"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

The "Guru of Advanced Thinking About Advanced Radios" of Rockwell-Collins
gave an interesting talk at the Cedar Rapids Central States Conference a few
years ago.

One point he made was that (even) Collins had to buy enough chips for their
complete expected production run, and eventual spare parts, right at the
design-in stage. Otherwise either -

1) The part would be unavailable before the production run was completed, or
2) A part with the same number would be available, but it would be enough
different that it would either not work or would degrade performance.

Even the Big Boys have parts problems.

73 de bob w3otc

The "Guru of Advanced Thinking About Advanced Radios" of Rockwell-Collins
gave an interesting talk at the Cedar Rapids Central States Conference a few
years ago.

One point he made was that (even) Collins had to buy enough chips for their
complete expected production run, and eventual spare parts, right at the
design-in stage. Otherwise either -

1) The part would be unavailable before the production run was completed, or
2) A part with the same number would be available, but it would be enough
different that it would either not work or would degrade performance.

Even the Big Boys have parts problems.

73 de bob w3otc

John Woodgate ) writes:

They are not so easy to obtain in small quantities. They were aimed at
high-volume consumer product manufacturers.

And that leads to another reason why they aren't used.

They are intended for very specific use, in something that will be
built in large quantities with the same design.

But what works for an AM/FM broadcast radio may not be best for some other
use.

I remember when RCA came out with the CA3088 AM receiver on an IC back
in 1971. QST ran an article about it, hinting at big things, yet also
pointint out deficiences. It was intended for a 455KHz IF, so you'd
be stuck with image problems as you started using the IC in the shortwave
range. I think there might have been limitations on the IF strip so
you couldn't run it at a higher frequency. The mixer was a single
transistor, and if I'm remembering, it was used as the local oscillator
also. Maybe okay in a generic broadcast receiver, but not great for
higher frequencies or where better performance was desired. The detector
was built in, and of course, it was AM only. There was no easy way to
bypass that detector, at a time when few hams would want to build an
AM only receiver.

In trying to fit a very specific application, it was lousy for more
general use.

Since then, there have been plenty of AM and AM/FM radios in an IC.
Some have worked better than others for other uses (who can forget
Ralph Burhan describing Loran C receivers using them?), mainly because
they were less integrated, or at least had pinouts in the right places.

Less grandiose ICs work better. The Motorola FM IF strips were at
first just the IF strip, and since they were intended for narrow band
FM, they were better suited for use in amateur applications. Even the
later variants, that added the front end, had the advantage that the
input and outputs were available off-IC so one could fiddle with things
where needed.

And then when you get to the point where an IC is simply taking care of
one stage, such as a mixer, or an IF amplifier, there is infinitely
more use of them in various designs. Of course, they are less useful
to mass marketers, because they take up more space and give more performance
than needed for AM/FM broadcast, so there is a limited market for them.

Michael VE2BVW

John Woodgate ) writes:

They are not so easy to obtain in small quantities. They were aimed at
high-volume consumer product manufacturers.

And that leads to another reason why they aren't used.

They are intended for very specific use, in something that will be
built in large quantities with the same design.

But what works for an AM/FM broadcast radio may not be best for some other
use.

I remember when RCA came out with the CA3088 AM receiver on an IC back
in 1971. QST ran an article about it, hinting at big things, yet also
pointint out deficiences. It was intended for a 455KHz IF, so you'd
be stuck with image problems as you started using the IC in the shortwave
range. I think there might have been limitations on the IF strip so
you couldn't run it at a higher frequency. The mixer was a single
transistor, and if I'm remembering, it was used as the local oscillator
also. Maybe okay in a generic broadcast receiver, but not great for
higher frequencies or where better performance was desired. The detector
was built in, and of course, it was AM only. There was no easy way to
bypass that detector, at a time when few hams would want to build an
AM only receiver.

In trying to fit a very specific application, it was lousy for more
general use.

Since then, there have been plenty of AM and AM/FM radios in an IC.
Some have worked better than others for other uses (who can forget
Ralph Burhan describing Loran C receivers using them?), mainly because
they were less integrated, or at least had pinouts in the right places.

Less grandiose ICs work better. The Motorola FM IF strips were at
first just the IF strip, and since they were intended for narrow band
FM, they were better suited for use in amateur applications. Even the
later variants, that added the front end, had the advantage that the
input and outputs were available off-IC so one could fiddle with things
where needed.

And then when you get to the point where an IC is simply taking care of
one stage, such as a mixer, or an IF amplifier, there is infinitely
more use of them in various designs. Of course, they are less useful
to mass marketers, because they take up more space and give more performance
than needed for AM/FM broadcast, so there is a limited market for them.

Michael VE2BVW

On 28 Dec 2003 21:06:32 GMT, donutbandit wrote:

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

Realistically, now-a-days, IC's are mostly "systems-on-a-chip", and
are usually custom-designed for a specific application; jelly-bean
analog chips (except perhaps OpAmps and linear voltage regulators) are
gradually fading from the scene.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On 28 Dec 2003 21:06:32 GMT, donutbandit wrote:

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

Realistically, now-a-days, IC's are mostly "systems-on-a-chip", and
are usually custom-designed for a specific application; jelly-bean
analog chips (except perhaps OpAmps and linear voltage regulators) are
gradually fading from the scene.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"Richard" wrote in message
...
Although I have been interested an amateur radio for about 30 years, I've
never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these
three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

Okay, from what folks have said, I gather that as time has moved on, ICs
relevant to construction of AM/FM radios have tended, more and more, not to
appeal to homebrewers because their specs are seen as not being that good,
and they have lost much of their flexibility/applicability - due to current
design/production/marketing trends.

"Richard" wrote in message
...
Although I have been interested an amateur radio for about 30 years, I've
never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these
three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

Okay, from what folks have said, I gather that as time has moved on, ICs
relevant to construction of AM/FM radios have tended, more and more, not to
appeal to homebrewers because their specs are seen as not being that good,
and they have lost much of their flexibility/applicability - due to current
design/production/marketing trends.

The "Guru of Advanced Thinking About Advanced Radios" of Rockwell-Collins
gave an interesting talk .... One point he made was that (even) Collins
had to buy enough chips for their complete expected production run, and
eventual spare parts, right at the design-in stage. Otherwise either -
1) The part would be unavailable before the production run was completed, or
2) A part with the same number would be available, but it would be enough
different that it would either not work or would degrade performance.

How true, how true!

I worked at Fairchild Semiconductor's Research and Development Lab from
1967-71, where we designed and built SYMBOL, a computer with a radically-
different architecture (OS, compiler, editor, etc., were all in HARDware
[and I do NOT mean ROM'd firmware; just lots and lots of gates and flip-
flops]). When we began actual construction, we tried to stockpile --
from Fairchild Semi's production line -- enough of every IC type we
thought we'd need, but we ran short by about 100 flipflops, so we got
three more "tubes" from Production.

It is safe to say that those hundred FF's caused us MORE TROUBLE than
the other 4,000 FF's: after two years of production, those later FF's
had so much FASTER "setup" time that our design rules failed when we
put those FF's and earlier ones on the same printed circuit board!

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)