[Boatanchors] Boatanchors Digest, Vol 124, Issue 43

Mon May 26 16:39:40 EDT 2014

I agree. As an official 'old f*art' and Vietnam Combat Vet, Sunday was a difficult day for me.
Not so much as what I went through, or seeing my best friends die, what REALLY pisses me off is this:
Ask "the new generation" anything (!!) about Global Warming, Iraq, etc, they have NO clue!
Show them a picture of John Kerry, Joe Biden, and the response is 'almost' comedic.

At times (recently) I wonder why I did what I did, for this great country. Then I remember, I did it for my Mom and Dad, and my Grandparents. Unlike today's generation, I wasn't thinking about "SELF"........

ron
N4UE
USN UDT/ Diver / EOD

-----Original Message-----
From: boatanchors-request <boatanchors-request at mailman.qth.net>
To: boatanchors <boatanchors at mailman.qth.net>
Sent: Mon, May 26, 2014 2:39 pm
Subject: Boatanchors Digest, Vol 124, Issue 43

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Today's Topics:

   1. Re: Tube shields CORRECTION (Jim Wilhite)
   2. Re: Veterans Day (Bill Cromwell)
   3. Re: Tube shields CORRECTION (hwhall at compuserve.com)
   4. Re: Tube shields CORRECTION (hwhall at compuserve.com)
   5. Re: Veterans Day (Tom Nicholson)
   6. Re: Tube shields CORRECTION (rbethman)

----------------------------------------------------------------------

Message: 1
Date: Mon, 26 May 2014 12:21:27 -0500
From: "Jim Wilhite" <w5jo at brightok.net>
To: <boatanchors at mailman.qth.net>
Subject: Re: [Boatanchors] Tube shields CORRECTION
Message-ID: <86D0C5DA6B4A4C3DA19F939F01E2E662 at JimPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

Some of them maybe yes, but many did not have mechanical contact with the 
tube.  The receiver that I speak about particularly is the NC 183D and some 
others Hammarlund made.  There is nothing to hold the tube in place.  In lab 
grade receivers you could find some of that, say the HRO 60 had springs in 
the shields over the mixer and oscillator but not on the RF stages.

Jim
W5JO

-----Original Message----- 

One of the main purposes of shields is mechanical stability in vibration
rich environments.

Frank

------------------------------

Message: 2
Date: Mon, 26 May 2014 13:31:46 -0400
From: Bill Cromwell <wrcromwell at gmail.com>
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Veterans Day
Message-ID: <53837A82.3090106 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 05/26/2014 01:05 PM, WA5CAB--- via Boatanchors wrote:
> There was nothing illegal or immoral about the Vietnam War.  Limp wristed
> liberals will please keep your thoughtless opiions to yourselves, especially
> today.
>
> Robert & Susan Downs - Houston
> Vietnam vet and Air Force Brat respectively.
> MVPA 9480
>
>
I usually avoid this kind of thread altogether but today I'm standing 
with Bob and others.

73,

Bill  KU8H

------------------------------

Message: 3
Date: Mon, 26 May 2014 13:59:09 -0400 (EDT)
From: hwhall at compuserve.com
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Tube shields CORRECTION
Message-ID: <8D1472353CC4808-C48-1DB1F at webmail-d266.sysops.aol.com>
Content-Type: text/plain; charset="us-ascii"

or a 120VAC one with a large sand resistor that drops the RPM so that 
noise doesn't become an issue.

I've also seen suggestions to use 240vac fans to get lower run noise, and no 
resistor to heat up. They can probably be bought cheaper than 120vac versions 
since they are less desirable to most folks.

 Wayne

 WB4OGM

-----Original Message-----
From: rbethman <rbethman at comcast.net>
To: boatanchors <boatanchors at mailman.qth.net>
Sent: Mon, May 26, 2014 10:40 am
Subject: Re: [Boatanchors] Tube shields CORRECTION

Jim,

You are so right!

