Science Fair Project
 

On Fri, 09 Feb 2007 17:51:26 -0800, Jim Kelley
wrote:

We can only hope that your unfortunate correspondent
continues trying to imagine it long enough to happen upon the reason.

Jim, If you prefer to think of our correspondent as a shrinking
violet, destiny is already written in the thread. The suggestions
I've offered have been seconded by several others. Do you want to
explain any one or all of them?

73's
Richard Clark, KB7QHC

Science Fair Project
 

"David G. Nagel" wrote in message
...

FCC part 15 regulations specify that a low power am transmitter can not
exceed a very low power level ( I don't remember off hand how much)

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

PART 15_RADIO FREQUENCY DEVICES--Table of Contents
Subpart C_Intentional Radiators
Sec. 15.219 Operation in the band 510-1705 kHz.

(a) The total input power to the final radio frequency stage
(exclusive of filament or heater power) shall not exceed 100 milliwatts.

and the antenna must be attached to the transmitter and must not exceed
about 5 or 6 feet.(b) The total length of the transmission line, antenna
and ground
lead (if used) shall not exceed 3 meters.

Science Fair Project
 

"John" wrote in message
...

The last paragraph of my post got munged. It should be:

and the antenna must be attached to the transmitter and must not exceed
about 5 or 6 feet.


(b) The total length of the transmission line, antenna and ground lead (if
used) shall not exceed 3 meters.

Science Fair Project
 

John wrote:
"David G. Nagel" wrote in message
...

FCC part 15 regulations specify that a low power am transmitter can not
exceed a very low power level ( I don't remember off hand how much)

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

PART 15_RADIO FREQUENCY DEVICES--Table of Contents
Subpart C_Intentional Radiators
Sec. 15.219 Operation in the band 510-1705 kHz.

(a) The total input power to the final radio frequency stage
(exclusive of filament or heater power) shall not exceed 100 milliwatts.

and the antenna must be attached to the transmitter and must not exceed
about 5 or 6 feet.(b) The total length of the transmission line, antenna
and ground
lead (if used) shall not exceed 3 meters.



Thank you for the information. This is something I know but not in
intimate detail. This is what the student was looking for but the dark
side of the net had to have it's way with the subject.

I hope it helps the student with his science project.

Dave Nagel
WD9BDZ

Science Fair Project
 

On Sat, 10 Feb 2007 12:06:06 -0600, "David G. Nagel"
wrote:

I hope it helps the student with his science project.

Hi Dave,

That is of infinite improbability. How many times do we have to tell
adult amateur radio enthusiasts the necessity of matching (a warning
already offered from the shadows of this thread)?

So, shall we consider the merit of a total length of 3 meters in the
AM band? If this discussion is so studiously avoided by those who
weep away about the dearth of information, what chance does a naive
student have to rummage up the details?

The Rr summons up to roughly 20mOhms. Are any of the scolds going to
offer the implications of this value? Are there any suggestions of
using commercial tower sections to cut down on Ohmic loss? Any
matching details for the massive SWR? Any hints on how to load the
structure? Details for a top hat? Would the top hat consume part of
that 3 meter restriction?

Would a loop perform better? What dimensions? How to build the
capacitors? Talk about underwhelming help....

the dark side of the net had to have it's way with the subject.

The dark side is not patronizing with soothing but impotent nostrums.
The topic reduces to one of two resolutions:
1. Deep consideration of many issues;
2. Buy a kit that works as advertised.
One takes many here a lifetime of consideration and books are devoted
to this study, the other satisfies a need.

73's
Richard Clark, KB7QHC

Science Fair Project
 

Richard Clark wrote:

On Fri, 09 Feb 2007 17:51:26 -0800, Jim Kelley
wrote:


We can only hope that your unfortunate correspondent
continues trying to imagine it long enough to happen upon the reason.


Jim, If you prefer to think of our correspondent as a shrinking
violet, destiny is already written in the thread. The suggestions
I've offered have been seconded by several others. Do you want to
explain any one or all of them?

73's
Richard Clark, KB7QHC

So what you're saying is that although you could explain how to make a
loopstick antenna resonate at 1 MHz and properly couple it to a
crystal oscillator circuit, you feel that someone else should do it
for you.

ac6xg

Science Fair Project
 

"T" wrote in message
oups.com...
Thank you mr. kelly for trying to help me out, but obviously richard
is too hostile to want someone else, even a kid, to learn anything
about radio engineering. [you know, since he probably never tinkered
with electronics when he was a kid and asked someone for advice] =
sarcasm

i'm slightly disappointed in him. a grown man, who attacks eager to
learn children over the internet. do you not have friends? a life?

besides if you don't help people, but instead show them hostility,
don't you think they may become discouraged? maybe even give it up and
quit? if there is no one interested in this type of engineering, then
it may cease to exist.

all i'm saying is, be an encourager, help others, and go with god.

