"John Smith" wrote in message
...
Only thing I caution them of is high rf levels at these freqs--they have
little fear of microwaves until the dangers are made clear... they
constantly search ebay for microwave mosfets... when they mention ideas of a
PA out of a microwave oven--one does do some worry...

I'd worry aout someone who starts suggesting disassembling a microwave oven
too...

On the other hand, if they get themselves a bunch of microwave 'FETs from
eBay, by the time they actually manage to make a working power amplifier
they'll have had to absorb so much knowledge that they'll undoubtedly already
appreciate how much power they're playing around with!

"You can't really be creative unless you understand the situation."

Ohh, now I see--we are all just waiting for "that guy/gal"....

Warmest regards,
John
--
Sit down the six-pack!!! STEP AWAY!!! ...and go do something...

"Michael Black" wrote in message
...
|
| "Joel Kolstad" ) writes:
|
| I think that was Edison? Einstein said something like, "Creativity is
more
| important than knowledge," which unfortunately a lot of people seem to
want to
| interpret as "Hence, knowledge is unimportant," which is not at all what
he
| meant.
|
| You can't really be creative unless you understand the situation. On the
| other hand, people can spout things but be unable to do anything with
| it because they aren't extracting from the situation.
|
| Creativity is an extrapolation. A good example is Charles Kitchin's
| work with regen and superregen receivers. He went back, looked at early
| material, understood it, and then implemented solid state versions.
|
| Michael VE2BVW

Joel:

Do a search of the net, you will see some of the designs, circuits, boards
there...
These kids are a real network of hobbyists... takes 'em about a week to pick
it up (well, that might be exaggerating)...

.... and while they mention the microwave oven--I don't think anyone is
attempting it!!! Think of the poor birds landing on that antenna and trying
to keep warm in the winter!!! frown

Warmest regards,
John
--
Sit down the six-pack!!! STEP AWAY!!! ...and go do something...

"Joel Kolstad" wrote in message
...
| "John Smith" wrote in message
| ...
| Only thing I caution them of is high rf levels at these freqs--they have
| little fear of microwaves until the dangers are made clear... they
| constantly search ebay for microwave mosfets... when they mention ideas
of a
| PA out of a microwave oven--one does do some worry...
|
| I'd worry aout someone who starts suggesting disassembling a microwave
oven
| too...
|
| On the other hand, if they get themselves a bunch of microwave 'FETs from
| eBay, by the time they actually manage to make a working power amplifier
| they'll have had to absorb so much knowledge that they'll undoubtedly
already
| appreciate how much power they're playing around with!
|
|

Hi John,

"John Smith" wrote in message
...
Do a search of the net, you will see some of the designs, circuits, boards
there...

Any pointers to 802.11b/g amplifiers? Most of the results I get Googling are
for the more "traditional" designs (from RF component vendors, booksellers,
etc.) -- I didn't see any homebrew 2.4GHz amp schematics aimed at the casusal
WiFi enthusiast.

... and while they mention the microwave oven--I don't think anyone is
attempting it!!!

Someone claiming they can take a magnetron from a $59 Wal*Mart microwave oven
and turn it into a reasonably linear power amplifier has a pretty poor
understanding just what it is that (1) amplifiers and (2) magnetrons from
cheap microwave ovens are meant to do. :-)

From: Paul Keinanen on Wed,May 11 2005 12:13 am

On 10 May 2005 13:59:13 -0700, wrote:

From: Paul Keinanen on 10 May 2005 09:11:19 -0700

In a radio receivers, the signal levels vary
from less than a microvolt to several volts, so the crosstalk issues
are much more demanding.

I will disagree on radio receivers on such wide dynamic
ranges. "Several volts" INTO a receiver front end?
No. Such levels aren't encountered in practical
locations and would, definitely, cause enough IM
that would create much distortion and spur products.

Look at a multitransmitter contest site with one transmitter on each
band, the voltage induced to the receiving antennas for other bands
can be quite large.

In a production model receiver? Mais non. That's
not a design prerequisite, never was, not even with
the Rhode & Schwarz designs featuring very high
3rd IP specifications.

