Expansion K0UO New Site #2 & DX with Stand-Alone Towers
Updated: 3 hours ago
K0UO has established a second antenna site, (which is considerably larger than the primary site 1), located on an elevated hilltop area where K0UO had a 300-foot tower previously situated. This site is intended for Commercial, DoD, and ham radio applications, positioned hundreds of feet above the surrounding ranch land, ensuring an environment free of RFI noise.
Test range: For ISR equipment testing, the range is expanding several miles to the west and north of 4KS Walz Airport for ISR, EME, RFI, and RF test site number 2, by RSI Corp. This is part of the Vance AFB 1D MOA DAF Proposed Action, which has been approved, to acquire new airspace that provides the 71 FTW and other groups with autonomous scheduling and ensures easy access to airspace needed for low-altitude non-hazardous flight training and equipment testing, such as electro-optical infrared EO/ISR sensors, operator mission stations with FM tactical radios, and data link systems.
Optimizing Terrain & Low-Angle Takeoff: This new site with the significant height-above-average-terrain (HAAT) provided by the hill, your low-angle radiation footprint on lower bands. Now maximizing this by tailoring ground counterpoise and radial networks to slope down the hill contours, reducing ground absorption losses and pulling the radiation angle down for long-haul DX. with wideband X-rhombics arrays arranged along the ridge line will deliver exceptional forward gain and directivity compared to flat-land configurations.
Stand-along towers: Ham radio enthusiasts understand that the effectiveness of their antenna setup is crucial for successful long-distance communication.
For those committed to DX (distance) and Contest operations, having access to dedicated stand-alone towers provides a significant advantage. RSI Corp and K0UO/R offer a range of stand-alone towers up to 500 feet in height, specifically designed for DX and contest activities, as well as far-field antenna testing. K0UO is also developing a new larger site, number 2. This new site, along with these towers, are located in rural ranching areas, free from other users or interference, making them perfect for ham radio enthusiasts aiming to maximize their communication potential.
Why Stand-Alone Towers Matter for DX Operations
When it comes to ham radio, antenna height and location are critical. Stand-alone towers that reach up to 500 feet provide significant elevation above the surrounding terrain. This height allows antennas to operate at low takeoff angles, which is essential for long-distance signal propagation. Signals sent at low angles travel farther by bouncing off the ionosphere, enabling communication with distant stations across continents.
The rural ranching locations of these towers mean there is minimal Radio Frequency Interference (RFI). Urban areas often have noise from electronics, power lines, and other sources that degrade signal quality. These towers are isolated, with no other antennas mounted on them, ensuring a clean environment for clear, strong signals.
Site Number 2 Planning and Design overview
Features of RSI Corp and K0UO/R Stand-Alone Towers
Exclusive Use: No other users share these towers, so you have full control over antenna placement and orientation.
Height: Towers up to 500 feet tall provide excellent elevation for HF antennas.
Fiber Optic Connectivity: Each tower is served by fiber optics, supporting fast and reliable data transmission for remote control or digital modes.
Rural Location: Positioned in quiet, rural ranching areas, these towers avoid urban noise and interference.
Versatile Orientation: Antennas can be oriented in various directions to maximize signal strength and reception quality.
Far Field: Expanded testing area site.
K0UO uses AN-SOF and Scilab model programs, however testing is still required.
K0UO with the RSI Corp antenna Far Field Test Range uses advanced RF measurement to confirm all the antennas preformance.
A actual photo of an area in the Kansas Gypsum Hills (The Red Hills)
How Tower Height Enhances Antenna Performance
Elevation plays a key role in antenna effectiveness. Here’s why:
Low Takeoff Angles: Signals launched at low angles travel farther by reflecting off the ionosphere, ideal for DX contacts.
Reduced Obstructions: Taller towers clear trees, buildings, and terrain features that can block or weaken signals.
Improved Signal-to-Noise Ratio: Being above local noise sources improves reception clarity.
Better Antenna Patterns: Height allows antennas to achieve their designed radiation patterns without distortion from nearby objects.
For example, a 500-foot tower can elevate a Yagi antenna well above surrounding hills, enabling it to reach stations thousands of miles away with minimal signal loss.
Located at a distance of up to 20 miles from the main 4KS airport and K0UO/R site on the east side of the Kansas Red Gyp Hill ranching area, these towers are part of an extensive test range that facilitates a variety of radio frequency experiments and competitions. All can be connected with a private microwave internet point-to-point backbone network or fiber.
