1. 2 Meter Slot Cube Antenna Arrl Amateur Radio
2. 2 Meter Slot Cube Antenna Arrl Radio
3. 2 Meter Slot Cube Antenna Arrl Ham Radio
4. 2 Meter Slot Cube Antenna Arrl Antenna

Build a portable VHF yagi antenna for 2 meters. All you need is two rabbit ear antennas from Radio Shack, two CATV baluns, four feet of 3/4 CPVC pipe with one tee. 43 element Yagi for 2 mt. 43 Element Yagi for 144.200 MHz by VE7BQH. Quad antenna, how to build a quad antenna for ham radio use category is a curation of 85 web resources on, Shrunken Quad, The Cubical Quad is Beautiful, Two portable antennas for 6-meter. Resources listed under Quad Antennas category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. Dipole antennas often are the easiest to build, and then turned into inverted V antennas by raising the center of the antennas up into the inverted V style. It's a good idea to have your antenna at least one half ( 1/2 ) wavelength of the antenna. One quarter (1/4) wave is the minimum height above ground for effective performance.

The antenna works well but is difficult to rotate. The photograph below shows the antenna installed at my QTH. The top spreader is 50 feet above ground. The bottom about 20 feet above ground level. HF Skeleton slot. The drawing above shows the dimensions of my Skeleton Slot. It can be easily rotated. It is bi-directional. This two-element Cubical Quad antenna is designed for use on either the 10-meter ham band or the 11-meter Citizen's Band. When all was said and done, my SWR readings were 1.3 to 1.7 on the 10-meter band.

Build a 2 Meter, 5/4 Wave Antenna

By Mike Martell N1HFX

Many RASON members truly enjoyed last month's collinear antenna. This month I decided to build a 2 meter 5/4 wave antenna. This antenna is unique in that it is enclosed entirely in 3/4' PVC which makes the design a little more complicated. The primary problem is that PVC tubing has a significant velocity factor which causes RF to slow down. This means that an antenna encased in PVC will normally need to have it's physical length reduced by about 19%. To further complicate the design, a 5/4 wave antenna's impedance has a highly inductive component which must be tuned out to get a good match. Fortunately, the design in Figure 1 solves all of these problems.

This antenna is made with the following components:

About 2 feet of outdoor type 300 ohm TV twin lead (Used for matching system.)

About 5 feet of #18 stranded insulated wire (Used for radiating element.)

About 5 feet of RG58/U coax

One PL259 Connector

One PL259 female to female coupler

About 8 feet of 3/4' PVC tubing. (normally sold in 10 foot lengths)

Two 3/4' PVC end caps

About 8 feet of 1/4' hardwood dowel (normally sold in 4 or 5 foot lengths)

About 25 small tie wraps

Miscellaneous PVC cement, solder, small piece of tubing, etc.

The twin lead was originally cut for 20 inches with 4 7/8 inches cut back on the braid or ground side. The #18 insulated wire was cut to exactly 57 3/4 inches. The overall length of the antenna assembly is 77 3/4 inches. This indicates a velocity factor of about .81 compared to a normal 5/4 wave 146 Mhz antenna. See calculation below:

234 * 5 / 146 X .81 = 6.49 feet or about 77.88 inches

Now that we have all our parts, lets begin assembly by cutting back the insulation of the coax and the TV twin lead. We will need to cut back the coax to expose the center conductor as well as part of the braid. It is a good idea to lightly thin the braid with solder to prevent any strands from shorting out to the center conductor. Solder the center conductor to one end of the twin lead and solder the braid to the other end off the twin lead as in Figure 1. Notice the braid of the coax is soldered to the shorter part of the twin lead which is left open. This serves as our matching system which adds capacitance to our antenna to offset the inductive component of the antenna. Trim the twin lead to 20 inches and solder about 60 inches of #18 stranded wire to the twin lead as in Figure 1. The insulation should not be removed except as necessary for soldering.

Prepare the 1/4' hardwood dowel by joining two 4 or 5 foot lengths together. The ends can be joined by crimping a 1 inch length of 5/16' aluminum tubing or using a good quality wood glue. Now attach the coax, twin lead and wire assembly to the 1/4' dowel using tie wraps about every 3 inches. Pull the twin lead and wire to keep it as straight as possible. Before attaching the PL259 connector to the coax, drill a hole in one of the PVC end caps and slide it over the coax to prepare for permanent mounting in the PVC. Now attach the PL259 connector as well as any other connectors needed to check SWR. Cut back the open end of the twin lead to about 16 inches as in Figure 1.

