RadioBanter - Steel no good for chassis? (Which metal is best for old regen designs?)

Page 2 of 3

Show 40 post(s) from this thread on one page

RadioBanter (https://www.radiobanter.com/)

- Homebrew (https://www.radiobanter.com/homebrew/)

- - Steel no good for chassis? (Which metal is best for old regen designs?) (https://www.radiobanter.com/homebrew/21446-steel-no-good-chassis-metal-best-old-regen-designs.html)

Deos	October 20th 03 01:33 PM

Aluminum= nice to work with+very light+dose not rust+not really that
expensive

--
http://www.qsl.net/sv1hao
"David Forsyth" wrote in message
...
Hi all,

I recently became interested in trying to build a small two-tube regen
type
receiver for broadcast and/or shortwave reception. I designed a simple
chassis based on some vintage articles on the subject. This is the
classic
'metal box with attched front faceplate' design. I was going to use
cold-rolled steel since we have this at work and spot weld the face to the
main chassis, but then I got to thinking that perhaps the steel might
interfere with the coils. I noticed also after this that every old
article
that I've come across usually suggested aluminum for the chassis. They
don't make mention of the reasons for this, however. I was wondering if
ease of machinability for the amatuer working with simple hand tools, and
perhaps also weight savings, were main factors, or was it mainly for lack
of
magnetic interation with the coils? We also have sheets of aluminum,
brass,
and stainless that I can use but I'm not sure if they can be resistance
welded, so I would have to bolt the face onto the main chassis box.
Anyone
have any further ideas or insights?

thanks in advance,

Dave

Frank Dinger

October 20th 03 04:14 PM

The "dead bug" way? I'm not sure what this means - please forgive me I'm
new to this :-)
=========
This is a method of construction where components are soldered to unetched
printed circuit board islands (made with a special rotary bit which only
removes a thin ring from the copper surface ) or to insulated PCB patches
glued onto the unetched PCB ,with ICs glued to the PCB with the legs up
(hence dead bug) and connected to other components .
If permissible ,additional 'connecting points' are achieved by soldering
high value resistors (a number of MegaOhms) perpendicularly onto the PCB
with the other end serving as the connecting point.

It is also called ugly construction . Extensive info on these methods is
given in an excellent book for homebrewers :
"Experimental Methods in RF Design" Chapter 1. ; published by ARRL.

Frank GM0CSZ / KN6WH

Frank Dinger

October 20th 03 04:14 PM

Frank Dinger

October 20th 03 04:29 PM

If you're using octal type tubes, there are sockets made for industrial
relays which fit the tubes perfectly. They are as you describe; surface
mount with side terminals. They no doubt add a small amount of
inductance and capacitance which could affect VHF operation, something
to keep in mind. McMaster-Carr has them on page 819 of their online
catalog:
=============
These surface mount sockets have substantial screwed connections and are
made of PVC which as suggested might not be the optimum for VHF applications
,but also might not be able to cope with the heat produced by the relevant
valve (tube), especially when the valve is of the medium to high power
variety.

Frank GM0CSZ / KN6WH

Frank Dinger

October 20th 03 04:29 PM

Frank Dinger

October 20th 03 04:43 PM

Nowadays I prefer using PC board for mounting components. The Al chassis
being upside-down used as a shielded base. In many cases the smaller
components can be just soldered together in "basket weave" construction
supported by the ones that need to be soldered to the PC-board ground
plane.
Decades ago Pete Sulzer did his prototypes in full basket-weave style
without a ground plane - but few people can visualize ground loops well
enough to build RF circuits that way. When you visited his company you'd
see his prototypes hanging from nails on the wall.
===============
Talking about nails ,some time ago in the dutch amateur radio mag.
'Electron' , there was an article describing a kid's radio.
,dubbed 'Nail Radio' . Its construction was on a piece of timber into
which copperclad nails had been hammered in circuit diagramme configuration
.. The components (for this medium wave receiver) were subsequently soldered
to the nail heads.
A superb way to introduce newcomers to electronics and radio home-brewing.

Frank GM0CSZ / KN6WH

Frank Dinger

October 20th 03 04:43 PM

--exray--

October 20th 03 05:27 PM

Frank Dinger wrote:
Nowadays I prefer using PC board for mounting components. The Al chassis
being upside-down used as a shielded base. In many cases the smaller
components can be just soldered together in "basket weave" construction
supported by the ones that need to be soldered to the PC-board ground

plane.

Decades ago Pete Sulzer did his prototypes in full basket-weave style
without a ground plane - but few people can visualize ground loops well
enough to build RF circuits that way. When you visited his company you'd
see his prototypes hanging from nails on the wall.

