Assembly Handbook and Coax Transformer construction details for the Mosley TA-36 Tri-band beam antenna.
I have constructed a transformer as described above and terminated the transmitter end of the transformer with a 51 Ohm chip resistor, I then measured the impedance at the pigtail end using an Autec research Vector analyst. At 14.2 MHz the impedance was 29 -j12 ohms at 21.2 MHz 24 -j1 ohms and at 28.8 MHz 20+j8 ohms. These are very likely correct impedance’s to provide a conjugate match for the driven element of a multi-element beam antenna. Tests on an actual beam in the coming weeks will reveal whether this transformer will give a good match from the beam to a 50 ohm feed line.
After an inquiry regarding the manufacture of a transformer, Mosley stated that “A field repair can be done, but usually the match is not achieved”. Moseley Electronics Still produce the Original transformer at $99.95 USD, Shipping and handling not included.