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  #511   Report Post  
Old February 10th 04, 05:29 AM
Leo
 
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On 10 Feb 2004 04:55:13 GMT, (Len Over 21) wrote:

In article , Leo
writes:

Remember, morse code gets through when everything else will.


....That line still makes me laugh every time I read it!


It is absolutely, positively, 100% true. Brian Burke's phrase should
go into the textbooks. :-)

I understand that Morse is good for getting through poor conditions
better than voice. Makes sense, it is narrowband and binary (well,
tri-state if you count the spaces...) encoded. From the experimenting
(read: fooling around) that I have been doing over the past couple of
months, I have been repeatedly amazed with the ability of BPSK-31 to
get clean copy through pretty bad conditions. Even DX signals that
appear as weak vestiges on the waterfall display can be easily decoded
with near 100% accuracy, using just a PC sound card as an interface.
Frequency stability of my old Heath TX is a problem, but I'm working
on it.....

Now there's something that will get through when nothing else will.
And, it types itself out, too. (that's a real boon for the perennially
lazy - like me)

I believe that BPSK-31 was created within the amateur community -
there must have been similar narrowband technologies used by the
military which predated it - any idea what they were?


PSK31 was designed/innovated by Peter Martinez, G3PLX, in the
UK, then air-tested by several over much of Yurp. Years ago.

There's a whole heaping lot of techniques/systems used by the
militaries (of the world, actually) on sending data/teleprinter over
both wire and radio circuits. Too many to recount in here. Few of
the militaries or the governments or the commercial carriers bother
with narrowband-specific communication circuits since they have
needs to send much data quickly. The advance in Information
Theory and Coding (generic other than morse code or character
codes) have applied themselves to other things besides comm
applications: Single-error correction, double-error detection for
computer memory applications to real-time analysis of seismic
effects on building structures. Real-time Fourier Analysis has
been at the heart of that and includes mundane things like the
little audio bargraph displays on home music systems (usually
combined with "equalizer" settings of same).

The "MIT Redbook" by Peterson and Weldon is a thick text
chock full of all sorts of data coding schemes, error correction of
same, plus ways other than Forward Error Correction to send data
best without extra bits (something alluded to in Shannon's seminal
1948 paper that became familiarly known as "Shannon's Law").

The VLF Alert messages in the USN submarine fleet is not a
subject of discussion. Those are digital, encrypted, and have some
other features to work through all kinds of RF interference. The
militaries/governments/commercial carriers generally confine them-
selves to rather standard medium- to high-throughput systems for
radio circuits without going into complicated schemes. The various
"TOR" modes are very close to those. Add to that the ALE or
Automatic Link Establishment interrogation-response on auto-
measurement of signal quality and that is the broad picture of what
goes on by non-amateur communications HF to VHF. Note: Some
of the details of everyday encryption are in the grey area of talk and
I won't go into that due to prohibitions of U.S. law. If any such appear
on the Internet, it has been cleared for public viewing, not classified.

A wide example of medium- to high-rate data communications allied
to the basics of PSK31 is the common data modem used with
personal computers. It can, with a good POTS line (Plain Old Telephone
System), send 56K data rate material over a 3 KHz bandwidth. There
are, literally, millions of those modems in existance; 152 million
personal computers were sold worldwide in 2003 alone according to a
story in LA Times Business section for 9 Feb 04.

The standard data modem with PCs uses a combination of amplitude
and phase modulation of a carrier tone plus some rudimentary digital
state re-arrangments to get a rate increase far above conventional
single-mode modulations yet it does not violate Shannon's Law. Many
who can only grasp the single-mode concepts keep trying to say "it
isn't possible!" yet the possible is happening 24/7 worldwide by the
millions. The generality of such dramatic rate versus bandwidth can
be applied anywhere. PSK31 was one of those, cleverly arranged
by Martinez to fit into a bandwidth equal to a morse code spectral
space and perform just a bit better at an average throughouput of
about 30 WPM. The PSK31 system is a complex one yet quite
easy to implement with the aid of a (now) common personal
computer. The PC isn't absolutely necessary since a dedicated
terminal or radio modem can be built in a smaller package...but
still needs a keyboard, display-printer to complete the data terminal.

What is astounding, in a world of technological plenty, that there are
so many radio-backwoodsmen demanding that all revert to village
blacksmith or horse & buggy driver or other primitiveness in a hobby
activity to fulfill some mythical "requirement of knowing 'basics'" in
order to be "as good as them!" Their "knowledge" of data comms is
relegated to the memorizing-of-manufacturer's-advertisements-
descriptions for "technical familiarity"...if a description says that a
system operates at a low data rate, they cannot envision the possible
scaling to a high data rate...and vice-versa, very high data rate scaled
down to slower speed and narrower bandwidth.