I've been IN such situations on aircraft installations
where the potential RFI was much stronger than in ham
DXpedition or Field Day setups. The work-arounds to
make the receivers operate is NOT a design criteria,
not in avionics-oriented design plans.

Of course, in a competent receiver design only the
frequency band of interest is filtered out before processing. However,
if the antenna is connected directly to the backplane and the modules
do their own filtering, the large composite signal on the backplane
will radiate all around the system.

Possibly, IF and only IF the antenna IS connected
to the "backplane" (or motherboard). Why must it be
so? Look at the PC. Sound cards have their audio
input (at microphone levels) on a separate connection).
No interference doing that.

In non-contest sites large wire or log-periodic antennas can collect a
quite large signal voltage (in the order of 0 dBm, 220 mV or more).

Perhaps, but that still isn't a design criterion for
present-day ham receivers.

Also if the final IF is within or below the receiver tuning range and
a diode ring mixer is used as the SSB demodulator with +7 or +17 dBm,
you must keep this BFO signal and harmonics from entering the front
end.

Yes...but that was a problem a half century ago, too! :-)


Even the SDR is going to need some switchable front end band pass
filters in order to survive in the hostile RF environment these days
with a lot of strong signals even in ordinary sites.

Diode switching. My two-decade old Icom R-70 has that
to select approximate octave-bandwidth bandpass filters
to cover 50 KHz to 30 MHz. Has its own little PCB,
probably because every single L, C, diode, and resistor
is included on that board...no shielding except from
the side wall of the cabinet and part of the cast frame.

I've had that little receiver within a city block from
AM BC station KMPC running 50 KW into its towers. Worked
fine with a temporary long-wire antenna despite the RF
around that station.

In transceivers, there would be several points that would need
switching.

Of course. That's what was done two decades ago.

I used the CANbus as an example, since the cable can be tens or
hundreds of meters long depending on speed and thus, it could be used
to control some internal points in a transceiver as well as wire all
devices in the ham shack as well as in the tower. For instance, the
same controller could control the antenna rotator, command the antenna
preamplifier to bypass mode, turn the transvertter into transmit mode,
select the VFO frequency for transmit (in split operation) and finally
turn the transmitter on.

Right, no problem...except for the individual ham
installer who then has to set up the "program" to
do all those things. Can they? :-)

I think a better approach is something like SGC does
in their automatic antenna tuners. They add a
frequency meter function to their tuner micro-
controller, a small section of Flash memory to
hold data, measure an RF input, adjust the coupler
switches to compensate for VSWR, then record that
data in memory. Any future frequency close to the
recorded memory can use the same settings.

Near-ultimate in modularity is thus achieved. Needs
only DC power to operate and doesn't care what kind
of transmitter is connected to it...as long as its in
specification for power and frequency. Absolutely
"plug-and-play!" :-)


What is lacking is STANDARDIZATION.

This is definitely a big problem.

Yes and no. :-) It's like a recipe for "tiger
soup:" "First, you have to catch a tiger..."

In a similar way, there must be SOME idea of
what kind of control range, modulation, etc.,
etc. would be expected...and for what radio
service. The FCC in the USA can't yet come to
grips on that, nor has industry made much
progress outside of their own product lines.

Right now, it is more like Pandora's Box.


That can't be worked out in newsgroups,

A newsgroup is a good place for open ended discussions between people
with experience in quite different fields.

I agree. But, like the infamous "John Smith,"
it can be infiltrated with someone who doesn't
have either the experience or the courage to
use his/her real name. Raises the noise
level enough to make some go QRT for a while.


Writing a formal specification may require some formal organisation,
but on the other hand quite a few successful RFCs in the IT sector are
written by a single person or a small group.

Ahem...that INDUSTRY specification is going to
range considerably farther than some small group
within one company. As to IT (Information
Technology), I've not seen ANY industry-wide
softwares which extend beyond corporate levels
and that's been for the last three decades.
LANGUAGES not counted there.

and willingness to compromise

That is the problem in formal committees, in which most delegates from
various vendors have large commercial interests in the subject and in
order to be able to produce even some kind of standard, all features
from various vendors are included.

