The "Two Transistor challenge" - taking things a bit too far?
 

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138

The "Two Transistor challenge" - taking things a bit too far?
 

In article ,
"gareth" wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138

And the diode + FET! But I agree, counting transistors when capacitors
and coils can cost much more in both money and space has been
meaningless for about fifty years. Remember really advanced seven
transistor radios?

--

Percy Picacity

The "Two Transistor challenge" - taking things a bit too far?
 

"Percy Picacity" wrote in message
...
In article ,
"gareth" wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138

And the diode + FET! But I agree, counting transistors when capacitors
and coils can cost much more in both money and space has been
meaningless for about fifty years. Remember really advanced seven
transistor radios?

I had a Sinclair Micro 6, that was how I discovered Top Band (160m)
--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.co.uk

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 11:38, FranK Turner-Smith G3VKI wrote:

I had a Sinclair Micro 6, that was how I discovered Top Band (160m)

I'm sure I still have mine. Sadly, the 250 ohm earpiece met with a
terminal end and I've never found a replacement.

Building radios etc. were the signs of being a geek or nerd in the days
before home computers.

Did you also build the Sinclair Calculator that came along in about
1973? Painfully slow to use, a quick slide rule user could probably beat
it in a calculation which had a few trig functions in it, but geek 'must
have' ;-)

Back to the title, Some clubs run competitions along the lines of:

Build an 80m tx with the fewest components.

OR

Build a 20m rx with with the fewest components.


There are rules as to whether the battery counts etc., use or not of
ICs. ....

While I follow the QRP scene, I don't pretend to be an ardent QRPer or
QRP builder so I'm not fully briefed on the rules. Those are simply an
outline I recall.

Whoever started the thread is, I assume, an ardent and active
constructor. Perhaps he/she will share some of their designs to inspire
others to follow their example.

The "Two Transistor challenge" - taking things a bit too far?
 

"Brian Reay" wrote in message
...


Did you also build the Sinclair Calculator that came along in about 1973?
Painfully slow to use, a quick slide rule user could probably beat it in a
calculation which had a few trig functions in it, but geek 'must have' ;-)

I built the 'Wireless World' calculator about 72/73, it's still around
somewhere. I thinkthe kit cost about £40, a lot of money then (for me at
least) which was less that half the price of ready made one.

Whoever started the thread is, I assume, an ardent and active constructor.
Perhaps he/she will share some of their designs to inspire others to
follow their example.

I don't think the above para was needed, but perhaps you don't read all of
the theads.


--

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 13:12, I'm Old Gregg wrote:
"Brian Reay" wrote in message
...


Did you also build the Sinclair Calculator that came along in about
1973? Painfully slow to use, a quick slide rule user could probably
beat it in a calculation which had a few trig functions in it, but
geek 'must have' ;-)

I built the 'Wireless World' calculator about 72/73, it's still around
somewhere. I thinkthe kit cost about £40, a lot of money then (for me at
least) which was less that half the price of ready made one.


Much less. A class mate was bought a Sinclair Scientific by his father
for £180. That was a staggering sum of money. A good 3 bed room semi
could be bought for about £3800 at that time in the area. When the
Sinclair kit came out, New Scientist did an offer for £14.95.


Whoever started the thread is, I assume, an ardent and active
constructor. Perhaps he/she will share some of their designs to
inspire others to follow their example.

I don't think the above para was needed, but perhaps you don't read all
of the theads.

I don't, even while laid up following a knee op. I've other things to do.

The "Two Transistor challenge" - taking things a bit too far?
 

On 2/18/2014 5:58 AM, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138



I'm not familiar with this particular challenge - but similar ones I've
seen are more about the design than the cost.

Jerry, AI0K




--
==================
Remove the "x" from my email address
Jerry Stuckle

==================

The "Two Transistor challenge" - taking things a bit too far?
 

In article ,
Jerry Stuckle wrote:

On 2/18/2014 5:58 AM, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138



I'm not familiar with this particular challenge - but similar ones I've
seen are more about the design than the cost.

Jerry, AI0K

True, but it is still a ridiculous constraint. It is about as sensible
as designing something where the first digit of every component value
had to be '4'.

--

Percy Picacity

The "Two Transistor challenge" - taking things a bit too far?
 

"Brian Reay" wrote in message
...

Whoever started the thread is, I assume, an ardent and active constructor.
Perhaps he/she will share some of their designs to inspire others to
follow their example.


Why is it that almost every post from you contains a snide or an
infantile interjection, OM?

Grow up, Brian!

The "Two Transistor challenge" - taking things a bit too far?
 

"I'm Old Gregg" wrote in message
...
"Brian Reay" wrote in message
...

Whoever started the thread is, I assume, an ardent and active
constructor. Perhaps he/she will share some of their designs to inspire
others to follow their example.

