Topband: Short receiving verticals question

[Eric NO3M]

ON4UN describes a method of "over swamping" the base of the topless 
verticals used in his four-square receive array.  On 80M, he switches in 
additional series resitance to arrive at a total feedpoint resistance of 
300 ohm, then steps down to 75 ohm using a split winding 4:1 (2T:1T 
ratio) transformer (also serves to mitigate common-mode).  This 
effectively increases operating bandwidth. See section 1.28 "The Mini 
Receiving Four Square at ON4UN" in Chapter 7 / Receiving Antennas, Fifth 
Edition.

I am doing some experiments with a 630M element currently using the same 
concept (though it is top loaded).  1.2:1 bandwidth was originally a 
mere 5 kHz.  With the additional swamping resitance and step-down, it is 
now at least around 20 kHz.

73 Eric NO3M