Math for the Rhombic & V Beams Array

https://www.k0uo.com/post/rhombic-math-design

Chart detailing rhombic antenna specifications and measurements, including frequency ranges and dimensional values for both un-terminated and terminated configurations, with adaptable frequency settings for user customization.

The above is all the info/data that you need to build a Rhombic

Design chart illustrating the relationship between wave angle, height, and tilt angle for optimizing the construction of rhombic antennas for maximum output.

Diagram illustrating the dimensions and phase angles of a horizontal rhombic antenna relative to wave direction and ground reflection.

NOTE, Don't underestimate the performance of the Rhombic, unless you have personally built and used one. Because of their excessive size (area) covering many acres, you see their real advantage of thousands of feet of wire in the air, which creates receive signal diversity, by capturing signals at different times and different angles, vastly eliminating fading QSB, and firing out the transmitted RF in the same way. Traveling wave antennas are very unique and unlike many other antenna in common use, and modeling will not show this major advantage.

L. B. Cebik, W4RNL Model below

These are for 80 meters and need to be one half wave high to control ground loss

Azimuth Patterns of Rhombic Antennas, for both Un-terminated and Terminated

Performance comparison of 3.5-MHz long-wire arrays: The table showcases gain, take-off angle, front-back ratio, and beamwidth for single long-wire, V, and rhombic array types, comparing unterminated and terminated states. Notably, the rhombic terminated type offers the highest gain and front-back ratio.

More into at https://antenna2.github.io/cebik/content/ao/ao11.html

WA7ARK recommends NEC5 (newer MOM algorithm) from Lawerence Livermore Labs greatly adds to modeling capability (adds buried conductors) and makes it much easier to write models (many less restrictions compared to NEC2d)

I now model all my antennas using NEC5 and HFTA (High Frequency Terrain Analysis) to evaluate the take of angle of the various antennas over real ground, and use 3/8" Triple Galvanized Wire Rope Cable is used for the antenna wire.

One of the K0UO's Rhombic fed point and view of the other supports poles

NOTE, Don't underestimate the performance of the Rhombic, unless you have personally built and used one. Because of their excessive size (area) covering many acres, you see their real advantage of thousands of feet of wire in the air, which creates receive signal diversity, by capturing signals at different times and different angles, vastly eliminating fading QSB, and firing out the transmitted RF in the same way. Traveling wave antennas are very unique and unlike many other antenna in common use, and modeling will not show this major advantage.

The K0UO amateur ham radio antenna range, and testing site has the use of over a 1200 acres around the main antennas for far field measurements, using a portable tower or drone loaded with calibrated RF EME survey instruments (used for ham, DOD and Commercial), see the far field test page. https://www.k0uo.com/post/model-and-then-do-far-field-test

The K0UO antenna test range site makes use of the 4KS Walz airport and its surrounding area as a practical learning environment for STEM (Scientific, Technical, Engineering, & Mathematics) antenna projects in a real-world outdoor setting. If your group has a university aerospace or antenna research STEM program, please let me know. The KØUO Rhombic Antenna Farm and Antenna Test Range: Home to the World's Largest amateur radio (ham), High Frequency (HF) Wire Arrays, miles of wire in the air and on the air daily.

See the other pages on K0UO for much more design info

TO SEE the complete Blog list check @  https://www.k0uo.com/k0uo

To build a 20 meter Rhombic to get 10D takeoff

https://www.youtube.com/watch?v=R-q6pmGJggo

https://antenna2.github.io/cebik/content/amod/modeling.html