The vast majority of these old BAs would do much better with removing 
these shields that do NOT have RF issues and installing a muffin fan to 
take the heat out.

Either computer CPU fans with a 12VDC rating at VERY low current draw, 
or a 120VAC one with a large sand resistor that drops the RPM so that 
noise doesn't become an issue.

Bob - N0DGN

On 5/26/2014 12:19 PM, Jim Wilhite wrote:
> Correct me if I am wrong, but I don't think the purpose of those shiny 
> shields was to aid heat transfer.  My recollection is they are to 
> prevent the tubes from emitting a signal of any sort and came into 
> being because of WW2.  Moral receivers on shipboard require 
> extraordinary shielding to prevent submarines from hearing the 
> oscillator and mixer signals so the shields were developed for 
> miniature tubes following the metal tube of WW2.
>
> Those metal tubes with the octal base are nothing more than miniature 
> tubes in the can with (usually) pin 1 grounded to prevent radiation.  
> I would surmise that following the war manufacturers continued with 
> various shields should subsequent wars break out like Korea which they 
> thought might flare up to a world conflict.
>
> Jim
> W5JO
>
> -----Original Message-----
> There are a number of people who have tried painting the "shiny" 
> shields with flat black paint, both inside and outside, that have 
> found a reduced tube temperature.  Over the years, I have tried this a 
> few times and the temperature of the tubes did seem to be lower.  
> However, I never actually measured the temperature and, as such, the 
> reduction in temperature is more anecdotal than scientific.
>
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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------------------------------

Message: 4
Date: Mon, 26 May 2014 14:06:35 -0400 (EDT)
From: hwhall at compuserve.com
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Tube shields CORRECTION
Message-ID: <8D147245DB3C0E8-C48-1DBFF at webmail-d266.sysops.aol.com>
Content-Type: text/plain; charset="us-ascii"

 The IERC shields, and some variations on the type, were developed in response 
to studies of tube heat and reduced operating lifetime. Before that, it seems 
that shields were indeed simply to control interference to or from the tube. 
Electric Radio had an interesting article a few years ago on tube shields, and 
tube life versus temperature. There were some subtle issues discussed, like the 
transparency of different tube glasses to different IR wavelengths as plate heat 
increased, and the effects of objects surrounding a tube and its shield.

Wayne

 WB4OGM

-----Original Message-----
From: rbethman <rbethman at comcast.net>
To: boatanchors <boatanchors at mailman.qth.net>
Sent: Mon, May 26, 2014 10:40 am
Subject: Re: [Boatanchors] Tube shields CORRECTION

One reason for *some* shields, such as the *IERC* types, is that the are 
lined with a pleated liner that conducts heat to the same type metal 
outer piece.

The whole intention is to wick heat away from the tube at a faster rate 
than simple convection.

These also have a base that is also designed to work as a complete unit.

The tubes with these run significantly cooler that the shiny nickel or 
chrome plated ones.

Bob - N0DGN

On 5/25/2014 6:48 PM, Bob Jackson wrote:
> I always assumed that tube shields were used to keep stray RF either in or out 

of the tube or both. Are there other reasons as well like keeping them securely 
in their sockets via the little springs inside the shield?
>
> Bob

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------------------------------

Message: 5
Date: Mon, 26 May 2014 14:26:58 -0400
From: Tom Nicholson <Gunsrus1942 at Comcast.net>
To: Bill Cromwell <wrcromwell at gmail.com>, boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Veterans Day
Message-ID: <53838772.8020008 at Comcast.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I also try to keep politics out of Ham radio etc. BUT there comes a time 
that one must stand and be counted! We also will stand with Robert & Susan!

