The carrier current project which had been planned, has been pulled.
The carrier current project which had been planned, has been pulled.
Noticing that the radios tune 520kHz, and seeing that Part 15.219 allows activity from 510 to 1705kHz, it seemed like a natural.
Here in the midwaste the 520 channel is completely open, awaiting my claim.
Have you so far detected my mistake?
Part 15.219 applies to 3-meter intentional radiation, but NOT to carrier current.
The carrier current allowance comes under Part 15.221, but has a different frequency span. It covers 525 to 1705kHz.
The disappointment goes deep, but at least I didn’t order a 520kHz crystal.
Why did the FCC make that slight difference between the two modes of radiation?
Clear Frequency During the Day?
Carl, do you have ANY frequency
on the low end of the AM band
that is at least empty during the
day? Here in West Hartford, 620 KHz
and 550 KHz are really clear.
Unfortunately, I have tried carrier
current here – only to find out that
my 5 watt LPB transmitter doesn’t
work anymore. I was going to get
a crystal for 620. The project is
not scrapped. I have a friend who
can fix anything. He wants to look
at the LPB transmitter.
The only other problem is – I had
a transmitter- to- power- line- coupler on
loan from a friend, but he needed it
back. Still, the project is not dead.
It’s just sleeping.
Best Wishes,
Bruce, MICRO1690/1700
What To Do
Bruce MICRO please get your LPB fixed, and here the situation is this:
520 is clear;
530 has an Illinois traffic TIS station;
540 is too close to
550kHz a 5kW local;
560 too close;
570 the only choice as we go on;
580 too close to
590 1kW sports station.
So, based on the above, is 570 worth doing?
570 kHz
Hi Carl. Well, 570 KHz is not too different
from 520 except for the obvious nighttime
interference. But I don’t think there is
anything wrong with being a Part 15 day
only station. Also, 570 is not directly
adjacent to the locals you mention.
One thing that is fun to do: Get a good
radio – turn it on and tune it to 570. Listen for
a couple of weeks and see what you
hear. Try not to turn the radio off. Just leave
it on in the background. This is how I chose
my daytime 1690 frequency. (I just thought
up one more thing – if you hear any splatter
from the 550 or the 590 then maybe 570
won’t work.)
Also, maybe there is a channel up in the 600s
you could try.
I’m not an expert, but I think once you start getting
higher than the 700s, carrier current doesn’t
work too well, but I don’t really know.
Best Wishes,
Bruce, MICRO1690/1700
P.S. Crystals under 1000 KHz are really
expensive. As an alternative – I was
thinking of putting a carrier current
operation on 1020 KHz, which is clear
during the day, just to see what would
happen. Of course, this is all academic
until the LBP gets fixed and I get another
coupler from somewhere. :^)
Oh yeah, I forgot
Carl, the title of this thread is “Project Pulled.”
Don’t pull the project around. It’s
too heavy.
Bruce, MICRO1690/1700
Very Heavy Humor
Bruce MICRO
You have a sense of humor that runs very deep down.
You are so right.
The project IS too heavy to pull around.
I will PUSH it around.
The Project is Pushed.
STEERING WHEEL?
Best Wishes, Bruce, MICRO1690/1700
channel spacing
It is best to have at least 30 Khz spacing above and below your intended frequency of operation. The list of frequencies your looking at only have 20 Khz above and below. Chances are excellent that listeners will pick up whistle if tuned to those other stations and are close to your location. The FCC channel spacing standard is 30Khz and occupied bandwidth is 10Khz ..even for non-licensed stations such as 15.219 and 15.221. It is also advisable to follow the NRSC curve specification which will also avoid the excess “splatter” and undetectable side bands produced without the NRSC spec which most AM radios will not even hear..unless it is a C-QUAM capable receiver.
It is also a myth that only the low portion of the AM band is usable for carrier current. My station operates on 1670 and is carrier current feeding the neutral wire and it covers well over 2/3 of the entire city of Casper with a power of 19 watts into a TCU-30 coupler.
It is true however that certain portions of the band work well in some locations and other portions of the band not work at all. It is best to experiment with a transmitter that can cover the entire band so as to test and locate the best frequency to use as well as the best coupling configuration to the grid based on the frequency used.
In other words…a frequency of 520Khz might not couple effectively in your area due to the power grid distribution configuration..but the frequency 1020 may work perfectly with the grid configuration.
CC broadcasting takes a lot of experimenting and testing to find the right combination that works for a given installation location. Different coupling configurations can also lead to the right combination that will work.
Addendum:
As to the reason why the FCC created such a confusing set of rules regarding the frequencies in one part and frequencies in another part can be considered as the biggest mystery of all time. Other than a manual crank tuning style radio, there is no digital radio that will tune 525, or 1705….but the rules state those two frequencies. Odd because of the standard 10Khz channel spacing which totally ignores 525 as well as 1705.
Just one of the confusing traits among others in the Part 15 section of the rules. Someday it might get straight…..someday.
RFB