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Author Topic: 3 Easy 1090MHz ADS-B DIY Antennas for Beginners  (Read 7529 times)
ABCD567

Posts: 108




Ignore
« on: December 19, 2016, 02:01:55 PM »


STARTER
When DVB-T Dongle is purchased, a whip antenna is supplied with it. Every beginner uses this whip in his starter setup.
Improve the performance of this whip antenna by three simple steps given below:
[/size]
  • Whip is too long for 1090 MHz. Cut it to 67mm.
  • Magnetic base provides an insufficient ground-plane. Enlarge ground-plane by placing the whip over a Metallic Can/Box/Plate. An added advantage of placing whip over an iron/steel can is that whip's magnetic base will cling to the can and keep the whip stable & upright.
  • Signal is weak indoors. Place whip near a window or in attic to get maximum signal.
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NEXT STEP
Once your setup is up and running, you will be happy, but soon after you will want to increase your range. You can then try some easy and sure antenna, like Spider & Cantena. In next three posts below, there are "how to make" instructions for Spider, Cantenna & Handy Spider.
.
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VENTURING BEYOND......
Next step may be to venture through alluring collinear antennas Like Coaxial Collinear (Coco), and Wire Collinears with coils and/or stubs. These antennas are very alluring, as these are easy to make. All postings for these on internet & youtube claim "high gain excellent antenna". The problem shows up when these antennas are put to service, and give poor performance. Collinears are easy to make, but very hard to get right, and except for few lucky ones, most DIY Collinear makers end up with a poor performing antenna.
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3 EASY ANTENNAS FOR BEGINNERS

The main disadvantages of stock antenna supplied with DVB-T USB Dongle are:
Problem (1): It has a very short lead. Due to this, in most cases the antenna cannot be placed at an optimum location.
Problem (2): The stock antenna is not optimized for 1090 Mhz.

.
.
.
SOLUTION FOR PROBLEM (1):
The short cable length can be overcome by connecting a MCX to F pigtail to the DVB-T USB Dongle, and connecting to the pigtail, the required length of commonly available RG6 cable with a DIY antenna at other end of RG6 cable.


Tip:
(a) For RG6 coax lengths in excess of 5m/15ft, coax attenuation will be high, and an amplifier may become necessary.
(b) Even with short lengths of Coax, use of amplifier increases plane count & range.
.
.
.
SOLUTION FOR PROBLEM (2):
The non optimized antenna can be replaced by a DIY antenna which has a ¼ wavelength vertical whip connected to core of coax cable, and a ground plane connected to shield of coax. The ground plane can be formed by a disc, a number of horizontal radials, a number of slanting radials, or a food/drink can.
.
.
.
Below are 3 different easy antennas for beginners: Spider, Cantenna, and Handy Spider.
These all have a ¼ wavelength vertical whip connected to core of Coax cable, but use different methods of providing ground plane connected to shield of coax.

.
Logged
ABCD567

Posts: 108




Ignore
« Reply #1 on: December 19, 2016, 02:03:29 PM »


EASY ANTENNA # 1 : SPIDER

Parts Required:

1. SO-239 Connector




2. PL-259 UHF to F adapter (to connect RG6 coax to SO-239 Connector)



3. Copper wire pieces 10 cm long - 5 pieces for 4 Leg Spider, 9 pieces for 8 Leg Spider.

4. Small Nuts & bolts 4 pieces for fixing wires at 4 corners of SO239 adapter



Schematic & Dimensions




Finished Antenna 4 Legs (Does not require soldering)
Built by jepolch



Finished Antenna 4 Legs (Does not require soldering)
Built by beckerm13





Finished Antenna 8 Legs (Requires Soldering - Performs better than 4 Legs)
Built by autok
http://www.atouk.com/wordpress/?page_id=237




.
Logged
ABCD567

Posts: 108




Ignore
« Reply #2 on: December 19, 2016, 02:05:16 PM »


EASY ANTENNA #2 : CANTENNA

Please scroll down to see photos & sketches giving construction details.


Completed Cantenna

Designed & Built by Author of this post (abcd567)





The whip at top is ¼ wavelength i.e. 69mm (see dimension drawing below)
The whip is core wire of coax cable.
It can be bare copper wire OR copper wire + core insulation.
Shield (braid+foil) MUST be removed from the whip.

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VRS Coverage
The range rings are 50 nm apart, the outermost blue ring is 300 nm from the receiver.



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Test Setup for Plotting VRS Range Curve
Cantenna >> 15 ft / 5 m RG6 Coax >> Generic DVB-T (black) >> Windows Laptop


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HOW TO MAKE

Image 1 of 4 : Construction Details 1



Image 2 of 4 : Construction Details 2



Image 3 of 4 : Construction Details 3


Image 4 of 4 : Fully Assembled



DIMENSIONS
Sketch 1 of 2: Pepsi Can Dimensions




Sketch 2 of 2: Whip Measurements.
Any one of the two connectors shown in the sketch below can be used



Details of whip
This detail is for insulated whip.
The whip can also be un insulated bare copper wire like core wire of coax








Cantennas using other types of cans:


Built by giacomo1989


Built by jepolch


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Logged
ABCD567

Posts: 108




Ignore
« Reply #3 on: December 19, 2016, 02:06:32 PM »


EASY ANTENNA #3 - HANDY SPIDER
No Soldering Required, No SO239 Connector Required


