Admittedly no numbers here, but I'd sure use galvanized water pipe, UNLESS
there's a local junkyard where you might find something else. Water pipe is
heavier than the fencepost, I think.
It that 4' makes you nervous, drop the beam a foot and see how it does.
On the other hand, if you're willing to pay for the IR, then the cost of the
mast doesn't amount to much.
Wilson
W4BOH
----- Original Message -----
From: <towertalk-request@contesting.com>
To: <towertalk@contesting.com>
Sent: Wednesday, March 09, 2011 3:00 PM
Subject: TowerTalk Digest, Vol 99, Issue 19
> Send TowerTalk mailing list submissions to
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> When replying, please edit your Subject line so it is more specific
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>
> Today's Topics:
>
> 1. Re: Tower for Challenging Terrain (Pete Smith)
> 2. Emotator rotor motor problem (Glen)
> 3. Re: Emotator rotor motor problem (Jim Hargrave)
> 4. Sorry to bring up an oldie - Mast Material (Rick Scott)
> 5. Re: Sorry to bring up an oldie - Mast Material (Dave Hachadorian)
> 6. Re: Sorry to bring up an oldie - Mast Material (Dave Hachadorian)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 09 Mar 2011 06:08:27 -0500
> From: Pete Smith <n4zr@contesting.com>
> Subject: Re: [TowerTalk] Tower for Challenging Terrain
> To: towertalk@contesting.com
> Message-ID: <4D775FAB.2080700@contesting.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> My local cable company (Comcast) used to give away the occasional short
> ends (less than 100 feet), but closed their scrap yard a couple of years
> ago, citing the tight economy and the rising price of scrap metal.
>
>
> 73, Pete N4ZR
>
> The World Contest Station Database, updated daily at
> www.conteststations.com
> The Reverse Beacon Network at http://reversebeacon.net, blog at
> reversebeacon.blogspot.com,
> spots at telnet.reversebeacon.net, port 7000
>
>
>
> On 3/8/2011 11:56 PM, Jim Brown wrote:
>> On 3/8/2011 7:02 PM, Jerry Gardner wrote:
>>> My run will be approx. 400-450 feet, so I'll have to find a similar
>>> source of hardline.
>> It has been suggested many times on this list that we contact CATV
>> companies to ask for their junk lengths of CATV hard line. Yes, it's 75
>> ohms, but the loss is quite small, and the additional loss due to
>> mismatch is also small.
>>
>> 73, Jim K9YC
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 9 Mar 2011 09:29:21 -0500
> From: "Glen" <k4kv@mds-ham.com>
> Subject: [TowerTalk] Emotator rotor motor problem
> To: "tower talk" <towertalk@contesting.com>
> Message-ID: <OLEMLLLENPOJJLABJGKJCEFOHAAA.k4kv@mds-ham.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello,
>
> My Emotator 747 rotor motor now fails to turn right, but turns left just
> fine.
>
> I removed the rotor this morning and put it on the bench, same thing.
>
> Removed the top and bearing ring. Inside looks fine. Watched motor as I
> applied power LEFT
> and no problems. When applying power RIGHT, motor starts to move and
> makes
> a snap noise, as if
> it is internally jammed from moving that direction.
>
> I will check the current both ways, but expect RIGHT to be higher since
> there is a jam.
>
> Anyone have any experience with a DC rotor motor that will only turn one
> way????
>
>
> 73's
>
> Glen K4KV
> I suppose getting a replacement motor will not be fun :-(
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 9 Mar 2011 08:53:37 -0600
> From: "Jim Hargrave" <w5ifp@gvtc.com>
> Subject: Re: [TowerTalk] Emotator rotor motor problem
> To: "Glen" <k4kv@mds-ham.com>
> Cc: Towertalk <towertalk@contesting.com>
> Message-ID: <OCEJJBNIIHKIDEJBLMEBEEKGCBAA.w5ifp@gvtc.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Check the brushes.
> A worn brush will sometimes jam in one direction and still run ok in the
> other direction.
>
> 73s de Jim
> W5IFP
>
>
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com]On Behalf Of Glen
> > Sent: Wednesday, March 09, 2011 8:29 AM
> > To: tower talk
> > Subject: [TowerTalk] Emotator rotor motor problem
> >
> >
> > Hello,
> >
> > My Emotator 747 rotor motor now fails to turn right, but turns left
> just
> > fine.
> >
> > I removed the rotor this morning and put it on the bench, same thing.
> >
> > Removed the top and bearing ring. Inside looks fine. Watched
> > motor as I
> > applied power LEFT
> > and no problems. When applying power RIGHT, motor starts to
> > move and makes
> > a snap noise, as if
> > it is internally jammed from moving that direction.
> >
> > I will check the current both ways, but expect RIGHT to be higher since
> > there is a jam.
> >
> > Anyone have any experience with a DC rotor motor that will only turn
> one
> > way????
> >
> >
> > 73's
> >
> > Glen K4KV
> > I suppose getting a replacement motor will not be fun :-(
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 9 Mar 2011 09:51:13 -0800 (PST)
> From: Rick Scott <w7psk@yahoo.com>
> Subject: [TowerTalk] Sorry to bring up an oldie - Mast Material
> To: towertalk@contesting.com
> Message-ID: <623100.31806.qm@web111511.mail.gq1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> Im really confused. Id like to buy Local, because the mail order houses
> have
> Really high prices and high shipping
> plus they only do 5 or 10ft intervals.
>
> Ive seen all manor material from them from chrome molly to Aluminum and
> AES even
> has Fiberglass.
>
> I have a Glen Martin 9ft roof mount tower. Its just shy of 4ft from the
> rotor
> to the top of the tower. Right now I have
> a 2 1/2" Fence Post mast (really heavy wall) that I hold an A4S up with.
