Please Name My Blog » antenna

The 2 meter Omni Samurai Antenna

mypapit — Sun, 04 Jul 2010 12:11:41 +0000

My friend, 9W2AZV gave me the drawing for this 2 meter antenna, I haven’t tried building it yet. The antenna seems to share common design with a collinear antenna. I ran this schematic in MMANA-GAL and found out the antenna has a very nice flat radiation pattern which maximize the transmission reach.

Here’s the the antenna design:

Tak-Tenna Compact and Space Saving HF Antenna Review

mypapit — Sun, 04 Oct 2009 19:14:17 +0000

Tak-Tenna is a type of compact antenna which is suitable for those who has space constraints on erecting their HF antenna. It is small enough that a 40 meter Tak-Tenna is just about the size of a 4-element Yagi 2 meter antenna. Here’s photographs of 40-meter Tak-Tenna in action. Compare that to the typical 40-meter dipole or Inverted-V configuration ! Thus it has the advantage of space-saving and unobtrusive setup when compared to other design of HF-antenna.

Tak-Tenna is available in 3 models – 40, 20, and 10 meters, with the 40 meter model can be use on 40, 30, 20, 15, and 10 meters with a tuner.

Refer to this article: “The TAK-Tenna™ Review – A Limited Space HF Antenna Review” for further review on Tak-Tenna performance and advantages.

Tak-Tenna can be ordered from the official Tak-Tenna website

Simple L antenna (2 meter antenna)

mypapit — Mon, 21 Sep 2009 10:49:39 +0000

Here’s the simplest antenna that you can build to transmit with your HT or mobile rig when you have nothing else to rely to. The configuration gives you a 3.5dBi gain and it is simple to construct when you’re at outdoor.

I built this antenna, specially for hitting repeaters during lightning storm, as my usual high mounted antenna might attract lightning.

This antenna can be built using any conductive wire. Though, for my configuration, I use thick copper wires with the length A = 0.525m and B=0.4815m. The A-B angle is about 100-110 degree. It gives SWR 1.0 between 145.5MHz – 145.8MHz and SWR 1.3 at 148.0MHz, the edge of 2 meter amateur radio band.

12 Element UHF Yagi Antenna tuned for 457MHz

mypapit — Sun, 09 Aug 2009 16:16:38 +0000

Here’s a 12 Element UHF Yagi antenna that I designed for my friend, 9w2azv. He’s going to use that antenna for his client, that needs to hit a repeater 10 kilometers away from their location.

Here’s are the measurement for the antenna :

Polar Plot for the Antenna (E-Plane)

Polar Plot for the Antenna (H-Plane) at 2 Wavelength height

Here is the YagiMAX file : 10 Element Yagi 457MHz

Simple 10 meter loop antenna

mypapit — Sat, 23 May 2009 17:57:17 +0000

Here’s a diagram for a simple 10m loop antenna. Although 10 meter band is not very good at this time of the year, the operating condition is predicted to be improving in the next couple of years.

Simple Antenna for 10 meter operation

A/B Value for 28.2 MHz
A = 73″
B = 146″

A/B Value for 28.5 MHz
A = 72″
B = 145 3/4″

A/B Value for 27.5555 MHz (freebander)
A = 73 1/2″
B = 150 3/4″

Data from MMANA-GAL software

The antenna can be build from Copper wire or aluminum tube.
Here’s the MMANA-GAL file for reference : 10meterloop_simple.maa

My Homebrew 10 Meter Moxon antenna in my backyard

mypapit — Fri, 04 Jul 2008 03:04:10 +0000

I took some time off to build my first HF antenna using the plan I’ve obtained few months ago. I chose moxon as my first 10 meter HF antenna as it is small and compact and it is directional, allowing me to focus it into a single direction for a pretty quiet QSO, without much interference.

