From W8EK at flham.net  Sun Oct  2 16:46:12 2011
From: W8EK at flham.net (Ken Simpson, W8EK)
Date: Sun, 02 Oct 2011 16:46:12 -0400
Subject: [QCWA] QCWA at Melbourne FL Hamfest, Oct 8
Message-ID: <4E88CD94.7040709@flham.net>


QCWA at Melbourne FL Hamfest, Saturday, October 8

We plan to have a display table and a forum at the Melbourne
FL hamfest, this coming weekend, Saturday, October 8.

Our display table should be towards the front stage area.
The forum is scheduled to be held at 9 AM in Meeting Room 1.

Please stop by the booth, sign in, and say hello.
Then be certain to attend the forum.

See you there.

Thanks.

73,

Ken, W8EK

Ken Simpson
QCWA National Director
E-mail to W8EK at FLHam.net or W8EK at arrl.net
Voice Phone  (352) 732-8400


From wa9vrh at dishmail.net  Mon Oct  3 17:09:54 2011
From: wa9vrh at dishmail.net (Larry WA9VRH)
Date: Mon, 3 Oct 2011 16:09:54 -0500
Subject: [QCWA] First Wednesday CCA AM Night  Oct.5th!!!
Message-ID: <006001cc8211$9012d530$e0636a4b@KWM380>

FIRST WEDNESDAY AM NIGHT!!! Sponsored by the Collins Collectors Association.

Wednesday October 5th, 2011 on 3880 kcs at 7:30 PM local East Coast time
marks the start of the latest chapter of First Wednesday AM Night, drawing 
hundreds of vintage stations
from across the country.

 We encourage stations to check-in on AM using Collins and other AM
transmitters, new and old.  It's an opportunity to revel in this nostalgic 
mode, enjoy giving
vintage equipment a "run," and sharing some storytelling about classic 
vacuum tube homebrew and
commercial designs. Typically more than a hundred stations take part in the 
evening's
coast-to-coast AM event; by the time it concludes at 10:00 PM Local PST.

LISTEN for the following anchors and stop by to say hello, won't you? You
don't have to be running Collins or vintage gear to be welcomed into the 
group.

 Bob W0YVA from 7:30 LCL to 8:30 LCL Eastern time

 Jim W0NKL then steps in at 7:30- 9:00 LCL Midwest

Chuck KD0ZS steps in at 8:00 to 9:00 LCL Mountain

Mickey  WA6FIZ  starts  7:30 LCL West Coast time


comments please to wa9vrh at dishmail.net
 


From WA2ARS at aol.com  Sun Oct  9 13:25:35 2011
From: WA2ARS at aol.com (WA2ARS at aol.com)
Date: Sun, 9 Oct 2011 13:25:35 -0400 (EDT)
Subject: [QCWA] QCWA Orlando Fl Citrus Chapter #45 Meeting Thursday October
	13th
Message-ID: <67b3f.688d8aaf.3bc3330f@aol.com>

Citrus Chapter #45 Orlando FL.  will  be meeting 1:30PM-3:30PM Thursday 
October 13th, at the  Golden  Corral, 5535 S.Kirkman Rd.Orlando Fl.32819.  

Take I-4  West toward Tampa,to Exit 75B  merge onto 435 N/S Kirkman Rd.
Golden  Corral is on  right.
OR
West Colonial Hwy 50 to Kirkman Rd   (Hwy435)5.2 miles U-Turn Major 
Blvd.Golden Corral on right.


Anyone in  the area is welcome and  encouraged to attend. YLs and XYLs are 
also  welcome.

Please attend if you  can.

Mort Cohen  WA2ARS
Treasurer, QCWA Citrus Ch.#45

EMail  _WA2ARS at aol.com_ (mailto:WA2ARS at aol.com) 

From vic.w4vic at verizon.net  Sun Oct  9 14:02:11 2011
From: vic.w4vic at verizon.net (Vic Culver)
Date: Sun, 09 Oct 2011 12:02:11 -0600
Subject: [QCWA] QCWA CHAPTER 119 OCTOBER MEETING -- LADIES DAY
Message-ID: <4E91E1A3.3020709@verizon.net>


From schrick at copper.net  Mon Oct 10 11:53:33 2011
From: schrick at copper.net (Gerd)
Date: Mon, 10 Oct 2011 11:53:33 -0400
Subject: [QCWA] QCWA Meeting Tomorrow
Message-ID: <4E9314FD.9090805@copper.net>

Chapter 9 meets tomorrow, Tuesday 11 Oct. at the MCL Cafeteria in 
Kettering (Luncheon Meeting)

CU there!
Vy73, Gerd, WB8IFM.
-- 
Gerd & Traudl Schrick 4741 Harlou Dr Dayton, OH, 45432-1618 USA 
(937)253-3993 Schrick at copper.net WB8IFM

From vic.w4vic at verizon.net  Mon Oct 10 13:22:36 2011
From: vic.w4vic at verizon.net (Vic Culver)
Date: Mon, 10 Oct 2011 11:22:36 -0600
Subject: [QCWA] RESENDING QCWA Chapter 119 October Meeting -- Ladies Day
Message-ID: <4E9329DC.5040507@verizon.net>

Sorry, folks -- Win 7 strikes again!  Let's see if content of message 
makes it to you this time.

QCWA Chapter 119 will celebrate Ladies Day at our October meeting on 
Saturday, October 15, 2011 at 12:00 Noon at the Marker 20 Restaurant, 
21 E. Queens Way, Hampton, VA.  This special meeting will honor our 
QCWA Lady Members, and the spouses who provide such strong support for 
our OM members.  If you are in the area for the weekend, this would be 
a wonderful opportunity for you to have a great lunch with a wonderful 
group of QCWA folks.  Reservations are requested so that we may insure 
proper recognition for our ladies -- e-mail: vic at w4vic.com will do the 
trick.

The Marker 20 Restaurant is across the street and across a parking 
area from the Virginia Air and Space Museum.  What better way to spend 
the day than to explore this richly appointed Air and Space Museum, 
supported by many of our QCWA Members as docents and visitor guides, 
and to have a great lunch near the waterfront in Hampton VA.  It will 
be our pleasure to host your visit.  73, Vic, W4VIC, President, QCWA 
Chapter 119 Inc.

From kf5lo at att.net  Fri Oct 14 10:52:45 2011
From: kf5lo at att.net (Victor Martin)
Date: Fri, 14 Oct 2011 07:52:45 -0700 (PDT)
Subject: [QCWA] QCWA Fort Worth Chapter 72 Lunch Meeting
In-Reply-To: <1313607284.33470.YahooMailRC@web80007.mail.sp1.yahoo.com>
References: <1313607284.33470.YahooMailRC@web80007.mail.sp1.yahoo.com>
Message-ID: <1318603965.11700.YahooMailRC@web80015.mail.sp1.yahoo.com>

Greetings,
?
Sorry for the late notice.? Mark your calendar for Saturday, October 15, 2011 
(tomorrow) as a reminder of the monthly Fort Worth QCWA Chapter 72 lunch 
meeting.
It will be at the Spring Creek Barbecue in West Fort Worth (8628 Camp Bowie W 
(works in Google maps).? It is also known as Hwy 80 and Weatherford Hwy.? (Click 
the following http://www.qcwa.org/chapter072map.html) The Doors open at 11:00.
Hope to see you there.
73,
Ted Martin
KF5LO
Secretary
Kf5lo1 at verizon.net
(817) 656-3243

From ve3jx at sympatico.ca  Sat Oct 15 18:57:36 2011
From: ve3jx at sympatico.ca (VE3JX)
Date: Sat, 15 Oct 2011 18:57:36 -0400
Subject: [QCWA] AARC Bulletin #11-032 **Last week of Charter Sub Special for
	WRO!**
Message-ID: <BLU0-SMTP774C79E104B3FC1E4E083983E60@phx.gbl>

Greetings all,

Alas, it had to happen sooner or later.  

