These days, propagation conditions are rather poor. See how condx were last March 29th:
It is time to find a new way to improve the signal when portable. As for me, building and testing antennas is one of the most interesting parts of our hobby,
A good way to increase the chances for DX would be to design a beam antenna for the countryside. Well, it sounds good but it is a bit difficult. I settled my target for 14 MHz, a good choice nowadays to get some DX during daylight.
We won’t have towers and rotors there, what should I do? I recalled a past experience when I built a vertical Moxon antenna (2 element) made with wire elements for 21 MHz. It worked great but scaling that beam to 14 MHz is huge and that band is pretty closed nowadays!
My head was thinking and I decided to run some simulation models (Mmana) with ideas I had. I run different alternatives and then one atracted my attention. I optimised the model doing modifications until I achieved the best performance. What were the key features of this antenna?
- It was a novel design based on 2 element Delta loop
- It was a 50 ohm direct feed antenna
- It required a single vertical support pole plus 4 guying cords
- It exhibited up to 5,5 dBd in its optimum design and 10 dB Front/Back
I had enough reasons to decide it was time to try that in the real life.
Last week I cut long wires at home (this can be a bit annoying for the family in the living room, hi) and tested briefly the resonance in a park.
It seemed to be okay so I decided to give it a try for the first time on a summit.
Let me introduce the 2BD (2 element Delta beam) aerial.
Date: 29th March 2019
Summit: EA2/NV-092, Mt. Erreniega.
Target: compare my 2 element Delta loop with a End fed Half wave and check it it produces any DX.
Jorge EA2LU was kind to join me and we agreed to run a brief test with the antennas prior to activating the summit. We would run the first minutes calling as a beacon (/B) to see our signal level on automatic decoder stations afterwards (RBN network).
Weather was okay on top, clear sky, but a bit windy. Anyway we decided to proceed.
Jorge helped me to install the antenna which took about half an hour. It is difficult to deploy two full size loops on ground and then to raise the pole without having some troubles with tangled wires, specially if wind is present.
This is how the antenna looks like one up in the air, beaming NA:
(wires are color enhanced for ease of visibility)
The antenna was difficult to maintain against the wind so we didn’t reach the expected highest point planned to be 9 m above ground; instead the top would be at about 7 m. This would affect performace degrading a bit the radiation lobes. SWR was just fine on 14.062 MHz (1,2:1).
Later we erected the second antenna, an EFHW inverted vee with the appex 8 m high.
See Jorge and his EFHW just in front of me:
Then we settled our rigs (KX2 & KX3) to 10 w output power and started sending a beacon. We did so for about 5 minutes, This is the data I got after returning home and checking the Internet:
Data confirmed Jorge had better signal towards EU: 9 dB better than me on OH. It had sense bearing in mind the F/B in my antenna.
In the other hand, I had about 2 – 3 dB better than Jorge on NA. Not much but it helps. As said, the Delta was not as high over ground as planned.
We started our activation. Jorge run first on 60m, then 40m, 30m and 20m a few minutes at the end.
I had the monoband antenna so I stick with 20m, CW for most of the time.
Did the antenna worked?
Well, it did! My logbook shows 7 qso with regular North american chasers (state & received reports shown), apart from some EU chasers:
K0RS (CO, 539), N4EX (NC, 549), KB7HH (AZ, 529), NE4TN (TN, 559), K9IR (IL, 329), K4MF (FL, 449) & AC1Z (NH, 339).
Best DX was KB7HH, Jack, located in Arizona (8900 kilometers /5562 miles), isn’t it great?
I tried to work for some minutes N3II/P wich I received ok a little up, at 14.062,5, but he didn’t hear me, a pity! In the other hand I got a call from LA1KHA/P S2S, thanks Kjell!
After 1 hour calling on CW, I was tired and wind was developing. Jorge had worked a big number of EU chasers and even K0RS and NE4TN himself.
Jorge’s improvised seat…
We decided to end the activation, but a look at sotawatch revealed some USA stations nearby on 20m.
Both Jorge and me worked S2S both K2JB (W4C/WM-058) and NY4G (W4T/SU-042), great!
I must say the EFHW from Jorge also worked fine to get the S2S contacts.
Let me thank Guru EA2IF who was very helping sending some spots to announce both Jorge and me on Sotawatch.
9 DX qso from USA in my log let me think the 2 element Delta works all right, and I am willing to find a date for extensive testing. It is not an antenna for a regular activation, but for special events: international S2S events or even Field contests.
I know this desing could be of interest for any of you, so I will prepare a separate article whenever possible to describe its technical details and provide useful information if you want to replicate it.
See how close the two deltas are in the top of the pole as seen from below. This helps a lot to hold it with a single support and still keeps the directivity in the beam:
I searched on Internet to check if this design was ever published but couldn’t find something similar, because existing 2 element Deltas are spaced parallel, not like my design. Well, I have invented something, it seems!
I am so happy with the outcome of this experiment that I decided to give name to this antenna. The 2 Beam Delta antenna is born. I added a logo if you make one yourself and want to print a stick for the carrying bag
(Not any commercial purpose intended…)
Hope you find the proposal interesting.
73 de Ignacio EA2BD