I don't think the above para was needed, but perhaps you don't read all of
the theads.


Thanks, Jon.

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014 11:38:43 +0000, FranK Turner-Smith G3VKI wrote:

I had a Sinclair Micro 6, that was how I discovered Top Band (160m

I had a one transistor radio lit in the early '60s - a crystal set with a
one transistor audio stage, that was show I discovered more than one
station at once! I later bought a WS19 for much the same price.



--
M0WYM
Sales @ radiowymsey
http://stores.ebay.co.uk/Sales-At-Radio-Wymsey/
http://sales-at-radio-wymsey.ebid.net/

The "Two Transistor challenge" - taking things a bit too far?
 

"Brian Reay" wrote in message
...
On 18/02/14 13:48, Stephen Thomas Cole wrote:
Brian Reay wrote:
While I follow the QRP scene, I don't pretend to be an ardent QRPer or
QRP builder so I'm not fully briefed on the rules. Those are simply an
outline I recall.
That's my interpretation of this "scene", folk are getting kicks out of
getting results within strictly defined and, in real world terms,
impractical limits. To each their own!
I think such competitions stimulate a bit of homebrew, innovation, ...
etc. I may be incorrect but I think there may even be a periodic
competition run by the GQRP club.
I think that there are skills here which could be 'transferred' to the
commercial or military design arena. Many things impact reliability, some
of the most obvious are component count and solder joint count.

I think that anyone who describes such things as, "impractical" has not
got a single clue about amateur radio. CB radio, perhaps.

The "Two Transistor challenge" - taking things a bit too far?
 

On 2/18/2014 9:05 AM, Percy Picacity wrote:
In article ,
Jerry Stuckle wrote:

On 2/18/2014 5:58 AM, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138



I'm not familiar with this particular challenge - but similar ones I've
seen are more about the design than the cost.

Jerry, AI0K

True, but it is still a ridiculous constraint. It is about as sensible
as designing something where the first digit of every component value
had to be '4'.


Not necessarily. It takes skill to minimize components in a design
without degrading performance. Anyone with a modicum of RF design
experience can design a 5 or 10 transistor transmitter which has
reasonable output and no chirp. To do so with 2 transistors is much
more difficult.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

The "Two Transistor challenge" - taking things a bit too far?
 

"Brian Reay" wrote in message
...

Now I see who has started this thread, it is clear is was designed to turn
it into another of his vehicles for abuse, as he is doing.
I suggest the we civilised amateurs leave him to fester.

You make the mistake of judging me by your own behaviour,
exemplified earlier in this same thread.

The "Two Transistor challenge" - taking things a bit too far?
 

I paid about £180 for an HP35 in 1973, this calculator used reverse polish
notation (no equals key).

The "Two Transistor challenge" - taking things a bit too far?
 

Jerry Stuckle wrote:
On 2/18/2014 9:05 AM, Percy Picacity wrote:
In article ,
Jerry Stuckle wrote:

On 2/18/2014 5:58 AM, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138



I'm not familiar with this particular challenge - but similar ones I've
seen are more about the design than the cost.

Jerry, AI0K

True, but it is still a ridiculous constraint. It is about as sensible
as designing something where the first digit of every component value
had to be '4'.


Not necessarily. It takes skill to minimize components in a design
without degrading performance. Anyone with a modicum of RF design
experience can design a 5 or 10 transistor transmitter which has
reasonable output and no chirp. To do so with 2 transistors is much more difficult.

Indeed. This reminds me of the classic story about pre-Apple Woz
redesigning an Atari game's circuit design and taking the IC count down by
two-thirds or so, earning a fee for each one he pulled out of the design.
Steve Jobs then stole most of the total fee by telling Woz that the
commission was worth about a tenth of what it was in reality, but that's
another tale for another day!

--
Stephen Thomas Cole // Sent from my iPhone

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 15:21, Phi wrote:
I paid about £180 for an HP35 in 1973, this calculator used reverse
polish notation (no equals key).
That seems cheap for an HP at the time. As I recall, that was the launch
price of the Sinclair, although it soon dropped.

The Sinclair was also RPN, as were the early Texas calculators I think.
Sinclair lacked the "Enter" button, using the + key its place.

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first
calculator to offer true algebraic entry (ie following BODMAS/BIDMAS
convention) was Texas. Even today some cheap calculators don't follow
the convention. One of the many things I warn pupils of when I teach
calculator use.

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014, Brian Reay wrote:

On 18/02/14 15:21, Phi wrote:
I paid about £180 for an HP35 in 1973, this calculator used reverse
polish notation (no equals key).
That seems cheap for an HP at the time. As I recall, that was the launch
price of the Sinclair, although it soon dropped.

