How do uhf antennas work

If you could do it… …another way to have one antenna work really well for multiple frequencies is to change its size. About the Author. He is the author of over 8, articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.

A whip enables movement which is particularly useful if you are trekking through bush that will continuously be connecting with your aerial. Depending on the material that your antenna is made of will determine how much flexibility it has. If your chosen antenna is quite flexible you may be able to forgo a whip altogether — you just need it to suit your use. If you need it to be able to bend it to get it into a carport or bounce back after being pulled in tree branches you may opt for a whip and an antenna that is already flexible.

A cheap cruddy cable is not going to last you very long and it may even prevent you from clear transmissions. Do your best to keep the cable as short as possible and use a quality coax cable to reduce any signal loss or noise in transmissions.

You may have to invest in a more expensive one but trust me it is going to be worthwhile. This is probably the most important aspect of a UHF antenna. Gain is measured in decibels dB.

If you are trekking through the hilly countryside or scouting across the vast outback it is going to determine what gain you need. This is around the dB range and is best suited for hilly terrain. You need to picture the signal as an apple, it is wide but short in distance. This is great for hills as it give you the height and depth required for communication at different levels of elevation. This is best used for terrain that is flat.

The signal is more of a flat platter shape — it is long in distance but shallow in depth. Amazing for adventures in the vast outback as it goes for long ranges. Your climate and the conditions you are traveling through can also affect the signal of your transmissions.

If there is a lot of dust, cloud or electricity in the air it can cause interference as the signal tries to pass through it. Your choice really comes down to what you need it for. You should ask yourself these questions to assist in deciding what is going to be the best option for your needs.

Moderate gain antenna — Great all rounder for a combination of hilly and flat terrain. Around dB. Otherwise you can opt for both a low gain and high gain antenna to accommodate any terrain and ensure you have the required range you need. This brings us to our next point. If you are in a convoy or a group where you are only going to be communicating with vehicles roughly 1km in front or behind you a short rubberised antenna, around mm should suffice. It is recommended to ensure at least one or two people in your group have a set up that can reach further distances in case of an emergency.

If you are looking to communicate with those further than 1km radius you are more than likely going to want to invest in a fiberglass or aluminum antenna as they are a little sturdier than a rubberised one.

Duplex mode is a setting on the UHF radio see manufactures manual on how to activate the Duplex mode , its function is to enable transmitting on one channel whilst receiving on another.

See UHF channel chart for Duplex channels. Important information when using a Duplex Channel:. Do not use these channels in Simplex mode as it will interfere with other users. The same goes for CH 31 — CH 38, in this case your voice will be carried hundreds of km away and could make the repeater unusable during your broadcast. A UHF in a vehicle on simplex mode has limited range. If there are hills or large buildings blocking the line of sight the radio signals may not be transmitted clearly and sometimes not at all.

This is where repeater towers and duplex mode can assist the two way communication. Repeater towers are usually found on top of hills, buildings such as water tanks and broadcast towers.

As always, your location will determine what broadcast channels you will receive. With any TV antenna installation, this will depend on the transmitting towers in your area and what kind of TV antenna you will need to receive them, which, in turn, will depend on factors such as terrain and obstacles between your home and the broadcast towers.

Go to www. The virtual channel column represents the channel displayed on the television. The DTV channel column represents the actual transmitting frequency.