Re: 80m antenna for limited space.

For anyone who is interested in the full set of data:

The first 3 blocks of data are the measured Antenna impedance, Type-26 unun winding impedance, and Type-2 unun winding impedance.

From those impedances I calculated the unun efficiencies shown in the mauve block.

I then used TLD to calculate the coax losses for each unun shown in the grey block.

Finally I calculated the expected net advantage of the Type-2 unun and compared it to the results from the field strength measurements - yellow block.

So, as an example, taking the 20m band data:

Antenna impedance = 1011-j1845

Type-26 winding impedance = 278+j301

Type-2 winding impedance = 585-j3430

Type-26 efficiency = 12.1%

Type-2 efficiency = 82.6%

Type-2 efficiency advantage = +8.3dB

Type-26 coax loss = 1.3dB

Type-2 coax loss = 3.7dB

Type-26 coax loss advantage = +2.4dB

Predicted Type-2 net advantage = +5.9dB

Measured FS advantage = +5.2dB

Reassuringly, the predicted differences in unun performance follow the same trends as the measured differences in field strength.

Steve G3TXQ