The Sinclair was also RPN, as were the early Texas calculators I think.
Sinclair lacked the "Enter" button, using the + key its place.

I don't remember the TI calculators having RPN. I remember them as being
more reasonably priced versions of "electronic slide rules", which was
what they called them originally.

It's odd to look back now. I think that HP35 that a fellow ham got in
1972 or maybe 73 (a group buy at his place of employment) was the first
pocket calculator I ever saw close up. So many functions, yet so few
compared to what you can get on a $10 calculator today

I don't know what the first TI scientific calculator cost, but it was less
than the HP by far, and soon you could get one in the $50 range, and then
$30 range, which is when I got my TI-30.

Such a big change, a sudden surge in articles in the ham magazines showing
equations, suddenly you could actually work things out without needing
much math skill.

I think it was the National scientific calculator that had RPN, coming
later but also being quite cheap.

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first calculator to
offer true algebraic entry (ie following BODMAS/BIDMAS convention) was Texas.
Even today some cheap calculators don't follow the convention. One of the
many things I warn pupils of when I teach calculator use.

That's interesting. I look at the cheapest of the cheap scientific
calculators, and the functions are at least the same as my TI-30 from
about 1977. I assume the calculators have gotten so cheap because the
work was done long ago, buying old technology to implement cheap today.

Michael

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014, gareth wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or "build a
receiver without any ICs" after ICs had come around.

SOme of the time it's not about design, but the building, so one can just
copy what existed.

In some cases, this is just about getting people to build something, so a
two transistor whatever is simple and might attract more people.

But in suggesting a problem, people may come up with interesting
solutions. I remember a bit years ago where a bipolar transistor was used
to generate two different crystal controlled frequencies, the frequency
chosen by how polarity was applied. I forget the details, but it relied
ont he transistor having some amplification in an unexpected area.

If people don't have to be frugal, then such things never get found.

Or think about in the thirties. People had little money, so yes, a simple
transceiver would be a great thing. Someone decided to build that, in
effect a tube that was a superrenerative receiver and on transmit a
modulated oscillator. It helped get people on 10metres (I think) and
56MHz, and 112MHz and so on. It would generate activity on an otherwise
unused band because it was cheap and simple, so people built them. The
cost of the switch was less than the cost of the tubes. And every so
often, such a thing would be banned, as rules for more stability came into
effect, and usually by then that band was populated. So the concept moved
to a higher frequency, until it was deemed to unstable for there too, and
up to the next band. They even existed in the 420MHz band, and while
generally nobody built them, at 1296MHz people often got a start with
APX/6 surplus that amounted to simple equipment. 20 to 30 years ago,
23,000MHz got a boost with surplus door openers. SImple equipment gets
more people onto a band than complicated equipment, and some will move on
to fancier equipment.

That same sort of thing, an active element switched between a superregen
receiver and a modulated oscillator still existed till at least 30 years
ago, in license free walkie talkies, first in the 27MHz range and then in
the 49MHz range. Even then the cost of the switch was seen as simpler than
more transistors.

It can also teach something. You can reuse the transistor for two
functions, by switching the three leads of the transistor, which means
much more complication. But if people see that, they may learn that
design can become simpler by more complication. More transistors seem to
complicate things, but if it does away with switching, it may simplify the
design overall.

Michael

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014, Percy Picacity wrote:

In article ,
Jerry Stuckle wrote:

On 2/18/2014 5:58 AM, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138



I'm not familiar with this particular challenge - but similar ones I've
seen are more about the design than the cost.

Jerry, AI0K

True, but it is still a ridiculous constraint. It is about as sensible
as designing something where the first digit of every component value
had to be '4'.

But the constraint causes some to think.

An analogy is the superregenerative receiver. Forty years ago it as still
used in some places, but the various handbooks would give a very brief
description and basically treat it like a black box. It was like broken
telephone, the basics lost to history, "everyone" knowing the basics but
not really.

I remember later seeing a schematic where the quenching was done with a
separate device. The descriptions I'd previously seen had been mostly
about how the same device does the quenching, as if that was important to
understand why there was quenching. Seeing a separate oscillator made me
realize that the quenching oscillator was in effect modulating the
regenerative receiver. No wonder those things were wideband, put a square
wave on any oscillator and and you'd get multiple sidebands.

If you have a separate quenching oscillator, you can better control the
waveform and the "modulation level".

I didn't pursue it, but I realized that if you fiddle with such things,
you might end up with a narrower bandwidth superregen receiver.

And that's what Charles Kitchin did. He had an article in COmmunications
Quarterly where he went back to the early days of the receiver, understood
what was going on back then, and then tried to update it, with solid state
devices, but also by trying to control the quenching. And he claims he
has narrower superregen receivers.

