0:15 Look at all those massively wide copper straps going into the building on the left! Is the whole site covered underneath the ground with copper to provide a ground plane for the antenna?
i'm quite impressed that those can be even 90% efficient (based on a quick google search) - i would have assumed that it was much lower based on the lack of a core as well as the huge amount of space between. i wonder how strong the stray magnetic field would be from this as well.
@@vinylcabasse I guess I misunderstood what you meant I still don't think the stray field would be very strong though ( well, as much as you can call something connected to a radio mast "not strong" )
There's actually only one core. The lower ring holds a core, toroidally wound, while the upper ring just holds a regular ring coil... further spaced, but still wrapping in the same direction through the same core as the toroidal windings.
I wonder how driving up to the fence with a couple of large transformer coils in the back rectified leading to a battery bank would go? Surely there's some thick waves to ride there!
@@etherealrose2139 The fall off is exponential? If the power is high enough surely there is something left to gather? Not free of course, well I'm not paying anyway but that's semantics. . .. Over time if it's enough to overcome charging resistance + power stored is still + But I concede, the time it would take to pay for the copper in the coils alone is too much, let alone the bank ect
Where would this be, I've seen a couple of these masts with the "hat" on top which I assume helps to keep the signal more effective and gives it distance. Cheers.
70 Kilowatts. I am jealous. I only have 2KW - BUT I use a 10.5 db gain antenna (Kt34XA upgraded to KT36XA) which becomes 22KW effectively, according to my db calculator. So I don’t feel quite so inadequate. VE6MRV
The entire tower needs to be energized because the whole tower is the antenna. There isn't some small antenna at the top, but rather the entire tower is the antenna.
Because tower impedance changes and RF voltage will be quite high at some parts of the tower. If you take a simple, old school 103" CB whip, it is fed low impedance at the base with coax, and the Z and RF voltage is lowest. 1/4 wave away, at the tip, voltage is highest in that case, and even with low power CB you could get an "RF burn" at the tip. So any lighting wire would arc at some point on the AM tower
The core is rarely air... in fact it's all in the lower ring, with the primary winding spiralling around it. The secondary winding is a straightforward wrap around the secondary ring, coupling it to the (air-gapped) core in the primary.
can someone else explain the rings? like are they safety protocol for something? what do they do. all I heard was something with 220v. are they used for disconnecting power? I'm lost
The rings transfer AC power to the lights on the tower without also connecting the mast itself to the AC power source, which would result in some fireworks.
Hold a fluorescent tube. We used to do that near Winter Hill, UK. When the old analogue TV TX was pushing huge amounts of power they lit for some distance.
The entire tower is hot with RF and is above ground so far as RF. Think of an old school CB antenna. The entire antenna is insulated from the car body, and fed at the base with coax. Now think of THAT as a 70KW am tower. Much higher voltages and highest at the top
maybe 5-10% at most? toroidal transformers encapsulate the majority of the magnetic field internally, the only place for losses to go is in heating the core itself.
None of the three involved devices is going obsolete any time soon. We need towers to spread radio signals over long distances, we need visual features like lights on towers to guide planes away from obstacles and terrain, and we still use transformers to couple AC power. They're elementary tools we use to manipulate electromagnetic radiation, not just old technology.
