Hello T-Talkers !
Wondering what your recommended sources for SS hardware nowadays??
If you recommend a source, could you say yes or no as to knowing if made in
China or not??
For those businesses recommended, but unknown if mfd. In China, I will find out
and recap to you.
In my biz we stay away from anything MIC, unless , for instance, it is a Times
Microwave product where they have a US citizen handling QC at the Chinese
factory they lease.
I have attached a link to a fairly good synopsis of the various types, and
grades of SS
https://www.unifiedalloys.com/blog/stainless-grades-families
Tnx, 73, good DX, Steve Davis, K1PEK
DAVIS RF Co.
DAVIS ROPE AND CABLE, LLC (metallic cable)
From: TowerTalk <towertalk-bounces@contesting.com> on behalf of
towertalk-request@contesting.com <towertalk-request@contesting.com>
Date: Thursday, November 10, 2022 at 12:01 PM
To: towertalk@contesting.com <towertalk@contesting.com>
Subject: TowerTalk Digest, Vol 239, Issue 9
Send TowerTalk mailing list submissions to
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of TowerTalk digest..."
Today's Topics:
1. Re: Antenna ID help (jcjacobsen)
2. Re: More friction needed (JVarney)
3. Re: Antenna ID help (Jim W7RY)
4. Mast clamp friction (k7lxc@aol.com)
5. Tnx for all the mast friction comments! (k7lxc@aol.com)
6. m2 rotator slippage (STEPHEN L SALA)
7. Re: Antenna ID help (Floyd Rodgers)
8. Re: More friction needed (Grant Saviers)
9. Re: More friction needed (JVarney)
----------------------------------------------------------------------
Message: 1
Date: Wed, 09 Nov 2022 09:52:47 -0800
From: jcjacobsen <jcjacobsen@q.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <96WVN5WTCIU4.EKDC04CPXB2C@luweb02oc>
Content-Type: text/plain; charset=utf-8
Hello Towertalkians
Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line,
probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
So I'm turning to the collective memory of the old timers on the reflector.
11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
Any help out there??
Thanks in advance.
73 K9WN Jake
------------------------------
Message: 2
Date: Wed, 9 Nov 2022 10:25:55 -0800
From: JVarney <jvarn359@gmail.com>
To: "[TowerTalk]" <towertalk@contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID:
<CANx7Etau459BoSsaEcLqxkcnByCeCwgSc_S5bbkyCG=5RFgOVQ@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Dave AB7E wrote>> Personally, I think the idea of using multiple U-bolts is
the best way to go. <<
I agree. And instead of shooting from the hip and guessing, with U-bolts
you can calculate and
engineer the number and size of U-bolts needed to resist the mast torque.
This is a simplified
version of the procedure in TIA-222-H
Nominal torsional strength of U-bolt assembly = Tr = 0.075 (D)(Tp)
Tp = assumed U-bolt leg tension = (20 ksi)(Ag of leg)
where D = mast diameter, Ag = gross area of U-bolt leg. English units.
U-bolts should not be tightened past yield and should be limited to 0.85 Fy
Ag.
===
Example: 3 3/8 U-bolts and a 2-in mast.
Ag leg = 0.19 sq in
Tp = 20 ksi x 0.19 = 3800 lbs
Tr = 0.075 ( 2 in )(3800) = 570 in-lbs per leg
System Tr = (3 U-bolts)(2 legs each)(570 in-lbs) = 3,420 in-lbs torque
resistance
===
Considering a Yaesu G-800 has a brake resistance 0f 4,000 in-lbs, the 3
U-bolts is
in the ballpark for a medium tribander. If you ignore the 20k yield
assumption and use
42k yield for stainless and tighten to 0.85FyAg, that gets you 1,000 in-lbs
per leg,
equal to 6,000 in-lbs total torque resistance.
This simplified estimate ignores vertical slippage forces due to the weight
of the
mast and antenna acting on the U-bolts, which reduces the available torque
resistance somewhat.
73 Jim K6OK
------------------------------
Message: 3
Date: Wed, 9 Nov 2022 12:26:38 -0600
From: Jim W7RY <jimw7ry@gmail.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <8adc514b-7877-edd4-5fd9-dd943c608c5f@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
If you post this on towertalk on the groups.io list, you could attache a
picture.
Feel free to join.
