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 Antenna Tilt Plate Build 
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Post Antenna Tilt Plate Build
Ok, here's the rub, with the Tennamast or any other tilt/luff over mast, your beam is always going to be 90 degrees to the mast, so when you luff it over, you can only bring it down till the longest element or the boom touches down. Not ideal if you need to work on the antenna.
I'd seen an American product called TiltPlate, built by an American ham, but the cheapest version is in the region of 750.00 usd, no way I could get that one past the missus. :whistle:
So I sat the other night with a sheet of A4 and a pencil and started drawing, what follows is what I came up with.
The large plate mounts on the stub mast, and the beam mounts to the smaller plate, as the mast luffs over, gravity plays its part and the beam stays parallel to the ground as it comes down, I hope that makes sense.

10mm plate, 250x500mm, 250x250mm, 2x25mm pillow mount bearings, a 250mm length of 25mm stainless bar and a good handful of U clamps, 28mm, and 52mm.
How someone can sell these pillow mount bearings for less than a fiver each I'll never know, the aluminium plate and S/S bar came from an ebay supplier, as did the U clamps.
This was drilled and cut by my friend and myself in a couple of hours this afternoon.

So far this project has cost less than Ā£100.00 and should make dropping the Mosley TA63M a bit easier and more convenient.
Next installment is getting it mounted to the mast and the antenna mounted to it, that will happen next time my neighbour is away as with the mast luffed over, I'm in their garden.

Brian

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Brian
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Sat Jun 08, 2013 5:41 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Now that's clever but my only concern is the weight. It also looks as though it might add quite a lot of wind load to the top of the mast.

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Sat Jun 08, 2013 5:45 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Yes i agree fantastic idea
One thing to point out about the position of the boom
a lot of larger beam's have truss's that stand above to take the weight of the boom or/and element's
So if the boom bolt's and stubmast bolt's where moved to the opposite side's you have them
this would allow the stub to go higher for one truss and also allow for the element truss to stand up above
You would just then have to built something as a stop instead of using the boom to keep it straight when
the mast is upright
Maybe a couple of long nut's and bolt's ???

The only reason i mention this is because i looked at the plate from the USA and when i spoke to Tom at Optibeam
i learned they don't fit but Tom does say if you send the plate to him when buying an Optibeam he will modify them.

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Sat Jun 08, 2013 6:27 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Hi Ian, I haven't finalised the way its going to mount as of yet, the way it is in the pics was a dry run just to get a feel for the way to fit it.
We have toyed with the long bolt and some lock nuts to keep it straight, and mount the boom on the other side of the plate.
There are phasing bars on the Mosley TA63M that will be mounted to it, that may have clearance issues so I'm not quite there yet with the final mounting.

Keith, you're quite right, its quite meaty, but there is an option to trim down the main plate a bit to reduce the wind loading, we had thought of trimming it in a similar shape/way to the boom plate. I don't think it will have a major impact on the strength of the mount.

Thanks for the comments so far, its always good to get some different views and opinion.

MM0WAX

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Sat Jun 08, 2013 6:40 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
MM0WAX wrote:
Hi Ian, I haven't finalised the way its going to mount as of yet, the way it is in the pics was a dry run just to get a feel for the way to fit it.
We have toyed with the long bolt and some lock nuts to keep it straight, and mount the boom on the other side of the plate.
There are phasing bars on the Mosley TA63M that will be mounted to it, that may have clearance issues so I'm not quite there yet with the final mounting.

Keith, you're quite right, its quite meaty, but there is an option to trim down the main plate a bit to reduce the wind loading, we had thought of trimming it in a similar shape/way to the boom plate. I don't think it will have a major impact on the strength of the mount.

Thanks for the comments so far, its always good to get some different views and opinion.

MM0WAX



Well for a first draft it's looking damn perfect :D
Hope you get the minor bit's sorted now
Be good to see something like this produced over here
Post us some more pic's as you move on

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Sat Jun 08, 2013 6:48 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Hi Brian

Nice looking job!

Good luck with the final tweeks to get it working.

I believe the same US firm also make a Tilt Plate type device for the Hexbeam.