===============
Talking about nails ,some time ago in the dutch amateur radio mag.
'Electron' , there was an article describing a kid's radio.
,dubbed 'Nail Radio' . Its construction was on a piece of timber into
which copperclad nails had been hammered in circuit diagramme configuration
. The components (for this medium wave receiver) were subsequently soldered
to the nail heads.
A superb way to introduce newcomers to electronics and radio home-brewing.

Frank GM0CSZ / KN6WH

hehehe...as a kid I built a crystal radio like that. No soldering though.
-Bill

--exray--

October 20th 03 05:27 PM

Gary S.

October 20th 03 06:14 PM

On Mon, 20 Oct 2003 16:43:06 +0100, "Frank Dinger"
wrote:

Talking about nails ,some time ago in the dutch amateur radio mag.
'Electron' , there was an article describing a kid's radio.
,dubbed 'Nail Radio' . Its construction was on a piece of timber into
which copperclad nails had been hammered in circuit diagramme configuration
. The components (for this medium wave receiver) were subsequently soldered
to the nail heads.
A superb way to introduce newcomers to electronics and radio home-brewing.

A real circuit "board".

Any technique that works, is good technique.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

Gary S.

October 20th 03 06:14 PM

Avery Fineman

October 21st 03 12:31 AM

In article , "David Forsyth"
writes:

On a second side note - does anyone happen to know what the formula would be
to calculate the capacitance between two metal plates of a given area and
given spacing, having an air dielectric?

From the good ol' "Green Bible" (ITT Reference Data for Radio
Engineers, 4th Edition, 1956, page 133), for only two plates,
dimensions in inches, air dielectric:

Capacitance (pFd) = 0.225 x Square Area / spacing

Assuming the plates are the same size and shape.

Len Anderson
retired (from regular hours) electronic engineer person

Avery Fineman

October 21st 03 12:31 AM

David Forsyth

October 21st 03 01:05 AM

Thanks Len!

Dave

"Avery Fineman" wrote in message
...
In article , "David Forsyth"
writes:

On a second side note - does anyone happen to know what the formula would
be
to calculate the capacitance between two metal plates of a given area and
given spacing, having an air dielectric?

From the good ol' "Green Bible" (ITT Reference Data for Radio
Engineers, 4th Edition, 1956, page 133), for only two plates,
dimensions in inches, air dielectric:

Capacitance (pFd) = 0.225 x Square Area / spacing

Assuming the plates are the same size and shape.

Len Anderson
retired (from regular hours) electronic engineer person

David Forsyth

October 21st 03 01:05 AM

kenneth scharf

October 30th 03 02:03 AM

David Forsyth wrote:
The "dead bug" way? I'm not sure what this means - please forgive me I'm
new to this :-)

Dave

"Bill Hennessy" wrote in message
. ..

Yes, I have found when building regenerative receivers wood is the best
chassi. However a metal front panel is a must. However I only use

battery

tubes with low voltage. Never more than 45 volts. But when building
solid-state regeneratives. A good ground plane helps. Build it the dead
bug way.

'Dead bug' refers to IC's mounted upside down with their legs
sticking up in the air like a dead roach.

kenneth scharf

October 30th 03 02:03 AM

kenneth scharf

October 30th 03 02:07 AM

Michael A. Terrell wrote:
Michael Black wrote:

"Ralph Mowery" ) writes:

Aluminum is usually easier for most to work with with simple hand tools.
Steel is fine but it might rust and look bad after a while. Make the
chassie out of whatever kind of metel that you think is the best for you to
work with . Electrically there will be little if any differance.

And of course, everyone did use steel (once things progressed beyond
wood and bakelite chassis) right up until aluminum because readily
available and/or cheap enough, at which point I doubt anyone used
steel except if what they were building was really really heavy, ie
a kilowatt modulator or final.

Michael VE2BVW

I have seen a few nice layouts on Brass chassis, as well. Easier to
work than steel, and you can still solder to it. I built some tube RF
decks on 1/16" brass sheet stock, and mounted them into a steel cabinet
years ago.

I think RL Drake used copper chassis on their tube ham gear. Looked
real nice when new and shiny! I've build some equipment in home made
boxes made out of copper (you can get small pieces of sheet copper from
the hobby shop). Not cheap, but solders easy and makes a great ground
plane!

kenneth scharf

October 30th 03 02:07 AM

Michael A. Terrell

October 30th 03 02:54 AM

kenneth scharf wrote:

Michael A. Terrell wrote:
Michael Black wrote:

"Ralph Mowery" ) writes:

Aluminum is usually easier for most to work with with simple hand tools.
Steel is fine but it might rust and look bad after a while. Make the
chassie out of whatever kind of metel that you think is the best for you to
work with . Electrically there will be little if any differance.

