I could not find my original data, so I create a new set to try to show
where I have a 'problem'.

Below, a random short inverted-V for 80, delivering a Z-in of around
16.3 - j 826 ohms

CM Short Inverted V for 80 Mtr.
CE
GW 1 25 -9.829825 0 14.117083 -0.3 0 21 5e-4
GW 2 3 -0.3 0 21 0.3 0 21 5e-4
GW 3 25 0.3 0 21 9.8298245 0 14.117083 5e-4
GE
LD 5 0 0 0 58000000
GN 2 0 0 0 14 .006
EX 0 2 2 0 1 0
FR 0 1 0 0 3.6
XQ

************************************************** ******

Next, the data that was entered in the Cebik spreadsheet, Tab E
http://www.cebik.com/download/ant-match.xls

Using 50 ohm 'coax' (0.66) as feed/match line and 300 open-line (0.8)
as stub.

Yes, a strange combination, but I choose these to get exceptional
results.

Antenna Load Resistance RL 16.3 Ohms
Antenna Load Reactance XL -826 Ohms
Frequency in MHz FQ 3.6 MHz
Zo of Matchline ZL 50 Ohms
Velocity Factor of Matchline VFL 0.66
Zo of Main Feedline ZF 50 Ohms
Velocity Factor of Feedline VFF 0.66
Zo of Stub ZS 300 Ohms
Velocity Factor of Stub VFS 0.8

Match-Line Length A 84.56 degrees 12.910 meters ----
Shorted stub length 0.33 degrees 0.061 meters
Open stub length 90.33 degrees 16.716 meters ----

Match-Line Length B 88.51 degrees 13.513 meters
Shorted stub length 179.67 degrees 33.249 meters
Open stub length 89.67 degrees 16.594 meters


Electical lengths (ant. to stub) 12.910/0.66 = 19.5606 mtr
(stub itself) 16.716/0.8 = 20.895 mtr

************************************************

Below the Nec-file with Tr-Line lengths as calculated above and a third
50 ohm line from
stub junction to the house.

Delivering a Z-in of 0.93 + j 24.2 ohms ?, If you ask me this should
have been around 50 ohms.

CM Short Inverted V for 80 Mtr.
CE
GW 1 25 -9.829825 0 14.117083 -0.3 0 21 5e-4
GW 2 3 -0.3 0 21 0.3 0 21 5e-4
GW 3 25 0.3 0 21 9.8298245 0 14.117083 5e-4
GW 989 1 -0.1 0 0.5 0.1 0 0.5 5.e-4
GW 998 1 -0.1 16.72 8.09 0.1 16.72 8.09 5.e-4
GW 999 1 -0.1 0 8.09 0.1 0 8.09 5.e-4
GE
LD 5 0 0 0 58000000
GN 2 0 0 0 14 .006
EX 0 989 1 0 1 0
FR 0 1 0 0 3.6
TL 2 2 999 1 50 19.5606
TL 999 1 998 1 300 20.9
TL 999 1 989 1 50 7.59
XQ

Arie.