The first commercial telegraph circuit opened in 1844. Queen
Victoria's coronation was about 1847 and she reigned into the 1900s
beginning while radio was first demonstrated as a communications
means in 1896. Among the PCTAs there is a terrible radio
"victorianism" both in technology and morality...the chronology and
subsequent utterances of those PCTAs is too coincident to overlook!

In this arena of PCTA radio-backwoodsmen (who can manually fell
giant redwoods in their fantasies), there can be NO talk of what
any radio service is doing other than what is blessed and codified by
the league. [see numerous utterances of the resident gunnery nurse]

"Shannon?" Who's he? He didn't have a DXCC, hasn't worked a DX
contest, isn't a dues-paying league member. Claude Elwood is "SK"
bless his joyful soul, but he did establish the relationships, the
framework on getting the highest data (of any kind, not just teleprinter)
through any given bandwidth on any communication circuit. No village
smithy anvils needed to bang out wireline morse on a solid-state
radio and pretend to be "advancing the state of the radio art." :-)

[expletive deleted]

[morse testing deleted]

[more expletives!...:-) ]

LHA / WMD


Excellent answer - thanks very much!

73, Leo


  #512   Report Post  
Old February 10th 04, 06:14 PM
N2EY
 
Posts: n/a
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Leo wrote in message . ..
On 9 Feb 2004 15:25:04 -0800, (N2EY) wrote:

Leo wrote in message . ..

I understand that Morse is good for getting through poor conditions
better than voice.


Much better than any form of analog voice.

Makes sense, it is narrowband and binary (well,
tri-state if you count the spaces...) encoded.


Exactly.

From the experimenting
(read: fooling around) that I have been doing over the past couple of
months, I have been repeatedly amazed with the ability of BPSK-31 to
get clean copy through pretty bad conditions. Even DX signals that
appear as weak vestiges on the waterfall display can be easily decoded
with near 100% accuracy, using just a PC sound card as an interface.


The soundcard is only part of the system. The decoder is quite smart,
in that
it stores and examines the received data and does a "best fit"
decoder. You can read all about it at several websites.


Good point - I've compared it to RTTY from the decoding standpoint -
RTTY seems to be much more prone to losing characters or dropping out
entirely when the signal is weak or noise is high.


Part of that is the modulation method used and part is the encoding.
There's a good explanation of the varicode philosophy and the PSK31
modulation method on a number of websites.

btw, PSK31 in BPSK mode works at around 45-50 wpm. The speed depends
on the exact text sent because the length of each character varies,
but the average character is 6 to 7 bits long.

But it's important to realize what constitutes "poor conditions".
Against purely amplitude noise it's quite robust. But against phase
noise of various
types it is not robust at all. All depends on the situation.


Frequency stability of my old Heath TX is a problem, but I'm working
on it.....


What rig is it?


Heath SB-400. The Pride of 1964


Amazing how well a 40 year old box full of glowbottles is still
useful, huh?
15 Hz stability from a one-tube Hartley is pretty decent.

With a narrowband signal like this, it doesn't take much drift! I'm
seeing a frequency decrease of up to 15 Hz, beginning a few seconds
after keying. B+ to the VFO appears to be well regulated - maybe not
tight enough though. Might have to replace the 0A2 with a few zeners
- haven't tried that yet....


First try replacing the 0A2 regulator and 6AU6A oscillator tubes -
different
ones may have slightly different characteristics.

But the real problem may be that the heater voltage is changing when
transmitting, rather than the B+. Another possibility is that heat
from the
6146s and power supply may be causing a bit of drift, because PSK31 is
a very
high duty cycle mode and a lot of heat gets dissipated on transmit.

One cure to consider is to build an external VFO, either LC or
synthetic, to do the job. The SB-400 LMO tunes 5.0 to 5.5 MHz, and it
tunes "backwards" (5.5 MHz on the VFO is the low end of the band
selected). Such a VFO could be mounted
externally to eliminate any changes to the rig itself.

I copied the heterodyne scheme of the Heath SB-series for the
Southgate Type 6 transceivers, btw. Found some Heath filters at the
1978 Rochester hamfest and
built a rig around them. Now it's on "standby" duty since the Type 7
entered service about 10 years ago.

Now there's something that will get through when nothing else will.