The towers are registered with the FCC Antenna Structure Registration (ASR) system. Several notable structures are listed, including the following:
#1,216,715 at a height of 59.5 meters on site, with HF LPDA & large HRS Curtains
#1,252,737 reaching 70.2 meters,
#1,252,738 towering at 89.6 meters,
#1,260,299 standing at 42.6 meters,
#1,314,639 at 88.4 meters,
#1,216,786 reaching a height of 97.5 meters, HF antennas and many spare 7/8in hadline coax for antennas as needed, this tower is on a 300ft hill 800ft AGL
#1,252,503 at 77.7 meters,
#1,235,485 at an impressive height of 149.4 meters dedicated to FM broadcasting, It has had many ham antennas and feed line are in place
and finally, ASR# 1,252,009 standing at 85.30 meters.
Practical Uses for Stand-Alone Towers
These towers are perfect for:
DX Contests: Compete with the best by using high-gain antennas on tall towers to reach distant stations quickly.
Projects: For DoD and Commercial equipment testing including IRS.
Far-Field Antenna Testing: Test antenna designs in a clean environment without interference from other antennas.
Group Operations: Clubs or groups can share tower access for coordinated contesting or experimentation.
Remote Operation: Fiber optic connections allow remote control of radios and antennas, enabling operation from anywhere.
Setting Up Your Antenna on a Stand-Alone Tower
To get the most from these towers, consider the following:
Choose the Right Antenna: High-gain directional antennas like Yagis or phased arrays work well for DX.
Optimize Orientation: Point antennas toward target regions or rotate them as needed for contests.
Use Quality Feedlines: Low-loss coax or balanced lines preserve signal strength. K0UO still has rolls of hardline to use.
Implement Grounding and Lightning Protection: Tall towers are vulnerable to lightning; proper grounding protects equipment.
Plan for Maintenance Access: Ensure safe climbing or use of hoists for antenna installation and upkeep. RSI Corp has an OSHA trained tower contractor crew
One of K0UO's 300 foot steel towers in the Red Gyp Hill of KS, that he cut down a few years ago, he didn't want to keep the required FAA lights operational moving forward with the low number of commercial users, however still a great hill top location for the K0UO Site Number Two with is using the base and guy anchor for the Rohn 65 195 foot tower
K0UO Now Adding Antenna Site Number 2
K0UO has established a second antenna site, (which is considerably larger than the primary site 1), located on an highly elevated hilltop area where K0UO had a 300-foot tower previously situated. This site is intended for Commercial, DoD, and ham radio applications, positioned hundreds of feet above the surrounding ranch land, ensuring an environment free of RFI noise.
All the system are using AI self-healing for automatically changing from malfunctioning radios, bad rotor boxes and the arrays and station controls as needed.
A major HF array construction project is currently in progress, aiming to develop an even larger second site on family ranch land. This ambitious project is strategically located on a very high hilltop plateau in the Red Gyp Hill, situated a few miles to the west of the main K0UO site. The choice of this elevated location is crucial, as it not only offers stunning panoramic views of the surrounding area but also provides a unique chance to create a space that is both functional and visually appealing.
In terms of design and construction, the project is being executed with great attention to detail and sustainability in mind. The design incorporates eco-friendly materials and practices, ensuring that the structures harmonize with the natural environment rather than disrupt it. The use of renewable energy sources and the natural gas, is also being considered to minimize the carbon footprint of the new location.
The planning phase has involved extensive engineering to meet DoD and other commercial specifications, we are tasked with creating a layout that maximizes the advantages of the hilltop setting.
The antennas performed excellently with the relay box situated at ground level, offering a glimpse inside the relay box. The wires appear to be scattered in all directions. One might suspect an impedance issue, but it was not evident. The late Roy Callison of Bisbee, AZ, ham call W7YRV/SK also had nine X Rhombics arrays, which he developed, he had one for every 20 degrees. That was a truly remarkable accomplishment for an amateur station. this site is building on that. K0UO using much longer elements while also using a re-enterant system for 90% efficiency.
1. The Core Architecture: Cross-Phased Geometry
A standard planar rhombic consists of two V-shaped long-wire antennas connected to form a flat diamond. The X-Rhombic alters this by crossing or splitting the elements into an X-configuration, forming intersecting spatial loops. This design causes RF current to undergo spatial phase adjustments, enhancing performance.
