[TowerTalk] TowerTalk Digest, Vol 136, Issue 10

ftravanty W9JCC at wi.rr.com
Fri Apr 4 12:48:49 EDT 2014

I plan on taking my Yaesu G-2800SDX rotor  down this summer to replace 
an intermittent  position feedback pot, that has been acting up for the 
last three years. It's been in service for over 15 years with low usage. 
I suspect moisture possibly thaw &freezing in the winter. Couple of 
questions. Anyone have any pot failure history with the G-2800 series 
rotor? Anyone have factory setup instructions for re assembly , and is 
it worth trying to shield the pot shaft bushing from water in this model 
Frank W9JCC

On 4/4/2014 11:00 AM, towertalk-request at contesting.com wrote:
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> Today's Topics:
>     1. Re: TIC Potentiometer (Scott Bullock)
>     2. Re: Fulton 2500 winch single or dual speed? (Patrick Greenlee)
>     3. Elementary feedline loss question (Pete Smith N4ZR)
>     4. Re: TIC Potentiometer (john at kk9a.com)
>     5. Re: TIC Potentiometer (Steve London)
>     6. Fwd:  Elementary feedline loss question (Hans Hammarquist)
>     7. Re: Icom Filters FL-52A and FL-96 (K7LXC at aol.com)
>     8. Re: Elementary feedline loss question (David Robbins)
> ----------------------------------------------------------------------
> Message: 1
> Date: Fri, 4 Apr 2014 09:34:26 -0400
> From: Scott Bullock <scottb at radios-online.com>
> To: David Robbins <k1ttt at arrl.net>
> Cc: "<towertalk at contesting.com>" <towertalk at contesting.com>
> Subject: Re: [TowerTalk] TIC Potentiometer
> Message-ID: <AF12D689-D485-43B9-95C2-4C80EAE68470 at radios-online.com>
> Content-Type: text/plain;	charset=us-ascii
> Like I said some don't have the problems like we have :) Saltwater environment...maybe this is why I dunno. Some people have never has issues on any of these rotors ever. I seem to be on a first name basis with mr Murphy  :) Hi Dave
> Scott
> N1CX
> Salty's
> www.radios-online.com
>> On Apr 4, 2014, at 9:26 AM, "David Robbins" <k1ttt at arrl.net> wrote:
>> I have 5 of them up in the air, some getting pretty old, and haven't
>> replaced a pot in at least 10 years, so far back I can't remember the last
>> one I did... in fact I just went and found the bag of spare parts for TIC
>> stuff... I bought 3 clarostat pots in 2003 and still have 2 of them.
>> David Robbins K1TTT
>> e-mail: mailto:k1ttt at arrl.net
>> web: http://wiki.k1ttt.net
>> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Scott
>> Bullock
>> Sent: Friday, April 04, 2014 13:18
>> To: Patrick Greenlee
>> Cc: towertalk at contesting.com
>> Subject: Re: [TowerTalk] TIC Potentiometer
>> Yea it's a shame a multi thousand dollar piece of equipment is rendered
>> useless by just a drop of water. Some people have never had a problem like
>> this. Some like us up here have helped keep vishay in business lol. Seems to
>> happen less in dry environments like out west etc.
>> I've spent thousands of hours thinking abt these problems. It's crazy.
>> Always a stupid little thing that causes them to fail.
>> Had thought abt putting silicone on the shaft also and may work, in my case
>> I never thought there would be enough heat inside the Bellhousing to dry
>> that washer out. Was happy to see we got a few seasons out of that mod. Have
>> seen pots go bad on brand new rotors less than 2 weeks old. Any of these
>> that has the shaft pointing up this is more susceptible to happen to. No
>> drain for water to get out...
>> Scott
>> N1CX
>> Salty's
>> www.radios-online.com
> ------------------------------
> Message: 2
> Date: Fri, 04 Apr 2014 08:49:22 -0500
> From: Patrick Greenlee <patrick_g at windstream.net>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Fulton 2500 winch single or dual speed?
> Message-ID: <533EB862.7010307 at windstream.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> You were lucky to only have to go to a clinic to get skin flap
> reattached.  A free wheeling multi-speed winch (coffee grinder - jib
> sheet on racing boat) malfunctioned and went free wheeling killing the
> crewman manning it with the equivalent of a terrific upper cut punch.  I
> subsequently sailed aboard that boat and for safety the winch was locked
> into one gear.  I assure you I always kept my head over the winch out of
> the swinging arc of the handles on either side.
> It is best to not employ manual winches that free wheel as they are an
> accident waiting for a chance to happen.  When injury or death are
> potential consequences, a few $ more for safety should be a no brainer.
> Patrick NJ5G
> On 4/3/2014 10:57 PM, Roger (K8RI) on TT wrote:
>> On 4/3/2014 12:06 PM, jcjacobsen at q.com wrote:
>>> How do,
>>> Gerald is looking for a new winch for his tower.
>>> Please, be careful that you don't get a winch that has a FREE WHEEL
>>> position.
>> Been there, done that, and had to go to the emergency room to get the
>> hide put back on the back of my hand.  It was just a glancing blow
>> that peeled the skin off nearly half the back of my hand from knuckles
>> almost to the wrist bone.
>>>    Nothing worse than the winch getting in that mode and having the
>>> handle whipping around at a rapid pace,
>> I'd say getting hit by it rates right up there.
>>>    not to mention the tower dropping at the same or greater rate. Most
>>> marine/boat winches are free wheeling.
>> Mine has a latch, but I was lowering a mast that wasn't terribly heavy
>> and had it unhooked. My hand slipped off the handle, but the handle
>> stopped pointing straight up. I knew better, but it was stationary.
>> Just as I grabbed, it went around once so fast I couldn't see it
>> move!  Had it hit square it would have broken a bunch of those small
>> bones.  As it is I only have a scar that covers about a third of the
>> back of my left hand.
>> Those winches can be dangerous and it only takes a moment of
>> inattention  to put you in a lot of pain.
>> 73
>> Roger (K8RI)
>>> 73
>>> K9WN Jake
>>> _______________________________________________
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> ------------------------------
> Message: 3
> Date: Fri, 04 Apr 2014 09:53:55 -0400
> From: Pete Smith N4ZR <n4zr at contesting.com>
> To: TOWERTALK at contesting.com
> Subject: [TowerTalk] Elementary feedline loss question
> Message-ID: <533EB973.70707 at contesting.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> If I terminate a long 50-ohm coaxial cable with a 50-ohm dummy load, and
> put an MFJ-259B on the other end, and it reads R=56, X=0 at a given
> frequency, what is the mathematical relationship between the measured R
> (leaving calibration out of it, for now) and the loss in dB?

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