In article , Bill wrote:

Henry Kolesnik wrote:

You got to know when to hold them and when to fold them. I've folded, ...


I wish that Jon could actually experience this and see that his
thinking 'outside the box' isn't going to be an automatic revelation
that 80 years of radio has simply overlooked.
Thirty minutes on the bench could save 'light-hours' of ramblings.

I don't follow your reasoning on this, what is Jon going to learn in
"Thirty minutes on the bench"? I would venture next to nothing? Thirty
weeks on the bench might be more like it, and even then there won't be
time to explore all avenues. As far as 80 years of radio go, Jon's
constraints are different than might have existed when tube radios were a
mass application, he may be able to make different tradeoffs than were
practical then.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

John Byrns wrote:

In article , Bill wrote:


Henry Kolesnik wrote:


You got to know when to hold them and when to fold them. I've folded, ...


I wish that Jon could actually experience this and see that his
thinking 'outside the box' isn't going to be an automatic revelation
that 80 years of radio has simply overlooked.
Thirty minutes on the bench could save 'light-hours' of ramblings.


I don't follow your reasoning on this, what is Jon going to learn in
"Thirty minutes on the bench"? I would venture next to nothing? Thirty
weeks on the bench might be more like it, and even then there won't be
time to explore all avenues. As far as 80 years of radio go, Jon's
constraints are different than might have existed when tube radios were a
mass application, he may be able to make different tradeoffs than were
practical then.


Regards,

John Byrns

Don't be silly just for the sake of being a 'devils advocate', John. If
Jon can achieve his plug-in TRF boards with any semblance of a $1.95
flea-market AA5 selectivity then I would be pleased.
What I haven't heard from Jon beyond musings that suggest that 80 years
of radio have missed his point is a bit of actual soldering on the bench
to make up these mythical circuits. At least Mr. Windbag No-Snip
Patrick appears to have walked the walk before but Jon is reluctant to
take your, my, Patrick's or anybody else's advice about how to meet his
goal...and at this stage seems to be fishing without good bait for
somebody who is in agreement.
Jon's "tradeoffs" are ultimately the clue. Once presented with the
facts and a million lines of newsgroup advice its time to go to the
bench and actually MAKE one of these panacea BCB BP filters. I strongly
suspect that this effort would clue Jon into some of the realities of
how things work and no amount of chatter from us could be of further
benefit other than our own wing flapping.

-Bill M

snip,

In today's world there *is no* market for a tubed AM radio, and a
kit would sell in such tiny numbers, that I was led to think there
is no market, and I would never profit.

I agree with you the market is small, and not profitable. But people
do things for reasons beyond just monetary profit.

Whether anyone else would make a profit is a moot point. They
wouldn't need my design though. And if they did use my design,
they'd still have to work hard at making a prototype free of bugs on
their own.

O.k. Thanks for clarifying.

Have you ever run a business?

laugh/

I am very aware of business, thank you, having co-founded several
startup companies and non-profit ventures the last few years, plus
three sole proprieterships, one of which is still active in the ebook
publishing industry.

Try running a business which pays the bills and puts food on the table,
and which makes you attractive to women, (or a man,whatever is your bent)

Try doing it without capital.

This makes you think twice about time wasting.



I already have described my radio design in full in numerous
postings.

O.k., I'll dig through Google and see what you've said on your tuner.
Love to hear it. Have you made any recordings of received stations?

Nope. I don't believe recording and replaying it
would convey the sound properly.

AM is not regarded as hi-fi by all my friends, its just a tolerable
midi fi medium, great for replays of the Goon show, and forms of music
which don't need a hi-fi medium, like most pop and folk music.



The living better get busy if they want to build a decent AM tuner,
and stop dithering about, if they want one by then end of next
month!

Well, maybe I seem impatient, but... smile/

You seem to have all the time to discuss it all, and make nothing,
like the original armchair solderer, and that's hardly impatient....



And about the so-called "kit", I myself know that it is not a money
maker -- I'm sure you will agree with that.

Well then just design and build your own.

I just might, or as part of a team of like-minded individuals.

When you have tested your first prototype, we might compare notes,
but why before? You could proove you mean to contribute to the
exercize by doing a lot on your own.

snip,

switching 120 sets of LCs to allow only 2 RF amp tubes to be used

presents huge wiring problems, and is, unless *you* prove otherwise,
a complete waste of time.

Agreed about the huge wiring problems, and agreed about having to
prove it, or someone having to prove it. One reason for mentioning it
as I have is to engage the collective creativity of the many people
here in the newsgroups -- to think positive, and to think of a clever
way to make it work. Or, it may catalyze some other idea leading to
some improvement somewhere.

There is a point where *you* have to un-tether yourself from the crowd
and do your own experiments, and make conclusions of your own.
In the absense of anyone else volunteering to do the donkey work
of R&Ding a test circuit, there is only yourself who is left to
realize this dreamy obsession of yours.


snip


Good luck,

Patrick Turner.

