Topband: K9AY "SWR" observations

[VO1HP]

Today just for fun I measured my K9AY system from the shack end of the coax using an MFJ-259B

The loops are fed with RG6 from the antenna to a junction point in the yard where the RG6 interconnects with RG58 which runs into the shack and terminates on the Loop controller.(WX0B)
Total feedline lengthapprox 120ft.

Here's what I see:

Minimum SWR 1.2:1  at 2.8 Mhz

Resonance Mode on MFJ 
X=0  at 2.0Mhz

R=58   X=26  at 1.83 Mhz   SWR 1.6

Max Match Efficiency  99% at  2.8Mhz
MAtch Efficiency  93% at  1.83Mhz

At 1.83 Mhz min SWR (1.5) occurs with Terminating resistor switch in position 1

At 2.8 Mhz min SWR (1.2) occurs with Terminating resistor switch at position 8

So what am I seeing here?....should I be seeing loop resonance closer to 1.8 Mhz?  Shouldn't best efficiency match be closer to  the 160M band?  Does it matter that the best match is 1 Mhz away from where I want to operate?

The loops appear to be working but becasue the K9AY is only about 50ft from my tower and 160M Inv L there is some distortion of the pattern but would that proximity impact on loop measurement that i am seeing.?

Can anyone enlighten me?

73 Frank VO1HP
www.vo1hp.ca