How to build a ham radio is a great question and needs a vast knowledge of electronics and operating principles for both beginners and expert ham operators. Those who are interested in wireless technology ham radio provide him basic knowledge of electronics theory and radio communication knowledge.
Once you are fully equipped with ham radio station you can connect anybody anywhere within the globe even in space, in disaster of ocean and hurricane in land. It is noted that it is a most reliable communication in emergency even when disaster strikes and all other communication like internet and telephone connections fail, the tower being destroyed.
Before you go for building a ham radio you must have some theoretical knowledge about electronics with its circuits and some of operating principle.
Ham Radio Spectrum: Like other wireless technology ham radio uses electromagnetic radiation to send voice signals anywhere around the world, Morse code and digital data throughout the globe with the help of a transmitter, a receiver and an antenna.
This electromagnetic radiation travel in the form sinusoidal wave having different wavelength and different frequency range. The radio waves cover a vast field of waves or rays in radio communication. This spectrum of radio frequency band has so many bands and FCC the federal communication committee allows only a few bands to use in ham radio. FCC has allowed 1.6 MHZ to 1240 MHZ for AM radio band in radio communication of ham radio station.
VHF Very High Frequency: Very high frequency ranges from 30 MHZ to 300 MHZ and the ham radio generally use 144-148 MHZ. VHF is best suited for simplex communication which works line of sight from 2 radio stations set at two different locations.
This band is assumed to be highly reliable and less susceptible to noise and interference from nearby strong signals. Many ham radio operators like this band mostly in order to get maximum utilization.
Using this VHF band the ham radio operators take advantage of repeaters that are set up by radio clubs especially on the roof of high raised building or specially built towers. These repeaters are powered by solar power or built in power back up in order to have a reliable source in case of emergency and disaster strikes.
UHF Ultra High Frequency: UHF ultra high frequency ranges from 300 to 3 GHZ and ham radio uses 400-450 MHZ. UHF has shorter wave length than VHF and is prone to interference from nearby strong signals. The positive side of UHF is having higher band width with wider frequency range and better audio signal quality.
Building Own Ham Radio: When you are going to build your own ham radio you should have through knowledge of equipment and parts needed for its construction. Now to start with choose a clean space well lighted where you can assemble all tools, kit, parts, and equipments.
When everything is ready follow the instruction manual very carefully. It is noted that in such building soldering is very important. Make sure that your working area is secured otherwise other people, pets, and children may damage the tools and parts any time.
The following thing must be considered.
- Ham radio kit: The different parts to build a ham radio are Li-ion NiMH batteries, Tubes and parts, Iron powder and ferrite coil forms, test equipment, coils and transmitter RF parts, crystal, oscillators, circuit board, crystal radio parts, cores, replacement transformer, ICs, ceramic transmitting tubes, band pass filters, chokes, Dial scale, DF equipment, Electronic parts, vacuum tubes, Hammond transformer and chesis.
- Antenna and Accessories: Antenna, analyzer, coax switches, VHF, UHF antenna, antenna parts, bencher, power dividers, wires, connectors, rotator parts, towers, safety equipments, quad antennas, HF antenna, tower accessories, mobile antenna, antenna support, ham stick antenna, portable radial system and aluminum communication tower.
Moon bouncing, distance dialing and digital data transfer plays important role in this radio communication. Some ham radio operators get their signal by bouncing them with the moon itself. Some other ham operators like to connect the operators remaining at long distances. With the help of digital data the ham operators can send images or important pictures from one place to another place.
Tools and tackles: The following tools are urgently needed when you are going to build a ham radio.
- Any quality screwdriver set.
- Electrical tester of low voltage.
- Needle nose pliers.
- Nut drivers.
- Slotted screwdrivers.
- Soldering guns/irons.
- Wire nippers.
- Wire –insulation strippers
Amateur ham radio operators those who have already possessed FCC license are allowed to build a ham radio legally and operate high power transceiver connected to huge number of antennas. The most complicated part of ham radio is to build a SSB single side band high frequency transceiver.
The whole radio architecture consists of filtering, amplification and multiplication. In the year 1920 the consumer receiver used TRF tuned radio frequency. The antenna system would collect signals which were fed by 4 stage of filtering and 3 stage of amplification.
The output of last filter was sent to a envelope detector called a diode and amplification was done as output of loudspeaker. Since this architexure is very expensive and Edwin Armstrong changed it with super heterodyne principle to reduce costing. Thus Edwin Armstrong had a great contribution in the field of radio communication world.
SSB Receivers: Instead of demodulating the radio signals by envelope detector a diode SSB receiver down converts IF using 2nd frequency mixer. Thus the purpose of amplifications achieved and fed to the loudspeaker.
Actually a SSB receiver multiplied down the radio frequency to audio frequency which can be easily heard. IF filters bandwidth ranges from 1.8-2.5 khz which is matched with bandwidth human speech. USB and LSB refers to shifting human voice just above and below of carrier frequency respectively.
SSB Transmitter: A SSB single side band transmitter is simply the reverse of SSB receiver. It is noted that filters double balanced mixer combindly works in both direction. Relays or pin diodes are combined with amplifiers in a particular design that it is able to reverse with transmitting mode. When you transmit SSB the frequency is amplified which is radiated out of antenna. The use of ham radio is beyond our imagination.