Friday, December 30, 2016

Simple Ham Radio Antennas--The WH2T mini short loop antenna. Post #997.

The WH2T mini short loop antenna
(http://www.iw5edi.com/ham-radio/?a-multi-band-super-mini-loop-antenna.160).
Author:  Simone (IW5EDI).
Accessed on 30 December 2016, 21:45 hrs, UTC.
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Comment:

Loops are fascinating antennas.  They generally provide some gain over a dipole and exhibit low noise on receive. Loops can be used as multi-band HF antennas if they are designed and fed properly...almost sounds like child rearing.

In this post, Simone (IW5EDI) has designed what he calls "a super mini loop antenna" capable of covering all HF Amateur Radio bands between 80 meters and 10 meters, including the WARC bands.  Simone says the inspiration for this antenna comes from an inverted triangle loop designed by Dr. Ace (WH2T). A working copy of this loop was built and used successfully by Don (K8THU).

As with any loop antenna design, Simone says it's important to pay attention to details:

"This antenna works as a Full Wave Loop on 80 Meters and also works as a 2 wavelength open loop or Bi-Square on the 40 Meter band.
The gain is around 4 dBd on 40 mtrs, but it will seem much higher due to the very low angle, radiation pattern. Any antenna tuned for 80 Meters should also work on 20 and 10 meters as well. If an antenna works on 40 it should work on 15 as well. A tuner will probably be needed for 10, 18 and 24 MHz Band operations.

The loop is an inverted vertical triangle with the base along the top and what would be the apex hanging down. Or it could be erected horizontally if needed.

The feed point at the bottom uses a 3:1 or 4:1 balun and is then fed with any needed length of 50 ohm coax. The top center is broken with an insulator and has a 29 feet 10 inch length of 450 ohm ladder line connected across the insulator.
IMPORTANT - The 450 ohm ladder line is shorted across at the bottom end. "

If you want a HF multi-band, moderate gain, and quiet antenna, you may want to try this design from Simone (IW5EDI).

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Aloha es 73 de Russ (KH6JRM).