After 33 issues of WorldRadio online available for free, CQ Communications has decided to make WRO a "paid-for" item.  Below is CQ's announcement of this and a special 1-year Charter subscription offer for $9.97.

If you enjoy WRO, then you have one week to take advantage of the special offer.  After that, the regular price will be $2.99/issue, or 19.99/year.  So, don't delay!

Cheers,

Dave Hayes VE3JX
WRO QCWA Columnist

P.S.  CQ's other publications are going to be available in digital as well as paper.  Details for them are also below.



From: CQ Communications 
Sent: Saturday, October 15, 2011 3:38 PM
Subject: Last week of Charter Sub Special for WRO!


      Having trouble viewing this email? Click here  

                 
                    
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                  Greetings! 
                        Just a quick note to remind you that there's only one week left to get 50% off on a WorldRadio Online subscription! The 1-year WorldRadio Online Charter Subscription Special ends on October 24th. 

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                  November issue debut is scheduled for October 25th - order today!
                  Time is running out to take advantage of WorldRadio Online's Charter Subscription - 50% OFF- special pricing. This "online only" magazine combines its traditional focus on the people and groups who make up the ham radio hobby with regular coverage of popular ham topics, including DXing, emergency communications, antennas, "trail-friendly radio" and much, much more!  Click here to order!  
                    

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                  Hurry, this Special Offer ends October 24, 2011. 

                  Don't miss WorldRadio Online's November issue debut on October 25th! Order your 1-year Charter Subscription today for $9.97 that's 50% Off the regular one-year subscription price of $19.95.
                      

                 
                   
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From broske at hutchtel.net  Mon Oct 17 16:28:31 2011
From: broske at hutchtel.net (Bob Roske)
Date: Mon, 17 Oct 2011 15:28:31 -0500
Subject: [QCWA] Charitable Gift Annuity (CGA)
Message-ID: <BE056033E37640308CB734A41D309D3B@BobsWeb>

As of July 1, 2011 Charitable Gift Annuity (CGA) Rates have RISEN for those age 70 and older.  So, if you've ever considered funding a CGA to benefit QCWA, now would be a GREAT time to do it.....Regardless of your age, the benefits of a CGA are advantageous.

BY FUNDING A CHARITABLE GIFT ANNUITY, YOU RECEIVE:
  An immediate charitable deduction
  Fixed payments for life
  Income tax savings
  Estate tax savings
  Capital Gains tax savings

To learn more about funding a CGA that will work for you, please consult your financial advisor or tax consultant, or attorney.





-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.1831 / Virus Database: 2090/4557 - Release Date: 10/17/11

From w7wll at arrl.net  Mon Oct 17 11:50:41 2011
From: w7wll at arrl.net (Don Tucker)
Date: Mon, 17 Oct 2011 08:50:41 -0700
Subject: [QCWA] QCWA
Message-ID: <EFD0766E284845DD80286639005A21D2@Sue>

Anyone know the history of the rack dimensions, how they got to the weird 
numbers they are. I know they came from RR signaling equipment, but the who, 
when and why the odd dimensions. A group of us ex electronics folks 
discussed this over coffee and realized all these years we had just accepted 
the standards. 



From w2bzy at cfl.rr.com  Wed Oct 19 17:41:48 2011
From: w2bzy at cfl.rr.com (Bob Cumming)
Date: Wed, 19 Oct 2011 17:41:48 -0400
Subject: [QCWA] history of the rack dimensions
Message-ID: <7.0.0.16.2.20111019173853.05bee178@cfl.rr.com>

Per:  en.wikipedia.org/wiki/19-inch_rack



Overview and history

Equipment designed to be placed in a rack is typically described as 
rack-mount, rack-mount instrument, a rack mounted system, a rack 
mount chassis, subrack, rack mountable, or occasionally simply shelf. 
The height of the electronic modules is also standardized as 
multiples of 1.75 inches (44.5 mm) or one 
<http://en.wikipedia.org/wiki/Rack_unit>rack unit or U (less commonly RU).

Because of their origin as mounting systems for 
<http://en.wikipedia.org/wiki/Railroad_signaling>railroad signaling 
<http://en.wikipedia.org/wiki/Relay>relays, they are still sometimes 
called relay racks, but the 19-inch rack format has remained a 
constant while the technology that is mounted within it has changed 
to completely different fields. The 19-inch (482.6 mm) standard rack 
arrangement is widely used throughout the 
<http://en.wikipedia.org/wiki/Telecommunication>telecommunication, 
<http://en.wikipedia.org/wiki/Computer>computing, 
<http://en.wikipedia.org/wiki/Sound_recording_and_reproduction>audio, 
<http://en.wikipedia.org/wiki/Entertainment>entertainment and other 
industries, though the 
<http://en.wikipedia.org/wiki/Western_Electric>Western Electric 
<http://en.wikipedia.org/wiki/23-inch_rack>23-inch standard, with 
holes on 1-inch (25.4 mm) centers, prevails in telecommunications.

19-inch racks are often used to house professional audio and video 
equipment, including 
<http://en.wikipedia.org/wiki/Amplifier>amplifiers, 
<http://en.wikipedia.org/wiki/Effects_unit>effects units, interfaces, 
<http://en.wikipedia.org/wiki/Headphone>headphone amplifiers, and 
even small scale audio mixers. They are also widely used for 
<http://en.wikipedia.org/wiki/Computer_server>computer server 
equipment, allowing for dense hardware configurations without 
occupying excessive floorspace or requiring shelving. A third common 
use for rack-mounted equipment is industrial power, control, and 
automation hardware.

Typically, a piece of equipment being installed has a front panel 
height 1/32-inch (0.031 inches (0.787 mm)) less than the allotted 
number of Us. Thus, a 1U rackmount computer is not 1.75 inches (44.5 
mm) tall but is 1.719 inches (43.7 mm) tall. 2U would be 3.469 inches 
(88.1 mm) instead of 3.5 inches (88.9 mm). This gap allows a bit of 
room above and below an installed piece of equipment so it may be 
removed without binding on the adjacent equipment.

In 1965 a durable 
<http://en.wikipedia.org/wiki/Fiber_reinforced_plastic>fiber 
reinforced plastic 19-inch rackmount case was patented by ECS 
Composites and became widely used in military and commercial 
applications for electronic deployment and operation. 
State-of-the-art rackmount cases are now also constructed of thermo 
stamped composite, <http://en.wikipedia.org/wiki/Carbon_fiber>carbon 
fiber and <http://en.wikipedia.org/wiki/DuPont>DuPont's 
<http://en.wikipedia.org/wiki/Kevlar>Kevlar for demanding military 
and commercial uses.



Fastening

Originally, the mounting holes were 
<http://en.wikipedia.org/wiki/Taps_and_dies>tapped to receive a 
particular type of threaded <http://en.wikipedia.org/wiki/Screw>bolt. 
This is still frequently used in some government and military 
applications, often in conjunction with slide rails for ease of 
maintenance. However, it is no longer typical for frequently changed 
server racks, due to the possibility for the threads to become 
damaged or for a bolt to bind and break off, rendering the mounting 
hole unusable. Tapped-hole racks are still used for hardware that 
rarely changes, such as phone, network cabling panels, TV 
broadcasting facilities, studios and relay racks.

The tapped-hole rack was first replaced by clearance-hole racks. The 
holes are large enough to permit a bolt to be freely inserted through 
without binding, and bolts are fastened in place using cage nuts. A 
<http://en.wikipedia.org/wiki/Cage_nut>cage nut consists of a 
<http://en.wikipedia.org/wiki/Spring_steel>spring steel cage, 
designed to clip onto the open mounting hole, within which is a 
captive nut. In the event of a nut being stripped out or a bolt 
breaking, the nut can be easily removed and replaced with a new one. 
Production of clearance-hole racks is less expensive because tapping 
the holes is eliminated and replaced with fewer, less expensive, cage nuts.