Frank Dresser wrote:

"Jon Noring" wrote in message
...

[snip]


This is functionally *equivalent* to having 120+ independent and
optimized TRF circuits (one for each channel) -- that's what I
intended to say.

[snip]

How would each of the 120+ independent TRF circuits get optimized? With a
scope and a sweep and marker generator? Any one of the channels might be
easy enough, but 120 is asking alot. Even moreso, with the complication of
Wide/DX option. And it's not like there a wonderful victory after the
struggle. Wideband AM sometimes sounds very good, and sometimes not.

Have you heard wideband AM?

I have, and its very much better than the low fi crap coming from most
crummy receivers.
Its not up to FM standards, but its very listenable for news, pop,
rythym and blues, folk, interviews, etc.

AM DX is a total waste of time for me.

Patrick Turner.



Frank Dresser

John Byrns wrote:

In article , Bill wrote:

Henry Kolesnik wrote:

You got to know when to hold them and when to fold them. I've folded, ...


I wish that Jon could actually experience this and see that his
thinking 'outside the box' isn't going to be an automatic revelation
that 80 years of radio has simply overlooked.
Thirty minutes on the bench could save 'light-hours' of ramblings.

I don't follow your reasoning on this, what is Jon going to learn in
"Thirty minutes on the bench"? I would venture next to nothing? Thirty
weeks on the bench might be more like it, and even then there won't be
time to explore all avenues. As far as 80 years of radio go, Jon's
constraints are different than might have existed when tube radios were a
mass application, he may be able to make different tradeoffs than were
practical then.


It took years' full of late nights to fully understand tube audio amps,
and months of work to re-design my ex Trio AM/FM receiver,
and then another month or two full time to build decent AM only radio, from
antenna to speaker.

30 minutes is nothing.

Patrick Turner.

In article , Patrick Turner
wrote:

John Byrns wrote:

In article , Bill wrote:

Henry Kolesnik wrote:

You got to know when to hold them and when to fold them. I've
folded, ...


I wish that Jon could actually experience this and see that his
thinking 'outside the box' isn't going to be an automatic revelation
that 80 years of radio has simply overlooked.
Thirty minutes on the bench could save 'light-hours' of ramblings.

I don't follow your reasoning on this, what is Jon going to learn in
"Thirty minutes on the bench"? I would venture next to nothing? Thirty
weeks on the bench might be more like it, and even then there won't be
time to explore all avenues. As far as 80 years of radio go, Jon's
constraints are different than might have existed when tube radios were a
mass application, he may be able to make different tradeoffs than were
practical then.


It took years' full of late nights to fully understand tube audio amps,
and months of work to re-design my ex Trio AM/FM receiver,
and then another month or two full time to build decent AM only radio, from
antenna to speaker.

30 minutes is nothing.

Earth to Patrick, that was exactly my point!


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

In article , Bill wrote:

John Byrns wrote:

In article , Bill wrote:

I wish that Jon could actually experience this and see that his
thinking 'outside the box' isn't going to be an automatic revelation
that 80 years of radio has simply overlooked.
Thirty minutes on the bench could save 'light-hours' of ramblings.

I don't follow your reasoning on this, what is Jon going to learn in
"Thirty minutes on the bench"? I would venture next to nothing? Thirty
weeks on the bench might be more like it, and even then there won't be
time to explore all avenues. As far as 80 years of radio go, Jon's
constraints are different than might have existed when tube radios were a
mass application, he may be able to make different tradeoffs than were
practical then.

Don't be silly just for the sake of being a 'devils advocate', John.

I'm not being the "devils advocate", I'm just saying that the problem is
more complex than you are making it out to be and a mere thirty minutes on
the bench is not going to resolve much.

If Jon can achieve his plug-in TRF boards with any semblance of a $1.95
flea-market AA5 selectivity then I would be pleased.

These threads have grown to a point where I have not been able to follow
them all. I have been following most of the discussions like the
superhet, TRF, and segmentation of the MW band posts, but I have not yet
read the ones related to channel based receivers, which I hope to read
through as time permits. Perhaps that explains my confusion with relation
to the "thirty minutes on the bench", if you are referring to a
channelized TRF approach to receive all 117 or so MW channels, then I
would think you wouldn't need to go to the bench at all to realize it
isn't practical. A smaller number of channels, say half a dozen or so
might be practical.

I think the best approach for the all out audiophile would be the one
suggested by Randy, or was it Sherry? Gutting out a National NC-100, and
rebuilding the band selection assembly with 5 sets of 3 optimized band
pass filters to segment the MW band into 5 parts.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

John Byrns wrote:


I'm not being the "devils advocate", I'm just saying that the problem is
more complex than you are making it out to be and a mere thirty minutes on
the bench is not going to resolve much.