The material I used in building this moxon are :

Green ground (12 Gauge ?) wire, it has 7 copper wire inside it.
PVC pipe (3/4″ diameter) as necessary to hold the wire in place, you can use other materials too, as long as it formed the basic dimension of moxon antenna

Antenna Plan and Results
I use the plan described in this post; 10 Meter Band Compact Directonal Antenna and started building it immediately. The result of the antenna can be seen here :

Performance
Although I build it only as a temporary antenna (thus its flimsy), it performed rather well when compared to other types of popular 10 meter band antenna in my place (Delta Loop, Inverted-V) as the antenna is directional and it does not requires the use of transformer balun.

I’ve managed to make contact with 12 stations in 6 days since it has been erected.

Some tips working on 10 meter band

Use a good low loss cable such as RG-8 or Belden 9913
Make sure you know where you point your antenna, the direction of your antenna is crucial if you ever to make contact with distant station.
The propagation is pretty good during daytime between 3pm – 8pm by my observation, use that time window wisely.
Use directional antenna like Moxon or Yagi as they allow you to focus your transmission to a certain direction and eliminate excessive interference on the band.
Be patient

That’s it and good luck!

p/s:
I wouldn’t recommend PVC pipes if you are planning to erect a permanent antenna as they are flimsy. Use aluminium pipes or copper tubes as they are more durable and offers best performance.

The Homebrew Slim Jim Antenna Gain

mypapit — Tue, 10 Jun 2008 07:43:49 +0000

I’ve been searching for information regarding the radiation angle and the gain of slim jim antenna, but found none of it. So I decided to build the model of the antenna inside the ever useful MMANA-GAL software to get the information I needed myself.

From what I can surmise, the slim jim has a slightly lower radiation angle than vertical dipole antenna and is easier to mount, thus it is suitable to use for point-to-point communication VHF-UHF operation. It has a gain of about 2.8dBi-3.2dBi in free space and 4.8-5.8dBi when mounted at about 30feet from the ground. Here’s the result of MMANA-GAL :

Slim Jim mounted 30 feet above ground

Slim Jim in free space

Moxon Antenna Plan for 27MHz CB and Freeband Operation

mypapit — Tue, 03 Jun 2008 12:16:57 +0000

Here’s another 11 meter Moxon Antenna plan suitable for 27MHz CB, Freeband and lower 28MHz Amateur Radio operation band.

Dimensions
A- 392.09 cm (154 3/8 inch)
B- 58.62 cm (23 1/16 inch)
C- 11.25 cm (4 7/16 inch)
D- 73.4 cm (28 7/8 inch)
E- 143.27 cm (56 7/16)

Gain, Radiation Pattern (mounted at approx 30feet)

Gain : Approx 10-11dBi (30 feet above the ground)
Freq range : 27.300 MHz – 28.300 MHz

The main advantage of Moxon rectangle antenna are :

Compact and Small
Has considerable gain
It can eliminate noise on HF band
Easy to construct
Suitable for HF operation (mid-low radiation angle)

Refer here for 10 meter Moxon Antenna Plan for Amateur Radio operation (28.2MHz-28.8MHz) : 10 Meter Band Compact directional antenna, Moxon

2 meter 5/8 ASTRA Antenna Plan – KakiBiawak

mypapit — Fri, 16 May 2008 05:00:38 +0000

I think many of you might have heard about this particular 2 meter VHF antenna. Called
“Antenna ASTRA” which derived from the name of one of the most popular Amateur Radio Society in Malaysia.

Here is the details of its construction. Click on the photograph to enlarge it.

KakiBiawak @ Astra Antenna in action

My Homebrew 2 meter VHF Antennas

mypapit — Sun, 06 Apr 2008 18:06:17 +0000

Here are the photos of my homebrew 2 meter VHF antennas. One is 6 element OWA yagi and another is a 2 meter Slim Jim for omnidirectional operation

The homebrew slim jim antenna was previously featured on my blog as well as its plan. The OWA Yagi 6 element antenna plan can be obtained from this post : 6 Element OWA Yagi Antenna for 2 Meter band plan