I'll just cite the ARINC standards which are
generally used internationally for all civil
avionics, from radio to radar, radionavigation
systems. ALL the interfaces to every avionics
box and the physical shape and mountings. NOT
a big commercial venture in terms of profit.
If you've been able to read the verbatim minutes
of ARINC meetings (I have), then you would see
that it can be done.

ARINC = Aeronautical Radio INCorporated, once a
radio communications provider for airlines,
later evolving into a combined industry-government
central standards organization for civil avionics.
[they have a website, BTW, but the documents are
horribly expensive now...]

From: "Dee Flint" on Wed,May 11 2005 3:14 pm

"John Smith" wrote in message
...
I don't think the "apple boys" had ever designed a complete computer
before
they did--indeed, don't remember anyone else (or team of engineers,
techs,
scientists, etc...) doing a desktop before then...

You mean, China, Russia, India, USA, Canada, So. American, Mexico,
etc--and
every gov't, business, private individual, ham and cb'er... is not a
big
enough market... these things would be manufactured in China
yanno!!!

Nope the entire world wide population of hams is NOT enough. The US
has
just under 700,000.

As of 11 May 2005, www.hamdata.com reports 723,737 total
U.S. amateur radio licensees.

Japan has somewhere around 1 million (there numbers are
hard to determine due to their licensing system). The remainder of
the
world combined has right around the same total of the US. This gives
a
worldwide ham population of under 2.5 million. So starting from
that
rough estimate, let's look at some figures. Very, very few people buy
a new
HF rig annually. Just using the people I know, it's more like every 5
to 10
years. So let's use an average of 7.5 years. That means a total of
333,000
new radios (rounding off the answer) sold in any given year. Now
split that
between 3 makers, yielding 111,000 units per maker.

Only "three?" :-)

That's pretty low
volume to undertake radical development. We're probably lucky that we
get
any new features.

Tsk, tsk. Having first started to legally transmit
RF (on HF) in 1953, I've been watching the progress
of most ALL radio technology for a mere half century.
...and seen the DESIGN as well as manufacturing shift
to Asia. In Japan alone, there are at least FOUR
corporations doing HF radio design, not just three.
USA designers and manufacturers ARE there NOW, but
none of them are Collins, National Radio, RME, or
Hallicrafters. [only Collins Radio is left of all
of them and they do NOT make ham equipment]

Take FREQUENCY CONTROL, an essential thing for stable
SSB work on HF. The PLL took care of that nicely
with - perhaps - Icom leading the way to get 10 Hz
increments at quartz crystal control. To save some
costs, the three major players (Icom, Yaesu, Kenwood)
switched over to DDS (Direct Digital Syntheses) after
trying out 'fractional-N' PLL synthesizers.

Asian DESIGNERS and manufacturers were there first
with the LCD screens to show analog information in
digital form. They may also have been the first to
include microprocessors and microcontrollers to act
as control-display interfaces, saving hundreds of
store dollars per unit and eliminating mechanical
couplings almost entirely.

Try DSP (Digital Signal Processing). That's in the
ham gear of TODAY. Not a "first" in amateur rigs
since it was first introduced on consumer electronics.
But, it is THERE. Today. [I could go on...:-) ]

100K production lots are "low volume to undertake
radical development?!?!?" Oh, my. Let's look at
that in more detail...say at 10K production runs.
Try, for example, with an average price of $1000
per HF ham transceiver. Sell price dollar flow
would be $10 MILLION. Designer-manuafcturer dollar
flow is roughly half that, $5 MILLION to split off
many ways: component costs, burden, advertising,
profit, losses on defects, to name the major items.
Perhaps $500K can be the amount amortized for the
actual R&D. At $50/hour in estimated engineering
salaries-plus-burden of Japanese companies, that's
10,000 man-hours for the design-development budget.
A team of 10 then has 1000 hours average to do one
task. At 50 hours per week, that's 20 weeks to
get what is largely (in practice) the production
side of the house going, at least a third of a
year.