I never saw the article, I did see some standalone superregen receivers he
talked about. But, the original article got flack "why dredge up the
superregen when nobody uses it and it's obsolete?". Precisely because in
going back to the beginning, he regenerates those beginnnings, so the
knowledge of the early days is out in present view for anyone interested
to pursue further.

He did the same with a similar article later in Communications QUarterly
about the regnerative receiver.

Knowledge gets lost. An idea becomes commonplace so the details are
boiled down, leaving so much that was discovered in the early days, or at
least discussed in the early days, missing from current books and
magazines. Only when you look at something as originally portrayed can
you give it a boost in current technology and maybe leap ahead.

Ladder filters were around for a long time before they made it big.

People spent endless time trying to improve direct conversion receivers
without really looking in the right direction. Yet, I can point to a 1974
article about proper termination of a mixer in a VHF converter that is
exactly what was done a decade or so later to direct conversion receiver
mixers that really seemed to fix some of the problems.

Or, that mid-1980s direct conversion receiver caused a resurgence in
interest in the phasing method, nothing really new initially but times had
changed, some of the problems lessened by newer technology, and then later
suddenly a realization that one could intersect this with digital signal
processing.

But if you don't fully understand the basics (in part because those basics
are assumed rather than stated), you can't make a leap forward, moving
something from the past into the future by applying the new to the old.

These two transistor challenges are like that, cause people to think and
maybe learn something or create something new.

Michael

The "Two Transistor challenge" - taking things a bit too far?
 

"Michael Black" wrote in message
news:alpine.LNX.2.02.1402181412260.14557@darkstar. example.org...
But the constraint causes some to think.

An analogy is the superregenerative receiver. Forty years ago it as still
used in some places, but the various handbooks would give a very brief
description and basically treat it like a black box. It was like broken
telephone, the basics lost to history, "everyone" knowing the basics but
not really.

Both regenerative ans superregenerative RXs are featuring in the approach
known as a "supergainer", as, indeed, are direct conversion RXs, in all
cases, repalcing the IF and product detector stages following the Xtal
filter.


I didn't pursue it, but I realized that if you fiddle with such things,
you might end up with a narrower bandwidth superregen receiver.

If as above, then the governing BW is determined by the Xtal filter


Knowledge gets lost

An outstanding example of that is over here with the floods on the
Somerset levels, where dredging and pumping knowledge going
back to the 1700s (including involvement by, "The Dutchman")
has been lost in 80 years of changes and mergings in the various
drainage and water catchment authorities and we are now left
with the Environment Agency run by dogooders who though it
to be more appropriate to blow up the pumping stations, omit
the dredging, and devote the money and effort into making
nature reserves!

. An idea becomes commonplace so the details are boiled down, leaving so
much that was discovered in the early days, or at least discussed in the
early days, missing from current books and magazines.

I found this out over 10 years ago, when I wanted to find out how
a railway steam locomotive REALLY worked,
and had to go back
to books from the 1920s and 1930s when it was THE technology of the
day, and every boys' book described it in some detail.

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 18:33, Michael Black wrote:
On Tue, 18 Feb 2014, Brian Reay wrote:


The Sinclair was also RPN, as were the early Texas calculators I
think. Sinclair lacked the "Enter" button, using the + key its place.

I don't remember the TI calculators having RPN. I remember them as
being more reasonably priced versions of "electronic slide rules", which
was what they called them originally.

I recall the "electronic slide rule" jargon being used. I could be wrong
about the early TIs. I have an American friend who may know, he was a TI
user as I recall.


It's odd to look back now. I think that HP35 that a fellow ham got in
1972 or maybe 73 (a group buy at his place of employment) was the first
pocket calculator I ever saw close up. So many functions, yet so few
compared to what you can get on a $10 calculator today

I don't know what the first TI scientific calculator cost, but it was
less than the HP by far, and soon you could get one in the $50 range,
and then $30 range, which is when I got my TI-30.

I invested in a TI50 to start my Uni. course, it cost around £50 as I
recall, The next model up, with the card reader, was about double that.

The Japanese were just bringing cheaper calculators into the market at
the time- Commodore in particular. This was 1979/80.

Such a big change, a sudden surge in articles in the ham magazines
showing equations, suddenly you could actually work things out without
needing much math skill.


As a Mathematician, I would argue that calculators enter the game when
it has become arithmetic ;-) (However, as few know the difference I tend
to 'go with the flow' before someone refers to one of my widely
circulated articles.)

I think it was the National scientific calculator that had RPN, coming
later but also being quite cheap.

I don't recall those. The only calculators I recall using RPN are HP,
Sinclair, and (I thought) some early TI ones- although that may be an error.