The next innovation in rack design has been the square-hole rack. 
Square-hole racks allow boltless mounting, such that the rack-mount 
equipment only needs to insert through and hook down into the lip of 
the square hole. Installation and removal of hardware in a square 
hole rack is very easy and boltless, where the weight of the 
equipment and small retention clips are all that is necessary to hold 
the equipment in place. Older equipment meant for round-hole or 
tapped-hole racks can still be used, with the use of cage nuts made 
for square-hole racks.



Structural support

Rack-mountable equipment is traditionally mounted by bolting or 
clipping its front panel to the rack. Within the IT industry, it's 
common for network/communications equipment to have multiple mounting 
positions, including table-top and wall mounting, so rack mountable 
equipment will often feature L-brackets that must be screwed or 
bolted to the equipment prior to mounting in a 19-inch rack. With the 
prevalence of <http://en.wikipedia.org/wiki/23-inch_rack>23-inch 
racks in the Telecoms industry, the same practice is also common, but 
with equipment having 19-inch and 23-inch brackets available, 
enabling them to be mounted in existing racks.

A key structural weakness of front-mounted support is the 
<http://en.wikipedia.org/wiki/Shear_stress>shear stress placed on the 
mounting rails and the leading edge of the equipment. As a result, 
4-post racks have become common, with such racks featuring a mirrored 
pair of rear mounting posts. Since the spacing between the front and 
rear mounting posts may differ between rack vendors and/or the 
configuration of the rack (some racks may incorporate front and rear 
rails that may be moved forwards and backwards, i.e. APC SX-range 
racks), it's common for equipment that features 4-post mounting 
brackets, to have an adjustable rear bracket.

Servers and deep pieces of equipment are often mounted using rails 
that are bolted to the front and rear posts (as above, it's common 
for such rails to have an adjustable depth), allowing the equipment 
to be supported by 4-posts, whilst also enabling it to be easily 
installed and removed.

While there is no standard for the depth of equipment, nor specifying 
the outer width and depth of the rack enclosure itself (incorporating 
the structure, doors and panels that contain the mounting rails), 
there is a tendency for 4-post racks to be 600mm or 800mm wide, and 
for them to be 600mm, 800mm or 1010mm deep. This of course varies by 
manufacturer, the design of the rack and it's purpose, but through 
common constraining factors (such as raised floor tile dimensions), 
these dimensions have become quite common. The extra width and depth 
enables cabling to be routed with ease (also helping to maintain 
bend-radius for fibre and copper cables) and deeper equipment to be 
utilised. A common feature in IT racks, are mounting positions for 
"Zero-U" accessories, such as PDU (power distribution units) and 
vertical cable managers/ducts, that utilise the space between the 
rear rails, and the side of the rack enclosure.

The strength required of the mounting posts means they are invariably 
not merely flat strips but actually a wider folded strip arranged 
around the corner of the rack. The posts are usually made of 
<http://en.wikipedia.org/wiki/Steel>steel of around 2 mm thickness 
(the official standard recommends a minimum of 1.9 mm), or of 
slightly thicker <http://en.wikipedia.org/wiki/Aluminum>aluminum.

Racks, especially two-post racks, are often secured to the floor or 
adjacent building structure so as not to fall over. This is usually 
required by local building codes in 
<http://en.wikipedia.org/wiki/Earthquake>seismic zones. According to 
<http://en.wikipedia.org/wiki/Telcordia_Technologies>Telcordia 
Technologies Generic Requirements document GR-63-CORE, during an 
earthquake, telecommunications equipment is subjected to motions that 
can over-stress equipment framework, circuit boards, and connectors. 
The amount of motion and resulting stress depends on the structural 
characteristics of the building and framework in which the equipment 
is contained, and the severity of the earthquake. Seismic racks rated 
according to Telcordia GR-63-CORE are 
available,<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-0>[1] 
with Zone 4 representing the most demanding 
environment.<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-1>[2]<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-2>[3] 
Telcordia GR-3108-CORE specifies the usable opening of 
seismic-compliant 19-inch racks.


3U rackmount system

Heavy equipment or equipment which is commonly accessed for 
servicing, for which attaching or detaching at all four corners 
simultaneously would pose a problem, is often not mounted directly 
onto the rack but instead is mounted via rails (or slides). A pair of 
rails is mounted directly onto the rack, and the equipment then 
slides into the rack along the rails, which support it. When in 
place, the equipment may also then be bolted to the rack. The rails 
may also be able to fully support the equipment in a position where 
it has been slid clear of the rack; this is useful for inspection or 
maintenance of equipment which will then be slid back into the rack.

Slides or rails for computers and other data processing equipment 
such as <http://en.wikipedia.org/wiki/Disk_array>disk arrays or 
<http://en.wikipedia.org/wiki/Router_%28computing%29>routers often 
need to be purchased directly from the equipment manufacturer, as 
there is no standardization on such equipment's thickness 
(measurement from the side of the rack to the equipment) or means for 
mounting to the rail.

See also:  www.wisegeek.com/what-is-a-relay-rack.htm and 
www.facebook.com/pages/Relay-rack/109310605767033?sk=info


www.novexcomm.com/   discusses how Ham Radio is rediscovering the rack mount.

If you Google - 19" relay rack history  you will get many. many pages 
of info to wade through.

VRY 73

Bob Cumming
W2BZY
QRV 160M-3CM
from el98hr


From w7wll at arrl.net  Wed Oct 19 22:31:00 2011
From: w7wll at arrl.net (Don Tucker)
Date: Wed, 19 Oct 2011 19:31:00 -0700
Subject: [QCWA] history of the rack dimensions
References: <7.0.0.16.2.20111019173853.05bee178@cfl.rr.com>
Message-ID: <E0105DC7FA424C20B5079A515FC9205E@Sue>

Yup, been through it all, even books at the library, Bob. I even queried a 
lot of the engineers I worked with who were involved in designing products 
that would be rack mounted. They didn't know either.  All of the available 
information does not answer the question of who designed or engineered this 
set of dimensions or for whom and when. I used to work on several 
electronics trade association committees and even though the first standards 
for racks were issued by EIA and the military, no one could explain its 
origins except in very general terms, like in Wikipedia.

There must have been some 'reason' for the odd dimensions. Why 19 inches vs 
20 inches. And why the strange panel heights and vertical mounting spacing. 
Just noting it originated with railroad signaling relays, thus relay rack, 
doesn't convey much information.

It seems like a standard that suddenly just was there without questions.

Don W7WLL
----- Original Message ----- 
From: "Bob Cumming" <w2bzy at cfl.rr.com>
To: <qcwa at mailman.qth.net>
Sent: Wednesday, October 19, 2011 2:41 PM
Subject: [QCWA] history of the rack dimensions


Per:  en.wikipedia.org/wiki/19-inch_rack



Overview and history

Equipment designed to be placed in a rack is typically described as
rack-mount, rack-mount instrument, a rack mounted system, a rack
mount chassis, subrack, rack mountable, or occasionally simply shelf.
The height of the electronic modules is also standardized as
multiples of 1.75 inches (44.5 mm) or one
<http://en.wikipedia.org/wiki/Rack_unit>rack unit or U (less commonly RU).

