My 4 sq did pretty well in the ARRL DX contest and also in CQ 160 SSB. But it was noisy. Perhaps because the elements were not tuned, with resonances from 1.78 to 1.84 MHz
I decided to tune the elements to around 1.83. The impedances were:
42 Ohms for NE
40 Ohms for NW
32 Ohms for SE
22 Ohms for SW
Weird. Did NE have too few radials? I added 8 extra 60ft radials, and the impedance dropped to only to 39 Ohms. Not much.
And why the impedance of the SW element was so low?
The elements for SE and SW were in the radial field of my shunt fed tower and the radial field of 4 sq for 80. So perhaps they behaved as having more radials. The SW element was close to the shunt fed tower tuned for 160m and apparently coupled. After shorting the shunt fed, which detuned the tower, the SW impedance increased to 32 Ohms as in the SE element. Hurrah!
Due to unbalanced elements, F/B is only about 10 db although. This is perfect for contesting as beaming in one direction still leaves some signal in the other directions. For better directivity there are beverages used with the 4 sq in diversity mode.
The 4sq controller by DXE has an omnidirectional mode, seemingly perfect for general contesting. But initially it had a resonance at 1.70 and SWR jumped to 2.5 at 1.84. I contacted DXE and they claimed that the omni mode is for receiving and occasional transmit. After tuning all elements to 1.83, SWR around 1.83 is about 1.5. But the resonance is narrow, as opposed to nearly flat SWR in the 4 sq mode.
Recently I tried calling CQ beaming EU and looking at spots from RBN. Many EU spots that I never saw with the shunt-fed tower.
G4IRN-# 1828.1 NO9E 0355Z 13 CW 11 dB 20 WPM CQ
NN3RP-# 1828.0 NO9E 0355Z 13 CW 5 dB 20 WPM CQ
VE6JY-# 1828.1 NO9E 0355Z 13 CW 5 dB 20 WPM CQ
DR4W-# 1828.1 NO9E 0355Z 13 CW 6 dB 20 WPM CQ
VE6WZ-# 1828.1 NO9E 0356Z 13 CW 14 dB 20 WPM CQ
OE9GHV-# 1828.0 NO9E 0356Z 13 CW 8 dB 20 WPM CQ
G4ZFE-# 1828.1 NO9E 0356Z 13 CW 7 dB 19 WPM CQ
S54L-# 1828.0 NO9E 0357Z 13 CW 7 dB 20 WPM CQ
MM0ZBH-# 1828.0 NO9E 0357Z 13 CW 5 dB 20 WPM CQ
S53A-# 1828.0 NO9E 0357Z 13 CW 4 dB 20 WPM CQ
OK1FCJ-# 1828.0 NO9E 0358Z 13 CW 7 dB 20 WPM CQ