Not really. You will find times when the PSK-31 signal is clearly
audible in the speaker, well above the background amplitude noise, but
the decoder cannot make sense of it because the phase distortion is
too bad.


Haven't experienced that yet - at least when I see that, I'll know
what is causing it!


Exactly.

And, it types itself out, too. (that's a real boon for the perennially
lazy - like me)


It was meant as a replacement for conventional RTTY - as a "keyboard
to keyboard" mode. For example, the speed was chosen to be about what
*average* conversational keyboarding hams use.

btw, the code used in PSK-31 uses shorter symbols for the most common
characters and longer ones for the least common. Just like Morse code,
which is where the designers got the idea.


Didn't know that - great idea, though!


Yup. Even the use of 00 for a character space was derived from Morse.

I believe that BPSK-31 was created within the amateur community -


Yup - G3PLX, and a number of folks who helped him by testing it out on
the air and others who have developed software packages. A local ham
of my acquaintance (one of those longtime 20 wpm 1x2 Extras with
multiple EE degrees - we share two alma maters, btw) was one of the
team who helped test it out.

PSK-31 is another great tool in the toolbox, but not a replacement for
good old Morse Code.


Haven't formulated an opinion on that one yet - stay tuned!

Consider that it takes a lot more hardware to implement PSK31, and
that
the requirements of that hardware are much more stringent than what is
required to implement Morse code.

Consider also that Morse code, as used by hams, is an aural mode, but
doesn't
require talking. Thus it can be used in a number of situations where
other
modes can't. For example, it's not safe to drive and work PSK-31, but
mobile
Morse operation is safely enjoyed by many hams. Using voice is often
out of
the question when it is of prime importance not to disturb other
family members.

And when cost, size, weight and battery power considerations are
paramount, Morse code equipment is the natural choice. Check out the
new KX1 at

http://www.elecraft.com

for an example of what can be done with modern Morse code radio
equipment.

73 de Jim, N2EY
  #513   Report Post  
Old February 11th 04, 02:04 AM
Leo
 
Posts: n/a
Default

On 10 Feb 2004 10:14:34 -0800, (N2EY) wrote:

snip


Heath SB-400. The Pride of 1964


Oh yeah - and my basement!


Amazing how well a 40 year old box full of glowbottles is still
useful, huh?
15 Hz stability from a one-tube Hartley is pretty decent.

With a narrowband signal like this, it doesn't take much drift! I'm
seeing a frequency decrease of up to 15 Hz, beginning a few seconds
after keying. B+ to the VFO appears to be well regulated - maybe not
tight enough though. Might have to replace the 0A2 with a few zeners
- haven't tried that yet....


First try replacing the 0A2 regulator and 6AU6A oscillator tubes -
different
ones may have slightly different characteristics.


That was one of the things I tried when I rbuilt the TX back in the
summer - ended up with an 0A2WA regulator and a 6136 in the LMO. That
brought it much closer...that and some conductive silver grease in the
bearings of the LMO tuning cap (I didn't even know they made that
stuff till I dug into the Web and discovered that TRW used it when
they built the LMOs for Heath, and it dries out over time.....)


But the real problem may be that the heater voltage is changing when
transmitting, rather than the B+. Another possibility is that heat
from the
6146s and power supply may be causing a bit of drift, because PSK31 is
a very
high duty cycle mode and a lot of heat gets dissipated on transmit.


That is very possible - it's also possible that the drift is in one of
the other oscillator sections other than the LMO. Haven't had time to
tear it apart and see yet....one of these days!


snip


Thanks for the info!

73 de Jim, N2EY


73, Leo

  #515   Report Post  
Old February 12th 04, 04:00 AM
N2EY
 
Posts: n/a
Default

In article , Leo
writes:

On 10 Feb 2004 10:14:34 -0800, (N2EY) wrote:

snip


Heath SB-400. The Pride of 1964


Oh yeah - and my basement!


Amazing how well a 40 year old box full of glowbottles is still
useful, huh?
15 Hz stability from a one-tube Hartley is pretty decent.

With a narrowband signal like this, it doesn't take much drift! I'm
seeing a frequency decrease of up to 15 Hz, beginning a few seconds
after keying. B+ to the VFO appears to be well regulated - maybe not
tight enough though. Might have to replace the 0A2 with a few zeners
- haven't tried that yet....


First try replacing the 0A2 regulator and 6AU6A oscillator tubes -
different
ones may have slightly different characteristics.


That was one of the things I tried when I rbuilt the TX back in the
summer - ended up with an 0A2WA regulator and a 6136 in the LMO. That
brought it much closer...that and some conductive silver grease in the
bearings of the LMO tuning cap (I didn't even know they made that
stuff till I dug into the Web and discovered that TRW used it when
they built the LMOs for Heath, and it dries out over time.....)