2. Eliminating the "Height-to-Wavelength" Trap
Standard horizontal rhombics have a vertical takeoff angle tied to their height above ground. The X-Rhombic employs vertical tapering, allowing different vertical planes and sloping angles. This reduces sensitivity to height constraints, providing stable low takeoff angles across various frequencies without adjusting mast height.
3. Radical Sidelobe Damping
Parasitic sidelobes waste power and create vulnerabilities. Ayzenberg's X-configuration causes sidelobes to be 180° out of phase, resulting in destructive phase cancellation for off-axis radiation. This enhances the main forward beam's purity and improves directional ratios.
4. Maximizing Tower Efficiency (The Economy of Scale)
Building new towers was costly for the Soviets. The X-Rhombic's interlacing and stacking allowed use of existing arrays' footprints. By feeding the X-array in parallel, a single setup could function as multiple antennas, maintaining high-gain links to distant targets efficiently.
The X-Rhombic modifies the physical structure of a standard diamond loop by crossing the wire elements at the side corners rather than leaving them as flat angles. This specific, altered layout forces the traveling RF current to undergo spatial phase adjustments as it moves down the wire. Experienced antenna designers use the X-Rhombic layout to suppress unwanted side lobes even further and force more energy into a tighter, cleaner main forward beam than a standard flat rhombic can manage. This site is using AI self-healing for keep the site on the air.
X-Rhombic: A full rhombic loop where the side wires cross or split into an "X" configuration. An advanced cross-phased geometry modification of a standard rhombic, not a fraction of one.
To build an X-Rhombic antenna, you must alter the standard diamond layout by crossing the wire elements. This phase-reversal layout sharpens the main forward beam and suppresses side lobes.
Because it is a multi-wavelength traveling-wave antenna, it requires substantial physical space and highly sturdy support structures.
Step 1: Calculate the Dimensions
Rhombic dimensions are dictated by your lowest target operating frequency. For high gain, each leg should be at least 2 to 4 wavelengths long (λ).
Calculate Wavelength (λ)
Leg Length (L): Multiply λ by your chosen factor (e.g., 3λ or 4λ).
Tilt Angle (φ): The internal apex angle typically ranges between 50° and 70°, depending heavily on the leg length to align the wire radiation lobes cleanly with the center axis.
Step 2: Lay Out the Geometric Footprint
An sloping X-Rhombic requires just one tall support masts (utility pole, tower or tree) arranged in a precise diamond shape on flat terrain.
The Center Axis: A straight line from the input mast to the termination mast.
The Side Masts: Perpendicular to the center axis, defining the width of the array.
The "X" Crossings: Instead of routing the wires directly around the side masts like a standard rhombic, the wires cross over each other at the side positions. They must be insulated from one another at the crossover point using a heavy-duty ceramic or fiberglass spacer.
Step 3: Wire Routing and Insulation
High-tensile, copper-clad steel wire or wire rope is highly recommended to withstand the mechanical tension across long spans.
Input End: Secure two separate wires to the input mast insulators.
The Crossover: Run Wire A from the input mast toward Side Mast 1. Run Wire B toward Side Mast 2. At the mid-point (the side apex position), cross the wires past each other using the non-conductive spacer, anchoring the spacer assembly securely to the side masts via guy lines.
Termination End: Continue routing the wires down to the far termination mast, completing the elongated diamond envelope.
Step 4: Construct the Feed and Termination System
Because it is a traveling-wave system, it must be terminated correctly to remain unidirectional.
The Feedpoint: Connect a balanced, high-impedance open-wire transmission line (typically 600-ohm ladder line) to the input wires. Wire this into a high-power 12:1 or 4:1 current balun at ground level before running coaxial cable back to your transmitter.
The Termination Resistor: At the far apex, connect a 600 to 800-ohm non-inductive resistor. This resistor must be rated to handle roughly half of your transmitter’s total output power, as the remaining forward RF energy is dissipated as heat to maintain the sharp forward beam pattern. or use the K0UO re-phasing system for 90% efficiency
Traditional rhombic antennas are known for their simplicity and high gain over a wide bandwidth, but they require large physical space due to their long wire elements with lower efficiency. The re-entrant rhombic array addresses this limitation with several unique features:
Improved Bandwidth: The re-entrant structure can support a wider frequency range due to the increased electrical length and better impedance characteristics.
Enhanced Directivity: The shape modification focuses the radiation pattern more tightly, improving directivity and reducing side lobes.
Enhanced Efficiency: The design reduces losses due to reflections and mismatches, resulting in increased radiation efficiency and redirecting the power previously lost in termination back into the array, now up to 90% efficient.