"since new developments are the products of a creative mind, we must
therefore stimulate and ENCOURAGE that type of mind in every way
possible." -george washington carver

sorry to be so short, and thanks to everyone who tried to help,
taylor

Oh no! Another victim! This time it is an alleged kid. I thought everybody
gave him plenty of good, free advice.

Science Fair Project
 

On Mon, 12 Feb 2007 18:59:24 -0500, "Stefan Wolfe"
wrote:


"T" wrote in message
roups.com...
Thank you mr. kelly for trying to help me out, but obviously richard
is too hostile to want someone else, even a kid, to learn anything
about radio engineering. [you know, since he probably never tinkered
with electronics when he was a kid and asked someone for advice] =
sarcasm

i'm slightly disappointed in him. a grown man, who attacks eager to
learn children over the internet. do you not have friends? a life?

besides if you don't help people, but instead show them hostility,
don't you think they may become discouraged? maybe even give it up and
quit? if there is no one interested in this type of engineering, then
it may cease to exist.

all i'm saying is, be an encourager, help others, and go with god.

"since new developments are the products of a creative mind, we must
therefore stimulate and ENCOURAGE that type of mind in every way
possible." -george washington carver

sorry to be so short, and thanks to everyone who tried to help,
taylor

Oh no! Another victim! This time it is an alleged kid. I thought everybody
gave him plenty of good, free advice.


Hummm. . . Being "Short", huh? Short would have been simply "Go
jump in the lake, Buddy!"
Hehehehe

FFF

Science Fair Project
 

Richard Clark wrote:
On Sat, 10 Feb 2007 12:06:06 -0600, "David G. Nagel"
wrote:

I hope it helps the student with his science project.

Hi Dave,

That is of infinite improbability. How many times do we have to tell
adult amateur radio enthusiasts the necessity of matching (a warning
already offered from the shadows of this thread)?

So, shall we consider the merit of a total length of 3 meters in the
AM band? If this discussion is so studiously avoided by those who
weep away about the dearth of information, what chance does a naive
student have to rummage up the details?

The Rr summons up to roughly 20mOhms. Are any of the scolds going to
offer the implications of this value? Are there any suggestions of
using commercial tower sections to cut down on Ohmic loss? Any
matching details for the massive SWR? Any hints on how to load the
structure? Details for a top hat? Would the top hat consume part of
that 3 meter restriction?

Richard, I dare say that the 3 meter limit, and the horrible mismatch
achieved with such an antenna just might be part of the whole idea of
part 15 transmission. The user isn't supposed to put much of a signal on
the air. It's supposed to be a technically poor setup.

Of course, assuming that the science fair is taking place in a school
building, the student could operate as a campus transmitter. Lots of
extra steps and paperwork there though.


Would a loop perform better? What dimensions? How to build the
capacitors? Talk about underwhelming help....

Seems like a good way to go for the kid would be to buy a kit or
better, build a radio from scratch, keeping within the legal limits.

Asking for help in here can be confusing enough for a new Ham, let
alone a young schoolkid.




the dark side of the net had to have it's way with the subject.

I have these visions of you making Darth Vader sounds, and saying
"I...am your father T."...... 8^)


- 73 de Mike KB3EIA -

Science Fair Project
 

On Fri, 16 Feb 2007 15:18:36 -0500, Michael Coslo
wrote:

Richard, I dare say that the 3 meter limit, and the horrible mismatch
achieved with such an antenna just might be part of the whole idea of
part 15 transmission. The user isn't supposed to put much of a signal on
the air. It's supposed to be a technically poor setup.

Hi Mike,

All duly offered in the past.

Seems like a good way to go for the kid would be to buy a kit or
better, build a radio from scratch, keeping within the legal limits.

That too was offered.

the dark side of the net had to have it's way with the subject.

I have these visions of you making Darth Vader sounds, and saying
"I...am your father T."...... 8^)

Myself, I would substitute Dark Helmet from "Spaceballs"
"I am your father's brother's nephew's cousin's former roommate."
given the avalanche of other advice that filled the void.

Lone Starr:
"What's that make us?"

Dark Helmet:
"Absolutely nothing!"

73's
Richard Clark, KB7QHC