Because of their origin as mounting systems for
<http://en.wikipedia.org/wiki/Railroad_signaling>railroad signaling
<http://en.wikipedia.org/wiki/Relay>relays, they are still sometimes
called relay racks, but the 19-inch rack format has remained a
constant while the technology that is mounted within it has changed
to completely different fields. The 19-inch (482.6 mm) standard rack
arrangement is widely used throughout the
<http://en.wikipedia.org/wiki/Telecommunication>telecommunication,
<http://en.wikipedia.org/wiki/Computer>computing,
<http://en.wikipedia.org/wiki/Sound_recording_and_reproduction>audio,
<http://en.wikipedia.org/wiki/Entertainment>entertainment and other
industries, though the
<http://en.wikipedia.org/wiki/Western_Electric>Western Electric
<http://en.wikipedia.org/wiki/23-inch_rack>23-inch standard, with
holes on 1-inch (25.4 mm) centers, prevails in telecommunications.

19-inch racks are often used to house professional audio and video
equipment, including
<http://en.wikipedia.org/wiki/Amplifier>amplifiers,
<http://en.wikipedia.org/wiki/Effects_unit>effects units, interfaces,
<http://en.wikipedia.org/wiki/Headphone>headphone amplifiers, and
even small scale audio mixers. They are also widely used for
<http://en.wikipedia.org/wiki/Computer_server>computer server
equipment, allowing for dense hardware configurations without
occupying excessive floorspace or requiring shelving. A third common
use for rack-mounted equipment is industrial power, control, and
automation hardware.

Typically, a piece of equipment being installed has a front panel
height 1/32-inch (0.031 inches (0.787 mm)) less than the allotted
number of Us. Thus, a 1U rackmount computer is not 1.75 inches (44.5
mm) tall but is 1.719 inches (43.7 mm) tall. 2U would be 3.469 inches
(88.1 mm) instead of 3.5 inches (88.9 mm). This gap allows a bit of
room above and below an installed piece of equipment so it may be
removed without binding on the adjacent equipment.

In 1965 a durable
<http://en.wikipedia.org/wiki/Fiber_reinforced_plastic>fiber
reinforced plastic 19-inch rackmount case was patented by ECS
Composites and became widely used in military and commercial
applications for electronic deployment and operation.
State-of-the-art rackmount cases are now also constructed of thermo
stamped composite, <http://en.wikipedia.org/wiki/Carbon_fiber>carbon
fiber and <http://en.wikipedia.org/wiki/DuPont>DuPont's
<http://en.wikipedia.org/wiki/Kevlar>Kevlar for demanding military
and commercial uses.



Fastening

Originally, the mounting holes were
<http://en.wikipedia.org/wiki/Taps_and_dies>tapped to receive a
particular type of threaded <http://en.wikipedia.org/wiki/Screw>bolt.
This is still frequently used in some government and military
applications, often in conjunction with slide rails for ease of
maintenance. However, it is no longer typical for frequently changed
server racks, due to the possibility for the threads to become
damaged or for a bolt to bind and break off, rendering the mounting
hole unusable. Tapped-hole racks are still used for hardware that
rarely changes, such as phone, network cabling panels, TV
broadcasting facilities, studios and relay racks.

The tapped-hole rack was first replaced by clearance-hole racks. The
holes are large enough to permit a bolt to be freely inserted through
without binding, and bolts are fastened in place using cage nuts. A
<http://en.wikipedia.org/wiki/Cage_nut>cage nut consists of a
<http://en.wikipedia.org/wiki/Spring_steel>spring steel cage,
designed to clip onto the open mounting hole, within which is a
captive nut. In the event of a nut being stripped out or a bolt
breaking, the nut can be easily removed and replaced with a new one.
Production of clearance-hole racks is less expensive because tapping
the holes is eliminated and replaced with fewer, less expensive, cage nuts.

The next innovation in rack design has been the square-hole rack.
Square-hole racks allow boltless mounting, such that the rack-mount
equipment only needs to insert through and hook down into the lip of
the square hole. Installation and removal of hardware in a square
hole rack is very easy and boltless, where the weight of the
equipment and small retention clips are all that is necessary to hold
the equipment in place. Older equipment meant for round-hole or
tapped-hole racks can still be used, with the use of cage nuts made
for square-hole racks.



Structural support

Rack-mountable equipment is traditionally mounted by bolting or
clipping its front panel to the rack. Within the IT industry, it's
common for network/communications equipment to have multiple mounting
positions, including table-top and wall mounting, so rack mountable
equipment will often feature L-brackets that must be screwed or
bolted to the equipment prior to mounting in a 19-inch rack. With the
prevalence of <http://en.wikipedia.org/wiki/23-inch_rack>23-inch
racks in the Telecoms industry, the same practice is also common, but
with equipment having 19-inch and 23-inch brackets available,
enabling them to be mounted in existing racks.

A key structural weakness of front-mounted support is the
<http://en.wikipedia.org/wiki/Shear_stress>shear stress placed on the
mounting rails and the leading edge of the equipment. As a result,
4-post racks have become common, with such racks featuring a mirrored
pair of rear mounting posts. Since the spacing between the front and
rear mounting posts may differ between rack vendors and/or the
configuration of the rack (some racks may incorporate front and rear
rails that may be moved forwards and backwards, i.e. APC SX-range
racks), it's common for equipment that features 4-post mounting
brackets, to have an adjustable rear bracket.

Servers and deep pieces of equipment are often mounted using rails
that are bolted to the front and rear posts (as above, it's common
for such rails to have an adjustable depth), allowing the equipment
to be supported by 4-posts, whilst also enabling it to be easily
installed and removed.

While there is no standard for the depth of equipment, nor specifying
the outer width and depth of the rack enclosure itself (incorporating
the structure, doors and panels that contain the mounting rails),
there is a tendency for 4-post racks to be 600mm or 800mm wide, and
for them to be 600mm, 800mm or 1010mm deep. This of course varies by
manufacturer, the design of the rack and it's purpose, but through
common constraining factors (such as raised floor tile dimensions),
these dimensions have become quite common. The extra width and depth
enables cabling to be routed with ease (also helping to maintain
bend-radius for fibre and copper cables) and deeper equipment to be
utilised. A common feature in IT racks, are mounting positions for
"Zero-U" accessories, such as PDU (power distribution units) and
vertical cable managers/ducts, that utilise the space between the
rear rails, and the side of the rack enclosure.

The strength required of the mounting posts means they are invariably
not merely flat strips but actually a wider folded strip arranged
around the corner of the rack. The posts are usually made of
<http://en.wikipedia.org/wiki/Steel>steel of around 2 mm thickness
(the official standard recommends a minimum of 1.9 mm), or of
slightly thicker <http://en.wikipedia.org/wiki/Aluminum>aluminum.

Racks, especially two-post racks, are often secured to the floor or
adjacent building structure so as not to fall over. This is usually
required by local building codes in
<http://en.wikipedia.org/wiki/Earthquake>seismic zones. According to
<http://en.wikipedia.org/wiki/Telcordia_Technologies>Telcordia
Technologies Generic Requirements document GR-63-CORE, during an
earthquake, telecommunications equipment is subjected to motions that
can over-stress equipment framework, circuit boards, and connectors.
The amount of motion and resulting stress depends on the structural
characteristics of the building and framework in which the equipment
is contained, and the severity of the earthquake. Seismic racks rated
according to Telcordia GR-63-CORE are
available,<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-0>[1]
with Zone 4 representing the most demanding
environment.<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-1>[2]<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-2>[3]
Telcordia GR-3108-CORE specifies the usable opening of
seismic-compliant 19-inch racks.


3U rackmount system

Heavy equipment or equipment which is commonly accessed for
servicing, for which attaching or detaching at all four corners
simultaneously would pose a problem, is often not mounted directly
onto the rack but instead is mounted via rails (or slides). A pair of
rails is mounted directly onto the rack, and the equipment then
slides into the rack along the rails, which support it. When in
place, the equipment may also then be bolted to the rack. The rails
may also be able to fully support the equipment in a position where
it has been slid clear of the rack; this is useful for inspection or
maintenance of equipment which will then be slid back into the rack.