Trial Run - Indoor Near Large Window




Maximum Range Curve By VRS
Hardware Used for Range Curve Plotting:
Quick Spider >> 12 ft / 4 m RG6 Coax >> Generic DVB-T (black) >> Orange Pi PC


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HOW TO MAKE

STEP 1 - Stuff Required

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STEP 2 - Cut Coax Into Required Pieces

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STEP 3 - Remove braid & Insulation

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STEP 4 - Bend Wires

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STEP 5 - Assemble Radials

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STEP 6 - Bend Down Radials 45 Degrees

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Logged
ABCD567

Posts: 108




Ignore
« Reply #4 on: December 19, 2016, 02:07:43 PM »


ENHANCEMENT FOR OUTDOOR USE
1) Apply a rapid setting (5 minutes) sealant like 2-part epoxy, or silicone, or hot melt glue, or similar at the point where radials enter the outer jacket of coax.

2) After installation. wrap the F-connector in tape to prevent moisture ingress. You may also use outdoor type F connector which are water resistant.



.

Logged
ONAIR
Member

Posts: 3536




Ignore
« Reply #5 on: December 19, 2016, 02:14:49 PM »


STARTER
When DVB-T Dongle is purchased, a whip antenna is supplied with it. Every beginner uses this whip in his starter setup.
Improve the performance of this whip antenna by three simple steps given below:
[/size]
  • Whip is too long for 1090 MHz. Cut it to 67mm.
  • Magnetic base provides an insufficient ground-plane. Enlarge ground-plane by placing the whip over a Metallic Can/Box/Plate. An added advantage of placing whip over an iron/steel can is that whip's magnetic base will cling to the can and keep the whip stable & upright.
  • Signal is weak indoors. Place whip near a window or in attic to get maximum signal.
.
.
.

.
.
.

NEXT STEP
Once your setup is up and running, you will be happy, but soon after you will want to increase your range. You can then try some easy and sure antenna, like Spider & Cantena. In next three posts below, there are "how to make" instructions for Spider, Cantenna & Handy Spider.
.
.
VENTURING BEYOND......
Next step may be to venture through alluring collinear antennas Like Coaxial Collinear (Coco), and Wire Collinears with coils and/or stubs. These antennas are very alluring, as these are easy to make. All postings for these on internet & youtube claim "high gain excellent antenna". The problem shows up when these antennas are put to service, and give poor performance. Collinears are easy to make, but very hard to get right, and except for few lucky ones, most DIY Collinear makers end up with a poor performing antenna.
.
.
.
3 EASY ANTENNAS FOR BEGINNERS

The main disadvantages of stock antenna supplied with DVB-T USB Dongle are:
Problem (1): It has a very short lead. Due to this, in most cases the antenna cannot be placed at an optimum location.
Problem (2): The stock antenna is not optimized for 1090 Mhz.

.
.
.
SOLUTION FOR PROBLEM (1):
The short cable length can be overcome by connecting a MCX to F pigtail to the DVB-T USB Dongle, and connecting to the pigtail, the required length of commonly available RG6 cable with a DIY antenna at other end of RG6 cable.


Tip:
(a) For RG6 coax lengths in excess of 5m/15ft, coax attenuation will be high, and an amplifier may become necessary.
(b) Even with short lengths of Coax, use of amplifier increases plane count & range.
.
.
.
SOLUTION FOR PROBLEM (2):
The non optimized antenna can be replaced by a DIY antenna which has a ¼ wavelength vertical whip connected to core of coax cable, and a ground plane connected to shield of coax. The ground plane can be formed by a disc, a number of horizontal radials, a number of slanting radials, or a food/drink can.
.
.
.
Below are 3 different easy antennas for beginners: Spider, Cantenna, and Handy Spider.
These all have a ¼ wavelength vertical whip connected to core of Coax cable, but use different methods of providing ground plane connected to shield of coax.

.

    Thanks!  Gonna try some of those on the VHF and UHF ham bands!!  Roll Eyes
Logged
ABCD567

Posts: 108




Ignore
« Reply #6 on: December 19, 2016, 03:56:05 PM »

SIMULATION OF CANTENNA

Gain = 2 dBi
SWR 75 ohm = 1.3
Impedance = 64 - j 13 ohms





At 1090 Mhz:
wavelength = 275 mm
1/4 wavelength = 69 mm



I have tried 4 sizes of cans shown below (100 mm dia is not included in photo, but I tried it also). The best performer is the standard 12 oz / 355 mL drik can with dia 66 mm, almost 1/4 wavelength. The worst performer was 20 mm dia can (actually 3/4 inch copper water pipe + it's end cap).

The can's circular bottom's upper surface acts as ground plane, while cylindrical wall and inner surface of circular bottom make the 1/4 wavelength decoupling sleeve.




« Last Edit: December 19, 2016, 04:15:17 PM by ABCD567 » Logged
KH6AQ
Member

Posts: 7718




Ignore
« Reply #7 on: December 19, 2016, 04:38:47 PM »

I think the first antenna shown should be measured from the base of the magnet.
Logged
ABCD567

Posts: 108




Ignore
« Reply #8 on: December 19, 2016, 06:06:32 PM »

I think the first antenna shown should be measured from the base of the magnet.
You are partly right. Not exactly from base of magnet, but slightly above it, from the point where coax core is sodered to the whip. This point is 15 mm below the screw. Please see attached photo and sketch.

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