This article will show you SWR analysis of an Alpha-Delta DX LB Plus antenna installed 40 feet off the ground in an inverted-V configuration. The antenna ends are approximately 15 feet from the ground. I explained in details the tools and method used to measure my antennas in PART 1 entitled (SWR analysis of a G5RV antenna).
Here is the SWR graph of an Alpha-Delta DX LB Plus on frequencies ranging from 0.100 MHZ to 54.000 Mhz, which is the full scanning range of the AA54 analyzer:
Let’s now have a look at SWR on each Amateur bands:
80 Meter band: The load colis gives it a very narrow bandwidth on that band.
160 Meter band: The load coil gives it a very narrow bandwidth on that band.
Conclusion: The Alpha-Delta DX LB Plus has vary narrow bandwidth on 80m and 160m which you will have to tune (Cut or add wire) to your desired operation frequency. It really stands out on 40m with low SWR on the whole band and excellent results on 10M. Here again, you will have to tune 10m to your desired operation frequency.
Using multi-band antennas with loading coils such as the Alpha-Delta DX LB Plus can be a challenge to tune and results may not be what you expect. I learned a lot from using this antenna and thanks to the RifExpert AA54, I found what my most resonant frequency was on 20 meters and made my first Sound-Africa QSO (17,000 km) . I received a 9 + 10 dB signal.
Now that I’ve learned much about having a pair of resonant wire on each band, my next project will be to replace my Alpha-Delta DX LB Plus with a home brewed multi band fan-dipole. I experimented building a parallel fan-dipole a few weeks ago and got excellent results. I’m currently half way thru the project of building a 80-40-20-10m parallel fan-dipole and will post results on this site.