Tom & Ellen Nicholson
Tom -- USAF 1959 to 1963
Ellen -- 35 years as a Neurology Head Nurse at West Haven Ct. Veterans 
hospital

On 5/26/2014 1:31 PM, Bill Cromwell wrote:
> On 05/26/2014 01:05 PM, WA5CAB--- via Boatanchors wrote:
>> There was nothing illegal or immoral about the Vietnam War.  Limp 
>> wristed
>> liberals will please keep your thoughtless opiions to yourselves, 
>> especially
>> today.
>>
>> Robert & Susan Downs - Houston
>> Vietnam vet and Air Force Brat respectively.
>> MVPA 9480
>>
>>
> I usually avoid this kind of thread altogether but today I'm standing 
> with Bob and others.
>
> 73,
>
> Bill  KU8H
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

------------------------------

Message: 6
Date: Mon, 26 May 2014 14:39:06 -0400
From: rbethman <rbethman at comcast.net>
To: boatanchors at mailman.qth.net
Subject: Re: [Boatanchors] Tube shields CORRECTION
Message-ID: <53838A4A.5020002 at comcast.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

The only reason I suggested the 120VAC high RPM types is that there is 
an abundance of them from Computer racks, and a BIG surplus of them from 
old S-100 Bus computers.

I have a large number of them from such sources.  We used to replace the 
S-100 ones whenever owners complained about vibration.

I managed to replace them as instructed, then open the bushing cover and 
oil them.

They last for a very long time.  One bank of six came off an AT&T data 
comm box.

They upgraded the box and left the bank of them behind.  Serves well 
when in the kitchen, placed in the window while baking.

Bob - N0DGN

On 5/26/2014 1:59 PM, hwhall at compuserve.com wrote:
>
> or a 120VAC one with a large sand resistor that drops the RPM so that
> noise doesn't become an issue.
>
>   
> I've also seen suggestions to use 240vac fans to get lower run noise, and no 
resistor to heat up. They can probably be bought cheaper than 120vac versions 
since they are less desirable to most folks.
>    
>
>   Wayne
>
>   WB4OGM
>
>
> -----Original Message-----
> From: rbethman <rbethman at comcast.net>
> To: boatanchors <boatanchors at mailman.qth.net>
> Sent: Mon, May 26, 2014 10:40 am
> Subject: Re: [Boatanchors] Tube shields CORRECTION
>
>
> Jim,
>
> You are so right!
>
> The vast majority of these old BAs would do much better with removing
> these shields that do NOT have RF issues and installing a muffin fan to
> take the heat out.
>
> Either computer CPU fans with a 12VDC rating at VERY low current draw,
> or a 120VAC one with a large sand resistor that drops the RPM so that
> noise doesn't become an issue.
>
> Bob - N0DGN
>
> On 5/26/2014 12:19 PM, Jim Wilhite wrote:
>> Correct me if I am wrong, but I don't think the purpose of those shiny
>> shields was to aid heat transfer.  My recollection is they are to
>> prevent the tubes from emitting a signal of any sort and came into
>> being because of WW2.  Moral receivers on shipboard require
>> extraordinary shielding to prevent submarines from hearing the
>> oscillator and mixer signals so the shields were developed for
>> miniature tubes following the metal tube of WW2.
>>
>> Those metal tubes with the octal base are nothing more than miniature
>> tubes in the can with (usually) pin 1 grounded to prevent radiation.
>> I would surmise that following the war manufacturers continued with
>> various shields should subsequent wars break out like Korea which they
>> thought might flare up to a world conflict.
>>
>> Jim
>> W5JO
>>
>> -----Original Message-----
>> There are a number of people who have tried painting the "shiny"
>> shields with flat black paint, both inside and outside, that have
>> found a reduced tube temperature.  Over the years, I have tried this a
>> few times and the temperature of the tubes did seem to be lower.
>> However, I never actually measured the temperature and, as such, the
>> reduction in temperature is more anecdotal than scientific.
>>
>> ______________________________________________________________
>> Boatanchors mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Boatanchors at mailman.qth.net
>>
>> List Administrator: Duane Fischer, W8DBF
>> ** For Assistance: dfischer at usol.com **
>>
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>   
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

------------------------------

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------------------------------

End of Boatanchors Digest, Vol 124, Issue 43
********************************************