But, very very few designs are "brand-new" in ANY
catalog. The majority are revisions of the older
models, perhaps using the same "universal" cast
framework-support and cabinet but needing only the
front-panel face-lift. The time - at 10K run
lots - is plenty long enough to come up with the
"new improved state-of-the-art" things that glow
triumphantly (in purple prose) from the ads in
QST. :-)

Do the big makers have "single model" catalogs?
No. Not even the medium-sized ones. All have
MANY models and branches...such as the Handheld
transceivers. The HTs plus VHF/UHF base stations
tend to be the company bread-and-butter items,
sold - in almost the same features as for hams -
to industry, business, and government. With
some revisions of the basic structure those
become "amateur radios."

On the down side, the HF bands are NOT a big-
ticket item for communications as they once were.
Today the RF world is deep into cellular
telephony for sites and providers, and some
for users (at companies with large production
lines and consumer marketing structures). The
world of communications has moved UP and over
that mythical, artificial dividing line of
30 MHz.

From: "Michael A. Terrell" on Wed,May 11 2005 9:50 am

John Smith wrote:

So, although your original argument was how difficult a bus and
keeping
analog seperate from digital which would share various
signals--would be,
then, when the argument was made that someone just picked up a bunch
of
on-the-shelf items and went ahead and done it... you flip-flop--to
where now
it was so obivious someone should have done such a simple thing LONG
before
them...

I didn't "Flip-Flop" I know what's involved, including the million
dollar plus expense involved in designing one configuration of a
modular
radio.

Michael, don't let this POSEUR bother you. That
anony-mouse "John Smith" hasn't been there, hasn't
done it. He wants to be "Instant Guru" and wants
a "rep" without doing any work for it. From what
he states - all in generalities, no specifics -
he can't think things out close to necessary detail.

You were right to "plonk" him.


You have your head up your sorry ass, and I'm through wasting time
with your nonsense. Its obvious that you don't know a dam thing about
design when you compare the Apple II to a real design project. You
need
to get an education in design and stop trying to blow smoke up
everyone's ass.

Way to go! :-)

At some other time I wouldn't mind having a friendly
argument with you on the Apple ][...but not with this
anony-mouse hanging around trying to intrude and
smoke up the place. I still have my 1980-purchase
Apple ][+ and had a lot of fun with it...including
lots of calculations (Applesoft had 10-digit
accuracy with 5-byte FP variables, muy better than
4-byte single precision). I've gone into the hard-
ware and analyzed it thoroughly, scoped it, written
it up...submitted it as a manuscript only to find out
Howard W. Sams was already in production on a similar
book! :-)

In many ways, the PRODUCTION version of the Apple ][
was the forerunner of the IBM PC out of Boca Raton.
But designed (or rather re-designed) about two years
prior to the IBM PC. Uncanny similarity between the
two in basic structure, expansion slots, and - yes -
"open architecture." PRODUCTION planning went into
the ][ and it wasn't much like the original board-
only Apple.

But, the ][ on up to the Apple //gs were terrific RF
generators! :-) By contrast, a similar structure
using only three main chips (CPU from Western Design,
64K EPROM, 64K/128K Static RAM) can be very nice and
quiet RF wise because of the internal transistor
structures in those chips. [I've already done a
preliminary breadboard setup to verify that] Such a
controller system can adapt itself to many kinds of
"radio controller" applications without any of the
RF coupling problems. It's been done before by the
big three in Japan using older microcontrollers in
many different transceivers, all without disturbing
the receiver or the transmitter specifications.

Too many of the older hams are oriented towards a
"legacy radio" structure...mostly analog. That
just doesn't adapt to "plug-and-play" ease of adding
or modifying an SDR. Trying to use a common PC as
a "model" for an SDR is a bunch of nonsense. The
"bus" and "interface structure" is an analogue only
the broadest sense of the term. Doesn't apply,
either technically or organizationally.

wrote:

From: "Michael A. Terrell" on Wed,May 11 2005 9:50 am

John Smith wrote:

So, although your original argument was how difficult a bus and
keeping
analog seperate from digital which would share various
signals--would be,
then, when the argument was made that someone just picked up a bunch
of
on-the-shelf items and went ahead and done it... you flip-flop--to
where now
it was so obivious someone should have done such a simple thing LONG
before
them...

