A correction on the LOWFER Morse code speed: it's around 1/2000 word per second and that is about 1/30 word per minute. The bandwidth is closer to 0.03 Hz.
Setting up a 50-foot tower with industrial sized loading coil requires a lot of effort for a station that wants the little result described above for an AM modulated Long Wave signal.
Yet it's in the plans so KDX can say we are one of America's only Long Wave radio stations.
Trouble is, if I really do it, it will be harder to convincew people I'm not crazy.
Carl, your LF BC station project sounds like fun and I'll help out if you'd like.
It shouldn't be very difficult to get a proper antenna installed. The 50' antenna can take many forms. A standard 43' amateur self-supporting aluminum mast with a CB whip, or HamTenna, on the top, will work. Or, a ground lead up the side of a building with the remainder of the antenna being a guyed TV mast would also work. A third option is an inverted-L. The antenna goes vertical for some distance and then horizontal; like 25' up and 25' out. A shorter antenna can be made to work with the tradeoff being reduced range. With the series broadbanding resistance, the antenna impedance will be high (around 300 ohms) and the transmitter needs to be designed for this, or a matching network can be inserted between the transmitter and the antenna.
The loading coil does not have to be a big, loss-loss type used by the LOWFER guys. Because we need loss to broadband the antenna the loading coil can probably use #22 or thinner wire. I can work out the details (loss, size, etc.) if you'd like. An example of an air-wound 5mH coil is 600 turns of #22 bell wire close-wound on a 4" PVC pipe. The coil dimensions are 3" x 13". The ground system need not be low loss and a ground rod will do the job.
Great, davec! Thank you for the offer to help with the build of a part 15 LW transmitting system.
The inverted-L sounds interesting. Is it directional and if so what determines its direction?
I'll check around town for a HAM antenna installer, a professional 25' vertical tower might go better with picky neighbors.
I've built some coils for MW and enjoy doing that.
Also this year I want to arrive at a way of running 100' cables back to a 3-meter antenna for 1680 kHz AM.
I want the MW antenna to be as far from the building as possible for the fun of receiving the station from a distance.
The 25' tower could be attached to a building wall, which probably would dictate which direction the horizontal wire would be hung.