Slides or rails for computers and other data processing equipment
such as <http://en.wikipedia.org/wiki/Disk_array>disk arrays or
<http://en.wikipedia.org/wiki/Router_%28computing%29>routers often
need to be purchased directly from the equipment manufacturer, as
there is no standardization on such equipment's thickness
(measurement from the side of the rack to the equipment) or means for
mounting to the rail.

See also:  www.wisegeek.com/what-is-a-relay-rack.htm and
www.facebook.com/pages/Relay-rack/109310605767033?sk=info


www.novexcomm.com/   discusses how Ham Radio is rediscovering the rack 
mount.

If you Google - 19" relay rack history  you will get many. many pages
of info to wade through.

VRY 73

Bob Cumming
W2BZY
QRV 160M-3CM
from el98hr

______________________________________________________________
QCWA mailing list
Home: http://mailman.qth.net/mailman/listinfo/qcwa
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:QCWA at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html



-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.1831 / Virus Database: 2092/4562 - Release Date: 10/19/11



From harvey91 at windstream.net  Thu Oct 20 17:51:14 2011
From: harvey91 at windstream.net (J HARVEY CHASE)
Date: Thu, 20 Oct 2011 17:51:14 -0400
Subject: [QCWA] history of the rack dimensions
References: <7.0.0.16.2.20111019173853.05bee178@cfl.rr.com>
	<E0105DC7FA424C20B5079A515FC9205E@Sue>
Message-ID: <A2E72CDE980F4B21A0FCC5D80235EBF4@bhb33e2e9068b2>

As a former Bell System employee (1937 - 1940 [interrupted by service in US 
Navy] and 1945 - 1948) let me offer this: Bell System was highly resistant 
to accepting anything that was not developed by Bell Labs or within the Bell 
System (The "NIH" Not invented here complex, we called it. Yet the 19" relay 
rack was standard throughout the system. So I believe it is safe to say that 
it was first used by Bell System. Let me add also: Don't rely to heavily on 
anything you find in Wikipedia!
73, W4TG

----- Original Message ----- 
From: "Don Tucker" <w7wll at arrl.net>
To: <qcwa at mailman.qth.net>
Sent: Wednesday, October 19, 2011 10:31 PM
Subject: Re: [QCWA] history of the rack dimensions


