30 meter Quad
** If there are any questions - please send email - thank you .
After a number of years of procrastination and desiring a better Rx/Tx signal on the 30 meter band I finally decided to investigate the options. For quite some time, I have used an inverted vee dipole with the apex at approximately 14 meters up, positioned under my 5 band 2 element Quad. This antenna performed 'ok' but was lacking in many departments!
About a year ago I changed this to a full wave inverted vee loop. I have to admit, by doing this, general performance improved quite a bit over the standard half wave inverted vee. Still not 100% satisfied, I continued to search for a better option ..... it was at this time, I came across an extremely interesting webpage by
John is what I would call a true Ham in so far as he is a great 'home brewer' and has published his experiments and projects for one and all to view. He has been instrumental (in no small way) in helping me with my endeavor to further enhance antenna performance.
For those of you that have a 2 element quad, what I have done can be easily replicated. The Quad I have is a LightningBolt design - each of the 5 bands (20-10 meters) are individually fed directly with 50 Ohm coax from an Array Solutions RatPak switch. I have used coax chokes at each of the feed points. ( Go for choke details)
Each of the original spreaders will need to be lengthened by 3'4" (101.60 cm)to accommodate the 30 meter wire. Total spreader length is 15'6"(472.44 cm). Longer is better if room permits( the shorter the linear wires are - the closer the antenna is to full size by increasing the actual loop length - in my case, the room I have is such that I need to keep the measurements as described)
The total length of the loop is 84 feet (2560.32 cm)(21 feet per side[640.08 cm]) click to view John's drawing- on either side there is an 11'6" (350.52 cm) linear loading (cap. hat) wire spaced 6" (15.24 cm) in from the loop. The 6 inch jumper is at the centre point of each side (10'6") [320.04 cm]
To stop the spreaders drooping, I tied a support rope across the top spreaders - this is attached at the same points as the linear wires and measures 20'4" (619.76 cm)
The above measurements can vary, dependant on wire type and size used. I used the original wire supplied with the LightningBolt Quad which is 1.6mm ali welding wire.
Now to the performance results - in a word -excellent! Point it at the DX and work it! Has side nulls which is great in eliminating unwanted QRM! At time of writing, I am very pleased with this 30 meter antenna and now intend to add a reflector element in the near future ( will add info on this later)
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Update - 16 October 2007
I have now added a reflector to the Quad for 30 meters.
I kept the same dimensions as above for the outer loop (84 feet total length [2560.32 cm]) and made each of the linear loading wires 13'6" (411.48 cm)- the 6 inch (15.24 cm) spacing remains the same as does the positioning of the jumper on each side.
The spacing between the driven and reflector is approximately 14 feet (426.72 cm).
It has to be said that as this antenna is not full size, it is a bit of a compromise - however, it is a superb performer none the less with front to back being in the vicinity of 4-5 'S' units, and great side nulls @ 90 degrees.
The SWR is 1.4 : 1 across the band ( with a little fine tuning, this should improve)
Now to performance - excellent, sums it up! Signals never heard on the inverted vee dipole are S5 or better now! This antenna is certainly a 'pile-up creator/breaker' - If I can see/hear them - I can easily work them! As with Quads, they are the first to open the band and last to let it go!!!
This project was very inexpensive - total cost $6.00 for some wire joiners! That equates to around $1.50 a db gain!!!
My thanks to John EI7BA for his valued input.
