G4YDM - VHF DX Enthusiast

How to Work Distant Stations on VHF

How to work distant stations on VHF

FULL ARTICLE

Radio Hams around the world have the great privilege to use part of the Very High-Frequency radio spectrum to enhance their communication hobby, but how do you work long distance stations on VHF? This part of the radio spectrum is by nature a line of sight band under normal weather conditions, line of sight plus about a third of the distance is the normal range, however, there are conditions that do exist sporadically that offer the keen operator the fun of working many hundreds of miles.

Keep an eye on the weather forecast, sporadic E and Tropospheric ducts occur from time to time and offer good long propagation conditions. Meteor shower trails left behind meteor showers help propagate what is normally a line of sight frequency over several hundred miles.

Temperature inversion over the North Sea has given me the opportunity to contact stations in Scandinavian, this type of propagation occurs during differences in temperature between the sea and the surrounding atmosphere.

There is a tremendous amount of loss of signal strength on V.H.F. between the transmitter and the receiver, to counteract this physical fact many operators use a directional aerial comprising a boom where a number of elements have been attached to amplify the power from not only the transmitter, a directional beam amplifies the incoming signal too. Commercial radio masts erected for utility operators can easily overcome this problem by having multiple hilltop repeaters that receive the transmissions; they are then sent to other hilltops via microwave radio links or connected together via fiber cable and the internet.

Working longer distance on VHF is possible if you engage in this activity during certain organized events. Contests and other planned events including field days offer the chance for radio Hams to cover larger distances with their equipment. Linear amplifiers are used to boost the outgoing signal. Head for higher ground during these events, you will be amazed how many contacts can be made from a hilltop location.

Operating from the Pennines offer the VHF Ham radio operator the benefit of height, I have operated in a particular spot on the Pennines that is over 1300 feet above sea level. Using a transportable transceiver and a homemade Yagi aerial, I have communicated with other stations well over 200 miles away under flat radio conditions. Proving that height above sea level gives the operator a great advantage.

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John G4YDM

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