The Wavelength of Frequency

The wavelength is proportional to the reciprocal of the frequency. The wavelength of any wave is related to the frequency so that fλ = v, where f is the frequency in Hz, λ is the wavelength in meters, and v is the velocity of propagation in meters per second (m/s). Because radio waves propagate at the speed of light (which is also an electromagnetic wave), approximately 300,000,000 m/s in both free space and the earth’s atmosphere, the lowercase letter c is used to represent velocity (rather than v), so you can rewrite this expression in the form :

f(Hz) = c / λ(meters) = 3 x 10^8 / λ(meters)

These equations are sometimes abbreviated for use with the units kHz and MHz:

F (kHz) = 3 x 10^5 /λ(meters)

F(MHz) = 300 / λ (meters)

You can get an idea of the order of length of these waves  for several different frequencies: 100 kHz, 1 MHz (in the AM broadcast band), 10 MHz (in the shortwave bands), and 1000 MHz (microwave bands). If you work the equations, then you will find that these wavelengths are 3000 m (100 kHz), 300 m (1 MHz), 30 m (10 MHz), and 0.3 m, or 30 cm (1000 MHz). You can see from these numbers why 1 MHz is in what is called the medium-wave band, 10 MHz is in the short wave band, and 1,000 MHz is in the microwave (“very small” wave) band. At 100 kHz, which is 0.1 MHz, the wavelength is 3000 m, so this frequency is in the long wave

band.

Basic Antenna Book

For reference of Basic Antenna System , this book will help you.

Understanding Practical Antennas and Designs

Basic Antennas is a comprehensive introduction to antennas--basic concepts, practical designs, and details of easy-to-build antennas. You ll learn how to make antennas that really work! This book will provide a foundation in antenna theory and design necessary for anyone undertaking more advanced topics such as those presented in The ARRL Antenna Book. Includes: Dipole Antennas, Antenna Impedance, Transmission Lines, Practical Two Element Arrays, Wideband and Multiband Antennas Reflector Antennas, Yagis for HF and VHF, Loop Antennas, Antennas for Microwave Applications, Vehicle Antennas, Antenna Measurements, Plus, an Introduction to Antenna Modeling...and much more!

Ultra-Thin Indoor HDTV Antenna

There is no one magic antenna or antenna type that will deliver excellent TV reception in every
location. The main factors determining reception are the distance and direction from the TV
station transmitters to your home. Other factors include the transmitter's power and the height of
its tower, the terrain between the tower and your antenna, and the size and location of any large
buildings in the path of the transmission.
If you live within a few miles of the transmitter, and the signal path is relatively unobstructed,
you may be able to get adequate reception using a small set-top indoor antenna. But as you move
farther away, getting usable signal strength becomes trickier. This is where careful antenna
selection and installation become essential.
The information below will help you zero in on the type(s) of antenna that should work best for
you. Keep in mind that even in the same neighborhood reception conditions often vary from
house to house. For that reason, it's best to purchase your antenna from a dealer who offers no hassle returns with a money-back guarantee.


One of the good product recommend by customer reviews is Ultra Thin Indoor HDTV Antenna from AmazonBasics. These antennas coming with 4 types of model and range, from 25 Mile, 35 Mile, 50 Mile and 60 Mile. With 1 year limited warranty.  One of customer get almost 44 Digital Antenna channels found. This antenna for 50 miles range will worth your time and effort

Wi-Fi Antennas 802.11b/g and 802.11a and 802.11a/b/g antennas

Wi-Fi 2.4 GHz Antenna

The Speed of your wireless connection will vary depending on the strength of the signal you can receive and transmit. Antenna selection can therefore have a significant impact on the speed of your wireless link.

Types of Wi-Fi Antennas 

 There are two basic types of antennas for WLAN and cellular products :

Omnidirectional and directional. The two types are categorized by the direction in which they beam radio signals.

Omni-directional

Omnidirectional Antenna Pattern

Omni-directional antennas are designed to radiate signals equally in all directions. Use this type of antenna if you need to transmit from a central node, such as an access point, to users scattered all around the area. Omnidirectional antenna consist of 2,
Dipole antenna, and

Dipole Omnidirectional Antenna from TPLink Wi-Fi Antenna

Phonetone 6 dB 3G WCDMA Fiberglass Antenna

Fiberglass antenna

Directional Antennas

 

Directional Antenna Pattern

TPLink Directional Wi-Fi Antenna

Directional antennas provide a more focused signal than omnidirectional antennas. Signals are typically transmitted in an ovalshaped pattern with a beam width of only a few degrees. With higher gain, directional antennas can also be used outdoors to extend point-to-point links over a longer transmission distance, or to form a point-to-multipoint network.

