To all who are still looking to see what one of these things looks like:
Go to Google Images. Type in: Joslyn J732. The image on the far left is what
it looks like. Click on the photo.
You should see a link to MacLean Power Systems. If you click on the link, it
will take you to the MacLean Power Systems web site, with a description:
- Forged from 1/2-inch diameter steel with a 1/2-inch curved bolt complete
with Anco® locknut and are used with porcelain guy strain insulators.
- Minimum ultimate strength is 12,400 pounds.
So, the idea is that it is designed to go around a (I assume) 502 insulator.
So you attach your preform around the insulator - directly to the tower guy
bracket.
Tom, N2SR
From: George Dubovsky <n4ua.va@gmail.com>
To: Grant Saviers <grants2@pacbell.net>
Cc: towertalk <towertalk@contesting.com>; k3lr@k3lr.com
Sent: Saturday, March 19, 2016 12:41 PM
Subject: Re: [TowerTalk] [Bulk] Re: The other end of Phillystran - connections
to the tower
I mis-typed; it's J732.
73,
geo - n4ua
On Sat, Mar 19, 2016 at 12:38 PM, George Dubovsky <n4ua.va@gmail.com> wrote:
> Google Joslyn J372. Another fellow told me that they are available from
> Hubbell Power Systems, but 50 is the minimum order. Some enterprising DX
> type ham, perhaps with an ENGINEERING connection, might consider selling
> them... ;-)
>
> 73,
>
> geo - n4ua
>
> On Sat, Mar 19, 2016 at 12:29 PM, Grant Saviers <grants2@pacbell.net>
> wrote:
>
>> I'm curious what a "bent pin shackle" looks like. I know there are bow,
>> D, chain, and sling shackles all with various types of straight pins, e.g.
>> threaded, pin, bolt.
>>
>> Crosby is the top US maker, Chicago is another US brand at a cost
>> savings. Check rigging supply house near you for inventory or McMaster or
>> uscargocontrol.com
>>
>> Thanks for the tip re 10m interaction with big grips, I think I have that
>> problem.
>>
>> Grant KZ1W
>>
>>
>> On 3/19/2016 2:58 AM, George Dubovsky wrote:
>>
>>> But where do you get those shackles today? I have used Joslyn shackles in
>>> the past, acquired from another ham, but when I went looking for more two
>>> years ago, I couldn't find a vendor. I know it's utility hardware, but I
>>> couldn't figure out how to buy any.
>>>
>>> 73,
>>>
>>> geo - n4ua
>>>
>>> On Sat, Mar 19, 2016 at 3:32 AM, Tim Duffy <k3lr@k3lr.com> wrote:
>>>
>>> When installing the tower connection end of Phillystran guy cables, I
>>>> learned that a significant problem can happen with unintended Yagi guy
>>>> grip
>>>> (Preform) antenna interaction.
>>>>
>>>>
>>>>
>>>> The problem is this, if your guy grip tower terminations are close to
>>>> your
>>>> antenna mounting position (right underneath), and the terminations (guy
>>>> grips) are electrically connected to the tower, they can (in many
>>>> installations) interact and cause antenna pattern/VSWR problems. This
>>>> problem is worse on the higher bands like10 and 15 meters.
>>>>
>>>>
>>>>
>>>> For example at K3LR many Yagi's are side mounted on ring rotors.
>>>> Phillystran
>>>> or fiberglass guy attach to the tower right under each ring rotor.
>>>> After an
>>>> installation several years ago of some 10 meter Yagi's I noticed that
>>>> there
>>>> were three peaks and valleys in VSWR when rotating the antenna mounted
>>>> on
>>>> the ring. Closer inspection and modeling the three short lengths of
>>>> "connected" guy grips revealed that in fact the Preform guy grips were
>>>> long
>>>> enough (cumulative effect of 3 together) to impact the near field
>>>> environment of the Yagi. The problem is worse the more "horizontal" the
>>>> guy
>>>> wire is relative to the Yagi (lower guy wire connection points heading
>>>> to
>>>> ground mounted concrete guy dead men anchors) and the higher in
>>>> frequency
>>>> the antenna is (Preform length is more "meaningful").
>>>>
>>>>
>>>>
>>>> The solution is simple enough and easy at the time of installation. All
>>>> of
>>>> my guy grip installations now include a "bent pin shackle" (tower side)
>>>> and
>>>> a properly sized guy wire insulator - right at the guy attachment point
>>>> on
>>>> the tower. The other side of the insulator contains the proper guy grip
>>>> for
>>>> the Phillystran or Fiberglass guy material. This way the Preform is
>>>> totally
>>>> insulated from the tower.
>>>>
>>>>
>>>>
>>>> Once the insulators were installed at the tower connections, the VSWR
>>>> and
>>>> directional pattern of the Yagi antenna remained constant and
>>>> predictable
>>>> (as modeled) no matter where the antenna was pointed.
>>>>
>>>>
>>>>
>>>> You can see the tower insulators installed on the K3LR 20 meter tower on
>>>> this W8WWV drone video at the 5:18 mark
>>>>
>>>>
>>>>
>>>> https://www.youtube.com/watch?v=SA_NG-bVQuc
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> 73
>>>>
>>>> Tim K3LR
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
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>>>
>>>
>>
>
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