And of course, everyone did use steel (once things progressed beyond
wood and bakelite chassis) right up until aluminum because readily
available and/or cheap enough, at which point I doubt anyone used
steel except if what they were building was really really heavy, ie
a kilowatt modulator or final.

Michael VE2BVW

I have seen a few nice layouts on Brass chassis, as well. Easier to
work than steel, and you can still solder to it. I built some tube RF
decks on 1/16" brass sheet stock, and mounted them into a steel cabinet
years ago.

I think RL Drake used copper chassis on their tube ham gear. Looked
real nice when new and shiny! I've build some equipment in home made
boxes made out of copper (you can get small pieces of sheet copper from
the hobby shop). Not cheap, but solders easy and makes a great ground
plane!

Yes, I know what you mean. I still have some pieces of sheet brass,
angles, and small tubes for RF work. I use to solder small brass boxes
together for shields when I built filters and RF pre amps. I was using
K&S Engineering materials sold at hobby shops, but the last hobby shop
in Ocala closed about four years ago. I am looking for a place to get
some deep drawn brass boxes and small tubing to build some DC blocks,
detectors, and dummy antennas to sell as alignment aids for older
radios.
--

Michael A. Terrell
Central Florida

Michael A. Terrell

October 30th 03 02:54 AM

Jeffrey D Angus

October 30th 03 03:25 AM

kenneth scharf wrote:
I think RL Drake used copper chassis on their tube ham gear. Looked
real nice when new and shiny!

No, it was copper plated steel.

Jeff

--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." Benjamin Franklin
"A life lived in fear is a life half lived."
Tara Morice as Fran, from the movie "Strictly Ballroom"

Jeffrey D Angus

October 30th 03 03:25 AM

Frank Dinger

October 30th 03 01:03 PM

I have seen a few nice layouts on Brass chassis, as well. Easier to
work than steel, and you can still solder to it. I built some tube RF
decks on 1/16" brass sheet stock, and mounted them into a steel cabinet
years ago.

I think RL Drake used copper chassis on their tube ham gear. Looked
real nice when new and shiny! I've build some equipment in home made
boxes made out of copper (you can get small pieces of sheet copper from
the hobby shop). Not cheap, but solders easy and makes a great ground
plane!
========
For equipment NOT involving heavy components like large transformers ,you
could consider making a chassis out of (scrap) double sided printed circuit
board material , which is very easy to handle (drill ,cut ,solder) .
Components can be directly soldered to the chassis and RF screens of the
same material can be readily added.
When screening sections ,feed-through capacitors can be easily soldered .
Over the years I bought cut-offs up to large sheets of double sided PCB (at
amateur radio flea markets) , which can also be used to make front panels
and small cabinets/ enclosures.

Frank GM0CSZ / KN6WH

Frank Dinger

October 30th 03 01:03 PM

R J Carpenter

October 30th 03 05:06 PM

"Frank Dinger" wrote in message
...

Over the years I bought cut-offs up to large sheets of double sided PCB
(at
amateur radio flea markets) , which can also be used to make front panels
and small cabinets/ enclosures.

My stock of double sided epoxy board is a 4 ft by 4 ft sheet I bought at a
hamfest for $20 or 25 IIRC. I have some smaller pieces left over from the
past.

If you don't want to solder partitions or sides, you might do as I and buy a
10-ft length of extruded aluminum angle, 0.25 inches on a side. This way you
can screw things together without worrying about overheating / delaminating
the PC board. You can also take things apart if needed :-(

R J Carpenter

October 30th 03 05:06 PM

jakdedert

October 30th 03 05:33 PM

"R J Carpenter" wrote in message
...

"Frank Dinger" wrote in message
...

Over the years I bought cut-offs up to large sheets of double sided PCB
(at
amateur radio flea markets) , which can also be used to make front
panels
and small cabinets/ enclosures.

My stock of double sided epoxy board is a 4 ft by 4 ft sheet I bought at a
hamfest for $20 or 25 IIRC. I have some smaller pieces left over from the
past.

If you don't want to solder partitions or sides, you might do as I and buy
a
10-ft length of extruded aluminum angle, 0.25 inches on a side. This way
you
can screw things together without worrying about overheating /
delaminating
the PC board. You can also take things apart if needed :-(

I'd be careful about using aluminum for this. You could set up a situation
where over the years, the dissimilar metals would begin to react and cause
all sorts of gremlins. I'd think you'd want to use copper or brass angle
stock, which is also available, albeit more expensive...or plastic; or even
wood. The plastic channel stock that is used to join masonite wall panels
comes to mind. If you used nonconductive material, it would be easy to
connect the chassis parts electrically with a few bits of copper braid or
brackets.