For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first
calculator to offer true algebraic entry (ie following BODMAS/BIDMAS
convention) was Texas. Even today some cheap calculators don't follow
the convention. One of the many things I warn pupils of when I teach
calculator use.

That's interesting. I look at the cheapest of the cheap scientific
calculators, and the functions are at least the same as my TI-30 from
about 1977. I assume the calculators have gotten so cheap because the
work was done long ago, buying old technology to implement cheap today.

It is common to see 'clones' of quite respectable calculators which
function as the originals and only differ in their name and case colour.
Probably common parts.

The ones I was referring tend to be simple 4 function (or perhaps 4
function and a couple of others eg % Mem) which real 'cheapies'.

Perhaps it is just old designs no one has corrected.

--
73
Brian
G8OSN/W8OSN
www.g8osn.net

The "Two Transistor challenge" - taking things a bit too far?
 

"Michael Black" wrote in message
news:alpine.LNX.2.02.1402181359580.14557@darkstar. example.org...
On Tue, 18 Feb 2014, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or "build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to you?) can
be operated with only 12V on the anode.

The "Two Transistor challenge" - taking things a bit too far?
 

In message , Brian Reay writes
On 18/02/14 15:21, Phi wrote:
I paid about £180 for an HP35 in 1973, this calculator used reverse
polish notation (no equals key).
That seems cheap for an HP at the time. As I recall, that was the
launch price of the Sinclair, although it soon dropped.

The Sinclair was also RPN, as were the early Texas calculators I think.
Sinclair lacked the "Enter" button, using the + key its place.

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first
calculator to offer true algebraic entry (ie following BODMAS/BIDMAS
convention) was Texas. Even today some cheap calculators don't follow
the convention. One of the many things I warn pupils of when I teach
calculator use.


I used a National Semiconductor 4640 RPN calculator for about 30 years.
So much so that I can't use a "normal" calculator. I've still got it but
it needs the charger socket and the batteries replaced.

RPN can't be beat for long chain calculations.

My Window desktop calculator is RPN

http://excalibur.en.softonic.com/

Brian
--
Brian Howie

The "Two Transistor challenge" - taking things a bit too far?
 

In message , gareth
writes
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.

Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?

Not carping, just curious.

-----ooooo-----

BUT BUT BUT, this one has no switching, apart from the Morse Key! ...


http://www.vk2zay.net/article/file/1138

How does the receiver work ?

DIJ
--
Brian Howie

The "Two Transistor challenge" - taking things a bit too far?
 

"Brian Howie" wrote in message
...
In message , gareth
writes

http://www.vk2zay.net/article/file/1138

How does the receiver work ?

My assumption (YMMV) is that the key increases the power
from the oscillator on TX (and thus will cause a tracer on RX
and on QSK operation), the FET being used to switch RIT
in and out.

The "Two Transistor challenge" - taking things a bit too far?
 

On 2/18/2014 3:00 PM, gareth wrote:
"Michael Black" wrote in message
news:alpine.LNX.2.02.1402181359580.14557@darkstar. example.org...
On Tue, 18 Feb 2014, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or "build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to you?) can
be operated with only 12V on the anode.



I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At first
glance it sounds crazy - but it made for a very simple and efficient way
to couple the output of the magnetron to the waveguide.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

The "Two Transistor challenge" - taking things a bit too far?
 

"Jerry Stuckle" wrote in message
...

I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)


As in, "Flying by aeroplanes is perfectly safe, it's only when you crash
that it becomes dangerous"? :-)

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 20:21, Brian Howie wrote:
In message , Brian Reay writes

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first
calculator to offer true algebraic entry (ie following BODMAS/BIDMAS
convention) was Texas. Even today some cheap calculators don't follow
the convention. One of the many things I warn pupils of when I teach
calculator use.


I used a National Semiconductor 4640 RPN calculator for about 30 years.
So much so that I can't use a "normal" calculator. I've still got it but
it needs the charger socket and the batteries replaced.

RPN can't be beat for long chain calculations.


True.

Either way, RPN as the user interface has become a 'niche' market. Do HP
still offer RPN?

The "Two Transistor challenge" - taking things a bit too far?
 

On 18/02/14 20:31, Jerry Stuckle wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost
nearly
a week's wages for the average working man, and so it was good
economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of
switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or
"build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to
you?) can
be operated with only 12V on the anode.

No unusual at all.

Not only were a number of valves for the car radio (and possibly other)
markets available, I recall designs which use 'ordinary' valves with
6.3V AC heaters and a voltage doubler and rectifier to provide the "HT".
I recall a one valve design in Radio Constructor, which I build. It was
the 'cover article'. The design called for an Eddystone Box, far too
expensive, so I used a tin box from some short bread.


I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At first
glance it sounds crazy - but it made for a very simple and efficient way
to couple the output of the magnetron to the waveguide.