Same problem though: purchase price + shipping + import duty make them rather expensive.

You fancy working out a design for the Hex, once you've got yours sorted ;)

John

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Sat Jun 08, 2013 6:57 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
There is a copy of the tilt plate being designed by a retailer over in the UK he was asked by members of a club to reproduce the US version., Not sure if I should say who but I still except it to be over priced.

Yours looks good will be interested to see it once the antenna gets installed

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Sat Jun 08, 2013 7:08 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
JohnG7SSE wrote:
You fancy working out a design for the Hex, once you've got yours sorted ;)

http://www.nn4zz.com/HexLock.html

That's the one for the Hexbeam which needs cloning ;) and I've already forwarded it to a local as a 'challenge'.

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Sat Jun 08, 2013 7:14 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
What stops the antenna from tilting from the horizontal when it's in normal use... just thinking of a squadron of fat wood pigeons sat on the reflector? :blink:

Cheers, Dave.


Sun Jun 09, 2013 11:36 am
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
There is a locking mechanism available for just that issue.
But invariably gravity will do the job.

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Sun Jun 09, 2013 11:47 am
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
G7VQE wrote:
What stops the antenna from tilting from the horizontal when it's in normal use... just thinking of a squadron of fat wood pigeons sat on the reflector? :blink:

Cheers, Dave.


I know you could build a lock into it but if you take
my antenna it come's in at 45kg
Now that's alot of bird's to force that around :)

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Sun Jun 09, 2013 12:48 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Had a bit of a fiddle today, trimmed some excess off the main mounting plate, and drilled a couple of holes on the boom plate, to allow a couple of long adjust/stopper bolts. It now looks like the main plate will have the stub mast mounted on the same face as the bearings and the boom will be mounted on the outside of the hinged plate.
I'm hoping gravity will hold the beam horizontal, Mosley quote 60lbs for the TA-63-M so it'll have to some pigeon, more likely seagulls round here to tilt it away from horizontal.
I've had a look at the lock system on the American design and will try first without it, and if needed will have a bash at making it.

Some more pics
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Sun Jun 09, 2013 4:48 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
I suppose thinking about it a bit more and you've only got to mount the beam boom slightly off centre of the actual weight centre of the antenna for it to increase its effective weight holding it against the tilt plate.... if that makes any kind of sense? :this:

Confused myself there. :blush: excellent looking build quality!

Cheers, Dave.


Sun Jun 09, 2013 5:31 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
Well, the neighbours went missing for a few hours this afternoon, :yahoo: so I set about mounting the tilt plate. Dropped the director off the front of the beam and then removed the rest of the beam complete.
Offered up the tilt plate, and used the original stainless u bolts and supports to mount it.
The beam was a bit unwieldy but I managed on my own to get it attached to the plate. Then reattached the director.
Whilst it was down, I cleaned the attachment points for the phasing lines and lubed them with Penetrox, a conductive grease that was supplied by Ron Stone at Vine antennas. I also lubed the joints in the tubes on each of the driven elements. The Mosley has 2 driven elements, hence the phasing lines.
I'm quite happy to report that the plate has had little or no effect on the swr, something I had been fearing, due to the plate fitting between the phasing lines. I also wrapped one of the phasing lines with self amalgamating tape to try and isolate it from the plate, seems to have worked.
The tilt plate makes working on the beam a cinch now.
Some pics

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Some might recognise the choke, GM3SEK inspired, Fairite oval cores supplied by Farnells, type 31 material, this particular choke is good for
10-30mhz. 3 turns of rg8, then my main run of coax, which is rg213 back to the shack.


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I also used some copper grease to lube the top of the rotator cage where the stub mast goes through.


Image

MM0WAX

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Sat Jun 29, 2013 7:32 pm
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 Antenna Tilt Plate Build 
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Post Re: Antenna Tilt Plate Build
A little off topic, but do you find that the rotator jams when you are turning the beam in a strong wind or does the addition of the copper grease really help? I have the same mast and rotator cage as your self or at least it looks like a Tennamast.

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Sat Jun 29, 2013 7:38 pm
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