70cm Rear Mount EME Antenna 70cm24CROSS3R
Low Noise, best gain antenna for super weak EME – Q65 MAP65 signals on 70cm band. Highest possible suppression of all side lobes and the best G/T. Excellent for stacking.
Easy to put on any mast. You do not need to care whether it is fiberglass or not. Any metal pipe from 42 to 70 mm will be good enough.
Antennas-Amplifiers Product Benefits. A Major advance in Amateur Radio antenna design.
- F/B and G/T superiority.
All antennas have been calculated using state-of-the-art full 3D Electromagnetic Simulation Software including the influence of the boom, bracket, baluns, and connectors. The performance of antennas designed using these techniques is exceptional, far better than antennas designed using “wire” programs.
- No tuning antennas
Before dispatch, we assemble every antenna and test antenna characteristics. That means you may expect excellent electrical and mechanical characteristics including low SWR across the designed range immediately after assembling.
No need to move the dipole, cut, or tune any element to get perfect SWR on the intended frequency range. Everything is pre-tuned.
That lead also to another very important detail. When assembled and tested each antenna is complete with all washers, nuts, bolts guy rope supports, etc.
When packing all parts are already on the antenna without the possibility of “forgetting” important parts to put in the box. So you will always receive the complete antenna that we tested just before dispatching.
- Designs that work well in all weather conditions
- Low SWR and superior G/T, F/B, and F/S ratios across the entire bands
- Excellent mechanical properties
- High durability, built without compromise
Why all the above is very important? Why we do not use free wire programs like EZNEC (Pro), 4NEC2, MMANA-GAL, or AO? Like all other producers or simulators do?
EZNEC, 4nec2, or AO producers or simulators put on the web pages excellent “simulated” antenna patterns produced by wire programs. Looks good on a computer screen. But what about reality?
Elements are not infinitesimally thin.
Boom size is not 0 (zero) mm.
Boom corrections programs exist. But what about accuracy?
Electrical terminals from balun coaxial cable to dipole are probably at least 10 mm long which is not “simulated” 0 (zero) mm. It will lead to worsen SWR or when tuned to good SWR to sharp antenna resonance.
Real antennas are not in free space. They are surrounded by metal parts not calculated in any form by wire programs.
Errors made by poor programs like EZNEC (Pro), 4NEC2, MMANA-GAL, AO, etc. only for the above examples are unacceptable these days. They will lead to wrong antenna gain, especially F/B. At least 5-15 dB lower than predicted. That means if the antenna is “calculated” for F/B 30 dB it could be anywhere between 15dB to 25 dB. Unfortunately, that also means the antenna will have much worse G/T which will lead to bad contest results and poor EME reception.
This has nothing to do with the obtained SWR of 1: 1 on the antenna. SWR 1:1 is not related in any circumstances to antenna gain, F/B, or G/T.
What 70cm24CROSS3R mean?
70cm band– Frequency range 432 to 434 MHz with low SWR
24 – Elements. 12 for horizontal polarization and 12 for vertical polarization
Horizontal polarization – elements are parallel to Earth
Vertical polarization – elements are perpendicular to Earth.
CROSS – Elements mounted in a “+” format
3 – About 3m boom with extremely strong construction and guy rope support.
R – Rear-mounted antenna
Electrical Specifications 70cm24CROSS3R (PA432-CROSS-24-3RBGP)
Frequency Range: 432 – 434 MHz
Free Space Forward Gain: 15.5 dBi
Front-to-Back Ratio: 31 dB
-3 dB Horizontal Beamwidth: 32.7°
-3 dB Vertical Beam width:35.2°
Polarization: Horizontal, Vertical. With phase shift RHCP, LHCP
Distance Between Dipoles: 173 mm
Isolation Between Antennas: More than 30dB
Nominal Input Impedance: 50 Ohms
SWR Across Entire Band: < 1.2
Maximum Power Input: 850 W per antenna. 1700W for circular.
Matching Method: Direct feed through common mode choke (current balun)
Connectors: 2 x “N”
Mechanical Specifications 70cm24CROSS3R
Number of Elements: 24 (12 + 12)
Element Diameter: 4 mm Aluminum rod
Dipole Diameter: 8 mm Hard Copper tube plastic coated
Longest Element: 340 mm
Element Mounting Position: Above the boom and on side
Balun and Connectors: Included
Boom Length: 2.83 m
Single Antenna Length: 2.38 m
Boom Size: Tapered Boom 30×30 mm, 20×20 mm
Number of Boom Pieces: 2
Guy rope support: Yes, Included
Mounting Mast Diameter: 43 – 70 mm 1-11/16″ – 2-3/4″ OD
Clamp: M8 Stainless Steel
Survival Wind Speed: 150 km/h
Net Weight: 3.5 kg
Gross Weight: 5.5 kg
Turning radius: 2.9 m
Transportation Length: 1.5 m