A collection of 9 easy to build J Pole antenna projects for VHF UHF and also HF
This month I would like to share an idea from my sketchpad with you. I am planning to build a vertical delta-loop antenna for 20 meters. The reasons for choosing this design: My favourite HF band is 20m Delta-loops for 20m are manageable in size Loops are quiet on receive Vertically polarized loops are well suited for DX I found the delta-loop overview below at the website of W5SDC: Delta-loop overview. My choise of shape will be version D because if offers a low radiation angle, which is necessary for DX. The sketch below shows how I plan to build the antenna: Delta-loop antenna for 20m. A delta-loop antenna with ATU was described by WB8IMY and published in QST May 2002: One Stealthy Delta. This article is worth studying if you consider constructing a loop antenna. OZ1BXM Lars Petersen
A warning ahead: the following is a YMMV project. Coax collinears have come in very different flavours and it is very hard to find at least two sources which agree on a reproducible design. Ok, the…
In this DIY tutorial, we are demonstrating an AM Loop Antenna in detail. It enhances all feeble AM signals thus improving faint radio signals. So, every
433 MHz Coil Loaded Antenna: In my 433 MHz projects I have been using a cheap (0.70 cnts) pair of Tx/Rx modules. I have mostly used the transmitter and that is actually fairly OK with just a simple 1/4 lambda antenna, but is open for improvement The receiver however is a bit cr…
This indoor FM antenna greatly improves FM stereo reception. Its inexpensive and easy to build.
The theory of The Zero-Point Energy Field from classic to modern. Zero-Point Energy's applications in power exploitation. Zero-Point Energy creates free energy generators.
Murata has released a high gain antenna module that facilitates communication up to 4.62 Gbps. The new millimeter-wave RF antenna module will contribute
Instructions on building your very own aviation band antenna.
This technology stock photo features tv, television, and signal.
What is an Antenna? Why do we use Antennas. A tutorial on understanding what an antenna is and what are the different types of Antennas with properties.
The DB4 Antenna. Simple, very cheap, and very effective. If you are within 30-40 miles of your TV stations, then this is the antenna for you. Before you
This is a 200 Watt PEP step up transformer for end fed full and half wave antennas without radials, designed as a 200 Watt PEP upgrade by PA0EJH for the originaly Par Electronics designed 25 Watt HF endfedz multiband end fed antenna. The original design has a 27/3 turn ratio ( 1: 81 ) on a small 43 material toroid, but the larger toroid has more wire so the nr of turns had to be reduced for max.efficiency on 10m. The coil now has a 16/2 ratio ( 1: 64 ) For max. performance the 2 turns to ground must be twisted . The 100-150pF capacitor gives a better match on 10m.and both windings start at the ground side of the coil .Don't try to stack toroids for more power for this will increase overall inductance . This makes it impossible to tune the high bands. The best results are obtained with a small toroid.....The 3 band antenna has a length of aprox. 10.1m. followed by a coil of about 34 uH ( 90 turns 1mm transformer wire on a 19mm pvc tube ) and a endpiece of about 1.85m , offering you a perfect vertical or horizontal antenna for fieldwork at 40 -20 and 10m. There is also a 5 band version with aprox. 20.35m wire followed by a 110 - 120uH coil ( about 260 turns 1 mm transformer wire on a 19mm pvc tube ) and a aprox. 2.39m. endpiece. Use a longer wire for testing for surrounding objects can interact . *** Start tuning the antenna by tuning the long wire at the high bands with the coil and the endpiece attached, for the coil interacts. Many people do this the wrong way ! Don't use an other type of toroid like the nr 2 or 6 mix for the AL value of these toroids is far to low and will result in heavy losses. *** This antenna works on 80 - 40 - 20 -15 and 10m.without radials and has a verry low swr combined with a low noise level. Keep in mind that every end fed / vertical needs some kind of counterpoise to push against and in this case that's the coax , so don't forget a line choke near to your transceiver. Cul = transformer wire. Tranformer with 150pF and 3K3 resistor to ground Transformer on a smaller FT140-43 toroid for max. 100 Watt pep Update 2014-03-21 I live in a apartment on the first floor so you can imagine my antenna problems.... My balcony however is 10m. long ,so i mounted a horizontal endfed antenna without the coil, for 20-10m on the wooden windowframe . Because of the capacity of the wood and the paint overall length was reduced to aprox. 9m.. but provided a near 1:1 swr on 20 and 10m. First contact on 10m. was with 5B4AHL (5-9) on cyprus folowed by 9K2QA (5-9) in Kuwait and 4S7VG (5-8) in SRI Lanka despite of a huge pile-up. This antenna is going to stay HI. MONO BAND HIGH EFFICIENCY HALF WAVE ANTENNA If a high efficiency antenna is needed here are the data. Use thin 50 Ohm Teflon coax wire for the capacitor ( one side open ) . 1 cm coax is aprox. 1 pF. Tuning without the antenna : connect a 3300 Ohm resistor fom the coil end to the ground of the coax connector. cut the coax-capacitor carefully for lowest SWR . Connect the antenne and cut the antenna wire for best SWR . Calculate L and C for your own matching unit: http://www.daycounter.com/Calculators/L-Matching-Network-Calculator.phtml Reactance L and C : http://www.daycounter.com/Calculators/Reactance-Calculator.phtml
Diana Eng shows how to make your own End-Fed Half-Wavelength Antenna (EFHWA) for portable radio operations.
Nuts & Volts Magazine is written for the hands-on electronics hobbyist, design engineer, technician, and experimenter.
The Lost Art of Electroculture Gardening What is Electroculture Gardening? Electroculture gardening, sometimes called “soil-less gardening,” is an organic
This VSWR analyser looked interesting from K6BEZ. Certainly simple and low cost and probably just the thing to test the multiband SOTA antennas that I have been putting together lately. I happene…
