Mike Coslo wrote

What is the basis for 50 watts?


NCRP Report No. 86, "Biological Effects and Exposure Criteria for
Radiofrequency Electromagnetic Fields", Copyright 1986, National
Council on Radiation Protection and Measurements, and ANSI/IEEE
C95.1-1992, "Safety Levels with Respect to Human Exposure to Radio
Frequency Electromagnetic Fields, 3 kHz to 300 GHz", Copyright 1992,
IEEE, Inc.

73, de Hans, K0HB

"Mike Coslo" wrote

That says quite a lot.

You asked a reasonable direct question. "Yes" is a reasonable direct
answer, hard for anyone to misinterpret for "No" or "Maybe" or "Depends on
what 'is' means".

73, de Hans, K0HB

Hans K0HB wrote:

Mike Coslo wrote


What is the basis for 50 watts?



NCRP Report No. 86, "Biological Effects and Exposure Criteria for
Radiofrequency Electromagnetic Fields", Copyright 1986, National
Council on Radiation Protection and Measurements, and ANSI/IEEE
C95.1-1992, "Safety Levels with Respect to Human Exposure to Radio
Frequency Electromagnetic Fields, 3 kHz to 300 GHz", Copyright 1992,
IEEE, Inc.

And that 50 watts affects calss A different than Class B?

I seriously doubt that a person that cannot handle 100 watts shild have
any license. Maybe class A shouldn't be alloed to have antennas over 10
feet off the ground either. Nasy falls.

- Mike KB3EIA -

KØHB wrote:

"Mike Coslo" wrote


That says quite a lot.


You asked a reasonable direct question. "Yes" is a reasonable direct
answer, hard for anyone to misinterpret for "No" or "Maybe" or "Depends on
what 'is' means".

It tells me what you think is a serious answer. I though you were
perhaps being facetious or obtuse. You were not, and that tells me a lot.

- Mike KB3EIA -

"Mike Coslo" wrote

And that 50 watts affects calss A different than Class B?

Of course not. (This is another of those 'novel' questions.)

But my intention is that the Class B (learners permit with training wheels)
test be ultra simple, to allow as many applicants as possible. For that
reason, requiring qualification in esoterica like "Biological Effects and
Exposure Criteria for Radiofrequency Electromagnetic Fields" is
inappropriate. Thus the 50W power level recommended by the NCRP and
ANSI/IEEE ensures a modicum of safety for these beginners.

In the process of preparing for Class A (without training wheels) license,
the candidate would need to explore the RF-exposure safety issues which
would be on the qualification test. Then we could expect that they'd have
some appreciation of the hazards and how to ensure that their station is
engineered in compliance with the MPE criteria mandated by 97.13(c).

73, de Hans, K0HB

In article , Mike Coslo
writes:

Hans K0HB wrote:

Mike Coslo wrote

What is the basis for 50 watts?

NCRP Report No. 86, "Biological Effects and Exposure Criteria for
Radiofrequency Electromagnetic Fields", Copyright 1986, National
Council on Radiation Protection and Measurements, and ANSI/IEEE
C95.1-1992, "Safety Levels with Respect to Human Exposure to Radio
Frequency Electromagnetic Fields, 3 kHz to 300 GHz", Copyright 1992,
IEEE, Inc.

Hans dropped in a nice bibliographic note but did NOT say HOW
he arrived at his magical 50 W limit. :-)

Way too many variables in the amateur radio "station" arrangement
to say with some kind of certainty that 50 W is THE limit for any
class. FCC already showed that with a survey of some typical
California ham stations along with measurements of fields courtesy
of a couple of other government agencies and the hams who let them
all prowl around their property.

And that 50 watts affects calss A different than Class B?

I seriously doubt that a person that cannot handle 100 watts shild have
any license. Maybe class A shouldn't be alloed to have antennas over 10
feet off the ground either. Nasy falls.

100 Watts in a 50 Ohm system has an RMS RF Voltage of 70.7.
That's on the verge of burning human skin tissue.

50 Watts in a 50 Ohm system has 50 V RMS RF...still on the verge
of burning human skin tissue, although not as badly.

100 W of RF is little, piddly stuff to what I'm used to...like 15 KW up-
close-and-personal on HF, including walking around in antenna
fields of many and varied HF emitters...and 40 KW PEP HF stuff in
antenna fields in 1955. Most of us being personal with such powers
weren't suffering ill effects and almost all of us weren't licensed in
any "classes." We got the messages through.

---------

For some really in-depth looks at radio frequency radiation, go to the
Brooks AFB website and the documents at the USAF School of
Aerospace Medicine. The following is the cover page for one of the
shorter documents released in 1996:

http://www.brooks.af.mil/afrl/HED/he...uman-exposure/
cover.gif.html

That document title number is AL/OE-TR-1996-0035. It was
prepared in 1994. Be prepared to do a little math to find the
permissible RF field strengths...not much, just a little.

There's also FCC Office of Engineering and Technology
Bulletins 56 and 65 available on the FCC RF Safety webpage.
Only a few ANSI standards are free for download (if available),
the same with the IEEE site.

Maybe Hans will reveal what kind of aluminum suit he wears when
he fires up his "2.5 KW with increased drive" HF amplifier. :-)

LHA

"Bert Craig" wrote in
:

"Alun" wrote in message
...
"Bert Craig" wrote in
et:


"Alun" wrote in message
...
What is annoying is that a skill test is foisted on those who don't
have the desire to use the skill.

Alan, I'm gonna let you in on a secret...although I know that you're
already aware of it. Preparing for and passing the 5-wpm Elemnt 1
test does NOT leave one ready to use the skill OTA. It only gives
one a taste so that one may make an educated choice as to whether or
not they wish to persue CW any further.


