Slim Jim (J Integrated Match J-Pole) is probably the most easiest and powerful 2 meter antenna to build provided you have the exact measurement and material to build it.

This how to will show you how to build a 2 meter slim jim antenna from ordinary insulated copper wire commonly used for carrying AC (alternate current) electricity in your household.

Slim Jim construction basic
I am not only going show you the measurement of slim jim antenna for specific frequency, but I’m going to show you how to calculate slim jim antenna by your own using the basic formula below.

Basic Slim Jim Idea

The figure above shows that the longest side of slim jim is 3/4 wavelength long and the shorter side of the slim jim consist of 1/2 wavelength and 1/4 wavelength long seperated by a gap.

The feedline (coax cable) is normally connected 1/20 wavelength from the bottom of the slim jim antenna with the center conductor connected to the longest side and the shield/braid is connected to the shorter side.

Building the Slim Jim antenna
This guide assume you want to build a slim jim antenna that centered on 146MHz.

Calculation
The formula for calculating wavelength in metric system is 300/(freq MHz)

Using the formula from the figure, we have :

300/146 = 2.055 M
Wavelength = 205.5 cm

Wavelength x copper wire velocity factor = 205.5 cm x 0.94
= 193.17 cm

3/4 wavelength = 193.17 x 0.75
= 144.88 cm (57″)

1/2 wavelength = 193.17 x 0.5
= 96.585 cm (38″)

1/4 wavelength minus gap = 193.17 x 0.25 – 2.6 cm
= 45.69 cm (18″)

Coax tap = 193.17 x 1/20
= 9.6 cm (3 3/4″)

Building Materials

  • 3/4″ diameter PVC (20mm) – 6 feet (180 cm)
  • ordinary insulated copper wire for carrying altenate current (AC) – 11 feet (3.40 meter)
  • Cable ties

Tools

  • Soldering iron
  • Glue gun
  • Somthing to make a hole on PVC pipe

Wire Slim Jim Building Steps

  • First take the PVC pile and measure it according to the 3/4 wavelength formula above (144.88 cm).
  • Make two holes at the opposite side of the pipe. This hole is used for putting the copper wire through the pipe. Repeat this step 144.88 cm away from the top hole. Both of these holes will hold the copper wire.
  • Insert the wire through the hole until both end reaches each other on one side of the PVC pipe. Then measure the length of the wire and cut the wire on that side so the setup resembles the figure above.
  • Cut the wire insulation (but leave the wire uncut) 1/20 wavelength away (9.6 cm) from the bottom of the PVC pipe, again refer the figure above.
  • Solder the center of the coax cable at the longest side of the slim jim (3/4 wavelength part) and the braid/shield at the shorted part of the antenna.
  • Test the antenna using SWR meter to ensure that its SWR is at minimum or within acceptable level.
  • There you go, you’ve build yourself your own 2 meter Omnidirectional Slim Jim antenna for less than USD2 (RM 6.00)

2 Meter Wire Slim Jim Antenna in action

wire_slimjim.jpg

mypapit homebrew 2 meter slim jim

Tags: , , , , , ,



Reader's Comments

  1. 9W2KMC | May 18th, 2008 at 12:26 pm

    Hafiz, saya nak tanya sikit. Sesuai atau tidak kita gunakan dawai aluminium yang dikupas dari kabel elektrik hitam yang bekal letrik ke rumah. Setiap urat dawai tu lebih kurang sebesar lidi.

  2. discount24hrs | January 3rd, 2010 at 12:09 am

    Thank you for this idea i will try to build.

  3. efren suarez | September 15th, 2010 at 2:38 am

    thanks for this idea i’ll try to make it on my very own

  4. GNANA | October 17th, 2010 at 10:31 am

    hi,
    i homebrew this one. its very good .simple electrical wire using this antenna.i assambled one.now i am going on air to contect vu2tcd reapeter in south india.
    tnx 73′s de vu3dng
    october 17th 2010at 8;00am

  5. willywilly | May 19th, 2011 at 12:44 am

    what about the formula of the element spacing or the space between 3/4 wavelenght and opposite? thus it seriously matters? coz im planning to build an uhf slim jim using bronze rods and i will not be using the pvc pipe…….. 73′s

  6. mypapit | June 6th, 2011 at 4:57 am

    willywilly, the spacing is around 3/4″ because I use 3/4″ PVC pipe. Hope that help you

    - 9W2WTF

  7. blog | June 25th, 2012 at 10:46 pm

    It is definitely a fantastic along with valuable part of data. I’m happy which you contributed this particular helpful data along with us. Please stay people up-to-date such as this. Appreciate sharing.

Leave a Comment