I didn't "Flip-Flop" I know what's involved, including the million
dollar plus expense involved in designing one configuration of a
modular
radio.

Michael, don't let this POSEUR bother you. That
anony-mouse "John Smith" hasn't been there, hasn't
done it. He wants to be "Instant Guru" and wants
a "rep" without doing any work for it. From what
he states - all in generalities, no specifics -
he can't think things out close to necessary detail.

You were right to "plonk" him.

You have your head up your sorry ass, and I'm through wasting time
with your nonsense. Its obvious that you don't know a dam thing about
design when you compare the Apple II to a real design project. You
need
to get an education in design and stop trying to blow smoke up
everyone's ass.

Way to go! :-)

At some other time I wouldn't mind having a friendly
argument with you on the Apple ][...but not with this
anony-mouse hanging around trying to intrude and
smoke up the place. I still have my 1980-purchase
Apple ][+ and had a lot of fun with it...including
lots of calculations (Applesoft had 10-digit
accuracy with 5-byte FP variables, muy better than
4-byte single precision). I've gone into the hard-
ware and analyzed it thoroughly, scoped it, written
it up...submitted it as a manuscript only to find out
Howard W. Sams was already in production on a similar
book! :-)

In many ways, the PRODUCTION version of the Apple ][
was the forerunner of the IBM PC out of Boca Raton.
But designed (or rather re-designed) about two years
prior to the IBM PC. Uncanny similarity between the
two in basic structure, expansion slots, and - yes -
"open architecture." PRODUCTION planning went into
the ][ and it wasn't much like the original board-
only Apple.

But, the ][ on up to the Apple //gs were terrific RF
generators! :-) By contrast, a similar structure
using only three main chips (CPU from Western Design,
64K EPROM, 64K/128K Static RAM) can be very nice and
quiet RF wise because of the internal transistor
structures in those chips. [I've already done a
preliminary breadboard setup to verify that] Such a
controller system can adapt itself to many kinds of
"radio controller" applications without any of the
RF coupling problems. It's been done before by the
big three in Japan using older microcontrollers in
many different transceivers, all without disturbing
the receiver or the transmitter specifications.

Too many of the older hams are oriented towards a
"legacy radio" structure...mostly analog. That
just doesn't adapt to "plug-and-play" ease of adding
or modifying an SDR. Trying to use a common PC as
a "model" for an SDR is a bunch of nonsense. The
"bus" and "interface structure" is an analogue only
the broadest sense of the term. Doesn't apply,
either technically or organizationally.



As far as "John Smith" goes, he's gone. He is just another hopeless
wanabee who doesn't understand anything about the real world.

Len, I have worked from DC to 11 GHz on commercial designs and anyone
that thinks any design is easy just doesn't have any idea what's
involved. Its one thing to hack together an almost working prototype,
but its a whole different animal to design from the bottom up to meet
set specifications, make sure the components will be available, and if
the unit is to be sold, to make sure that it will clear the FCC, UL and
other requirements. If you decide to manufacture the equipment for sale
outside of the US you have the CE certification, and ISO 900X to deal
with.

If i had the money I would put together a nice kit to sell, but other
needs come first.

I designed my first receiver in the late '60s while I was still in
high school. It was mostly tubes, and a modular design so I could
replace sections to update the design. I had it almost done when I was
drafted. When I got out of the service my family had torn down my
workshop and the prototype and all my paperwork was gone. I learned a
lot about receiver design at Microdyne, and their telemetry receivers
were all modular. They had to be, because a customer would need
something special, so we would charge them to redesign a module or two
to adapt a standard product, rather than to design a complete receiver.

It would be interesting to set up a group to develop a modular
system, but getting people to agree on the specs can be more work than
the actual design.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

"Roy Lewallen" wrote in message
...
I think that's wildly optimistic. First, many, many licensed amateurs
aren't active and don't own a rig at all. Another very large fraction buy
only VHF/UHF gear. And, I don't know whether your figure of 700k hams with
U.S. licenses includes the large number who are residents of other
countries and also have licenses in those countries. Many of the foreign
hams I hear from give a U.S. callsign along with their native one.

