Put a snatch block at the top and run a cable up and over.
Then the come a long can go vertical, outside, and be as long as it wants.
Come to think of it, don't most come a longs have a running pulley on the
cable, for double lining?
Then all you need is the lift point at the top.
WL
-----Original Message-----
From: towertalk-request@contesting.com
Sent: Monday, April 25, 2016 10:41 AM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 160, Issue 83
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Today's Topics:
1. Re: [Bulk] Lifting a mast off the rotator (Don Moman VE6JY)
2. Rotor load bearing weight (Chuck Gooden)
3. RG-304 for CMC ? (Jim Thomson)
4. Re: RG-304 for CMC ? (Jim Brown)
5. Re: [Bulk] Lifting a mast off the rotator (Grant Saviers)
----------------------------------------------------------------------
Message: 1
Date: Mon, 25 Apr 2016 04:12:52 +0000
From: Don Moman VE6JY <ve6jy.1@gmail.com>
To: "TOWERTALK@contesting. com" <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] [Bulk] Lifting a mast off the rotator
Message-ID:
<CAJf7ZhQD52=z_9EqkGBe22q6W4JbvNpZLQ-3kOzYgXOQpahDiw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
When space is at a premium and you don't have to move the load too far, a
turnbuckle is the answer.
73 Don
VE6JY
On Mon, Apr 25, 2016 at 3:05 AM, Grant Saviers <grants2@pacbell.net> wrote:
Les,
IMO, the best idea is to attach a u-bolt with a hoist point bracket to the
mast and use a come-along inside to the tower top plate, although
come-alongs can be too long to fit. The shortest headroom lifters I've
found is are 500# and 1000# capacity lever chain hoists, < 8". This is my
strategy for a safe very heavy mast lift off the rotator, even if a foot
or
more of clearance is needed. A forged eye is fitted to a hole drilled in
the top plate of the tower as an attachment point. Once installed, the
attach points can be left for the "next time".
Other ways to go: the die pry bar set from Harbor Freight and the 4 ton
hydraulic frame straightener have been very handy for me to
lift/separate/straighten things.
#68339 or #1654 (the porta power from HF is now 2x the price from
Amazon)
http://www.amazon.com/Goplus%C2%AE-Porta-Power-Hydraulic-Repair/dp/B017H8R9E2/ref=sr_1_1?ie=UTF8&qid=1461551404&sr=8-1&keywords=hydraulic+frame+repair+kit
the jaw separator might be useful for lifting once a pry bar gives some
space for it, but needs a good purchase. Or use the small extension
cylinder to a u-bolt fastened lift point above the tower top. Or use a
small scissor jack, which I bought for taking apart rohn 25. The
cylinders
are also good for straightening bent tower parts.
On a used 2800 I acquired the prior owner had secured a cut off box end
wrench on the center bolt with a screw through the wrench handle and
threaded into the Orion plate about 2" out from the bolt, oriented so the
split mast clamp clears the wrench. Now I know why he did that.
Grant KZ1W
On 4/24/2016 19:11 PM, Les Kalmus wrote:
I came home from Visalia to find my antenna system freewheeling. The mast
holds 4 yagis, one of which is very large, and is rotated by an Orion
rotator.
If my suspicions are correct, the problem is the little 1/4" bolt holding
the shaft up into the bottom of the mast clamp has loosened and allowed
the
shaft to fall.
The tower is lowered and the antennas are tied off to a tree. I have
removed the mast clamp and now I have to raise the mast about 1/2" to
free
the centering block so I can remove it to inspect that bolt.
I have a come along with an additional block with which I can lift the
mast, but the carabiner I have won't fit into the small space between the
centering block and the inside of the mast.
Any suggestions on a way to either hook the mast from the bottom or to
clamp to it so I can raise it? We're talking maybe 400 lbs in the
complete
antenna system.