Lotta subtleties in old gear. Not as "primitive" as some folks try to tell
us...

But the real problem may be that the heater voltage is changing when
transmitting, rather than the B+. Another possibility is that heat
from the
6146s and power supply may be causing a bit of drift, because PSK31 is
a very
high duty cycle mode and a lot of heat gets dissipated on transmit.


That is very possible - it's also possible that the drift is in one of
the other oscillator sections other than the LMO. Haven't had time to
tear it apart and see yet....one of these days!


Two xtal and one tunable oscillator in that heterodyne scheme.

Upwards drift in the het osc will make the operating freq go higher
Upwards drift in the LMO will make the operating freq go lower
Upwards drift in the BFO will make the operating freq go lower

So there's a bit of compensation *if* the oscillators all drift the same way.

Thanks for the info!


You're welcome.

73 de Jim, N2EY



  #516   Report Post  
Old February 22nd 04, 03:14 AM
WA3IYC
 
Posts: n/a
Default

In article , Leo
writes:

On 17 Jan 2004 00:57:34 GMT, (N2EY) wrote:

In article , Leo


writes:

For some reason, this discussion keeps going off on a tangent from the
core "issue" that began our discourse.


There are several issues, not just one.


OK - I'm listening.


Perhaps I haven't stated it
clearly enough, or during the discussion the original issue has become
clouded.

Let's see what you've got, then.


Let's go.


I have responded to your comments below, but I fear that we will
continue forever if we are not discussing exactly the same issue.

I understand that, due to your standards, you find Kim's callsign
inappropriate.


That's correct. It's also an issue to some people.


OK - fair enough. And it shouldn't be.


But it is! And that's one of my points.

Your personal standards are
your own - no one else's.


They are shared in this case by some other people, so your
statement of "no one else's" isn't true.

Let's clear that one off - agreed?


Once you agree that they are shared by some but not all others, yes.

No issue there - that is entirely your right.


Some people say it isn't. Not you, but some others.


Others may, but who cares - it's none of their business.


Whether or not it's someone's business is an issue, too.

I also
understand that you do not wish to use it in any of your posts.


Also correct. And also an issue to some people, who say that my deletion of
Kim's call is "wrong".


Let's focus on that one, and agree that deleting her call from your
post is necessary for you to due to your standards. I have no issue
there at all. If you don't want to use it, OK. Let's clear this one
off too - agreed?


OK, fine. You have no problem with my not using her callsign.

Again, no issue there - I respect that.

For clarity, I'll restate it in clear and concise wording:

Kim feels that eliminating just her callsign from your post was
unfair, as it singled her out. I agree.


And I disagree. Kim singled herself out by choosing that callsign. As you
are aware.


Yes she did - and quite intentionally, too, as she has stated.


BINGO!

That wasn't, however, what I was saying in my statement above. Simply
that Kim feels that you singled her out too, by omitting just her call
from the list.


Understood.

Forget the inappropriatenesss of the call for a moment


Why? It is that inappropriateness which was the cause of the whole thing.

....do you see where she might get that feeling?


Sure.

Do you see where others might get the same or similar feelings?

Would finding a compromise
whereby neither your standards nor Kim's feelings - such as removing
all of the callsigns and listing only names for all participants -
have not been a fairer way to handle this situation for all concerned?


No, it wouldn't.


Honestly, I dont agree with you on this point.


That's OK. You can post her callsign, my callsign, or nobody's callsign in
*your* posts. Just don't try to get me to post them or not post them in *my*
posts....

It would have been an
easy compromise to make,


Easy - and not in acordance with my standards.

and woulld potentially have offended no one.


Incorrect. It would have offended me.

More on this further down in the post!

That's the only issue that I am discussing, Jim.


No, it isn't, but we'll get to that later. Right now, let's discuss that
issue.

It seems to me that what you're saying is that I should either include
everyone's callsign, or no one's.

Now since I don't wish to include Kim's callsign, that leaves only the
option of including no one's callsign, in order to accomodate Kim's feelings.


Agreed - in order to treat everyone equally, that would be the only
other option available given the situation.


But it would *not* treat everyone equally. Those with appropriate callsigns
would
not get to see them posted. Everyone would suffer for one person's choice.

But what about everyone else's feelings, including mine? I want my call
listed.

I would feel disrespected to be listed by name rather than callsign or name
and callsign on an amateur radio newsgroup.