I could be wrong about this, but judging by the debacle during the 70's
where a lot of aluminum wiring got installed in a lot of homes--and later
caused at least a few fires--I'd at least be cautious. I've also seen
several places in my old houses where iron piping was screwed directly into
brass fittings. I just dug up the faucet in my front yard, which a
neighborhood kid had hit with a lawnmower. Water was bubbling up out of the
ground. The shock from the mower was the final straw which crumbled the
iron pipe at the threads where it screwed into the brass tee. When finally
I got down to it, there was practically nothing of the threaded end left,
although the rest of the pipe was in good condition. I replaced it with a
plastic nipple...didn't really need a second faucet in the front yard
anyway.

jak

jakdedert

October 30th 03 05:33 PM

Jeffrey D Angus

October 30th 03 05:44 PM

jakdedert wrote:
I'd be careful about using aluminum for this. You could set up a situation
where over the years, the dissimilar metals would begin to react and cause
all sorts of gremlins.

I could be wrong about this, but judging by the debacle during the 70's
where a lot of aluminum wiring got installed in a lot of homes--and later
caused at least a few fires--I'd at least be cautious.

That was mostly hype stirred up by Jeraldo Riviera. Back when he
was still caucasion.

The real problem with aluminum wiring was three fold. 1. For a
given current ration, the aluminum wire has to be bigger than
copper. 2. Special terminations (screw and or compression type)
marked CuAl shoud be used along with a gel like "No-Ox" to protect
the connection 3. Proper torque on the fastenings is manditory.

Given the special requirements and the attitude of most workers
that "I know what I'm doing" of course it was a disaster.

I've also seen several places in my old houses where iron piping
was screwed directly into brass fittings. [ snip ] When finally
I got down to it, there was practically nothing of the threaded
end left, although the rest of the pipe was in good condition.

This is more the fault of the iron pipe. Not the bronze/brass
fittings. When you thread the end of a pipe, you remove the
galvanized coating. Exposed metal pipe = weak spot.

Jeff

--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." Benjamin Franklin
"A life lived in fear is a life half lived."
Tara Morice as Fran, from the movie "Strictly Ballroom"

Jeffrey D Angus

October 30th 03 05:44 PM

Michael A. Terrell

October 30th 03 06:00 PM

Jeffrey D Angus wrote:

That was mostly hype stirred up by Geraldo Riviera. Back when he
was still caucasion.

The real problem with aluminum wiring was three fold. 1. For a
given current ration, the aluminum wire has to be bigger than
copper. 2. Special terminations (screw and or compression type)
marked CuAl shoud be used along with a gel like "No-Ox" to protect
the connection 3. Proper torque on the fastenings is manditory.

Given the special requirements and the attitude of most workers
that "I know what I'm doing" of course it was a disaster.

Jeff

Aluminum wiring really made the news after the "Beverly Hills"
Nightclub (Just across the Ohio river from Cincinnati, in Soutgate,
Kentucky) burnt down, and it was completely wired with aluminum wire.
The fire was so hot that there was little left to determine the quality
of the the wiring job. The nightclub was built with very nice, real wood
paneling (3/4" thick), and the heat of the fire vaporized a lot of the
wire and fixtures.

It was a very nice place. One of the TV manufacturers used to have
their annual classes there. I think it was Admiral, but its been so long
I really don't remember.

http://www.cincypost.com/bhfire/
--

Michael A. Terrell
Central Florida

Michael A. Terrell

October 30th 03 06:00 PM

--exray--

October 30th 03 06:57 PM

jakdedert wrote:

and small cabinets/ enclosures.

My stock of double sided epoxy board is a 4 ft by 4 ft sheet I bought at a
hamfest for $20 or 25 IIRC. I have some smaller pieces left over from the
past.

If you don't want to solder partitions or sides, you might do as I and buy

a

10-ft length of extruded aluminum angle, 0.25 inches on a side. This way

you

can screw things together without worrying about overheating /

delaminating

the PC board. You can also take things apart if needed :-(

I'd be careful about using aluminum for this. You could set up a situation
where over the years, the dissimilar metals would begin to react and cause
all sorts of gremlins. I'd think you'd want to use copper or brass angle
stock, which is also available, albeit more expensive...or plastic; or even
wood.

