AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: abcd567 on June 18, 2022, 12:55:01 AM
-
DIY V-STUB ANTENNA MADE OF COAX
DIY V-Stub Antenna made of RG-6 coax. It can be made with any type of coax rated for 1 GHz or higher.
NOTE:
(1) On top, the small sliding piece of wire (with core insulation to hold the sliding wire in place) is for conveniently adjusting the length of top wire for best MESSAGE RATE (if no swr meter is available) or minimum SWR, if SWR meter is available.
(2) Being mechanically weak and prone to ingress of moisture inside the Coax, this antenna is NOT suitable for outdoor installation. It is intended for indoor installation near a window or in a balcony. Please see snapshot-2 below.
SNAPSHOT-1: ANTENNA CLOSEUP
(https://i.postimg.cc/d37xxmqF/V-Stub-top.png)
(https://i.postimg.cc/KjdHSkzM/V-Stub-bottom.png)
SNAPSHOT-2: INDOOR INSTALLATION
(https://i.postimg.cc/3NYcK4Q4/V-Stub-Indoor-800x800.jpg)
Pigtail required to connect RG-6 coax to Radarbox Flightstick or FlightAware Pro Stick
30 / 50 / 60 cm, F-female to SMA-male pigtail RG316 / RG58 / RG174
(https://i.postimg.cc/9QGFkyMy/V-Stub-pigtail-RG316.jpg)
OR
(https://i.postimg.cc/tgpCG7Zw/V-Stub-pigtail-RG174.png)
SWR MEASUREMENT RESULTS AFTER TUNING/TRIMMING TOP WIRE
(https://i.postimg.cc/jj1KvStB/V-Spider-Pilot-SWR.png)
COMPUTER SIMULATION RESULTS
Diagram 1 of 5: Geometry
(https://i.postimg.cc/dQXXTXBV/V-Stub-Geomery.png)
Diagram 2 of 5: GAIN & Radiation Pattern
(https://i.postimg.cc/VLCh9RGB/V-Stub-Gain-and-Pattern.png)
Diagram 3 of 5: SWR
(https://i.postimg.cc/BnfVmKRW/V-Stub-SWR.png)
Diagram 4 of 5: 3-D Radiation Pattern
(https://i.postimg.cc/3wKbTHKn/V-Stub-3-D-Pattern.png)
Diagram 5 of 5: Current+Phase
(https://i.postimg.cc/KYJpcsjF/V-Stub-Current-Phase.png)
-
BUILD FOR OUTDOOR INSTALLATION
For a stronger build, suitable for outdoor installation
(1) Use N-connector or SO239 connector.
(2) Use whip and radials made of 2mm or 2.5 mm dia wire . Please see photos below.
(https://i.postimg.cc/BQwVY89q/SO239-groundplane-A.jpg)
(https://i.postimg.cc/JhjYzPyn/so239-groundplane-B.jpg)
(https://i.postimg.cc/Qtb6pCJZ/so239-groundplane-C.jpg)
.
-
You can explain the antenna theory, because the dimensions other than the sides of V and radials, do not correspond to a multiple of the wavelength.
Thank you.
-
You can explain the antenna theory, because the dimensions other than the sides of V and radials, do not correspond to a multiple of the wavelength.
Thank you.
For Wire Collinear antennas, your requirement that all wire sections should necessarily be an exact multiple of wavelength, is not valid.
Please open and check dimensions of some successful commercial wire-collinear 1090 MHz antennas, or easier, please search the web for DIY wire collinear antennas, and you will find a lot of these do not meet your requirement of "all wire sections necessarily be multiple of wavelength". Some, but not all, wire sections may meet your requirement.
I have run a computer simulation of this design to verify & optimized it's dimensions, and posted results in the very first post. These results show it to be a good design (good gain, swr, and radiation paftern).
As the computer simulation software uses the laws & formulas of electromagnetic waves and their radiation, once the simulation software tells the dimensions give good gain, swr, and radiation patter, it means the design conforms to electromagnetic wave theories.
In addition to confirmation by computerized simulation software, I have checked it's performance by making it and doing a trial run, side by side with Flightaware 1090Mhz antenna, and compared results. The comparison proved that the V-Stub design performs good.
.
-
Thank you for explanation.
I thought it was a variation of half AMOS or Franklin antenna but the lengths were different.
May have a nice day
Chris