These features differentiate re-entrant rhombic arrays from traditional wire antennas and other directional antennas like Yagi or log-periodic arrays.
"Don't underestimate the performance of the Rhombic unless you've personally built and used one. Due to their large size, covering many acres, you realize their true advantage of having thousands of feet of wire in the air. This setup provides receive signal diversity by capturing signals at varying times and angles, significantly reducing fading QSB, and transmitting RF in the same manner. Traveling wave antennas are very unique and unlike many other antennas commonly used."
This X-Rhombic is many wavelengths long at 40 or 20 m, so the main lobe becomes narrow.
The takeoff angle drops to ~5–8°, which is excellent for very long-haul DX.
The front-to-back ratio improves because the termination if used absorbs more of the rearward energy at higher frequencies. (using re-entry system for even higher gain),
Pattern Characteristics on 40 or 20 meters
Very narrow beam — only 20~10° wide, so pointing accuracy matters,. with this system it is instantly switched between fixed azimuths every 20 D, without mechanical rotation.
Extremely low TOA — ideal for intercontinental paths, ~5–8°. with the hill toop and tower the AGL is nearly 500 feet, so toke off angels of less that 5° is posable.
High gain — ~18–20 dB means you’re effectively running the equivalent of hundreds of kilowatts ERP with a legal-limit transmitter.
Furthermore, the project is not just about expanding physical structures; it also represents a deeper commitment to preserving the Rhombic’s heritage and attributes. By establishing this second antenna location, the aims to create a legacy that can be enjoyed by future ham generations, offering them a place to connect with the world by remote ham radio, engage in learning and build lasting memories.
Overview of the Commercial Project, with can also be utilized for ham radio
Coherent GPSDO Phase-Matched Beamforming
Sample-Accurate IQ Streaming: Install GPS-disciplined oscillators (GPSDO) at both sites to lock internal 10 MHz reference clocks. Streaming synchronized raw IQ data over the fiber link via the SmartSDR API enables true multi-site phase-coherent processing.
Dynamic Software Null-Steering: Processing simultaneous IQ streams from Site #1 and Site #2 through processing software allows you to electronically steer deep spatial nulls directly onto co-channel noise or QRM while constructively combining weak DX signals.
Zero-Desense Cross-Site Full-Duplex
Physical TX/RX Isolation: Take advantage of the physical separation and fiber isolation by running full-power transmissions at Site #2 while actively receiving on high-gain arrays at Site #1 on the same band (or vice versa).
Bypassing Receiver Overload: Physical distance completely eliminates local front-end overload and heavy desense without requiring aggressive inline bandpass filters, allowing you to monitor and work weak signals while transmitting.
SmartSDR API & Real-Time Propagation Sounding
Automated Sounder Integration: Connect the SmartSDR API to real-time ionosonde or GNU Chirp Sounder receiver feeds monitoring ionospheric layer heights and critical frequencies.
Instantaneous Array Switching: When software detects high-band F2 openings, the control can automatically reconfigure slice receivers, select optimum beam headings at Site #2, and queue alerts before the band peak becomes widely active.
Remote Feedpoint Phase & Takeoff Angle Tilting
Active Feed Control: For large wire structures (such as Sterba curtains, delta loop arrays, or stacked rhombics), deploy digital RF phase and amplitude controllers at the feedpoints managed over the fiber link.
Elevation Pattern Tuning: Dynamically altering the phase relationship between array elements allows you to electronically tilt the vertical radiation angle (e.g., adjusting between -3 to 30 Degrees to match exact ionospheric hop geometry in real time.
everaging high-speed fiber and FlexRadio's SmartSDR architecture allows software to act as the central nervous system for Site #2 and Site #1. Integrating these advanced software-driven processing methods takes full advantage of your phase-locked dual-site topology:
Phase-Coherent IQ Digital Beamforming
GPSDO Sample Synchronization: Stream raw 24-bit I/Q data via SmartSDR DAX over the fiber link, phase-locked to 10 MHz GPS-disciplined oscillators at both sites.
Adaptive Null-Steering: Process dual I/Q streams through custom algorithms or GNU Radio DSP blocks using LMS adaptive filtering. This electronically synthesizes a combined steerable array pattern, placing sharp, deep nulls on localized noise or co-channel QRM while phase-combining weak DX signals.
Sounder-Driven Automated Azimuth & Band Switching
Real-Time Propagation Interfacing: Connect the SmartSDR API to local HF ionospheric sounders (such as a GNU Chirp Sounder) or real-time F2 and MUF data feeds.
