Understanding Solid State Linear Amplifiers
Solid State Linear Amplifiers
In recent years the technology of equipment available to the Amateur Radio Operator has increased dramatically. This has impacted all areas of equipment, transceivers, antennas, automatic antenna tuners and of course, amplifiers. Amplifiers manufactured by Tokyo Hy-Power, use the latest technology available.
This technology is incorporated starting at the conception phase, proceeds through the design and manufacturing phase and ultimately results in a high performance, highly technical amplifier for use by Amateur Radio operators throughout the world. Because our equipment are so technically advanced, some basic concepts should be understood in the operation of a modern, technically superior amplifier.
We cannot over emphasize the fact that the operation of a solid state amplifier should not be compared to, even lightly, to the operation of a tube type amplifier. The finals in solid state amplifiers are not tolerate of high reflective power.
Additionally, in order to protect the sensitive nature of the MosFet finals and other electronic components, numerous protection circuits have been incorporated in all our amplifiers to limit damage internally. These include protection against such issues as, high line voltage, high reflected power, excessive forward power, over current to the finals, over voltage to the finals, internal fuse blown, over driving of the finals, fan inoperative and many other parameters. The nature of these protection circuits allow the amplifier to safely trip immediately, sometimes faster than a meter can record a high reflective power or high drain voltage.
Because of the instantaneous response of these circuits couple with the finals low tolerance of high SWR’s, using a solid state amplifier not only requires, but demands that the operator install and maintain an efficient and precise antenna system.
The operator must insure that the antenna system is properly installed and adjusted. All coax fittings are properly assembled and secured, that the coax is of proper size and in good condition. There should also be adequate line voltage and amperage in at the Station to power not only the radio, but all accessories and most importantly the amplifier. All equipment must properly be connected to ground. And finally, there should be absolutely no stray RF anywhere in the shack.
The transceiver also needs to be examined for proper operation and T/R switching. ALC must be used and set properly to insure the integrity and long life of the MosFet finals. Transceivers with NO ALC that exhibit overdriving can fault trip the amplifier needlessly during voice peaks when the amplifier is operated close to its designed power output limit.
Because of the amplifier not only amplifies good RF, it also amplifies the RF discrepancies of the station and antenna system. Efforts to eliminate these faults should not be taken lightly. Stations with poor antenna systems incorporating unbalanced antennas…long wires, loops, verticals with an inadequate radial system all contribute to problems encountered, once an amplifier is introduced.
With all these factors taken into account, adequate time must be allocated to fix and cure all the problem areas in the station…This could be as quick as a few minutes or it could take a few hours analyzing the problems and finding a solution.
Please take in account all of these station requirements and if necessary the time needed to make the station/antenna system efficient and trouble free… For once you have a well designed, trouble free station; you can then truly enjoy the benefits of “INSTANT ON†High Power Amateur Radio Station.
Original source:
http://www.tokyohypower.com/solid_state_amps.html