Thank you for your response, i will keep them comming. Nice article but i have a question. How did u determined matching circuit components? Also, for antenna length calculation with 2. Thank you for your question,. For a quarter wavelength Wi-Fi antenna, the theoretical length should be Initially, I thought to make the PCB a little bit smaller to do so I was searching for some reference design that's why its written 23mm.
But I end up fabricating the board a little big and I also changed the antenna for that reason, the 23mm length is a mistake and I will change that. Get Our Weekly Newsletter! Helena St.
Related Content. Cheers, Jay. Thank you for pointing that out. Hello, Good stuff, i have a question though ,can this whole circuit be simulated? Log in or register to post Comment. This antenna is based on the dipole element. As shown in the illustration of figure 18, Not so much antenna types as antenna Retrieve Full Source. Document Retrieval.
Revisiting Rectangular Loop Antenna - Onlinepresent. Erwin B. Daculan and Elmer P. ECE Department, antenna at different side ratios isinvestigated as to its effect to antenna parameters. Retrieve Doc. Rubber Ducky antenna - Wikipedia The rubber ducky antenna Electrically short antennas like the rubber ducky are used in portable handheld radio equipment at VHF and UHF frequencies in place of a quarter one can surmise that it is possible to design a rubber ducky antenna that has about 50 ohms impedance at Post a Comment.
The low end of the range is about 3 MHz and there is plenty of band overlap. An outdoor version was built with ordinary PVC tubing in a square shape similar in dimensions to the Hula-Hoop not critical. The stiff 14AWG copper wire was replaced with a heavy braid to make it easy to thread the wire through the square shape. The circuit is identical except that the potentiometer and band switch are in a separate box near the receiver little white box and a 4-conductor wire caries the DC signals to the remote antenna box a PVC electrical junction box.
The relay was added after the photos of the outdoor box and board above. The wires coming down from the antenna include a cable with four-conductors to control the amplifier, a coax cable for the RF to the receiver, and a three-conductor cable for the antenna rotator. The performance of the indoor antenna is good, moved outside on a flipped-over garbage can it is great, but the performance of this rooftop loop is spectacular! Simply tune the radio to the desired frequency then tune the antenna for maximum noise, switching the band somewhere around 12 to 15 MHz.
The Q is low enough that retuning is only necessary when moving from one band to another. In some areas lower Q may be desired to prevent amplifier overload. In only a couple of days I've heard stations all over the world including some "numbers" stations with S9 clarity.
Reader Minoe from The Netherlands has graciously provided a board layout designed by circuitz4u. Minoe says, "the zip contains both the Eagle files and the Gerber files.
Here's another version of the circuit featuring a cable driver. This driver will reduce the gain loss due to heavily loading the TL The input impedance of the driver is quite high, and the output impedance is near 75 ohms.
This version is set up to tune from about 9 MHz to over 25 MHz and other tuning components could be selected for other applications. The power for the circuit comes in on the coax and another uH and coupling capacitor would be needed on the other end, too, with the inductor going to the power supply and the capacitor going to the receiver. The power supply and receiver share the coax ground. A good AM Band antenna can be a simple long-wire strung between two trees or across the top of the roof.
Even a modest length wire will give your receiver greatly improved reception with less static because the signal pickup is occurring some distance from the interference generating appliances in the house. An insulator mounted high in a tree so that the wire has a large vertical rise will give great results. Mount the antenna as high and as far from the house as practical. Use a good quality ceramic insulator for holding the wire and add a commercial lightning arrestor where the antenna meets the house Fig.
Ceramic insulators are available with built-in wood screws and can be screwed into a tree or the wood parts of the house by hand. The wire may be tied to the far insulator as shown but the wire will stretch with time and require adjustment. A "trick" is to pass the wire through the insulator and fasten a fishing weight to the end so that the weight hangs a few inches below the insulator. As the tree sways in the breeze, the weight will move up and down and the wire will remain straight!
I must confess that my long wire antenna is made with insulated wire thrown over a branch with a rock tied to the end Who has time to do it right? I do have an arrestor, however! A good place for the arrestor is directly above the point where the water line enters the house. Run a heavy gauge ground wire straight down to the water pipe and attach it with a brass grounding clamp assuming a copper water pipe - always use compatible materials or corrosion will result.
This connection also makes an excellent ground for the receiver. A shielded cable lead-in wire can give improved results when the residence has unusually noisy appliances.
If you do not have an AM radio with a coaxial antenna jack then consider using an auto radio. Auto radios are well shielded to prevent ignition noise from interfering with reception and all that is needed to make a superior receiver for the home is a 12 volt power supply and a speaker. Claudio Re reclaudio alma. Grazie Claudio. I commenti sono aperti a tutti e sono soggetti insindacabilmente a moderazione. FM World Caricamento in corso
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