Antenna Connectors

N Type Female Connector

PRSMA Connector

MCX Connector

Before you purchase an antenna for your wireless device, you should check the type of antenna connector that your device uses. You will need to buy an antenna with a matching connector. There are several types of antenna connectors, including MCX, TNC, N-type, SMA, and RP-SMA (RP stands for “reverse polarity” or “reverse ping”). On WLAN devices, the most commonly used antenna connector is PRSMA and N-type for IEEE 802.11 wireless applications. Make sure you are buying an antenna with the right connector type.

50 Miles Range Super Thin Amplified Indoor HDTV Antenna from 1byone

The Super Thin Amplified Indoor HDTV Antenna is a great antenna with aesthetic design and suitable for indoor use antenna in your Living Room or other room that you like to install.

I will share my research findings with you. 1Byone Indoor HDTV Antenna come with different range of Antenna , from 25 Miles, 35 Miles, 40 Miles with Stand, 50 Miles, and 55 Miles with Pole . Also there were Amplifier and Amplifier with USB for get better reception if your place far away from Broadcast TV Tower. This High gain TV Antenna Amplifier will help you.Almost 3523 Customers reviews this antenna and the average customer give 4 stars out of 5 for this product.
 
As mention in  Amazon.com , this antenna can received free broadcast High Definition TV Signals such as ABC, CBS, NBC, PBS, and Fox and support 1080 pixel High Definition. It was easily hidden between behind a picture, bookshelf or television.
Fast and easy set up with 3 steps - Unwrap, Plug it in and scan channels.

• Amazon Discount Link

What Negative Comment from Users about This Products ?

Some users convince that this antenna won't work for people who have their TV very fair away from windows. Because the length of the cables on the antenna are simply going to be too short for most people.  If your TV isn't within 2-3 feet of a window facing in the optimum direction, this won't work very well, if at all, for you.

The other major problem is that the suction mount for the antenna is pretty much worthless. It stuck on my window for approximately 15 seconds before falling off.

The antenna does work but you need to really be facing the right direction which can only be determined by trying it out. And the mount is really poor plus the short cables make it mostly unworkable for most people.

Another customer give negative comment about this antenna , "this antenna makes me really disappointed, also the amplifier makes the reception worse than better for most channels. My home is only 6 miles north from Seattle's downtown, using antenna only I can not get local channel 22, 33, 42, etc.; using "antenna + amplifier" I can get sort of reception on channel 22, but the same time worse reception on other channels."
Another customer said that this antenna  "It did not work. It did not increase my signal strength so I returned it "

Positive Feedback about this Antenna

 
 

Simple Transistor Tester with mA meter as Indicator

This Transistor circuit Tester use for testing whether your transistor it still in good condition or not. This circuit of transistor tester using mA meter as an Indicator.

This Transistor Tester use for check whether the transistor tested in good condition or not. If the transistor tested still in good condition, mA meter pin will move , if the transistor tested not in good condition mA meter will not move or steady.
Switch S1 and S2, is sliding switch for setting whether the transistor tested is NPN or PNP.

S3 is sliding switch for set capacity power of mA, in this circuit we use 1 mA meter.
S4 is Push On Switch for giving voltage current to tested transistor.

When we want to tested NPN Transistor, Switch S1 and S2 we connect to Q2 and Q4, and press Push On Switch S4 to test the transistor . If the transistor in Good condition, the pin of mA meter will move to on a number of measurement. If the transistor in not works well , the pin of mA meter will not move .

WSPR Radio Receiver Kit for 20 Meter Amateur Band Model RK-20

• Have fun receiving WSPR signals from around the world.
• Electronic Kit - Soldering and Assembly Required.
• Kit is for Intermediate to Advanced builders - not for beginners.
• Needs PC, USB port, sound card and free WSPR software to operate.
• User supplied antenna is required. No enclosure supplied.

Want some fun receiving specially coded WSPR radio signals from around the world. This receiver may be what you need. A PC with USB port and sound-card is needed. To operate you must install free software (search the web for WSPR software and articles). User supplies antenna wire and ground to operate. Power is taken from USB. The "weak signal propagation reporter" software or WSPR is designed to communicate with low power by Amateur Radio operators. Only 20M WSPR signals may be received with this unit. Photo shows all items in kit. Partially assembled kits may not be returned.
For WSPR software, you can download here for free use.

World Band Radio Antenna

• *The AN-LP1 is not recommended for use with Sony models ICF-SW10, ICF-SW11, ICF-SW77.
• *The AN-LP1 derives power from the radio when connected to Sony models ICF-SW1000T and ICF-SW7600G.

