All,

I have a situation, and would like some opinions rather than flames on
how to handle it. My wife teaches at a public school just off the
Easter Arizona Navajo reservation. Lately, a junior school science
teacher is starting up a science club and has asked me to provide for
the amateur radio side of the club and be its control operator.

She believes that the kids would be fascinated by the Morse code -
Dxing - Construction end of the hobby, even though Morse is no longer a
required test element.

The kids are mostly Navajo and thusly have a very limited technological
background (hence the reason for the club to stir the interest), so I
need something concrete with immediate payoff to keep their interest
hooked while getting them as ready as I can to write their Technician
exam. The nearest VEC is 4 hours away and I'd rather have as few fail
as possible.

I had thought to start an unlicensed micro-power code practice net
whose range would be limited to about a 30 mile radius, which is about
the size of the local reservation right next to the school.

What I want to do is provide each kid with a popcorn CW transceiver for
the colorburst frequency (3579 khz), a key, a short random wire, and a
battery. That way they could practice amongst themselves with
myself as occasional net control.

My question is this: so long as final output to the antenna is within
the requirement of part 15 unlicensed operation, is part 15 unlicensed
operation allowed within a band normally governed under part 97?
Part 15 operation would easily cover a 30 mile radius on 80M.

If no, I'll run the net under part 15 on the edge of the AM band near
160M.

Thanks in advance,

The Eternal Squire

wrote:
All,

I have a situation, and would like some opinions rather than flames on
how to handle it. My wife teaches at a public school just off the
Easter Arizona Navajo reservation. Lately, a junior school science
teacher is starting up a science club and has asked me to provide for
the amateur radio side of the club and be its control operator.

She believes that the kids would be fascinated by the Morse code -
Dxing - Construction end of the hobby, even though Morse is no longer a
required test element.

The kids are mostly Navajo and thusly have a very limited technological
background (hence the reason for the club to stir the interest), so I
need something concrete with immediate payoff to keep their interest
hooked while getting them as ready as I can to write their Technician
exam. The nearest VEC is 4 hours away and I'd rather have as few fail
as possible.

I had thought to start an unlicensed micro-power code practice net
whose range would be limited to about a 30 mile radius, which is about
the size of the local reservation right next to the school.

What I want to do is provide each kid with a popcorn CW transceiver for
the colorburst frequency (3579 khz), a key, a short random wire, and a
battery. That way they could practice amongst themselves with
myself as occasional net control.

My question is this: so long as final output to the antenna is within
the requirement of part 15 unlicensed operation, is part 15 unlicensed
operation allowed within a band normally governed under part 97?
Part 15 operation would easily cover a 30 mile radius on 80M.

If no, I'll run the net under part 15 on the edge of the AM band near
160M.

Thanks in advance,

The Eternal Squire

Wouldn't it be easier to just read part 15 rather than starting what
is bound to be a major flame war between the barracks lawyers?

--
Jim Pennino

Remove .spam.sux to reply.

writes:

All,

I have a situation, and would like some opinions rather than flames on
how to handle it. My wife teaches at a public school just off the
Easter Arizona Navajo reservation. Lately, a junior school science
teacher is starting up a science club and has asked me to provide for
the amateur radio side of the club and be its control operator.


[much snippage]...

I won't flame you at all -- I admire your elmering, and think it's a
great idea.

I'd be exteremely careful to make sure you meet the field-strength
requirements of Part-15 with whatever project you do -- it can be
remarkably easy to get foul of it and reliable measurements require
skill.

Besides 80m and the top of the AM ex-band you might also consider
the lowfer 1750m stuff ... Lots of kits out there for it, and an
active user community.

Of course getting them all licensed would be the best solutiuon ...

Junior high is probably just at the edge of where passing the novice
or tech written would be a cake-walk. As I used to joke to my
classes, "there's three parts to the written -- three engineering
formulae: E=IR ; c = f lambda ; 40inches in a meter., a handful of
common sense questions, and a few memorizable factoids" (band edges,
etc.)

I had a sixth grader of average intelligence in one class - it was a
little harder for her, but she passed it on her second try.