No reason why it shouldn't be done. I can imagine some of the more
"technically challenged" struggling with it but there are always those
who insist that all who have been designing kit for years have got it
wrong.

The "Two Transistor challenge" - taking things a bit too far?
 

In article , Brian Reay
wrote:

On 18/02/14 20:31, Jerry Stuckle wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost
nearly
a week's wages for the average working man, and so it was good
economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of
switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or
"build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to
you?) can
be operated with only 12V on the anode.

No unusual at all.

Not only were a number of valves for the car radio (and possibly other)
markets available, I recall designs which use 'ordinary' valves with
6.3V AC heaters and a voltage doubler and rectifier to provide the "HT".
I recall a one valve design in Radio Constructor, which I build. It was
the 'cover article'. The design called for an Eddystone Box, far too
expensive, so I used a tin box from some short bread.


I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At first
glance it sounds crazy - but it made for a very simple and efficient way
to couple the output of the magnetron to the waveguide.


No reason why it shouldn't be done. I can imagine some of the more
"technically challenged" struggling with it but there are always those
who insist that all who have been designing kit for years have got it
wrong.

Indeed it is rather similar to what was done with TV and monitor CRTs,
to interface the screen with people's living rooms at an appropriate
potential!

--

Percy Picacity

The "Two Transistor challenge" - taking things a bit too far?
 

On 2/18/2014 4:29 PM, Percy Picacity wrote:
In article , Brian Reay
wrote:

On 18/02/14 20:31, Jerry Stuckle wrote:

There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost
nearly
a week's wages for the average working man, and so it was good
economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of
switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or
"build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to
you?) can
be operated with only 12V on the anode.

No unusual at all.

Not only were a number of valves for the car radio (and possibly other)
markets available, I recall designs which use 'ordinary' valves with
6.3V AC heaters and a voltage doubler and rectifier to provide the "HT".
I recall a one valve design in Radio Constructor, which I build. It was
the 'cover article'. The design called for an Eddystone Box, far too
expensive, so I used a tin box from some short bread.


I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At first
glance it sounds crazy - but it made for a very simple and efficient way
to couple the output of the magnetron to the waveguide.


No reason why it shouldn't be done. I can imagine some of the more
"technically challenged" struggling with it but there are always those
who insist that all who have been designing kit for years have got it
wrong.

Indeed it is rather similar to what was done with TV and monitor CRTs,
to interface the screen with people's living rooms at an appropriate
potential!


Hmmm, they must have done it differently over there. I've been bitten a
number of times by not being careful around the anode lead on a CRT.
The cathode is nearer ground potential because it's exposed on the back
of the tube.

You'd think being bitten by 25KV the first time would teach me a lesson.
But some people never learn :)

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014, gareth wrote:

"Michael Black" wrote in message
news:alpine.LNX.2.02.1402181359580.14557@darkstar. example.org...
On Tue, 18 Feb 2014, gareth wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost nearly
a week's wages for the average working man, and so it was good economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the tens
of MegaHertz are now ten-a-penny, so what is achieved by competitions
such as the "Two Transistor Challenge" where it is the costs of switching
(manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they were
about "build a whole receiver using the same transistor type", or "build a
receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to you?) can
be operated with only 12V on the anode.

That's not new. There were some articles in the various hobby electronic
magazines in the fifties and sixties about running them at low voltage,
"starved circuits".

Of course, that was about the time when new tubes came along that could be
run off low plate voltage, a sort of last gasp before transistors took
over. You'd see such tubes in car radios in a very specific time span,
tubes for the RF stages, maybe in the IF but those might have been
transistors, and then the audio stage. That period when tubes weren't yet
really good at radio frequencies.

Or the COllins R392, that used 28v plate voltage.

The best "starved circuit" was an article by John W. Campbell (of science
fiction fame) in CQ in the late fifties. It was about running a CRT at
relatively low voltage in an oscilliscope. It drove up sensitivity so you
could do away with amplification for many purposes (and thus the scope was
broadband) but you lost deflection and I think brightness. The scheme
came out of Bell Labs, he mentioned some specially built CRTs for the
purpose that included magnifiers.

Michael

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014, Brian Reay wrote:

On 18/02/14 20:21, Brian Howie wrote:
In message , Brian Reay writes

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first
calculator to offer true algebraic entry (ie following BODMAS/BIDMAS
convention) was Texas. Even today some cheap calculators don't follow
the convention. One of the many things I warn pupils of when I teach
calculator use.


I used a National Semiconductor 4640 RPN calculator for about 30 years.
So much so that I can't use a "normal" calculator. I've still got it but
it needs the charger socket and the batteries replaced.

RPN can't be beat for long chain calculations.


True.