Automated Matrix Routing: As propagation software detects band openings or shifting ionospheric tilt, Node-RED or Python scripts automatically trigger the 18-position relay matrix at Site #2, selecting the optimum 20° X-Rhombic array heading before the band peak becomes widely active.
Digital Phase Control for Takeoff Angle Tuning
Feedpoint Phase Shifting: Manage IP-addressable RF phase and amplitude controllers at array feedpoints over the fiber network using Modbus/TCP or MQTT.
Dynamic Elevation Tracking: Adjust relative feed delays via software to dynamically tilt vertical radiation patterns (from 3° up to 30°), keeping the beam elevation locked onto real-time ionospheric hop geometry throughout changing solar conditions.
Digital Feed-forward Cancellation for Full-Duplex
Digital Reference Cancellation: Send a digital sample of Site #2's transmit I/Q waveform over fiber directly to the receive DSP pipeline at Site #1.
Zero-Desense Operation: An adaptive filter subtracts residual transmit energy in software, enabling zero-desense, simultaneous transmit and receive on identical frequencies without needing heavy physical inline filter networks.
Unified API Station State Machine
Centralized Middleware: Deploy Node-RED or custom Python services interacting directly with SmartSDR IP APIs, amplifier telemetry, and array switching matrices.
Automated Interlocks & Telemetry: Continuously monitor feedline SWR, thermal levels, and phase stability, automatically executing self-healing re-routes if hardware anomalies are detected.
As construction progresses, there is a palpable sense of excitement within the family and the RSI Corp friendly local ranchers. This new hilltop location is poised to become a vibrant hub of HF Contest and DX activity, where the beauty of the natural surroundings can be fully appreciated and cherished at the some time.
Benefits of Rural, Isolated Tower Locations
The rural ranching setting offers several advantages:
Minimal RFI: Far from urban noise sources, signals are clearer.
No Antenna Crowding: No other users on the towers means no interference or competition for space.
No Zoning or HOAs
Stable Environment: Open land reduces multipath reflections and signal distortion.
Privacy and Security: Remote locations limit unauthorized access.
Unlimited: Expansion opportunities
Towers: Height not limited by near by airports
Fiber: The site still has access to the new Rural Broadband high speed internet
These factors combine to create an ideal environment for serious ham radio operations.
Geographic Propagation Advantage of Kansas at this station: Thanks to its prime location, K0UO is perfectly positioned to excel in DX and radio contests, giving operators the chance to skyrocket their scores! Nestled in vast rural expanses with endless acres of land, the RF noise floor is practically non-existent. With neighbors miles apart, the station can pick up those faint signals that urban or suburban operators only dream of.
With arrays operating at take-off angles of 5 to 8 degrees, K0UO consistently leads the way, being the first to open and the last to close to Europe, Asia, and across the poles to Western Asia and the Middle East, while also keeping a steady connection to South America.
The K0UO site has miles of wire with incredibly high-gain "Rhombic Curtain and V Beam arrays". They truly reign supreme as the King of HF Wire Antennas, unmatched by any yagi!
Real-World Example: Contest Success with Stand-Alone Towers
A ham radio club used one of these 500-foot towers with a high-gain Yagi antenna during a major DX contest. The elevated antenna and clean environment allowed them to reach stations across multiple continents with strong, clear signals. Their score improved dramatically compared to previous contests where they used lower, shared towers in suburban areas.
Final Thoughts on Using Stand-Alone Towers for DX
Access to dedicated, tall stand-alone towers and K0UO site #2 in quiet rural settings offers ham radio enthusiasts a powerful tool for maximizing DX operations. The combination of height, isolation, and fiber optic connectivity creates an environment where antennas perform at their best. Whether you are a contest operator, antenna experimenter, or serious DXer, these towers provide the space and conditions needed to reach distant stations with clarity and reliability.
If you want to elevate your ham radio experience, consider how these stand-alone towers could fit into your plans. Their unique advantages can open new possibilities for communication and experimentation.
Ready to take your DX or contest operations to the next level? Explore the options for stand-alone towers, along with K0UO/R site number 1 & 2, and see how they can transform your ham radio setup.
In short, the new site X-Rhombic array farm provides instantaneous direction switching, while a stacked Yagi beam is constrained by the mechanical rotation speed of the antenna's mounting hardware.
So if you're considering a fixed-wire setup to eliminate rotor maintenance and require frequency flexibility, choose a Rhombic or V Beam.
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