I have done this in the past but I think I didn't have the centering
block at that time so it was easier to get something hooked into the
bottom
of the shaft.
Les W2LK
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------------------------------
Message: 2
Date: Sun, 24 Apr 2016 23:30:36 -0500
From: Chuck Gooden <Chuck.Gooden@comcast.net>
To: towertalk@contesting.com
Subject: [TowerTalk] Rotor load bearing weight
Message-ID: <571D9D6C.3000602@comcast.net>
Content-Type: text/plain; charset=windows-1252; format=flowed
Should the rotor in a tower, bear the weight of the antennas and mast?
Or should the weight be on a bearing plate, and allow the rotor to be
easily removed?
What are the pros and cons of either approach?
Chuck Gooden N9QBT
------------------------------
Message: 3
Date: Sun, 24 Apr 2016 21:35:08 -0700
From: "Jim Thomson" <jim.thom@telus.net>
To: <towertalk@contesting.com>
Subject: [TowerTalk] RG-304 for CMC ?
Message-ID: <FDF5DA7A23164DED97D9FA3604D02E22@JimPC>
Content-Type: text/plain; charset="UTF-8"
Date: Sun, 24 Apr 2016 17:14:14 -0400
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] RG-304 for CMC ?
What's the difference between using LMR-400, or BuryFlex with six 12"
dia Loops equally spaced, compared to bundling the same size loops into
a single bunch
or for that matter, grouping any coax together rather than equally
spaced loops?
It'd lower the resonant frequency, but other than that (and looking
neater), what about the choke's characteristics?
Would it narrow the range of high impedance? Lower, raise, or leave the
maximum impedance unaffected?
73
Roger (K8RI)
## Bunched up loops lowers res freq. Depending on choke config, it can
narrow the range of the choke, to the point where it covers 80m with high
5-6 k RS... but not 40m.
Lousy on 40m, like 650 ohms. This appears to be the case when Binoc
config is used in some cases. With binoc config, with torroids at the 9 +
3 oclock positions, the turns all end up bunched together for the entire
loops.
Bad news if LMR-400 /213-U /393 coax used. A LOT more C between turns
with the .405 OD cables...vs 58-U / 303 etc.
## One advantage to binoc config, is you can then wind in 1/2 turn
increments, like
4 - 4.5 ? 5 - 5.5 etc.
## 12 inch diam loops is a trick to maintain spacing between each loop.
With loops
equally spaced around the cores, now you end up with a mess that is almost 2
foot in diameter,
which is exactly what I dont want for a cmc...esp on a 80m rotary dipole,
mounted 10 ft up
the mast. 8.5 K in a little box, on 80m, with the CMC-230-5K is a more
elegant solution.
## 12 inch diam loop = 3 ft in circumference. 7 turns = 21 ft of
LMR-400..which is a lotta
weight,bulk,windload, etc. But it does provide outstanding high Z / RS
across 80+ 40m..and
160m.
Jim VE7RF
------------------------------
Message: 4
Date: Sun, 24 Apr 2016 22:44:40 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] RG-304 for CMC ?
Message-ID: <571DAEC8.6060704@audiosystemsgroup.com>
Content-Type: text/plain; charset=utf-8; format=flowed
On Sun,4/24/2016 9:35 PM, Jim Thomson wrote:
## Bunched up loops lowers res freq.
Right.
Depending on choke config, it can narrow the range of the choke,
Not if the core material is #31 or #43.
to the point where it covers 80m with high 5-6 k RS... but not 40m.
Lousy on 40m, like 650 ohms. This appears to be the case when Binoc
config is used in some cases. With binoc config, with torroids at the 9
+
3 oclock positions, the turns all end up bunched together for the entire
loops.
Bad news if LMR-400 /213-U /393 coax used. A LOT more C between
turns
with the .405 OD cables...vs 58-U / 303 etc.
This is nonsense.
## One advantage to binoc config, is you can then wind in 1/2 turn
increments, like
4 - 4.5 ? 5 - 5.5 etc.