> Yup, been through it all, even books at the library, Bob. I even queried a
> lot of the engineers I worked with who were involved in designing products
> that would be rack mounted. They didn't know either.  All of the available
> information does not answer the question of who designed or engineered 
> this
> set of dimensions or for whom and when. I used to work on several
> electronics trade association committees and even though the first 
> standards
> for racks were issued by EIA and the military, no one could explain its
> origins except in very general terms, like in Wikipedia.
>
> There must have been some 'reason' for the odd dimensions. Why 19 inches 
> vs
> 20 inches. And why the strange panel heights and vertical mounting 
> spacing.
> Just noting it originated with railroad signaling relays, thus relay rack,
> doesn't convey much information.
>
> It seems like a standard that suddenly just was there without questions.
>
> Don W7WLL
> ----- Original Message ----- 
> From: "Bob Cumming" <w2bzy at cfl.rr.com>
> To: <qcwa at mailman.qth.net>
> Sent: Wednesday, October 19, 2011 2:41 PM
> Subject: [QCWA] history of the rack dimensions
>
>
> Per:  en.wikipedia.org/wiki/19-inch_rack
>
>
>
> Overview and history
>
> Equipment designed to be placed in a rack is typically described as
> rack-mount, rack-mount instrument, a rack mounted system, a rack
> mount chassis, subrack, rack mountable, or occasionally simply shelf.
> The height of the electronic modules is also standardized as
> multiples of 1.75 inches (44.5 mm) or one
> <http://en.wikipedia.org/wiki/Rack_unit>rack unit or U (less commonly RU).
>
> Because of their origin as mounting systems for
> <http://en.wikipedia.org/wiki/Railroad_signaling>railroad signaling
> <http://en.wikipedia.org/wiki/Relay>relays, they are still sometimes
> called relay racks, but the 19-inch rack format has remained a
> constant while the technology that is mounted within it has changed
> to completely different fields. The 19-inch (482.6 mm) standard rack
> arrangement is widely used throughout the
> <http://en.wikipedia.org/wiki/Telecommunication>telecommunication,
> <http://en.wikipedia.org/wiki/Computer>computing,
> <http://en.wikipedia.org/wiki/Sound_recording_and_reproduction>audio,
> <http://en.wikipedia.org/wiki/Entertainment>entertainment and other
> industries, though the
> <http://en.wikipedia.org/wiki/Western_Electric>Western Electric
> <http://en.wikipedia.org/wiki/23-inch_rack>23-inch standard, with
> holes on 1-inch (25.4 mm) centers, prevails in telecommunications.
>
> 19-inch racks are often used to house professional audio and video
> equipment, including
> <http://en.wikipedia.org/wiki/Amplifier>amplifiers,
> <http://en.wikipedia.org/wiki/Effects_unit>effects units, interfaces,
> <http://en.wikipedia.org/wiki/Headphone>headphone amplifiers, and
> even small scale audio mixers. They are also widely used for
> <http://en.wikipedia.org/wiki/Computer_server>computer server
> equipment, allowing for dense hardware configurations without
> occupying excessive floorspace or requiring shelving. A third common
> use for rack-mounted equipment is industrial power, control, and
> automation hardware.
>
> Typically, a piece of equipment being installed has a front panel
> height 1/32-inch (0.031 inches (0.787 mm)) less than the allotted
> number of Us. Thus, a 1U rackmount computer is not 1.75 inches (44.5
> mm) tall but is 1.719 inches (43.7 mm) tall. 2U would be 3.469 inches
> (88.1 mm) instead of 3.5 inches (88.9 mm). This gap allows a bit of
> room above and below an installed piece of equipment so it may be
> removed without binding on the adjacent equipment.
>
> In 1965 a durable
> <http://en.wikipedia.org/wiki/Fiber_reinforced_plastic>fiber
> reinforced plastic 19-inch rackmount case was patented by ECS
> Composites and became widely used in military and commercial
> applications for electronic deployment and operation.
> State-of-the-art rackmount cases are now also constructed of thermo
> stamped composite, <http://en.wikipedia.org/wiki/Carbon_fiber>carbon
> fiber and <http://en.wikipedia.org/wiki/DuPont>DuPont's
> <http://en.wikipedia.org/wiki/Kevlar>Kevlar for demanding military
> and commercial uses.
>
>
>
> Fastening
>
> Originally, the mounting holes were
> <http://en.wikipedia.org/wiki/Taps_and_dies>tapped to receive a
> particular type of threaded <http://en.wikipedia.org/wiki/Screw>bolt.
> This is still frequently used in some government and military
> applications, often in conjunction with slide rails for ease of
> maintenance. However, it is no longer typical for frequently changed
> server racks, due to the possibility for the threads to become
> damaged or for a bolt to bind and break off, rendering the mounting
> hole unusable. Tapped-hole racks are still used for hardware that
> rarely changes, such as phone, network cabling panels, TV
> broadcasting facilities, studios and relay racks.
>
> The tapped-hole rack was first replaced by clearance-hole racks. The
> holes are large enough to permit a bolt to be freely inserted through
> without binding, and bolts are fastened in place using cage nuts. A
> <http://en.wikipedia.org/wiki/Cage_nut>cage nut consists of a
> <http://en.wikipedia.org/wiki/Spring_steel>spring steel cage,
> designed to clip onto the open mounting hole, within which is a
> captive nut. In the event of a nut being stripped out or a bolt
> breaking, the nut can be easily removed and replaced with a new one.
> Production of clearance-hole racks is less expensive because tapping
> the holes is eliminated and replaced with fewer, less expensive, cage 
> nuts.
>
> The next innovation in rack design has been the square-hole rack.
> Square-hole racks allow boltless mounting, such that the rack-mount
> equipment only needs to insert through and hook down into the lip of
> the square hole. Installation and removal of hardware in a square
> hole rack is very easy and boltless, where the weight of the
> equipment and small retention clips are all that is necessary to hold
> the equipment in place. Older equipment meant for round-hole or
> tapped-hole racks can still be used, with the use of cage nuts made
> for square-hole racks.
>
>
>
> Structural support
>
> Rack-mountable equipment is traditionally mounted by bolting or
> clipping its front panel to the rack. Within the IT industry, it's
> common for network/communications equipment to have multiple mounting
> positions, including table-top and wall mounting, so rack mountable
> equipment will often feature L-brackets that must be screwed or
> bolted to the equipment prior to mounting in a 19-inch rack. With the
> prevalence of <http://en.wikipedia.org/wiki/23-inch_rack>23-inch
> racks in the Telecoms industry, the same practice is also common, but
> with equipment having 19-inch and 23-inch brackets available,
> enabling them to be mounted in existing racks.
>
> A key structural weakness of front-mounted support is the
> <http://en.wikipedia.org/wiki/Shear_stress>shear stress placed on the
> mounting rails and the leading edge of the equipment. As a result,
> 4-post racks have become common, with such racks featuring a mirrored
> pair of rear mounting posts. Since the spacing between the front and
> rear mounting posts may differ between rack vendors and/or the
> configuration of the rack (some racks may incorporate front and rear
> rails that may be moved forwards and backwards, i.e. APC SX-range
> racks), it's common for equipment that features 4-post mounting
> brackets, to have an adjustable rear bracket.
>
> Servers and deep pieces of equipment are often mounted using rails
> that are bolted to the front and rear posts (as above, it's common
> for such rails to have an adjustable depth), allowing the equipment
> to be supported by 4-posts, whilst also enabling it to be easily
> installed and removed.
>
> While there is no standard for the depth of equipment, nor specifying
> the outer width and depth of the rack enclosure itself (incorporating
> the structure, doors and panels that contain the mounting rails),
> there is a tendency for 4-post racks to be 600mm or 800mm wide, and
> for them to be 600mm, 800mm or 1010mm deep. This of course varies by
> manufacturer, the design of the rack and it's purpose, but through
> common constraining factors (such as raised floor tile dimensions),
> these dimensions have become quite common. The extra width and depth
> enables cabling to be routed with ease (also helping to maintain
> bend-radius for fibre and copper cables) and deeper equipment to be
> utilised. A common feature in IT racks, are mounting positions for
> "Zero-U" accessories, such as PDU (power distribution units) and
> vertical cable managers/ducts, that utilise the space between the
> rear rails, and the side of the rack enclosure.
>
> The strength required of the mounting posts means they are invariably
> not merely flat strips but actually a wider folded strip arranged
> around the corner of the rack. The posts are usually made of
> <http://en.wikipedia.org/wiki/Steel>steel of around 2 mm thickness
> (the official standard recommends a minimum of 1.9 mm), or of
> slightly thicker <http://en.wikipedia.org/wiki/Aluminum>aluminum.
>
> Racks, especially two-post racks, are often secured to the floor or
> adjacent building structure so as not to fall over. This is usually
> required by local building codes in
> <http://en.wikipedia.org/wiki/Earthquake>seismic zones. According to
> <http://en.wikipedia.org/wiki/Telcordia_Technologies>Telcordia
> Technologies Generic Requirements document GR-63-CORE, during an
> earthquake, telecommunications equipment is subjected to motions that
> can over-stress equipment framework, circuit boards, and connectors.
> The amount of motion and resulting stress depends on the structural
> characteristics of the building and framework in which the equipment
> is contained, and the severity of the earthquake. Seismic racks rated
> according to Telcordia GR-63-CORE are
> available,<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-0>[1]
> with Zone 4 representing the most demanding
> environment.<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-1>[2]<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-2>[3]
> Telcordia GR-3108-CORE specifies the usable opening of
> seismic-compliant 19-inch racks.
>
>
> 3U rackmount system
>
> Heavy equipment or equipment which is commonly accessed for
> servicing, for which attaching or detaching at all four corners
> simultaneously would pose a problem, is often not mounted directly
> onto the rack but instead is mounted via rails (or slides). A pair of
> rails is mounted directly onto the rack, and the equipment then
> slides into the rack along the rails, which support it. When in
> place, the equipment may also then be bolted to the rack. The rails
> may also be able to fully support the equipment in a position where
> it has been slid clear of the rack; this is useful for inspection or
> maintenance of equipment which will then be slid back into the rack.
>
> Slides or rails for computers and other data processing equipment
> such as <http://en.wikipedia.org/wiki/Disk_array>disk arrays or
> <http://en.wikipedia.org/wiki/Router_%28computing%29>routers often
> need to be purchased directly from the equipment manufacturer, as
> there is no standardization on such equipment's thickness
> (measurement from the side of the rack to the equipment) or means for
> mounting to the rail.
>
> See also:  www.wisegeek.com/what-is-a-relay-rack.htm and
> www.facebook.com/pages/Relay-rack/109310605767033?sk=info
>
>
> www.novexcomm.com/   discusses how Ham Radio is rediscovering the rack
> mount.
>
> If you Google - 19" relay rack history  you will get many. many pages
> of info to wade through.
>
> VRY 73
>
> Bob Cumming
> W2BZY
> QRV 160M-3CM
> from el98hr
>
> ______________________________________________________________
> QCWA mailing list
> Home: http://mailman.qth.net/mailman/listinfo/qcwa
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:QCWA at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.1831 / Virus Database: 2092/4562 - Release Date: 10/19/11
>
>
> ______________________________________________________________
> QCWA mailing list
> Home: http://mailman.qth.net/mailman/listinfo/qcwa
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:QCWA at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.1831 / Virus Database: 2092/4562 - Release Date: 10/19/11
> 


From w7wll at arrl.net  Thu Oct 20 20:40:26 2011
From: w7wll at arrl.net (Don Tucker)
Date: Thu, 20 Oct 2011 17:40:26 -0700
Subject: [QCWA] history of the rack dimensions
References: <7.0.0.16.2.20111019173853.05bee178@cfl.rr.com>
	<E0105DC7FA424C20B5079A515FC9205E@Sue>
	<A2E72CDE980F4B21A0FCC5D80235EBF4@bhb33e2e9068b2>
Message-ID: <CA96EE9A62B24D698F365AD525518E6B@Sue>

Yup, saw a lot of them in Bell plants and offices, but I suspect in this 
case that they indeed did originate in the railroad industry. Just too much 
unrelated references and nothing pointing elsewhere (not just on the 
internet but in library sources, real books!!). I would not doubt however 
that Bell could well be the source leading to standardization of the rack 
dimensions that EIA and the military promulgated as standards. Just find it 
interesting that such an important piece of history seems to have been lost.

