[TowerTalk] Flag Antenna Transformer

[Tony Brock-Fisher]

I have a flag antenna which has worked well for several years. I used a Minicircuits T16-6 transformer to couple the ~800 ohm termination resistance of the antenna to 50 ohm line. Recently I decided to do some upgrades, so I followed the recommendations of many (here and elsewhere) and made a matching transformer using an FT-140-43 core and 34:8 turns, secondary and primary on opposite sides of the core. I didn't have any #28 wire so I used #24. I tested this with a miniVNA, terminating the antenna side with an 800 ohm noninductive resistor. The impedance does not look right at all; there is a lot of inductive reactance and the resistive part starts at 125 ohms and climbs steeply from 1.7 MHz. No on-the-air results yet.

I'm wondering if this is right or not - measurements indicate the DIY transformer is much worse than the T16-6 in terms of presenting a good match. 

This would not be the first case of theory saying it won't work but practice says it will - just looking for a reality check here. Seems to me like the core material is all wrong...

-Tony, K1KP