73, Jim W7RY
On 11/9/2022 11:52 AM, jcjacobsen via TowerTalk wrote:
> Hello Towertalkians
>
>
> Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line,
> probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
> So I'm turning to the collective memory of the old timers on the reflector.
>
>
> 11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
>
>
> Any help out there??
>
>
> Thanks in advance.
>
>
> 73 K9WN Jake
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
--
Thanks and 73, Jim W7RY
------------------------------
Message: 4
Date: Wed, 9 Nov 2022 18:38:05 +0000 (UTC)
From: <k7lxc@aol.com>
To: towertalk@contesting.com
Subject: [TowerTalk] Mast clamp friction
Message-ID: <908629317.427392.1668019085374@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
? ? Here is a cheap and elegant way to increase the friction.?
?Cheers,Steve? ? ?K7LXC? If I need for a clamp to hold without slipping, this
is what I do.? I am
a retired machinist.
I make my own 3 inch saddles from 3/4 x 1 1/2 billet aluminum.
I use hot dipped galvanized U-bolts, as SS bolts all seem to be 'one
time' use, before failure.
I use a light duty adhesive sprayed on the 'bore' part of the saddle.?
Women's hair spray works fine.
While wet, sprinkle silicon carbide particles on the adhesive. This size
is about like ground pepper from a pepper mill.
Assemble and tighten down.? The silicon carbide presses into both the
aluminum saddles and into the zinc on the galvanized mast. It will not
slip!?? Be careful in handling the mast/saddles; the silicon carbide can
be hard on the hands.
73 de Steve, NR4M
------------------------------
Message: 5
Date: Wed, 9 Nov 2022 18:39:48 +0000 (UTC)
From: <k7lxc@aol.com>
To: towertalk@contesting.com
Subject: [TowerTalk] Tnx for all the mast friction comments!
Message-ID: <1957544183.426550.1668019188891@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
Cheers,
Steve? ? ?K7LXC
------------------------------
Message: 6
Date: Wed, 9 Nov 2022 18:44:25 +0000
From: STEPHEN L SALA <k7awb@msn.com>
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] m2 rotator slippage
Message-ID:
<CH3PR14MB620281C362505B3ACCC14011ED3E9@CH3PR14MB6202.namprd14.prod.outlook.com>
Content-Type: text/plain; charset="utf-8"
steve k7lxc:
several years ago i had that same problem and your company sold me a large
metal two-piece bracket as a replacement for the M2 parts (yours had holes for
6 clamps.
it worked perfectly and it has been about ten years up there. don?t you have
one in storage to use yourself?
Stephen
K7awb
DN17es
------------------------------
Message: 7
Date: Wed, 9 Nov 2022 19:01:02 +0000 (UTC)
From: Floyd Rodgers <kc5qbc@swbell.net>
To: "towertalk@contesting.com" <towertalk@contesting.com>, jcjacobsen
<jcjacobsen@q.com>
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <84951341.439002.1668020462813@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
Most likely a klm of 70's? vintage.?
On Wednesday, November 9, 2022 at 11:52:59 AM CST, jcjacobsen via TowerTalk
<towertalk@contesting.com> wrote:
Hello Towertalkians
Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line,
probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
So I'm turning to the collective memory of the old timers on the reflector.
11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
Any help out there??
Thanks in advance.
73 K9WN? Jake
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 8
Date: Wed, 9 Nov 2022 13:49:47 -0800
From: Grant Saviers <grants2@pacbell.net>
To: Steve Dyer W1SRD <w1srd@yahoo.com>, "'towertalk@contesting.com'"
<towertalk@contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID: <f80b1c5e-3ead-e707-4474-dccc1df693f2@pacbell.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
The work can be done on many home shop lathes - 12x36 and even some
smaller, so check around for who might be willing to help.
A piece of tubing or a mandrel of most anything the size of the mast
minus 0.050" or so makes the setup easier - centering the two halves and
then boring to the desired diameter, recenter and repeat as necessary to
get a square bore and enough teeth and area on the teeth. Three or 4
cleaned up teeth per row on each half with 1/4" contact areas is what I
decided was about right. While I bored for a 3" mast, I think the
casting should work for a 2" bore.
An hour or two of lathe time if you can find a commercial shop willing
to take it on.
It's clear the design intent was to work with all mast diameters, but
that limits the possible tooth engagement. Then adding casting
variability created a marginal clamp system. Mold wear yields more
variability and base machining is difficult to get square on the cast
teeth. It's a classic problem in machining an iron casting - what is
the best reference surface or where should one be machined?