Don W7WLL
----- Original Message ----- 
From: "J HARVEY CHASE" <harvey91 at windstream.net>
To: "Don Tucker" <w7wll at arrl.net>; <qcwa at mailman.qth.net>
Sent: Thursday, October 20, 2011 2:51 PM
Subject: Re: [QCWA] history of the rack dimensions


As a former Bell System employee (1937 - 1940 [interrupted by service in US
Navy] and 1945 - 1948) let me offer this: Bell System was highly resistant
to accepting anything that was not developed by Bell Labs or within the Bell
System (The "NIH" Not invented here complex, we called it. Yet the 19" relay
rack was standard throughout the system. So I believe it is safe to say that
it was first used by Bell System. Let me add also: Don't rely to heavily on
anything you find in Wikipedia!
73, W4TG

----- Original Message ----- 
From: "Don Tucker" <w7wll at arrl.net>
To: <qcwa at mailman.qth.net>
Sent: Wednesday, October 19, 2011 10:31 PM
Subject: Re: [QCWA] history of the rack dimensions


> Yup, been through it all, even books at the library, Bob. I even queried a
> lot of the engineers I worked with who were involved in designing products
> that would be rack mounted. They didn't know either.  All of the available
> information does not answer the question of who designed or engineered
> this
> set of dimensions or for whom and when. I used to work on several
> electronics trade association committees and even though the first
> standards
> for racks were issued by EIA and the military, no one could explain its
> origins except in very general terms, like in Wikipedia.
>
> There must have been some 'reason' for the odd dimensions. Why 19 inches
> vs
> 20 inches. And why the strange panel heights and vertical mounting
> spacing.
> Just noting it originated with railroad signaling relays, thus relay rack,
> doesn't convey much information.
>
> It seems like a standard that suddenly just was there without questions.
>
> Don W7WLL
> ----- Original Message ----- 
> From: "Bob Cumming" <w2bzy at cfl.rr.com>
> To: <qcwa at mailman.qth.net>
> Sent: Wednesday, October 19, 2011 2:41 PM
> Subject: [QCWA] history of the rack dimensions
>
>
> Per:  en.wikipedia.org/wiki/19-inch_rack
>
>
>
> Overview and history
>
> Equipment designed to be placed in a rack is typically described as
> rack-mount, rack-mount instrument, a rack mounted system, a rack
> mount chassis, subrack, rack mountable, or occasionally simply shelf.
> The height of the electronic modules is also standardized as
> multiples of 1.75 inches (44.5 mm) or one
> <http://en.wikipedia.org/wiki/Rack_unit>rack unit or U (less commonly RU).
>
> Because of their origin as mounting systems for
> <http://en.wikipedia.org/wiki/Railroad_signaling>railroad signaling
> <http://en.wikipedia.org/wiki/Relay>relays, they are still sometimes
> called relay racks, but the 19-inch rack format has remained a
> constant while the technology that is mounted within it has changed
> to completely different fields. The 19-inch (482.6 mm) standard rack
> arrangement is widely used throughout the
> <http://en.wikipedia.org/wiki/Telecommunication>telecommunication,
> <http://en.wikipedia.org/wiki/Computer>computing,
> <http://en.wikipedia.org/wiki/Sound_recording_and_reproduction>audio,
> <http://en.wikipedia.org/wiki/Entertainment>entertainment and other
> industries, though the
> <http://en.wikipedia.org/wiki/Western_Electric>Western Electric
> <http://en.wikipedia.org/wiki/23-inch_rack>23-inch standard, with
> holes on 1-inch (25.4 mm) centers, prevails in telecommunications.
>
> 19-inch racks are often used to house professional audio and video
> equipment, including
> <http://en.wikipedia.org/wiki/Amplifier>amplifiers,
> <http://en.wikipedia.org/wiki/Effects_unit>effects units, interfaces,
> <http://en.wikipedia.org/wiki/Headphone>headphone amplifiers, and
> even small scale audio mixers. They are also widely used for
> <http://en.wikipedia.org/wiki/Computer_server>computer server
> equipment, allowing for dense hardware configurations without
> occupying excessive floorspace or requiring shelving. A third common
> use for rack-mounted equipment is industrial power, control, and
> automation hardware.
>
> Typically, a piece of equipment being installed has a front panel
> height 1/32-inch (0.031 inches (0.787 mm)) less than the allotted
> number of Us. Thus, a 1U rackmount computer is not 1.75 inches (44.5
> mm) tall but is 1.719 inches (43.7 mm) tall. 2U would be 3.469 inches
> (88.1 mm) instead of 3.5 inches (88.9 mm). This gap allows a bit of
> room above and below an installed piece of equipment so it may be
> removed without binding on the adjacent equipment.
>
> In 1965 a durable
> <http://en.wikipedia.org/wiki/Fiber_reinforced_plastic>fiber
> reinforced plastic 19-inch rackmount case was patented by ECS
> Composites and became widely used in military and commercial
> applications for electronic deployment and operation.
> State-of-the-art rackmount cases are now also constructed of thermo
> stamped composite, <http://en.wikipedia.org/wiki/Carbon_fiber>carbon
> fiber and <http://en.wikipedia.org/wiki/DuPont>DuPont's
> <http://en.wikipedia.org/wiki/Kevlar>Kevlar for demanding military
> and commercial uses.
>
>
>
> Fastening
>
> Originally, the mounting holes were
> <http://en.wikipedia.org/wiki/Taps_and_dies>tapped to receive a
> particular type of threaded <http://en.wikipedia.org/wiki/Screw>bolt.
> This is still frequently used in some government and military
> applications, often in conjunction with slide rails for ease of
> maintenance. However, it is no longer typical for frequently changed
> server racks, due to the possibility for the threads to become
> damaged or for a bolt to bind and break off, rendering the mounting
> hole unusable. Tapped-hole racks are still used for hardware that
> rarely changes, such as phone, network cabling panels, TV
> broadcasting facilities, studios and relay racks.
>
> The tapped-hole rack was first replaced by clearance-hole racks. The
> holes are large enough to permit a bolt to be freely inserted through
> without binding, and bolts are fastened in place using cage nuts. A
> <http://en.wikipedia.org/wiki/Cage_nut>cage nut consists of a
> <http://en.wikipedia.org/wiki/Spring_steel>spring steel cage,
> designed to clip onto the open mounting hole, within which is a
> captive nut. In the event of a nut being stripped out or a bolt
> breaking, the nut can be easily removed and replaced with a new one.
> Production of clearance-hole racks is less expensive because tapping
> the holes is eliminated and replaced with fewer, less expensive, cage
> nuts.
>
> The next innovation in rack design has been the square-hole rack.
> Square-hole racks allow boltless mounting, such that the rack-mount
> equipment only needs to insert through and hook down into the lip of
> the square hole. Installation and removal of hardware in a square
> hole rack is very easy and boltless, where the weight of the
> equipment and small retention clips are all that is necessary to hold
> the equipment in place. Older equipment meant for round-hole or
> tapped-hole racks can still be used, with the use of cage nuts made
> for square-hole racks.
>
>
>
> Structural support
>
> Rack-mountable equipment is traditionally mounted by bolting or
> clipping its front panel to the rack. Within the IT industry, it's
> common for network/communications equipment to have multiple mounting
> positions, including table-top and wall mounting, so rack mountable
> equipment will often feature L-brackets that must be screwed or
> bolted to the equipment prior to mounting in a 19-inch rack. With the
> prevalence of <http://en.wikipedia.org/wiki/23-inch_rack>23-inch
> racks in the Telecoms industry, the same practice is also common, but
> with equipment having 19-inch and 23-inch brackets available,
> enabling them to be mounted in existing racks.
>
> A key structural weakness of front-mounted support is the
> <http://en.wikipedia.org/wiki/Shear_stress>shear stress placed on the
> mounting rails and the leading edge of the equipment. As a result,
> 4-post racks have become common, with such racks featuring a mirrored
> pair of rear mounting posts. Since the spacing between the front and
> rear mounting posts may differ between rack vendors and/or the
> configuration of the rack (some racks may incorporate front and rear
> rails that may be moved forwards and backwards, i.e. APC SX-range
> racks), it's common for equipment that features 4-post mounting
> brackets, to have an adjustable rear bracket.
>
> Servers and deep pieces of equipment are often mounted using rails
> that are bolted to the front and rear posts (as above, it's common
> for such rails to have an adjustable depth), allowing the equipment
> to be supported by 4-posts, whilst also enabling it to be easily
> installed and removed.
>
> While there is no standard for the depth of equipment, nor specifying
> the outer width and depth of the rack enclosure itself (incorporating
> the structure, doors and panels that contain the mounting rails),
> there is a tendency for 4-post racks to be 600mm or 800mm wide, and
> for them to be 600mm, 800mm or 1010mm deep. This of course varies by
> manufacturer, the design of the rack and it's purpose, but through
> common constraining factors (such as raised floor tile dimensions),
> these dimensions have become quite common. The extra width and depth
> enables cabling to be routed with ease (also helping to maintain
> bend-radius for fibre and copper cables) and deeper equipment to be
> utilised. A common feature in IT racks, are mounting positions for
> "Zero-U" accessories, such as PDU (power distribution units) and
> vertical cable managers/ducts, that utilise the space between the
> rear rails, and the side of the rack enclosure.
>
> The strength required of the mounting posts means they are invariably
> not merely flat strips but actually a wider folded strip arranged
> around the corner of the rack. The posts are usually made of
> <http://en.wikipedia.org/wiki/Steel>steel of around 2 mm thickness
> (the official standard recommends a minimum of 1.9 mm), or of
> slightly thicker <http://en.wikipedia.org/wiki/Aluminum>aluminum.
>
> Racks, especially two-post racks, are often secured to the floor or
> adjacent building structure so as not to fall over. This is usually
> required by local building codes in
> <http://en.wikipedia.org/wiki/Earthquake>seismic zones. According to
> <http://en.wikipedia.org/wiki/Telcordia_Technologies>Telcordia
> Technologies Generic Requirements document GR-63-CORE, during an
> earthquake, telecommunications equipment is subjected to motions that
> can over-stress equipment framework, circuit boards, and connectors.
> The amount of motion and resulting stress depends on the structural
> characteristics of the building and framework in which the equipment
> is contained, and the severity of the earthquake. Seismic racks rated
> according to Telcordia GR-63-CORE are
> available,<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-0>[1]
> with Zone 4 representing the most demanding
> environment.<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-1>[2]<http://en.wikipedia.org/wiki/19-inch_rack#cite_note-2>[3]
> Telcordia GR-3108-CORE specifies the usable opening of
> seismic-compliant 19-inch racks.
>
>
> 3U rackmount system
>
> Heavy equipment or equipment which is commonly accessed for
> servicing, for which attaching or detaching at all four corners
> simultaneously would pose a problem, is often not mounted directly
> onto the rack but instead is mounted via rails (or slides). A pair of
> rails is mounted directly onto the rack, and the equipment then
> slides into the rack along the rails, which support it. When in
> place, the equipment may also then be bolted to the rack. The rails
> may also be able to fully support the equipment in a position where
> it has been slid clear of the rack; this is useful for inspection or
> maintenance of equipment which will then be slid back into the rack.
>
> Slides or rails for computers and other data processing equipment
> such as <http://en.wikipedia.org/wiki/Disk_array>disk arrays or
> <http://en.wikipedia.org/wiki/Router_%28computing%29>routers often
> need to be purchased directly from the equipment manufacturer, as
> there is no standardization on such equipment's thickness
> (measurement from the side of the rack to the equipment) or means for
> mounting to the rail.
>
> See also:  www.wisegeek.com/what-is-a-relay-rack.htm and
> www.facebook.com/pages/Relay-rack/109310605767033?sk=info
>
>
> www.novexcomm.com/   discusses how Ham Radio is rediscovering the rack
> mount.
>
> If you Google - 19" relay rack history  you will get many. many pages
> of info to wade through.
>
> VRY 73
>
> Bob Cumming
> W2BZY
> QRV 160M-3CM
> from el98hr
>
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>
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From W8EK at flham.net  Mon Oct 31 11:29:27 2011
From: W8EK at flham.net (Ken Simpson, W8EK)
Date: Mon, 31 Oct 2011 11:29:27 -0400
Subject: [QCWA] QCWA Activities in the SE US
Message-ID: <4EAEBED7.5070904@flham.net>


