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/

"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.

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

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

"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.

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

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

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.

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

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

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