5 wpm is certainly too slow to prove much, but it only still exists at
that level as a residual requirement to meet the old s25.5, which has
since been changed so that no code test is required atall. If the FCC
truly thought that a CW test was necessary, the speed would be higher.

Agreed, I was pointing out a very beneficial secondary benefit. It
"requires" one to place themselves in a position from which to make an
educated decision.

As I mentioned in another post, the mode is really not the
issue...the having to really learn it is. Do away with the published
Q&A pools and watch the whining escalate.

Well, I think that the real issue is that it's a different kind of
test.

Exactly.

Also, if
I hear CW on my frequency I may be able to read it with some
difficulty, but if I hear RTTY or PSK31 there is no chance.

You may have just touched on a selling point for CW.

73 de Bert
WA2SI

Whilst that is true, the point I was making is actually that since I
can't read RTTY or PSK by ear, and they are legal modes, it doesn't
help all that much that I can read CW (albeit not terribly well, since
I never use it).

73 de Alun, N3KIP

I understand the point you were making. If I could just ask you why you
bothered to take the code test(s)?

73 de Bert
WA2SI




To get all the _phone_ frequencies

"Bert Craig" wrote in
:

"Alun" wrote in message
...
"Kim W5TIT" wrote in
:

"Bert Craig" wrote in message
news "Dee D. Flint" wrote in message
gy.com...

"Alun" wrote in message
...
It just so happens that I don't
like CW, in the sense of I have no desire to use it. That
should be OK too, but for some reason it bothers you. Why?

No it does not bother me that someone who has learned it chooses
not to use it. They have made that decision from a position of
knowledge and experience. This is radically different from a
person judging it and saying they will never use it when they do
not have that knowledge and experience to draw on.

Dee D. Flint, N8UZE

Right on the money, Dee. Larry pointed this out earlier, but not as
eloquently as you.

73 de Bert
WA2SI



It fascinates me that you won't accept someone's plain and simple
truth that they don't like CW--even if they don't have experience
with it--because you reason that they need to have "knowledge and
experience" with it. Well, I know people who are quite well-versed
in CW who don't like it, people who haven't ever even tried it and
don't like it, and people who have taken and passed a 5wpm test and
don't like it. I also know people from those same three categories
that do like CW operation.

It's pretty much as simple as folks who do or don't like most other
things in life. Either ya like it or ya don't.

Kim W5TIT




I think that you have hit upon a very important point there, Kim. A
good analogy might be not liking an item of food that you haven't
tried, because it looks disgusting on your plate. If you eat some you
might like it, or not, but there are probably all kinds of other
things that contain the same nutrition. These guys are like a parent
telling a child that they have to eat their brocolli. But they aren't
my parents and I don't like brocolli, or CW. I take vitamins, and work
phone.

Slight difference, Alun. Nobody's forcing anybody to learn code. There
exists a no-code Technician license for those who do not wish to have
to pass the 5-wpm code exam.

73 de Bert
WA2SI




Not really true. No HF privileges with that licence, as we all know.

KØHB wrote:

"Mike Coslo" wrote


And that 50 watts affects calss A different than Class B?


Of course not. (This is another of those 'novel' questions.)

But my intention is that the Class B (learners permit with training wheels)
test be ultra simple, to allow as many applicants as possible. For that
reason, requiring qualification in esoterica like "Biological Effects and
Exposure Criteria for Radiofrequency Electromagnetic Fields" is
inappropriate. Thus the 50W power level recommended by the NCRP and
ANSI/IEEE ensures a modicum of safety for these beginners.

I would counter that it is a good idea for the initiate to know right
off the blocks that RF has some potential problems associated with it.

And while everyone talks about RF exposure, there are other problems
associated with RF that a person should know before they are allowed to
legally operate a rig. I had a problem trying to tune a longwire once,
and my trusty MFJ tuner nailed me good - bad knob design - it shouldn't
have the metal rim on the knob, which allows for some capacitive
coupling, so it seems. RF burns hurt! Power was probably around 50 watts.

I think the responsible thing to do, if safety is a concern, would be
to get those safety guidelines out of the way BEFORE going to advanced
licenses.


I also hope that your regulations would prohibit the Class B hams from
making or using a magloop antenna. I just did some calcs on a small
magloop for 40 meters, and at 50 Watts there is almost 5 kV across the
tuning cap. Ouch!


In the process of preparing for Class A (without training wheels) license,
the candidate would need to explore the RF-exposure safety issues which
would be on the qualification test. Then we could expect that they'd have
some appreciation of the hazards and how to ensure that their station is
engineered in compliance with the MPE criteria mandated by 97.13(c).

I think the candidate needs to know the safety issues long before this.
If the potential ham is smart enough to learn them for class A, they
should be smart enough to learn them for class B. If safety is first,
they shouldn't learn it second.

"N2EY" wrote:

(snip) The idea isn't that they'll have a high
level of expertise right off, but that they'll reach
that level through the 'incentive' of having to
either upgrade or leave the air. (snip)


To me, the entire idea is a solution seeking a problem. Since I don't
think the current license holders are lacking, I don't see any real benefit
(and I don't think the FCC will either). Regardless, his proposal would
require a complete re-write of all the rules relating to license class, when
a single sentence added to the existing rules would accomplish virtually the
same thing - "All license holders, except Extra, must obtain the next higher
license class within five years of obtaining their current license." Another
sentence might describe what will happen if that doesn't occur.


Dwight Stewart (W5NET)

http://www.qsl.net/w5net/