The suggestion was not that the issue would be resolved in 30 minutes
but actually sitting down with a few components to make a plug-in BPF
would be very enlightening.

-BM

[Comment and question on NC-100 toward the end]

John Byrns wrote:

...if you are referring to a channelized TRF approach to receive all
117 or so MW channels, then I would think you wouldn't need to go to
the bench at all to realize it isn't practical. A smaller number of
channels, say half a dozen or so might be practical.

I think 15 or so channel slots will be fairly easy to implement, and
nearly all metropolitan areas I know of probably don't have more
than 15 stations of sufficient power and fidelity to make it worth
tuning any more (or the end-user will not want to listen to
conservative talk radio, but will listen to ordinary news, sports,
oldies, and progressive radio stations, etc.)

Again, the idea of the channel TRF approach is to be able to really
fine tune the bandpass filters for each channel. Several here say it
simply won't work, and I scratch my head on this one since the
simplest is to take an existing working TRF circuit using a variable
capacitor to tune the radio, remove the tuning capacitor, and replace
each gang with a fixed capacitor of the right value (probably with a
trimmer capacitor to fine tune the center frequency) -- it is now a
single channel receiver, and should work identical to the original
circuitry, but now it won't tune.

Now, can't one now extend this, and alter that part of the circuity,
adding LC components with the right value in the right ways to improve
the bandpass shape and proper electronic interfacing with the
properties of the RF section for that particular frequency? Obviously
the problem is figuring it all out, but one now has a lot of degrees
of freedom to work with -- no need to compromise any more as is needed
whenever one tries to continuously tune the circuit. I assume if one
can optimize it this way for one frequency (say the midpoint of the AM
band, around 950 khz), then one can then optimize it for each channel
in the 500 to 1800 khz range by simultaneously changing the values of
all the LC components as needed.

Of course, the question is how much is gained in performance taking
this approach. If several here believe it will make little difference
in real-world performance, then it makes no sense to even consider
the channel TRF approach, at least for high-fidelity purposes.

*****

Now moving to classic super-hets, the mention by John Byrns of the
National NC-100.

I think the best approach for the all out audiophile would be the
one suggested by Randy, or was it Sherry? Gutting out a National
NC-100, and rebuilding the band selection assembly with 5 sets of 3
optimized band pass filters to segment the MW band into 5 parts.

I recall last year a few people mention the NC-100. Is this radio
reputed to have excellent audio fidelity (I suppose when the variable
bandpass control is set wide) in addition to excellent selectivity and
sensitivity? And can the circuitry be modernized (e.g., modern tubes),
etc.? The idea of making it a 5 band AM radio is certainly
interesting.

Jon Noring

Jon Noring wrote:

I recall last year a few people mention the NC-100. Is this radio
reputed to have excellent audio fidelity (I suppose when the variable
bandpass control is set wide) in addition to excellent selectivity and
sensitivity?

No - not at all - nor the point. What the NC-100 (and NC-120) have is a
"sliding catacomb" band change mechanism. This is a cast metal box with
three compartments front to back - duplicated five times left to right.
Each compartment (front to back) houses the frequency critical coils
(and trimmers); etc.) for each RF stage of the radio (the NC-120 has an
additional one compartment deep five-wide box appended to the rear of
the radio to add yet another tuned RF stage). Each compartment has five
contacts that stick "up" towards the radio's chassis (15 total; 20 in
the case of the NC-120). The band-change mechanism is a rack and pinion
affair that "slides" the entire box left and right - so that one set of
compartments (and their contact fingers) line up with the mating
contacts sticking down from the chassis. In this way - each band has
it's own complete set of RF coils completely isolated and brought into
the circuit as needed. Much like a strip TV tuner - but done linear
rather than turret style. The advantages are extreme shielding - and a
good bit of room in each compartment to put all of the frequency
determining components (note only the tuning cap and tubes are above
chassis - and are the only "shared" RF components).

I think Randy mentioned that the NC-100/120 have a product detector -
but that's not to imply that the fidelity is any good - just that many
usable parts and ideas are already in place (guess you could count the
power supply and amplifier as well). They are communications receivers -
first and foremost - but they do offer some intriguing possibilities for
TRF or multi-band BCB experimentation.

And can the circuitry be modernized (e.g., modern tubes),
etc.?

Nothing wrong with the tubes they have- you could go with miniature
equivalents - but since the copper plated chassis is already huge - why
bother? I don't believe any significant performance gains (in the BCB)
would be realized by "more modern" tubes.

The idea of making it a 5 band AM radio is certainly
interesting.

That's the point - whether it would be the BCB divided into 5
continuously tuned bands - each optimized as best fit in five segments -
or 5 specific BCB stations... each tweaked to "perfection" - the
foundation is all there.

--
Sherry