[UK-CONTEST] Mast Winches

[Dave G3RXP]

Thank you David, John and George for your replies,

Im making progress Im now working in Kg hi.

Yes Im all for overrating the required component. I remember it used to be
twice the value of the calculated component (Marcone principal) would
suffice but we are now limited by cost and I am no different now Im retired.
Ive just read the spec for my winch and it says 2000lbs so 1000Kg would do I
expect -I bet you cannot get one of those for a tenner.

Thank You again
Dave G3RXP



----- Original Message ----- 
From: "David" <g3yyd at btinternet.com>
To: "UK-Contest at contesting. com" <UK-Contest at contesting.com>
Sent: Tuesday, February 07, 2012 12:35 PM
Subject: Re: [UK-CONTEST] Mast Winches


> There is also a need on the luffing winch to take into account the
> mechanical lever effect of having a long length between the pivot point
> and
> the antennas coupled with a short length between pivot point and the winch
> rope attachment point. This will "amplify" the load of the antenna by the
> ratio of the two lengths.
>
> Say head unit, rotator, antenna etc is 50Kg and the length ratio is 4 to 1
> then the force at the rope anchor point will be 200KG plus that of the
> tower
> sections, which is slightly more complex to calculate as it is distributed
> along its length but you get the idea.
>
> I would err on the side of caution and go for bigger rather than risk
> going
> too small. If that winch should fail think about what damage it could be
> done to you.
>
> Personally if I had to replace my luffing winch I would go to an electric
> winch.
>
> 73 David.
>
>
>
> -----Original Message-----
> From: uk-contest-bounces at contesting.com
> [mailto:uk-contest-bounces at contesting.com] On Behalf Of John Lemay
> Sent: 06 February 2012 17:07
> To: 'Dave G3RXP'; uk-contest at contesting.com
> Subject: Re: [UK-CONTEST] Mast Winches
>
> Dave
>
> This is a difficult one to answer without knowing a little more about your
> mast, ie the weight of each telescoping section, head unit etc, and
> importantly the length on each side of the pivot when the mast is
> horizontal.
>
> However: Firstly you are correct that the maximum load on the winch is
> when
> the mast is horizontal (or with the head unit lower than the pivot point).
>
> I would suggest that a 250lb winch is insufficient. This is based on my
> Versatower, which has a 650kg winch, purchased on the advice of the
> manufacturer many years ago.
>
> Presumably any helpful markings on your current winch have long since
> disappeared ? A possible clue might be in the diameter of wire rope that
> you
> are using.
>
> One source of a worm gear winch is:-
>
> http://www.dlhonline.co.uk/delta-galvanised-hd-wormgear-winch-1353-p.asp
>
> You would need to check that the size and layout of the winch is suitable
> for the fixing points on your tower of course.
>
> I'm a satisfied customer and have no other connection with the company.
>
> It's probably a good time to fit new wire rope(s) too !
>
> Regards
>
> John G4ZTR
>
>
>
>
> -----Original Message-----
> From: uk-contest-bounces at contesting.com
> [mailto:uk-contest-bounces at contesting.com] On Behalf Of Dave G3RXP
> Sent: 06 February 2012 16:37
> To: uk-contest at contesting.com
> Subject: [UK-CONTEST] Mast Winches
>
> Hi Guys,
>
> Im sure one of you can give me some advice on winches for masts.
>
> I have a 60ft tower (with a 3 ele steppir and an ali scaffold
> pole -yardarm)
> used to support 2 ele inverted V wire beam for 40m) which has a winch for
> lower /raise which also works to tilt the mast over.
>
> I have been using a winch with worm and wheel gearing (40:1 ratio -with 4
> pulley wheels at the base of the mast, so another 4:1 ratio - bit of a
> bind
> but easy to wind up.) which has the safety feature of not needing a break
> so
> when you stop turning the handle the winch just stops.
>
> Well the worm / wheel gearing has now become distorted as it is 20 years
> old
> so I need to buy another winch.
>
> Im looking for a winch which has worm and wheel gearing (No loud clicking
> of
> the break stops) but Im not sure of the loading that is required how do I
> measure that without letting the mast fall over? I can get another winch
> that has a loading of 250lbs but how good is that -  do I need more? The
> greateast loading is when the mast is tilted over -  I would think.
>
> Or I could always buy an electric winch but are they expensive.
>
> Thanks 73 Dave
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