Either way, RPN as the user interface has become a 'niche' market. Do HP
still offer RPN?

Yes, but they are still higher priced, so you'd be going out of your way
to buy one. I seem to recall seeing one in a flyer that could be switched
between RPN and "normal", which I suppose has advantages. But, if you have
both, I suspect the pull is towards "normal".

I have a minor collection of early scientific pocket calculators. Some
TI, including the one that could be hooked to a printer (and the printer).
And some HP, but the batteries don't keep a charge.

I should get one of the HP going, not only are they RPN, but they have LED
readouts, astonish people with the ancient technology. Just as soon as I
figure out how to get that battery clip back on my TI LED watch from 1977.

Michael

The "Two Transistor challenge" - taking things a bit too far?
 

Michael Black wrote:

What I find intriguing is the realisation that valves ("tubes" to you?) can
be operated with only 12V on the anode.

That's not new. There were some articles in the various hobby electronic
magazines in the fifties and sixties about running them at low voltage, "starved circuits".

Of course, that was about the time when new tubes came along that could
be run off low plate voltage, a sort of last gasp before transistors took
over. You'd see such tubes in car radios in a very specific time span,
tubes for the RF stages, maybe in the IF but those might have been
transistors, and then the audio stage. That period when tubes weren't
yet really good at radio frequencies.

Or the COllins R392, that used 28v plate voltage.

The best "starved circuit" was an article by John W. Campbell (of science
fiction fame) in CQ in the late fifties. It was about running a CRT at
relatively low voltage in an oscilliscope. It drove up sensitivity so
you could do away with amplification for many purposes (and thus the
scope was broadband) but you lost deflection and I think brightness. The
scheme came out of Bell Labs, he mentioned some specially built CRTs for
the purpose that included magnifiers.


Indeed Michael.

Anyone active on the home brew scene must have seen projects using valves
with low HT supplies, they were quite common and popular in the UK. I
expect someone with access to back issues of Radio Constructor could turn
up a couple per volume. RC was a popular, if slightly old style, magazine
which seemed to include more valve projects than the other magazines of the
day. Sadly, it is no more.

I think some valves were developed for use in 'Walkie Talkies' which were
baseless (ie were wire into circuit via flying leads not plugged into
sockets) and were designed to operate with a low HT.

There were also valves for hearing aids which were, I suspect, similar.

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014 15:31:18 -0500, Jerry Stuckle wrote:

I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At first
glance it sounds crazy - but it made for a very simple and efficient way
to couple the output of the magnetron to the waveguide.

Microwave ovens still do that. At least, my Toshiba does.

--
Jim Mueller

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.

The "Two Transistor challenge" - taking things a bit too far?
 

Michael Black wrote:
On Tue, 18 Feb 2014, Brian Reay wrote:

Either way, RPN as the user interface has become a 'niche' market. Do HP
still offer RPN?

Yes, but they are still higher priced, so you'd be going out of your way
to buy one. I seem to recall seeing one in a flyer that could be
switched between RPN and "normal", which I suppose has advantages. But,
if you have both, I suspect the pull is towards "normal".

HP calculators were always the most expensive, at least in the UK.

I think Casio probably have the bulk market sewn up. Anything you can't do
with one of their £8 scientifics (other than perhaps function plotting) is
probably something to do on a package.

I have a minor collection of early scientific pocket calculators. Some
TI, including the one that could be hooked to a printer (and the printer).
And some HP, but the batteries don't keep a charge.

I should get one of the HP going, not only are they RPN, but they have
LED readouts, astonish people with the ancient technology. Just as soon
as I figure out how to get that battery clip back on my TI LED watch from 1977.

I suppose I have an informal collection as I probably have all of my old
calculators.
I never reduced myself to a digital watch.

The "Two Transistor challenge" - taking things a bit too far?
 

On Tue, 18 Feb 2014 20:00:32 +0000, gareth wrote:

What I find intriguing is the realisation that valves ("tubes" to you?)
can be operated with only 12V on the anode.

You're thinking of the American way to do things. European car
manufacturers were slow to change to 12V electrical systems, so they used
tubes that worked with 6V on the plate. An example is the EF98, http://
http://www.mif.pg.gda.pl/homepages/f...030/e/EF98.pdf.

I've seen data sheets with even lower voltage ratings but I can't put my
finger on one right now.

--
Jim Mueller

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.

The "Two Transistor challenge" - taking things a bit too far?
 