You can tin the edge of the PCB and avoid this for the most part.

-Bill

--exray--

October 30th 03 06:57 PM

jakdedert

October 30th 03 09:52 PM

"Jeffrey D Angus" wrote in message
...
jakdedert wrote:
I'd be careful about using aluminum for this. You could set up a
situation
where over the years, the dissimilar metals would begin to react and
cause
all sorts of gremlins.

I could be wrong about this, but judging by the debacle during the 70's
where a lot of aluminum wiring got installed in a lot of homes--and
later
caused at least a few fires--I'd at least be cautious.

That was mostly hype stirred up by Jeraldo Riviera. Back when he
was still caucasion.

The real problem with aluminum wiring was three fold. 1. For a
given current ration, the aluminum wire has to be bigger than
copper. 2. Special terminations (screw and or compression type)
marked CuAl shoud be used along with a gel like "No-Ox" to protect
the connection 3. Proper torque on the fastenings is manditory.

Given the special requirements and the attitude of most workers
that "I know what I'm doing" of course it was a disaster.

I've also seen several places in my old houses where iron piping
was screwed directly into brass fittings. [ snip ] When finally
I got down to it, there was practically nothing of the threaded
end left, although the rest of the pipe was in good condition.

This is more the fault of the iron pipe. Not the bronze/brass
fittings. When you thread the end of a pipe, you remove the
galvanized coating. Exposed metal pipe = weak spot.

That might be the case if every iron pipe also exhibited this effect. The
only place I've found it was when an iron pipe was mated with a brass
fitting. A similar situation occurred in my kitchen wall, where the faucets
(mounted on the wall) were connected to the brass elbows nailed to the studs
with a short iron pipe. The ends of both pipes were corroded to hell within
the brass. I had to dig the rotton bits of iron out of the brass threads
(not as difficult as it sounds, the iron was completely oxidised and
crumbling) without damaging the brass. Otherwise, I'd have to had opened up
the wall to replace the elbows. Just a few years later, when the kitchen
was remodeled and a more conventional sink installed, the replacement pipes
were already noticably corroded. Any time two dissimilar metals are placed
in contact with each other, galvanic action occurs. Given a bit of
moisture, corrosion occurs; thus the No-Ox paste for copper to aluminum
terminals.

A Galvanic chart appears on this manufacturers website:
http://www.katonet.com/Techinfo/News...may-jun-00.htm

jak

Jeff

--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." Benjamin Franklin
"A life lived in fear is a life half lived."
Tara Morice as Fran, from the movie "Strictly Ballroom"

jakdedert

October 30th 03 09:52 PM

jakdedert

October 30th 03 09:56 PM

"--exray--" wrote in message
...
jakdedert wrote:

and small cabinets/ enclosures.

My stock of double sided epoxy board is a 4 ft by 4 ft sheet I bought at
a
hamfest for $20 or 25 IIRC. I have some smaller pieces left over from
the
past.

If you don't want to solder partitions or sides, you might do as I and
buy

a

10-ft length of extruded aluminum angle, 0.25 inches on a side. This way

you

can screw things together without worrying about overheating /

delaminating

the PC board. You can also take things apart if needed :-(

I'd be careful about using aluminum for this. You could set up a
situation
where over the years, the dissimilar metals would begin to react and
cause
all sorts of gremlins. I'd think you'd want to use copper or brass
angle
stock, which is also available, albeit more expensive...or plastic; or
even
wood.

You can tin the edge of the PCB and avoid this for the most part.

-Bill

Probably, but the object was to eliminate heating the copper board. Other
coatings would work, as well. Zinc chromate primer is what they use in
aircraft construction.

jak

jakdedert

October 30th 03 09:56 PM

Dave Platt

October 30th 03 10:13 PM

In article ,
jakdedert wrote:

I've also seen several places in my old houses where iron piping
was screwed directly into brass fittings. [ snip ] When finally
I got down to it, there was practically nothing of the threaded
end left, although the rest of the pipe was in good condition.

This is more the fault of the iron pipe. Not the bronze/brass
fittings. When you thread the end of a pipe, you remove the
galvanized coating. Exposed metal pipe = weak spot.

That might be the case if every iron pipe also exhibited this effect. The
only place I've found it was when an iron pipe was mated with a brass
fitting.

The hardware stores around here sell special unions, with insulated
threaded fittings, for mating iron/steel pipes to brass. I've
pondered whether these might be useful for making certain forms of
(non-DC-connected) copper-tubing J-pole antennas.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

All times are GMT +1. The time now is 04:57 AM.

Page 2 of 3

Show 40 post(s) from this thread on one page