Now we are ready for final tuning. Slide the antenna, dowel assembly inside the 3/4' PVC first. All SWR readings must be taken with the antenna, dowel assembly inside the PVC tubing or the antenna will appear electrically shorter than necessary. Check SWR on both the top and bottom edge of the band. If the SWR is higher at 147.995 Mhz than at 144.005 Mhz then the antenna is too long and should be shortened. Cut off no more than a 1/4' at a time of the #18 wire. Also, trim the open end of the twin lead by no more than 1/8' at a time to further lower SWR. Remember the twin lead is simply a matching system which changes impedance and has no real effect on the electrical lengh of the antenna. The final lenghs of the #18 wire and twin lead should very closely resemble those listed in Figure 1. The prototype antenna achieved SWR readings of less then 1.2 to 1 across the entire 2 meter band. Remember to keep the antenna away from metal objects when checking SWR.

2 Meter Slot Cube Antenna Arrl Amateur Radio

After the antenna is properly tuned, trim the antenna dowel assembly to about 7 feet. Leave a few inches of coax attached to the bottom of the dowel so that the mast will be away from the twin lead portion of the antenna when mounted. Trim the PVC tubing to about 7' 2' and cement the top end cap. Double check SWR before cementing the bottom end cap. After SWR has been doubled checked, slide the antenna, dowel assembly into the PVC and cement the bottom end cap. If desired, styrofoam spacers may be used to get a very snug fit. Waterproof the bottom end cap where the coax leaves the antenna. When completed, the antenna should resemble Figure 2.

When mounting the antenna, use a PL259 female to female coupler. Do not use RG58/U for the entire feed line because it is too lossy. Use good quality RG8/U or similar coax for the feedline. Of course, do not forget to waterproof the female to female coupler. Mount to any mast using standard TV antenna clamps at the bottom of the antenna and keep it high and away from other metal objects for best performance and lowest SWR.

Although not actually measured, this antenna should give at least 6 dB gain if mounted high enough. Remember, the small diameter of the radiating element has no effect on the radiation resistance. The only real benefit with using a large diameter radiating element is durability and slightly improved bandwidth. This antenna should give many years of reliable performance for a fraction of the cost of a commercial antenna.

DE N1HFX

Cubical quad antenna includes:
Cubical quad antenna basicsQuad beam antenna with reflector & director2 metre cubical quad design

The cubical quad antenna lends itself to use at VHF and UHF, and a 2 metre quad or two meter quad is easy to make using a few items that are easy to obtain or may even be available anyway. It should be remembered when considering its use that the quad, when fed at the bottom gives horizontal polarisation.

Construction of the 2 metre cubical quad does not require any specialised tools and can be accomplished using the basic tools available to any radio amateur or short wave listener.

At the outset it as decided to make each element the same size, and then use small electrical stubs to extend or decrease the electrical size of the element. A small short circuit stub makes the reflector inductive, thereby effectively making it longer than the resonant length. Similarly an open circuit stub makes the director capacitive and effectively shorter than an electrical resonant length.

2 metre cubical quad construction

A quad for internal use can be made quite simply by constructing a simple wooden frame. Each element is made up from a cross of available wood approximately 12.7 x 12.7 mm (1/2 by 1/2 inch) wood – it requires tow lengths each, i.e. a total of six for a 3 element 2 metre cubical quad.

The wood is not critical so see what is available and adjust the design to suit. The length of each member of the cross member of the quad is 720mm.

At both ends of each piece of wood a small slot is cut to accommodate the wire. This slot can be cut with a saw, or alternatively it is possible to drill a hole of sufficient size to enable the wire to easily pass through. At the centre cut a section out as shown.

In some ways the slot provides more flexibility because it enables the length of the loop to be altered to tune the 2 metre quad to exact electrical resonance.

The next stage is to join and glue two cross members to make the characteristic ‘X’ of the 2 metre cubical quad antenna. The two small sections removed from each cross member should slot neatly together.

Having completed the mechanical construction of the ‘X’ frames, the wire can be added and brought to a small two way terminal block. The wire should be of a reasonable diameter, typically 12 or 14 SWG is good.

The wire is brought to a two way terminal block and secured in this way. The coax or stub can then be attached to the connections in the terminal block and held securely.

The weight of the coax should not be left to be held by the antenna wire, but the coax should be loped and secured to the boom or the mounting pole.

The stubs should be around 7 or 8 centimetres long – their length is not terribly critical, and can be adjusted. The wires can be around 14 SWG and left to remain parallel under their own strength. The short circuit one can use a single section from a terminal block. The position of this one can be adjusted to give the best performance.

The boom for the antenna is made out of two lengths of 25 x 25 mm wood. If necessary the spacing of the parasitic elements can be adjusted with these two lengths of wood acting as a clamp. However once all the adjustments have been made then all the elements should be firmly screwed and glued to the boom.

2 Meter Slot Cube Antenna Arrl Radio

2 metre cubical quad summary

2 Meter Slot Cube Antenna Arrl Ham Radio

Although in many ways this 2 metre cubical quad design is rudimentary, it is nevertheless one that can be build with a minimum of tools and expertise.The antenna can be adjusted to provide the best performance for the particular situation in case, however it should not be used externally as it is not sufficiently robust to withstand the rigours of the weather. However when used internally it has given a good account of itself.

2 Meter Slot Cube Antenna Arrl Antenna

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