Power is distributed from an electrical substation to the public as 3-phase power. Typically one transformer on one phase will power several houses. All the houses on the transformer secondary are in parallel.
Carrier current injected onto both hot lines referenced to neutral will be carried to all circuits on the secondary lines. The carrier current will not pass from the secondary of the transformer to the primary which is why coverage is limited to connections on the secondary side of one transformer.
Some large, multistory apartment buildings are fed from a 3-phase transformer bank, three separate transformers on three separate phases. Each transformer supplies 120/240 VAC referenced to the transformer secondary neutral.
As such, it is possible that the service to different apartments may not be on the same transformer.
That being the case, unless you are using neutral injection your CC signal being fed to circuits on one transformer would be isolated from the other two. Neutral injection might work as all the neutrals are bonded together.
Even though three phases are in use, the power fed to each panel would be considered single phase.
In some cases, actual 3-phase power is used to develop 120/208 VAC. This happens where each transformer outputs 120 VAC, 120 degrees phase shifted from one to the next. 208 VAC would be found when connecting between any two 120 VAC phases.
In that situation, the CC coupler would have to connect to all three phases to cover the whole building.
Again, neutral injection would cover the whole building but the problem with neutral injection in any situation would be obtaining an isolated ground to connect the other side of the coupler.
The reason to use 3-phase power for an application as such is to balance the loading equally across the 3 separate phases.
Therefore it may be a needless exercise to use 15.219 when operating an indoor system under part 15 ... I would say that 15.209 would be the better choice for indoor installations, ...
Just to note that an unlicensed system using intentionally radiating hardware totally inside that building might produce higher fields compliant with FCC §15.219 than one compliant with §15.209.
Even if the only goal is to serve receivers inside a building, they might better be served by the higher fields radiated by a transmit system possible under §15.219 than §15.209.
Proving compliance in either case is difficult, though, as using a transmitter that has a certificate of compliance for Part 15 AM may not actually meet either §15.209 or §15.219, depending on setup, and installation details.
Putting the coupler in the building's utility room would solve that problem.
RFB
Maybe hook it up in the utility room if you have an in with the building Super.
And, they'd probably require a licensed electrical contractor to hook it up, liability and all you know.
When the furnace maintenance man was doing a safety inspection I wondered if he'd ask about the carrier current equipment rack located 20-feet from where he was working, and wired as it is to the electrical service. I don't think he noticed it.
But in my thoughts I realized how strange it would be to explain that it was a radio transmitter that worked by sending radio through the power lines. Would that warrant a tip to homesick security?
Trying to explain all that to a building supervisor might be a hard sell, and something he would prefer not to risk.
dammit!!!! our neutrals between buildings aren't tied together!!!!!!
i don't do any better than the 219 here with 221!!!!
well next up is to do the reverse and load the cold water pipes as the hot and use the electrical ground as the ground.
You know a lot more than
I do about this, but please
take it easy anyway.
I think that some listeners
is better than none.
Here's my weird situation.
I have been in 2 houses on
my street where friends live.
One house is about 700 feet away.
The other house is about 1000
feet away.
I can get my station in the
"1000 feet away" house, but
not in the "700 feet away" house.
As I get this working better and
better and get into more friend's
houses, I will probably figure
out why this is the case.
In the meantime, It's an interesting
mystery.
Bruce, W 60 HZ, X-13
"our neutrals between buildings aren't tied together!!!!!!"
Your facing the same situation as the college dorm buildings, each being fed by their own step down transformer which will mean, each building has their own neutral.
Loading to the cold water pipe, which "may" be interconnected with all the buildings (if there isn't something isolating them..like non-conductive piping feeding each building from the main) might be the answer.
But your going to need an isolated ground and not use the power grid neutral or ground for that return path to the coupler.
On college campuses, to overcome this issue they ran coax to each building from a power splitter and then to another coupler for each building. Obviously that cannot be done where your at.
Use the 219 on the balcony for overall complex coverage and the 221 for your building. Beyond that...your pretty much stuck.
RFB
i have that behringer DSP9024 coming. the XYL bought it for me. that will boost my signal on the fringes a little better.
call it a poor mans optimod.
It's the best choice next to dumping a few grand on something most radios won't even hear or detect anyway.
RFB
i have long thought 3 grand for a used 30 y/o processor you cant get parts for anymore was overly ridiculous!!!! that sad1024 chip goes you have 3k doorstop