Wayne VK4WDM

[VK3AV]

When I had the hole for the mast drilled I had a trench cut as well. I placed a 90mm storm drain pipe (Bunnings) into the trench with a couple of 45 degree bends to bring it out of the ground near the mast. The heliax is not real flexible so the tube was assembled around the heliax and pull cords and the trench closed. I actually had to do this before the concrete arrived as the truck needed to drive over the trench to reach the mast.

My original intention was to run 2 x LDF4-50 underground to the mast and have remote switches between the antennas then I was offered another piece of used LDF4-50 so the plan changed a bit. Now each antenna has a separate feed line and at the moment some of them are above ground (makes mowing harder ). Someone said to me with respect to the storm pipe to always place something larger than you think that you will need as a rule of thumb. I had the two heliax, rotator cable (7-core trailer cable), 2 x 2-core to operate the remote switches. I also placed 3 draw cords so that I could add more items as time passed. Now these cords seem to be tangled a way down the pipe (discovered when I later tried to pull some RG-213 through). If I did it now I would use different pull cords. You can buy similar stuff to what Telstra use and it looks to be less likely to tangle. Rope Galore sell it.

Regards
Bernard

[VK3LU]

Bernard,
Are you in Whittlesea or Murrindindi shire and how was your experience in getting permission for the mast?
I live in Murrindindi shire and I am interested in their attitude to such things.

Cheers
Nev

[ZL3RC]

If you loose you draw cords the best way I know of to get another one through is to use compressed air.
Bung a plastic shopping bag down the pipe and tie your new cord to it. Then blast it down the pipe covering the open end behind the shopping bag with a rag or I used a block of foam rubber.
Watch it though as the cord will fly down the pipe sliding past your stopper, rag, and whips bits of flesh off if they get in the way
You don't need much air to do this and you'll be surprised how well it works and the muck it drives out of the pipe in front of the shopping bag
My best run was about 60m down some 32mm pipe but Ive seen contracts do much longer runs.

Roger.

[ZL1RS]

... I've seen it done exactly that way down a similar length of electrical conduit using the exhaust pipe of a vehicle as the 'compressed air' source.

73,

[ZL3OZ]

was going to put the hex beam on the NBS mast but it needs to be at the top and I wanted the 23cm yagi up there. Now I have a 'Plan B' for the hex mounting in the months ahead

Hi Bernard.
I am guessing your reason mentioning HEX needing to be on top is because of it having a plastic pipe riser through centre carrying the various terminations??
I built my own HEX beam a couple of years ago and in doing so I was confronted with this question of how to put the smaller wavelength antennas higher up.
I thought about this plastic centre thing for terminations and wondered about the fact the coax braid is effectively like a metal rod through centre of the HEX (as it goes up centre then runs down to the terminations for non hex readers) so what would happen if I made it a metal pipe and mounted an insulator strip of 10mm industrial plastic sheet (about 40mm wide) on brackets down the side of the metal centre pipe to take the terminations. Coax all cable tied outside pipe.
I took the risk and did it, and had no problems. As I was building everything from junk box and hardware store I cant compare re tuning, as it was a once effort for me but it (HEX) performs excellently on the HF and 6mtr bands (I have sep feeder to the 6mtr element so I can operate sep gear on 6 while op on HF) then I have extension pipe above the HEX with my 2mtr yagi and a vert 2m groundplane built onto the top of the boom of the 2m yagi, all up about 2mtrs above the top of the HEX . As attested by getting into VK5 and VK7 on 144.1 on the 23rd last month and numerous previous years on 2mtrs into VK and many HF contacts it works well.

So mod the HEX?? leave it with you.

Anyone interested see my QRZ page and I have a few pictures of the close up view of insulator strip if anyone wants. Its not rocket science.

Ken
ZL3OZ

[VK3AV]

Thanks for the suggestions re getting another pull cord down the storm drain pipe, Bob and Roger. I can see how that would work really well. Agreed re not getting in the way of the line either as it is shot down the pipe.

I have taken my own advise and ordered a roll of the Telstra approved rope from Rope Galore and will pull it through with one of the remaining cords. That should remove the tangle and let me use the Telstra approved rope to pull other things through. Whilst it seemed like a good idea at the time the cord that I used was 4mm polypropylene rope from Bunnings and the three lengths that I pulled through were quite coiled when loose and must have become tangled inside the pipe with each other and the coax.

Thanks for the Hex info Ken. I initially built the centre post for the hex using poly tube but did not like the result (coax down the inside of the tube) and rebuilt it as an aluminium air cored centre post. I had not explored the idea of adding something above it though I did see info from an amateur in the US who did just that with a smaller 2m antenna. As I wanted to have some larger antennas on the higher bands I decided on a different path. I have all of the parts ready to go.

My plan now is to use 8m of 75x75mm tube (delivered at the same time as the tube for the NBS mast) on the other side of my shed/garage and place the hex on it. I need to check the heights again but it should be higher than the roof of the house as well. The downside is needing to get another feed line to that location as a separate run or, alternatively, extending a line from the NBS mast over to it through the shed. At least with option 2 the feedline losses won't be quite so bad at those frequencies.

So if I now consider what needs to go down the underground 90mm tube (assuming feeding the hex via that path) I end up with - 3 x LDF4-50, 1 x LL400, 1 x RG213, 2 x rotator cable, 2 x 2-core power to coaxial relays, ?? power for transverters/PA's or whatever else I come up with in the future, as I would like to add more bands over time.

As an aside... we have tank water here and that is captured off the house roof, one side of the shed roof and off the top of the tank itself. One of the things that I do consider when sighting antennas is how many birds will be sitting over my roof and what will be the impact on my water quality... Would never have been an issue when I lived in the 'burbs.

Regards
Bernard