"Jerry Stuckle" wrote in message
...
On 2/18/2014 4:29 PM, Percy Picacity wrote:
In article , Brian Reay wrote:
On 18/02/14 20:31, Jerry Stuckle wrote:
There was a time, back inthe 1920s and 1930s, that any active device
(valves in them thar days, tubes for the leftpondians) would cost
nearly
a week's wages for the average working man, and so it was good
economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the
tens
of MegaHertz are now ten-a-penny, so what is achieved by
competitions
such as the "Two Transistor Challenge" where it is the costs of
switching (manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes they
were
about "build a whole receiver using the same transistor type", or
"build a receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to
you?) can be operated with only 12V on the anode.

No unusual at all.

Not only were a number of valves for the car radio (and possibly other)
markets available, I recall designs which use 'ordinary' valves with
6.3V AC heaters and a voltage doubler and rectifier to provide the "HT".
I recall a one valve design in Radio Constructor, which I build. It was
the 'cover article'. The design called for an Eddystone Box, far too
expensive, so I used a tin box from some short bread.

I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At
first
glance it sounds crazy - but it made for a very simple and efficient
way
to couple the output of the magnetron to the waveguide.

No reason why it shouldn't be done. I can imagine some of the more
"technically challenged" struggling with it but there are always those
who insist that all who have been designing kit for years have got it
wrong.

Indeed it is rather similar to what was done with TV and monitor CRTs,
to interface the screen with people's living rooms at an appropriate
potential!

Hmmm, they must have done it differently over there. I've been bitten a
number of times by not being careful around the anode lead on a CRT. The
cathode is nearer ground potential because it's exposed on the back of the
tube.

You'd think being bitten by 25KV the first time would teach me a lesson.
But some people never learn :)

I was a 1960s TV engineer in the UK. 15kV or so on the CRT anode was normal.
The viewer was protected by a thick layer of glass that also formed an
implosion guard. Colour CRTs had around 25kV on the anode, and in early
models with anode currents of 1mA or so the line output stage was lead
shielded to reduce X-radiation. Happy days.
--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.co.uk

The "Two Transistor challenge" - taking things a bit too far?
 

On 2/18/2014 7:06 PM, FranK Turner-Smith G3VKI wrote:
"Jerry Stuckle" wrote in message
...
On 2/18/2014 4:29 PM, Percy Picacity wrote:
In article , Brian Reay wrote:
On 18/02/14 20:31, Jerry Stuckle wrote:
There was a time, back inthe 1920s and 1930s, that any active
device
(valves in them thar days, tubes for the leftpondians) would
cost nearly
a week's wages for the average working man, and so it was good
economical
sense to try and use it as many ways as possible simultaneously.
Times have changes, and active devices with performance into the
tens
of MegaHertz are now ten-a-penny, so what is achieved by
competitions
such as the "Two Transistor Challenge" where it is the costs of
switching (manual, relays) which would be the major outlay?
Not carping, just curious.

There have always been "contests" like that, though sometimes
they were
about "build a whole receiver using the same transistor type", or
"build a receiver without any ICs" after ICs had come around.

What I find intriguing is the realisation that valves ("tubes" to
you?) can be operated with only 12V on the anode.

No unusual at all.

Not only were a number of valves for the car radio (and possibly other)
markets available, I recall designs which use 'ordinary' valves with
6.3V AC heaters and a voltage doubler and rectifier to provide the
"HT".
I recall a one valve design in Radio Constructor, which I build. It was
the 'cover article'. The design called for an Eddystone Box, far too
expensive, so I used a tin box from some short bread.

I remember back in the 70's we had radar sets with ZERO volts on the
magnetron's anode (DC ground). Of course, there was -3KV or so on the
cathode :)

I haven't done anything with radar in well over 30 years, so I don't
know if they still do it or not. But I wouldn't be surprised. At
first
glance it sounds crazy - but it made for a very simple and
efficient way
to couple the output of the magnetron to the waveguide.

No reason why it shouldn't be done. I can imagine some of the more
"technically challenged" struggling with it but there are always those
who insist that all who have been designing kit for years have got it
wrong.

Indeed it is rather similar to what was done with TV and monitor CRTs,
to interface the screen with people's living rooms at an appropriate
potential!

Hmmm, they must have done it differently over there. I've been bitten
a number of times by not being careful around the anode lead on a CRT.
The cathode is nearer ground potential because it's exposed on the
back of the tube.

You'd think being bitten by 25KV the first time would teach me a
lesson. But some people never learn :)

I was a 1960s TV engineer in the UK. 15kV or so on the CRT anode was
normal. The viewer was protected by a thick layer of glass that also
formed an implosion guard. Colour CRTs had around 25kV on the anode, and
in early models with anode currents of 1mA or so the line output stage
was lead shielded to reduce X-radiation. Happy days.

Yup, same here. Except when you jig the chassis up for testing, the
anode lead is basically hanging in the air. Also, the CRT makes a great
capacitor - if you don't discharge it enough times before disconnecting
the anode lead, it can still set you back on your backside :)

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================