The Sony AN-LP1 portable active antenna is just right for travelers who wants maximum performance from their world band radio. The flexible folding loop antenna is 19 inches (48 cm) when open, but folds down with a twist to a mere 7 inches (18 cm) and neatly fits in the supplied soft carrying case. A mounting clip and suction cup on the end of the loop allows easy placement in a variety of situations. The suction cup is especially useful for mounting the antenna to a window where reception will often be the best. A reselection knob selects operation from 3.85-21.95 MHz. The AN-LP1 requires two AA cells for about 40 hours of use. The supplied cable connecting the loop to the ANl-LP1 control box is 12 feet long. The supplied cable connecting the control box to the radio is 8 inches long. Output is to a 3.5 mm mini plug. Comes with an English, French, German and Japanese instructions from Sony. Item is made in Japan.

AM FM Radio Kit, Good for Educational

This Kit AM FM Radio, good for educational purposed for building AM FM Radio and for knowing more AM FM radio receiver . 

This Kit come with books as a guide for study more about the AM FM circuit, start from Audio Amplifier, AM Detector, AM IF, AM Amplifier, AM Mixer & Oscillator, FM Detector, 1st FM IF, 2nd FM IF, and FM RF Stages. Superheterodyne receiver of standard AM and FM broadcast frequencies.

 

• AM/FM Radio Kit (Combo IC & Transistor)
• Includes 64 page educational training guide
• with multiple choice questions and answers
• Training course of 56 pages is divided into 9 lessons: Audio Amplifier, AM Detector, AM IF, AM Amplifier, AM Mixer & Oscillator, FM Detector, 1st FM IF, 2nd FM IF, and FM RF Stages. Superheterodyne receiver of standard AM and FM broadcast frequencies. Makes an excellent classroom project. Requires 9V battery, not included.

FM Radio Kit with Auto Scan Frequency

This Kit FM Radio Using IC as FM Tuner and IC for Amplifier. This FM Radio Kit scan FM frequency in 88-108 MHz and using auto scan  for scans up and for reset.

• Build this kit to assemble a monophonic FM receiver (88-108mhz) with electronic auto-scan
• Will help you understand the basics of working with printed circuit boards
• Become familiar with a variety of electronic components
• Develop good soldering skills
• For 30 years Elenco has been using their strong engineering and design skills to develop reliable, affordable electronic test equipment, tools, and educational kits
  This kit is a monophonic FM (frequency modulation) receiver designed to receive FM signals in the frequency range (88-108mhz) it uses electronic auto-scan to search for FM stations. This scan system is done with two button switches-one switch scans up, the other resets to the start of the tuning position.
  

1byone® Window Antenna 50 Miles Super Thin HDTV Antenna with 20ft Coaxial Cable, Extreme Soft Design and Lightweight

• FREE FOR LIFE - Never Pay Your Cable or Satellite For Television Again! 1byone antenna can pull in all of your local news, weather, sitcoms, kids and sports programming with NO monthly contract or bills. Just plug it in and connect to your television and let the antenna do all the work.
• WINDOW ANTENNA - This 1byone window antenna is specially designed to match your window decoration. With its crystal transparent look and grace strips, it looks like a gorgeous art designed for your window.
• DETACHABLE AMPLIFIER - A detachable amplifier and USB power adapter give you a better choice. If your tv picture is not crystal clear, or you can not get the weak signals from far away towers, you can use this amplifier to boost the weak signals. Remove the amplifier/booster if your house is very close to the broadcast tower with strong signals. A booster will cause self-oscillate and you may get fewer signals than without.
• FULL HD, LONGER RANGE - 50 miles range to access from broadcast tower. It delivers full 1080p HD to any digital-ready TV. Comes with a 20-foot coaxial cable for greater flexibility. Makes it easier for you to place it in your house to get the best reception, especially for customers whose televisions are quite far away from windows.
• BUYER GUARANTEE - We stand behind our antenna 100% with one year warranty. Please Note: Freeview reception is dependent upon environmental factors, we cannot guarantee reception in all conditions. We do offer a 30 day money back guarantee on all new items in order for you to test the suitability in your area.

