Homebrew 2 meter Amateur Radio Antenna from Ordinary TV Rabbit Ears antenna
Ham Radio February 12th, 2008
Short on a good and reliable antenna for your amateur radio operation ?
Here’s how to make a simple 2 meter amateur radio antenna from ordinary tv antenna (Rabbit Ears Antenna).
For your information these antenna can be bought from local tv store at around RM4 a piece (less than USD2).
The best thing about these antenna that it has terminating point (screw) which you can screw in your coax cable to each dipole leg, as shown in the (rather blurry) photo.
After that, extend the telescoping element to the desired length to match your transmitting frequency.
Usually amateur radio operator working on 2 meter VHF would use antenna with vertical polarisation. In this case, you need to spread the dipole to vertical position like pictured above, connect it to your transceiver and be amaze by its transmitting (or receiving) power.
Main Advantage of This Antenna
- Embarassingly easy to construct
- Lightweight
- Can be adjusted to any frequency, because of its adjustable telescopic element
As you can see, the rabbit ear tv antenna can also make a good antenna during emergency situation. Its adjustable telescopic elements made it easy to reconfigure the antenna to transmit on different frequencies.
ps : You can use this dipole calculator, if you unsure about the dipole length.
Tags: amateur radio, antenna, dipole, diy, hamradio, homebrew
Portable 2 Meter Slim Jim antenna using 300 Ohm Twinlead
Ham Radio February 11th, 2008
Due to popular searches, I’ve included a diagram to make a flexible slim jim antenna. This antenna is useful to increase the range of your portable radio or as a simple QRP mobile antenna for emergency situation.
In order to proceed with this project you need
- about 165 cm (64 inch) 300 Ohm twinlead cable
- RG-58 coax cable (RG-8, RG-213 might be too big for soldering), any length but keep it shorter than 7 meters for portable radio
- Soldering iron
- Wire cutter
- Connector to your Rig (usually BNC type or UHF Male)
- insulating tape
This is an ideal antenna for first timers to build. It is powerful yet simple to construct, once you get the hang of it you would certainly have no problem to construct other variants of Slim Jim antenna using different material.
This exercise would also prepare you in the world of Amateur Radio where real hams homebrew their own antennas.
Important Notes
- Make sure you solder the center conductor to the longest part of the antenna, and the outer conductor (braid) at the shorter side of the antenna
- If you use this on mobile rig, keep transmission power lower than 50watt to avoid the antenna from being burned away.
- Make sure the antenna is held straight for best transmission and reception. Best way to make sure of that is to hang the antenna at a higher place or strap it to PVC pipe or other non-conductive pole
Advantages of 300ohm Twinlead Slim Jim Antenna
- Easy to construct
- Has radiation angle almost parallel to the ground which makes your transmission goes farther than 5/8 or ground plane antennas
- Wideband
- Portable; Easy to carry, store and deployed
- Can be use during emergency situation
- Light and flexible
Completed Antenna
Here is a screenshot of my own completed slim jim antenna which I use with my Icom V8 portable radio.
Upon connecting this antenna to your portable radio, you can feel its differences when compared to using the stock rubber duck or telescoping antenna.
Tags: amateur radio, antenna, diy, hamradio, homebrew, slim jim, slimjim
10dBi – 6 Element OWA Yagi Antenna for 2 Meter band plan
Ham Radio, Hobbies February 3rd, 2008
Here is a 6 element yagi my friend and I have built for experimenting with directional antenna. Theoritically the antenna has about 10dBi gain in its main lobe and a good Front-to-Back ratio, a perfect substitute if you don’t have means to get the popular V24 Silverthunder antenna.
Radiation Pattern Lobes
Dimensions (in inches)
Element, Length, Space from Reflector
Reflector – 40.52, —-
Driver – 39.96, 10.13
Director 1 – 37.38, 14.32
Director 2 – 36.31 25.93
Director 3 – 36.31, 37.28
Director 4 – 34.96 , 54.22
Calculated Center of gravity 23.87 inches
Dimensions (in cm)
Element, Length, Space from Reflector
Reflector – 102.92, —-
Driver – 101.50, 25.73
Director 1 – 94.95, 36.37
Director 2 – 92.23, 65.86
Director 3 – 92.23, 94.69
Director 4 – 88.80 , 137.72
Calculated Center of gravity :60.66 cm
The plan for the antenna has been taken from LB Cebik website. More article will follow that covers our construction of this Yagi antenna along with our reports of its improvement.
Tags: amateur radio, antenna, diy, hamradio, Hobbies, hobby, homebrew, radio, yagi
2 Meter Amateur Radio Slim Jim Plan
Ham Radio, Hobbies January 18th, 2008
Here are the plan I use for constructing and experimenting with Slim Jim antenna on 2 Meter VHF Amateur band. The measurement used are designed to center around 144-148 MHz radio frequency, which is used by amateur radio world wide.
FYI this is the plan that I use to construct my first ham radio antenna using PVC pipe and aluminium tube.
Credit to Pak Halim and Azmeer for giving this plan and showing me how to construct a proper antenna.
2 Meter Slim Jim using 300 Ohm tv cable (Ribbon Antenna)
Here’s the plan that I use for constructing Slim Jim antenna for portable radio (ICOM V8).
Both design are meant to be fed with 50-Ohm impedance coax feed line (RG-58/RG-8/RG-213) to obtain the most optimized results
Tags: amateur radio, antenna, diy, Ham Radio, hamradio, slimjim
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