This is also nonsense. Chokes wound for the HF bands using #31 and #43
material have VERY low circuit Q, typically on the order of 0.4. This
makes them broad as a barndoor! Their tuning is NOT critical.
## 12 inch diam loops is a trick to maintain spacing between each loop.
With loops
equally spaced around the cores, now you end up with a mess that is almost
2 foot in diameter,
which is exactly what I dont want for a cmc...esp on a 80m rotary dipole,
mounted 10 ft up
the mast. 8.5 K in a little box, on 80m, with the CMC-230-5K is a more
elegant solution.
## 12 inch diam loop = 3 ft in circumference. 7 turns = 21 ft of
LMR-400..which is a lotta
weight,bulk,windload, etc. But it does provide outstanding high Z / RS
across 80+ 40m..and
160m.
I don't know where you get this stuff, but it's nonsense.
73, Jim K9YC
------------------------------
Message: 5
Date: Mon, 25 Apr 2016 07:41:48 -0700
From: Grant Saviers <grants2@pacbell.net>
To: Jim Thomson <jim.thom@telus.net>, towertalk@contesting.com
Subject: Re: [TowerTalk] [Bulk] Lifting a mast off the rotator
Message-ID: <571E2CAC.2030100@pacbell.net>
Content-Type: text/plain; charset=windows-1252; format=flowed
The used OR-2800 was driving a 3" mast, but I have one driving a 2"
without a centering block w/o problems (so far) but a bigger load is
going onto the 2" mast shortly.
Medium strength Loctite is a good idea if the internal threads can be
degreased. Instead of a split ring washer, I use Nord-Locks for
critical fasteners. Check out their video re locking fastener tests.
http://cdn.nord-lock.com/wp-content/uploads/2015/12/Nord-Lock-Junker-test-HD_1280x720.mp4
Grant KZ1W
On 4/24/2016 21:00 PM, Jim Thomson wrote:
Date: Sun, 24 Apr 2016 20:05:13 -0700
From: Grant Saviers <grants2@pacbell.net>
To: Les Kalmus <w2lk@bk-lk.com>, TOWERTALK@contesting.com
Subject: Re: [TowerTalk] [Bulk] Lifting a mast off the rotator
Les,
On a used 2800 I acquired the prior owner had secured a cut off box end
wrench on the center bolt with a screw through the wrench handle and
threaded into the Orion plate about 2" out from the bolt, oriented so
the split mast clamp clears the wrench. Now I know why he did that.
Grant KZ1W
## slick idea, but it wont work if the optional m2 self centering 1/2
inch thick,
triangular chunk of AL is used. When the self centering device is use, a
really
long 1/4-20 SS bolt is provided.... to get from top of self centering
block....
all the way through the block, then to the threads in the steel base
plate.
## I have 2 of the OR-2800 rotors.... and the self centering block is
only required
if a 2 inch mast is used. And even then, its really not required with
a 2 inch mast.
## The self centering block is pyramid shaped, and the entire block
fits inside a
2 inch mast. Dunno if it will still fit inside a 2 inch mast, that has a
.375 wall thickness.
## If a 2 inch mast used, the clamp would normally be adjusted so its
just a bit bigger
than 2 inch. If 2 x thrust bearings are used, the self centering device
is def not required.
## I would not use it. Instead use the shorter 1/4-20 bolt.... but
use some blue loctite
on the threads. Purple locite is slightly weaker than blue loctite..and
will also work. Or at
least use a SS split ring lockwasher on top of a SS fllatwasher, below
the bolt head.
## the scissor jack is a good idea. The simple bottle jacks will also
work, but have a limited
amount of vertical lift distance. Cheap, and available from 1/2 to 20
ton. The issue with bottle jacks is:
you can precisely control the lifting function..... but when u go to let
it down, it comes down quickly.
Jim VE7RF
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