 Antenna HDTV with amplifier for 50 miles range , with elegant and soft design 

Amplifier 

Installation Diagram of HDTV Antenna

 Installation HDTV Antenna on Windows, simple and aesthetic

Antenna Installation 

Antenna Pattern and Model

Super Thin HDTV Antenna with Detachable Amplifier Signal Booster for the Highest Performance the Longest Reception Range, 10ft Coax Cable, Bigger Flat Size Gets the Larger Reception Range

• FREE FOR LIFE - Never Pay Your Cable or Satellite For Television Again! You Can Get All Local Crystal Clear Channels Absolutely Free! 1byone antenna can pull in all of your local news, weather, sitcoms, kids and sports programming with NO monthly contract or bills. Just plug it in and connect to your television and let the antenna do all the work.
• DETACHABLE AMPLIFIER KIT - Attach the amplifier kit and boost 15 miles range! TV reception may vary depending on your local surroundings. If you get fewer channels, remove the amplifier kit. (Note: the amplifier may cause self-oscillate if your house is super close to the broadcast tower.) The detachable amplifier kit gives you two options!
• HIGHER QUALITY - This 1byone HDTV Antenna will be the LAST antenna you will need to buy! If you have ever purchased other brand antennas, you will find out that 1byone antenna definitely is higher quality! There are so many hdtv antennas on the market at around $15, but some of the antennas are made of inferior materials, which can't stand moisture weather or exposed to sunshine. Buy 1byone tv antenna, you will get the real thing. You'll find out it's worth each dime you spent!
• LONGER CABLE, EASIER SETUP - a longer cable makes it easier for you to place it at the best position in your house to get the best reception, especially for customers whose televisions are quite far away from windows. 1byone has very detailed setup instructions coming with the package. You also can get to Customers Service for help. Buy 1byone antenna; get rid of any setup problems.
• BUYER GUARANTEE - We stand behind our antenna 100% with one year warranty. Please Note: Freeview reception is dependent upon environmental factors, we cannot guarantee reception in all conditions. We do offer a 30 day money back guarantee on all new items in order for you to test the suitability in your area.

Antenna Setup for Crystal Radio

Antenna for Crystal Radio can be setup in backyard or tall building, as high as possible , you can pick up much radio signal.





  Recommended Product Antenna :
This is Tune Trapper Marine Antenna for Boat, also suitable for Fiberglass boat Car, RV, where ground plane no exist. You can install it in any place that suitable, no power need, no ground, no amplifier need. Made in USA and water resistant. Have Tested, have good reception in AM/FM Band. Just plug in to your antenna connection in your radio and Tune to FM 87.5 MHz-108 MHz.
This Tune Trapper is 1/2 Wave Helical Dipole
For Marine used, this antenna is sealed housing by PVC for defend from harsh marine use.This Tune Trapper dimension is 24 inch long and 1/2 inch diameter, complete with 6 feet 95% copper wire with standard motorolla connector, is USA handmade. Performance is guaranteed, and this Tune Trapper in bench tested, for make sure crystal clear reception.

Radio Crystal With One Transistor 2SB178

This Circuit is simple with One NPN Transistor 2SB178, Signal

 selected from LC circuit and pick up with Germanium

 Diode IN34A or IN60 or OA70 and Amplified with Transistor 2SB178 and with Earphone or Headphone with Resistant about 8-2000 Ohm.

The component list

COMPONENT '60 Turns' = L
COMPONENT '500 pF' = CV
COMPONENT 'IN34A/IN60/OA70' = D
COMPONENT '10 nF' = C
COMPONENT '5K6' = R
COMPONENT '2SB178' = TN
COMPONENT '4K7' = R
COMPONENT 'Earphone 8 - 2000 Ohm' = SPKR
COMPONENT '100uF' = CE
COMPONENT 'SWITCH' = SWITCH
COMPONENT '1.5V' = BATTERY
COMPONENT '' = GND

Straight Radio or Crystal Radio

OA70 / IN34 / IN60 is Germanium Radio, choose only one type. Antenna high from Ground is high is possible, ground is a must to Steel Water pipe, or making one from a piece of copper approximately 1 meter down to the ground, so will be voltage between ground and radio wave pick up by antenna.

I have build this Radio and connected input speaker to line input notebook and running with Open Lab software and can pick up Radio Signal from about 6 km air distance.

====+  Parts List for   +====

10 nF                              1   Capacitor
VC 500 pF                     1   Variable Capacitor
OA70/IN34/IN60          1   D
GND                              1   GND
108 Turns,12 Turns        L Tap between 108 Turns and 12 Turns
8-2000 Ohm                  1   SPKR or Earphone 8 - 2000 Ohms


This is one of Product of Crystal Radio Kit with Mineral Gateway as Diode and without Battery, this crystal radio specification :

• Conduct a radio wave experiment
• Capture AM broadcasting radio waves
• Works without the need of a battery
• Science guide included (68 color pages)
• Another fun, educational product from the company that brings you Snap Circuits