I think the only reason we get the radios we do is that the manufacturers
can combine the design with equipment for other markets, such as public
safety for HTs. I've read that the lack of 220 MHz HTs is because of the
absence of a nearby public service band, so the manufacturers can't use
the same design for both services. I find that believable. I don't know
how important additional markets are to HF equipment development, or what
they would be these days. My guess is that the manufacturers don't make an
awful lot on their HF equipment lines.

In any case, the total market, particularly for HF gear, is surely much
less than this estimate.

Roy Lewallen, W7EL



Actually I agree. I was thinking of cutting that in half due to inactive
hams and got in a rush and forgot to do that.

Dee D. Flint, N8UZE

Well, I don't respond well to personal attacks, character assassinations,
juvenile exchanges--I really just don't have time--nothing to be gained
really--but, if you must, proceed at your desire...

rec.radio.cb has made me aware of such exchanges on newsgroups--and
thickened my skin... grin

John
--
Sit down the six-pack!!! STEP AWAY!!! ...and go do something...

wrote in message
oups.com...
| From: "Michael A. Terrell" on Wed,May 11 2005 9:50 am
|
| John Smith wrote:
|
| So, although your original argument was how difficult a bus and
| keeping
| analog seperate from digital which would share various
| signals--would be,
| then, when the argument was made that someone just picked up a bunch
| of
| on-the-shelf items and went ahead and done it... you flip-flop--to
| where now
| it was so obivious someone should have done such a simple thing LONG
| before
| them...
|
| I didn't "Flip-Flop" I know what's involved, including the million
| dollar plus expense involved in designing one configuration of a
| modular
| radio.
|
| Michael, don't let this POSEUR bother you. That
| anony-mouse "John Smith" hasn't been there, hasn't
| done it. He wants to be "Instant Guru" and wants
| a "rep" without doing any work for it. From what
| he states - all in generalities, no specifics -
| he can't think things out close to necessary detail.
|
| You were right to "plonk" him.
|
|
| You have your head up your sorry ass, and I'm through wasting time
| with your nonsense. Its obvious that you don't know a dam thing about
| design when you compare the Apple II to a real design project. You
| need
| to get an education in design and stop trying to blow smoke up
| everyone's ass.
|
| Way to go! :-)
|
| At some other time I wouldn't mind having a friendly
| argument with you on the Apple ][...but not with this
| anony-mouse hanging around trying to intrude and
| smoke up the place. I still have my 1980-purchase
| Apple ][+ and had a lot of fun with it...including
| lots of calculations (Applesoft had 10-digit
| accuracy with 5-byte FP variables, muy better than
| 4-byte single precision). I've gone into the hard-
| ware and analyzed it thoroughly, scoped it, written
| it up...submitted it as a manuscript only to find out
| Howard W. Sams was already in production on a similar
| book! :-)
|
| In many ways, the PRODUCTION version of the Apple ][
| was the forerunner of the IBM PC out of Boca Raton.
| But designed (or rather re-designed) about two years
| prior to the IBM PC. Uncanny similarity between the
| two in basic structure, expansion slots, and - yes -
| "open architecture." PRODUCTION planning went into
| the ][ and it wasn't much like the original board-
| only Apple.
|
| But, the ][ on up to the Apple //gs were terrific RF
| generators! :-) By contrast, a similar structure
| using only three main chips (CPU from Western Design,
| 64K EPROM, 64K/128K Static RAM) can be very nice and
| quiet RF wise because of the internal transistor
| structures in those chips. [I've already done a
| preliminary breadboard setup to verify that] Such a
| controller system can adapt itself to many kinds of
| "radio controller" applications without any of the
| RF coupling problems. It's been done before by the
| big three in Japan using older microcontrollers in
| many different transceivers, all without disturbing
| the receiver or the transmitter specifications.
|
| Too many of the older hams are oriented towards a
| "legacy radio" structure...mostly analog. That
| just doesn't adapt to "plug-and-play" ease of adding
| or modifying an SDR. Trying to use a common PC as
| a "model" for an SDR is a bunch of nonsense. The
| "bus" and "interface structure" is an analogue only
| the broadest sense of the term. Doesn't apply,
| either technically or organizationally.
|
|
|