On 1/17/2012 10:52 PM, Don Moman VE6JY wrote:
> I am familiar with the original HyGain version of that antenna, the 3-30
> mhz version and the double tower and large rotating mast.
>
> First point - you DON'T need a 70 ton crane for this. A smaller crane will
> easily handle the tower(s). Because the towers have to be joined together
> to allow the mast to tilt, it would be simpler to join both towers
> completely together on the ground, lift and guy. They are plenty rigid
> enough to be picked up in one piece. And again, you don't need a 70 ton
> crane for this. Forget about gin poles and the huge effort required - it's
> a one day job for a crane.
>
> And there are many styles of crane - look into all terrain and rough
> terrain types. My 40 ton rough terrain with 4 wheel steering can turn in a
> tighter circle than most pickup trucks. And it's still way more crane than
> you need for this.
I wanted to use one here, but there was no way to get one down the
street let alone into my driveway. They would have had to take down the
power lines, telephone lines, and cable. Then we'd have had to install
culvert in the ditch out front and fill it in wide enough to get the
crane into the driveway. Once in the driveway they'd have needed the
extension installed and thee is no place where it could be extended
horizontally. He needed to lift over 140 feet too place the top antennas.
The lift would have had to be from the back yard with the crane reaching
over the house from the front yard . Meaning the crane would have to be
positioned at least 40 feet from the base of the tower.
Shutting down power, telephone, and TV for a whole street for an
afternoon was pretty much out of the question.
73
Roger (K8RI)
>
> 73 Don
> VE6JY
>
> On Wed, Jan 18, 2012 at 3:36 AM, Dick Green WC1M<wc1m73@gmail.com> wrote:
>
>> Holy Cow, that is one massive antenna!
>>
>> Doug, since you have no prior experience erecting towers, I urge you to
>> hire
>> an experienced professional tower rigger to help you with this project. If
>> you can't erect the towers with a crane, as now required by the
>> manufacturer, you will have to carry out several steps that are potentially
>> extremely dangerous. A pro is much more likely to know what to do and what
>> not to do, and has a much better chance of doing the project safely than
>> you
>> do. This antenna is not worth your life.
>>
>> Here are some specific comments:
>>
>> 1. I don't know the structural characteristics of the towers (and neither
>> do
>> you), but I agree that no matter how strong the sections, 1" base bolts
>> call
>> for temporary guys. But I wouldn't fool around with ropes -- use steel guys
>> properly attached to the tower/anchors and properly tensioned. The load on
>> the tower won't be just the wind and your body weight. Tremendous force
>> will
>> be put on the tower, especially the top section, when you winch those 800
>> lb
>> sections. I sure wouldn't want to be the fellow at the top while that's
>> going on unless the sections below me were properly guyed (and even then I
>> guarantee the "pucker factor" will be significant -- it sure was for me
>> when
>> I was on the tower receiving my puny 10-foot Rohn 55 sections at 100 lb
>> each.)
>>
>> 2. If you have to fabricate a gin pole, get the design checked out by an
>> engineer. Failure of that component could be disastrous or even fatal.
>>
>> 4. Think about how you'll move the 20'+ gin pole up 20' to the top of the
>> tower to hoist the next section. Even if it's made of Rohn 25, it'll be
>> very
>> heavy. At a minimum, you'll need a pulley and rope system to haul the gin
>> pole up even with the top of the section you just installed. Assuming the
>> design includes a clamp system that allows you to slide the gin pole up
>> above the just-installed section, it's unlikely you'll be able to lift the
>> gin pole from the bottom while you're on the tower. Perhaps you'll have to
>> use a separate heavy-duty gin pole to extend the big gin pole with the
>> winch.
>>
>> 5. How are you going to raise the antenna? The manufacturer's site says
>> that
>> in the guyed configuration the mast tilts over for antenna maintenance. Is
>> that the model you have? If so how is the mast tilted? Is there a separate
>> winch pole/fixture? It will certainly have to be very heavy duty to handle
>> a
>> 2100 lb antenna with a 70' boom and 100'+ elements on a 100' mast.
>>
>> Just some thoughts.
>>
>> 73, Dick WC1M
>>
>> -----Original Message-----
>> From: Doug Ronald [mailto:doug@dougronald.com]
>> Sent: Tuesday, January 17, 2012 9:04 PM
>> To: TowerTalk@contesting.com
>> Subject: [TowerTalk] Safety of unguyed tower
>>
>>> I have seen heavy duty gin poles capable of lifting heavy tower
>>> sections,
>> but I have never found a place that sold them.
>>
>>> Where are they commercially available?
>> That was my first problem - the vendor no longer supplies them. Commercial
>> TV tower suppliers have them, but the cost is out-of-sight. I was on my
>> own
>> to fabricate the gin pole.
>>
>>
>>
>>> Telex / Hy-Gain made a dual tower system model T-3002 that sounds similar.
>>> The mast was in-between the towers and the rotator was installed at the
>> base
>>
>>> and there were guy wires at the top of the tower. Without knowing
>> specifics,
>>
>>> it's hard to determine if it's safe to install up to the guy point or
>>> if
>> temporary
>>
>>> guys are needed.
>> That is the product I have, a T-3002FA now from the company that bought-out
>> Telex, U S Antenna Products. The antenna itself is the LP1005AA Log
>> Periodic.
>>
>> -Doug
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>>
>>
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