80m NVIS Antenna

Built an 80m inverted V and based on VE3RIPs modelling stuck the apex up at 30'.    Found some old wire that I pulled down a few tears ago.  It was my 80 dipole ,  down low too!    The dimensions were more or less what I was looking for.  Put the antenna up just behind the house.  To my pleasant surprise it was optimized at 3.750 MHz good for a 1:1 match.   I could go +/- 500 kHZ and the VSWR remained below 2:1.   

The IFL from the Antenna to the SW was about 60'.   I couldn't resist testing the cable for loss before I hung an antenna off it .....

So the loss at 3.2 MHz was 1.7 / 2 = 0.85 db. 

The IFL going from the 4X1 SW to the Rack ...

From the rack where the antennas terminate in the house to the 4X1 coaxial sw just up behind the house the loss is 5.1 / 2 = 2.55 db @ 4.8 MHz.  So using the NanoVNA the cumulative loss to the 80m Inverted V is somewhere a little over 3 db.

Swept the Antenna from the rack after it was up....














Added a 20' chunks of rg59 and swept again...

The added cable changed the sweet spot slightly. 

And the overall return loss @ 1 MHz ( worst VSWR spot )

The return loss came in a 2.28 db so its 2.28 / 2 = 1.15 db of loss.  This is quite a bit different  then the two cables swept individually which yielded a 3 db loss. 

Its probable safe to say the cable loss is somewhere between 1 and 3 db at 3.750 MHz.