>
> A4 is going bad so I decided to get my dream antenna the standard SteppIR
> 3
> element beam and nothing else will go on the mast. I would
> like to get 8ft as that will give me 4ft above the tower, I can put the
> antenna
> at 2 - 3 feet and be ok.
>
>
>
> So I need 2" mast material,
>
> I would dearly like to buy local and we have a few metal shops but I need
> to
> know exactly what I have.
>
> I searched the forum and man there is a lot of material. K7XLC used to
> sell
> mast but his site doesnt.
>
> I posted on the local Snohmish County hams and I got a gazzilion answers.
>
> One guy swears by Home Depot stuff
> One says only buy Sched 40pipe nothing else needed
> Another says this and that.
> Another says 6061-T6 Extruded Tubing
>
>
> So not really wanting to open a can of worms, whats the best material to
> hold
> what I plan to put up
> for the best cost.
>
>
> Scotty W7PSK
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 9 Mar 2011 12:31:40 -0700
> From: "Dave Hachadorian" <k6ll@arrl.net>
> Subject: Re: [TowerTalk] Sorry to bring up an oldie - Mast Material
> To: "Rick Scott" <w7psk@yahoo.com>, "Towertalk reflector"
> <towertalk@contesting.com>
> Message-ID: <9B4B36FCB2C646618373242D70485489@Acer>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Here is a neat mast calculator:
> http://www.math.niu.edu/KARC/mast/
>
> Plugging in some numbers for 1.5" schedule 20 water pipe:
> Safety factor f 2
> Wind loading factor k .004 lb/ft2/mph2
> Maximum stress S 30,000 psi
> Outside diameter D 1.9 in
> Inside diameter d 1.61 in
> Total length of mast 8 ft
> Height above support h 4 ft
> Antenna 1 height h1 4 ft area a1 6.1 ft2
> Antenna 2 height h2 ft area a2 ft2
> Antenna 3 height h3 ft area a1 ft2
>
> Survival velocity: 63.0 mph
> Failure velocity: 89.1 mph
> Weight of mast: 21.79 lbs
> ---------------------------------------
> As indicated above, I wouldn't be confident in using Sch 20 water
> pipe. That 30,000 psi yield strength for water pipe is hard to
> prove, because water pipe is not specified for structural
> purposes. Also, the last time I priced water pipe, I was amazed
> to see how expensive it had become.
>
> You are much better off using structural tubing, which has a
> specified yield strength. If you go to a metal supplier and ask
> for structural tubing, he should be able to quote you some prices
> on various strength material. You will probably have to buy a
> 20-footer though. Another thing you can do is to order some
> galvanized steel mast from Texas Towers. They will sell you a 10'
> piece for $139, and cut off a foot, which makes it UPS-shippable
> (at least the last time I did it, in 1978). Their material is
> 87,000 psi. Plugging that into the calculator:
> ---------------------------------------
>
> Safety factor f 2
> Wind loading factor k .004 lb/ft2/mph2
> Maximum stress S 87,000 psi
> Outside diameter D 2 in
> Inside diameter d 1.75 in
> Total length of mast 8 ft
> Height above support h 4 ft
> Antenna 1 height h1 4 ft area a1 6.1 ft2
>
> Survival velocity: 107.0 mph
> Failure velocity: 151.3 mph
> Weight of mast: 20.07 lbs
>
> That will definitely work.
>
>
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>
>
>
>
> -----Original Message-----
> From: Rick Scott
> Sent: Wednesday, March 09, 2011 10:51 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Sorry to bring up an oldie - Mast Material
>
> Im really confused. Id like to buy Local, because the mail order
> houses have
> Really high prices and high shipping
> plus they only do 5 or 10ft intervals.
>
> Ive seen all manor material from them from chrome molly to
> Aluminum and AES even
> has Fiberglass.
>
> I have a Glen Martin 9ft roof mount tower. Its just shy of 4ft
> from the rotor
> to the top of the tower. Right now I have
> a 2 1/2" Fence Post mast (really heavy wall) that I hold an A4S
> up with.
>
> A4 is going bad so I decided to get my dream antenna the standard
> SteppIR 3
> element beam and nothing else will go on the mast. I would
> like to get 8ft as that will give me 4ft above the tower, I can
> put the antenna
> at 2 - 3 feet and be ok.
>
>
>
> So I need 2" mast material,
>
> I would dearly like to buy local and we have a few metal shops
> but I need to
> know exactly what I have.
>
> I searched the forum and man there is a lot of material. K7XLC
> used to sell
> mast but his site doesnt.
>
> I posted on the local Snohmish County hams and I got a gazzilion
> answers.
>
> One guy swears by Home Depot stuff
> One says only buy Sched 40pipe nothing else needed
> Another says this and that.
> Another says 6061-T6 Extruded Tubing
>
>
> So not really wanting to open a can of worms, whats the best
> material to hold
> what I plan to put up
> for the best cost.
>
>
> Scotty W7PSK
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 9 Mar 2011 12:45:18 -0700
> From: "Dave Hachadorian" <k6ll@arrl.net>
> Subject: Re: [TowerTalk] Sorry to bring up an oldie - Mast Material
> To: "Rick Scott" <w7psk@yahoo.com>, "Towertalk reflector"
> <towertalk@contesting.com>
> Message-ID: <1E766F9E9D0648AABD43B8861DF2ED58@Acer>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> In my previous posting on this subject, the I.D. that I used for
> water pipe was actually for Schedule 40 pipe, not Schedule 20.
>
> Naturally, I spotted the mistake 5 seconds after hitting the
> "send" button.
>
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> .
>
>
>
> ------------------------------
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> End of TowerTalk Digest, Vol 99, Issue 19
> *****************************************
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