David Forsyth wrote:

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.

Nothing wrong with steel. Altoid mint tin-plated steel boxes are very
popular for QRP projects, and tin-plated boxes are often used for
screening on commercial RF PCBs.

73, Leon

"Dead bug" construction means components mounted with legs up. I have not
seen this done with vacuum tube projects.
More important than the chassis material is that ground connections come to
a common point rather than scattered about the chassis.
Ray

My first Heathkit radio used copper-clad steel. I think this is a great
combination for electro-magnetic shielding from low frequencies where you
need the ferrous material to high frequencies where you need the highly
conductive copper skin. Galvanised steel isn't a bad choice either. Steel is
needed if you use the radio in the vicinity of CRT's, computers, etc.

Good luck,

Tom

David Forsyth wrote:
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


Steel will be fine. Your suspicions about workability are correct but
there is also plating/painting to consider.
-Bill

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.

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

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.

David Forsyth wrote:

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.

Nothing wrong with steel. Altoid mint tin-plated steel boxes are very
popular for QRP projects, and tin-plated boxes are often used for
screening on commercial RF PCBs.

73, Leon

"David Forsyth" wrote in message
...

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.

Your articles aren't old enough. After real wooden breadboards went out of
style, metal chassis were cadmium-plated steel. Aluminum chassis didn't
appear in wide ham use until a few years after WW2.

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.


For air-dielectric capacitors: two plates one centimeter on a side,
separated by one centimeter equals one picofarad. That's forgetting fringing
and other edge effects.

Bob C w3otc

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 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