--
Lawrence Statton - m s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
place them into the correct order.

I'm a bit more worried about having them memorize the Clapp, Colpitts,
and Pierce
Oscillators. Isn't that stuff still on Tech exam?

The Eternal Squire

On Jan 25, 8:01 pm, Lawrence Statton XE2/N1GAK
wrote:
writes:
All,

I have a situation, and would like some opinions rather than flames on
how to handle it. My wife teaches at a public school just off the
Easter Arizona Navajo reservation. Lately, a junior school science
teacher is starting up a science club and has asked me to provide for
the amateur radio side of the club and be its control operator.[much snippage]...

I won't flame you at all -- I admire your elmering, and think it's a
great idea.

I'd be exteremely careful to make sure you meet the field-strength
requirements of Part-15 with whatever project you do -- it can be
remarkably easy to get foul of it and reliable measurements require
skill.

Besides 80m and the top of the AM ex-band you might also consider
the lowfer 1750m stuff ... Lots of kits out there for it, and an
active user community.

Of course getting them all licensed would be the best solutiuon ...

Junior high is probably just at the edge of where passing the novice
or tech written would be a cake-walk. As I used to joke to my
classes, "there's three parts to the written -- three engineering
formulae: E=IR ; c = f lambda ; 40inches in a meter., a handful of
common sense questions, and a few memorizable factoids" (band edges,
etc.)

I had a sixth grader of average intelligence in one class - it was a
little harder for her, but she passed it on her second try.

--
Lawrence Statton - s/aba/c/g
Computer software consists of only two components: ones and
zeros, in roughly equal proportions. All that is required is to
place them into the correct order.

On 25 Jan 2007 19:29:27 -0800, wrote in .com:
I'm a bit more worried about having them memorize the Clapp, Colpitts,
and Pierce
Oscillators. Isn't that stuff still on Tech exam?

The Eternal Squire

OhHellNo! Techs need to memorize band edges and remember the 2 basic
rules: E = I * R, c = lambda * f, and a meter is really close to 40".

I doubt it's even on the _commercial_ exams any more, though it sure
was when I got my Second Phone, back in 1962.

--
Mike Andrews, W5EGO

Tired old sysadmin

On 25 Jan 2007 19:29:27 -0800, wrote in .com:
I'm a bit more worried about having them memorize the Clapp, Colpitts,
and Pierce
Oscillators. Isn't that stuff still on Tech exam?

The Eternal Squire

OhHellNo! Techs need to memorize band edges and remember the 3 basic
rules: E = I * R, c = lambda * f, and a meter is really close to 40".

I doubt it's even on the _commercial_ exams any more, though it sure
was when I got my Second Phone, back in 1962.

--
Mike Andrews, W5EGO

Tired old sysadmin

wrote in message
oups.com...
I'm a bit more worried about having them memorize the Clapp, Colpitts,
and Pierce
Oscillators. Isn't that stuff still on Tech exam?

The Eternal Squire


Nope. It's not on either the Tech or General exams. It does show up on the
Extra exam. Even at that a person might or might not get that question on
their particular exam. Take a look at the Tech test pool on the ARRL set.
You will see that it just covers basic stuff.

Dee, N8UZE

wrote in message
ups.com...

My question is this: so long as final output to the antenna is within
the requirement of part 15 unlicensed operation, is part 15 unlicensed
operation allowed within a band normally governed under part 97?
Part 15 operation would easily cover a 30 mile radius on 80M.

http://www.access.gpo.gov/nara/cfr/w...7cfr15_06.html

Part 15.223 says in part...

"Subpart C_Intentional Radiators
Sec. 15.223 Operation in the band 1.705-10 MHz.

(a) The field strength of any emission within the band 1.705-10.0
MHz shall not exceed 100 microvolts/meter at a distance of 30 meters.
However, if the bandwidth of the emission is less than 10% of the center
frequency, the field strength shall not exceed 15 microvolts/meter or
(the bandwidth of the device in kHz) divided by (the center frequency of
the device in MHz) microvolts/meter at a distance of 30 meters,
whichever is the higher level."