It looks like it is getting to be hamfest season, at least
in Florida, Georgia, and Alabama.  Here is a list of
activities I have planned, listed in chronological order.

Fri, Sat, and Sunday, November 4, 5, and 6
Lawrenceville, GA "Stone Mountain" Hamfest
details at
http://stonemountainhamfest.com/
We will have a display booth, and also have a forum
scheduled for 1 PM on Saturday in "The Forum Room".
Alinco, Kenwood, and Flex Radio are scheduled to be
at this hamfest.

Tuesday evening, November 8, 7:00 PM
Bankhead Amateur Radio Club meeting
Lawrence County E.M.A. Office
The Lehman Wood Building
555 Walnut St.
Moulton, AL
http://www.n4idx.com/
This is a regular amateur radio club in the Huntsville AL area.
I will be doing a power point presentation about QCWA.  We need
to get a QCWA chapter started in the Huntsville area, and this
is an attempt to do so.  If you know of any one in the greater
Huntsville area, please encourage them to attend this meeting,
and to bring their friends.

Thursday evening, November 10, 7:00 PM
Shelby County (AL) Amateur Radio Club meeting
American Red Cross Offices
4524 Southlake Parkway - Suite #5
Hoover/Pelham, AL 35244
just off I-65
http://w4shl.com/home.html
Pelham is a suburb of Birmingham, AL.  Basically, this will be
a repeat of the Nov 8 activity, but in the Birmingham AL area.
We need to get a chapter started in this area as well, so
again, please attend if possible, and get your friends to
attend.

Saturday, November 12
Montgomery AL Hamfest
Garrett Coliseum,
1555 Federal Drive, just West of Coliseum Blvd.
in North Montgomery, AL
details at
http://www.w4ap.org/modules.php?name=Hamfest
We will have a display booth and a forum.  At this point, I do not
know the time or location of the forum.

Wednesday, November 16, 6:30 PM
Gainesville FL Amateur Radio Club
AvMed Building, Health Care Park
4300 NW 89th Blvd,
Gainesville, FL.
http://www.gars.net/gars.htm
Gainesville already has a QCWA Chapter, but I will be doing a
power point presentation encouraging those that are not QCWA
members, but are eligible, to join and attend the chapter
meetings.

Saturday and Sunday, November 19 and 20
Starke FL Hamfest in
"Historic Downtown Starke Florida"
details at
http://www.angelfire.com/fl/arcba/hamfest.html
or
http://www.facebook.com/home.php?sk=group_129827083753201
They say that the hamfest will be taking over the entire
downtown square in Starke.  We will have a booth and also
a forum. This should be an interesting hamfest, in that it
will be different than most hamfests, and probably a bit
more "laid back."

Saturday, November 26
Okeechobee FL "Hamfest in the Woods"
details at
http://k4oke.com/
Freedom Ranch
11655 - 441 SE
Okeechobee, FL
We should have a display booth here, but this hamfest does not
have any forums.

Saturday and Sunday, December 3 and 4
Tampa Bay FL Hamfest
Manatee Civic Center
One Haben Blvd
Palmetto, Florida
details at
http://www.fgcarc.org/
We will have a display booth and a forum.  The forum is scheduled
for 1:00 PM on Saturday in the Terra Ceia Room.

Saturday, December 10
Ocala FL Hamfest
more details later


If you will be in the area of any of these hamfests and
club meetings, I encourage you to attend.  If you have any
questions, please e-mail me at W8EK at flham.net.

I hope to see you at some of these events.

Thanks.

73,

Ken, W8EK

Ken Simpson
QCWA National Director
E-mail to W8EK at FLHam.net or W8EK at arrl.net
Voice Phone  (352) 732-8400








