I originally thought the MF was 373 in Medford, but I am confident in my receivers frequency accuracy. I have not however heard MF again, from either location. and certainly not in the daytime. Even MEF in Medford is usually weak here. I would love to have heard MF in Ohio, and maybe I did, but I wont assume until I log it again.
The transformer I use is a small 1.25 inch moly toroid, with 100 turns of 24 ga. magnet wire and 5 turns of 18 ga. insulated wire. The 5 turn winding is secondary and feeds my 50 ohm input directly. the 100 turn winding is fed by a 25 foot tall, 35 foot long inverted L, against ground.
You may be aware of this but FWIW, U.S. beacons are modulated at 1020 cycles. Therefore a signal will be heard offset 1020 cycles either side of the carrier frequency. In other words, a beacon transmitting on a frequency of 373 will be heard at 372 and 374. Canadians mostly use 400 cycle modulation. Some beacons, especially Canadians, may only transmit one sideband, usually upper.
In actual practice this can be interesting, for example, if your receiver has narrow enough bandwidth, you may be able to receive a U.S. beacon and a Canadian beacon both assigned and transmitting on the same frequency. Tuning upwards you will first hear the U.S. lower sideband then the Canadian then the U.S. upper sideband.
This does not necessarily mean that you didn't hear the Ohio beacon. You may have heard it because MF Mansfield has been reported heard in California.
Otherwise, thanks for the transformer info.