For CW operation, your bandwidth is zero for all practical purposes. You
will therefore be allowed 15 uV/m at 30 meters.

From this I made a very crude estimate of your allowed transmitter output
power. Assuming your transmitter antenna is 100% efficient and radiates
hemispherically, your transmitter output power is allowed to be no more than
about 1.7 nanowatts (1.7e-9 watts). For ideal circumstances (0 dB receiver
antenna gain, 100% efficient receiver antenna), you would get less than 5 uV
at a receiver 400 meters away. I stress that this is for ideal
circumstances. If your transmitting antenna is less efficient, you can run
more power, but less of your power gets launched. How efficient is that
antenna, anyway? On the other hand, your antenna may have some directivity
which would further limit your power.

This is making my head hurt.

All that can really be said about this estimate is that, to be safe, you
should not have much more than about 2 nanowatts output power unless you
have the ability to measure the field strength according to regulations.

Good luck with your project.

73,
John

John,

So, say I had a CW oscillator on the colorburst frequency. I'll shunt
the output
with a 50 ohm resistor to ground. I'll put a random wire at the top of
the
resistor.

Basic equations yield P = (EE) / R

If R is 50 Ohms and maximum output power is 1.7e-9 watts, then E
is 4.1e-5 volts.

So, would a measurement of 40 microvolts or less across the resistor
be satisfactory?

Thanks,

The Eternal Squire

On Jan 25, 9:44 pm, "John" wrote:
wrote in oglegroups.com...

My question is this: so long as final output to the antenna is within
the requirement of part 15 unlicensed operation, is part 15 unlicensed
operation allowed within a band normally governed under part 97?
Part 15 operation would easily cover a 30 mile radius on 80M. http://www.access.gpo.gov/nara/cfr/w...7cfr15_06.html

Part 15.223 says in part...

"Subpart C_Intentional Radiators
Sec. 15.223 Operation in the band 1.705-10 MHz.

(a) The field strength of any emission within the band 1.705-10.0
MHz shall not exceed 100 microvolts/meter at a distance of 30 meters.
However, if the bandwidth of the emission is less than 10% of the center
frequency, the field strength shall not exceed 15 microvolts/meter or
(the bandwidth of the device in kHz) divided by (the center frequency of
the device in MHz) microvolts/meter at a distance of 30 meters,
whichever is the higher level."

For CW operation, your bandwidth is zero for all practical purposes. You
will therefore be allowed 15 uV/m at 30 meters.

From this I made a very crude estimate of your allowed transmitter output
power. Assuming your transmitter antenna is 100% efficient and radiates
hemispherically, your transmitter output power is allowed to be no more than
about 1.7 nanowatts (1.7e-9 watts). For ideal circumstances (0 dB receiver
antenna gain, 100% efficient receiver antenna), you would get less than 5 uV
at a receiver 400 meters away. I stress that this is for ideal
circumstances. If your transmitting antenna is less efficient, you can run
more power, but less of your power gets launched. How efficient is that
antenna, anyway? On the other hand, your antenna may have some directivity
which would further limit your power.

This is making my head hurt.

All that can really be said about this estimate is that, to be safe, you
should not have much more than about 2 nanowatts output power unless you
have the ability to measure the field strength according to regulations.

Good luck with your project.

73,
John

wrote:
John,

So, say I had a CW oscillator on the colorburst frequency. I'll shunt
the output
with a 50 ohm resistor to ground. I'll put a random wire at the top of
the
resistor.

Basic equations yield P = (EE) / R

If R is 50 Ohms and maximum output power is 1.7e-9 watts, then E
is 4.1e-5 volts.

So, would a measurement of 40 microvolts or less across the resistor
be satisfactory?

Thanks,

The Eternal Squire


Good question. And, although I support the effort, which was stated, in
helping the youngsters--you also must recognize I would be slow to give
advice. I don't wish to invoke the pointy-headed attorneys when I have
no horse in the race ... grin

Proceed at your own peril ...

Warmest regards,
JS