I think many masts slip because bolts are not tightened to spec and not
retightened evenly another couple of times. Also, using stainless steel
bolts, some of which have a tendency to stretch a bit over time. My
DB36 stock mast clamp slipped 3 times before I reinforced the aluminum
"C" clamps on the backside with 1/2" thick steel bar and used grade 8
bolts torqued to spec 3x. The stock "C" collar pair would close to tips
touching and that made further tightening useless.
I am also a big fan of the DX Engineering cast saddle U bolt clamp sets.
The saddle has a large contact area with the mast or tube and my
choice for all home brew antennas. Never had one slip. A great part
for making a multi U bolt mast clamp.
A u-bolt holding a tube against a flat plate may have only 2 contact
points. Using many u-bolts is one approach. Deforming the u-bolts to
increase the "wrap" is another. Or flattening the tube.
Grant KZ1W
On 11/8/2022 17:42, Steve Dyer W1SRD via TowerTalk wrote:
> What would a competent machine shop charge to do this? Most of us don't
> have a fully outfitted machine shop :-).
> 73,
> Steve
> W1SRD
>> Bolt the two clamp sections to a lathe faceplate and bore them to the
>> mast diameter.? Remove enough material to enlarge the contact area and
>> insure the bore is true to the bases.? Use grade 8 bolts and use a
>> torque wrench to max spec torque for the size bolt.? Repeat this
>> tightening 3 times.
>>
>> The clamp bore as cast wasn't straight to the machined base and only a
>> few "points" would have made contact in the 2800 I have turning a 375#
>> 100ft tip to tip 2L 80m beam.? Now it doesn't slip.
>>
>> Grant KZ1W
>>
>> On 11/8/2022 10:00, k7lxc--- via TowerTalk wrote:
>>> Howdy, TowerTalkians -
>>> ??? ? I need more friction between an M2 mast clamp and the mast. How
>>> could I do that? What materials would work? Tnx.?Cheers,Steve
>>> K7LXCCell: 206-890-4188
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 9
Date: Wed, 9 Nov 2022 16:02:12 -0800
From: JVarney <jvarn359@gmail.com>
To: "[TowerTalk]" <towertalk@contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID:
<CANx7EtaoOBaqqhECc_sz6Wts-i0wyYP1XVKERCShxa2unw5xEg@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Sorry my Gmail messed up the line breaks and made it
unreadable. Reposting for anyone interested in calculating
U-bolt torsion resistance for masts.
I'm fairly confident this method is a good approximation
because the TIA committee, composed of experienced engineers
in the tower industry, wouldn't write this into the
building code unless it had good support.
----------------------------------------------------------------
Dave AB7E wrote>> Personally, I think the idea of using multiple
U-bolts is the best way to go. <<
I agree. And instead of shooting from the hip and guessing,
with U-bolts you can calculate and engineer the number and size
of U-bolts needed to resist the mast torque. This is a simplified
version of the procedure in TIA-222-H
Nominal torsional strength of U-bolt assembly = Tr
Tr = 0.075 (D)(Tp)
Tp = assumed U-bolt leg tension = (20 ksi)(Ag of leg)
where D = mast diameter, Ag = gross area of U-bolt leg.
U-bolts should not be tightened past yield and should be limited
to 0.85 Fy Ag.
===
Example: 3 3/8 U-bolts and a 2-in mast.
Ag leg = 0.19 sq in Tp = 20 ksi x 0.19 = 3800 lbs
Tr = 0.075 ( 2 in )(3800) = 570 in-lbs per leg
System Tr = (3 U-bolts)(2 legs each)(570 in-lbs) = 3,420 in-lbs
torque resistance
===
Considering a Yaesu G-800 has a brake resistance 0f 4,000 in-lbs,
the 3 U-bolts is in the ballpark for a medium tribander.
If you ignore the 20k yield assumption and use 42k yield
for stainless and tighten to 0.85FyAg, that gets you 1,000
in-lbs per leg, equal to 6,000 in-lbs total torque resistance.
This simplified estimate ignores vertical slippage forces due
to the weight of the mast and antenna acting on the U-bolts,
which reduces the available torque resistance somewhat.
73 Jim K6OK
------------------------------
Subject: Digest Footer
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------------------------------
End of TowerTalk Digest, Vol 239, Issue 9
*****************************************
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