Yes, and I believe that Kim feels exactly the same way, Jim. For the
same reason as you, I suppose - she is also a ham. (She does not feel
that her call is in any way wrong, remember.)


I use the word "inappropriate". "Wrong" implies a moral judgement.

Maybe Dee, Dave, Carl, Dwight, Jim, Jim, Steve, et. al also want *their*
callsigns listed, and would feel disrespected if I listed by name only.

Don't the feelings of everyone else count?


Of course they do - but are you sure that these people world be that
upset by this?


I know I would be - that's one.

(except Dave, of course - he appears, from his recent
correspondence, to be annoyed that Kim is still breathing... )


I don't see any indication that Dave, K8MN wants Kim to die. I do see an
indication that Dave would like Kim to choose a more appropriate callsign.

So if we assume K8MN agrees with me, that's two.

Perhaps others would feel disrespected too.

So you're saying that Kim's feelings are more important than Jim's (N2EY) and
Dave's (K8MN) feelings. And maybe more.

In fact, if it had been my post, I would have revised it to names only
immediately after Kim's original complaint.


But it wasn't your post. It was my post.

By your logic, I should change my screen name and email address and how I sign
posts, because they are derived from my callsign, too.

And seen what comments
came back next. If I had several legitimate complaints (without the
agendas that we have seen in several recent posts {not yours, Jim!)
which obviously relate to Kim personally rather than just her
call...), then yes there would be no other alternative than to put the
calls back - but I would have written and offered Kim the option of
going by name only or dropping out before I went ahead.


So I should potentially disrespect a bunch of other hams with appropriate
callsigns to please Kim? And if some of them complain, I get to put their
callsigns back but not Kim's?

Why not just do what I did and avoid the potential of disrespecting hams with
appropriate callsigns?

At least I'd
be able to tell Kim that I tried to fix it for her, but it didn't work
out with the rest of the group.


That would be passing the buck.

Maybe it's just me, but I would try first to resolve her complaint if
possible, out of respect for her as a fellow amateur.


I respect her as a fellow amateur. But I also respect other amateurs
with appropriate callsigns.

I prefer
compromise whenever possible - not compromising my standards, but
finding a way to achieve a balance.

What about when your standards cannot be compromised?

Note also, Kim said that if I wouldn't use her callsign, she didn't want to
be on the list..


True, but that was after the had become frustrated with trying to
solve this issue.

She was not willing to do anything to solve the issue other than complain and
protest.

Your rights and
standards are not at question here.


Yes, they are. I've been told that "it's not my place" to determine whether
a callsign is appropriate or not. I've been told that my actions are "wrong".

Also, the word "prejudice" has been used...

As you are aware.


I did state that it is in fact no one individual's place to determine
what is or is not appropriate for the ARS - that role belongs to the
regulators, and to the will of the majority of us, I suppose.


It was that it was not *my* (N2EY's) place to decide.

Each of us is however completely in charge of determining what is
appropriate for us as an individual, however. No question there.


And I say it's appropriate for me to post the calls and words of hams with
appropriate callsigns and to edit out the calls and words of those who
use inappropriate ones.

Jim, my intent was not to criticize your standards


Well, you did. I could even say you disrespected me in the way you did it.

- simply to point
out that perhaps a more amicable solution to this issue was possible
without compromising anyone's standards - finding a common ground for
all.


I do not agree that your proposed solution wasn't a compromise to my standards.

That's it - that's my point.

And here's one more issue to think about:

Every community, including the ARS, has its standards. Consider
residential neighborhoods as an analogy.

Some community standards are concretely and legally stated, like
zoning ordinances and building codes. Others are part of the
general community culture, such as keeping one's property in
reasonable repair and not mowing your lawn at 3 AM. A lot
of the latter come under the heading of "being a good neighbor".

If someone wants to be accepted and respected in a community,
it is necessary to act (more or less) in accordance with reasonable
community standards. That doesn't mean everyone must be exactly
alike and never do anything different than the neighbors, but it
*does* mean that community standards need to be considered.

The fact that not all community standards are codified into law doesn't
mean they aren't important. For example, painting one's house in odd
colors and patterns may be legal in some communities, but it's not the
mark of being a "good neighbor".

What Kim wants to do is to reject the ARS' "community standards"
in her choice of callsign, yet still receive the same respect and
acceptance from other hams as those who choose appropriate callsigns.
Just like the person who paints their house purple and orange in a dazzle
pattern, then wonders why the neighbors put up fences and shrubs to
conceal the view.

73 de Jim, N2EY


73 de Jim, N2EY





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