Tokyo Hy-Power RF Linear Amplifiers

Solid State RF Linear Amplifier Engineering  

  
 
Understanding
Solid State Linear Amplifiers
UNDERSTANDING SOLID STATE LINEAR AMPLIFIERS
FAQ
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.

See also: "Technical Support"



Tokyo Hy-Power Labs, U.S. Support:

Contact Support by Email
Phone: 713-818-4544
Fax: Please call for our Fax number


Below are some useful websites.


(Palomar Engineers) www.palomar-engineers.com
(Amidon) www.amidoncorp.com
(PolyPhaser) www.polyphaser.com

Any questions, suggestions, comments, problems, or issues
please contact Tokyo Hy-Power Support USA
(Q) What are the advantages of Solid State Amplifiers?

(A) When properly setup and coupled with a resonant antenna system or automatic antenna tuner, you have truly one button operation, simply transmit. There is no knob twisting or meter watching, tune to a frequency and go!



(Q) I heard Solid State amplifiers are not tolerant of high SWR. How much SWR will the amplifier tolerate?

(A) The protection circuits on our amplifiers shut the amplifier down when the SWR reaches 2:1. It does not roll the power back but faults the amplifier to shutdown.



(Q) I have read that Solid State amplifier are “No Tune” amplifiers, can I simply connect my antenna and transmit?

(A) The “No Tune” feature refers to the amplifiers ability to operate anywhere on an Amateur Radio Band without tuning the amplifier to a particular frequency within that band. Simply select or confirm that the amplifier is on the correct band and operate. YOU STILL have to insure that the SWR of the antenna is below 2.0 and preferably below 1.8 on any frequency you have selected. This can be down by adjusting your antenna or using an antenna tuner between the Amplifier and the antenna.



(Q) Can I use the radio’s antenna tuner to adjust the SWR of the antenna?

(A) No you cannot. In addition of not having the necessary power handling capability, the tuner in the radio is between the radio’s antenna output connector and the radio’s power amplifier. The antenna tuner needs to be between the output of the amplifier and the antenna. If the radio has a built-in tuner, disable the tuner before operating the external antenna tuner/amplifier.



(Q) What is the proper way to operate the radio / amplifier / antenna tuner?

(A) We suggest at the very first transmission of the day on a particular band/antenna you tune the antenna FIRST with the amp in STBY. This allows you to quickly observe the condition of your antenna system and to confirm that it is in a healthy state BEFORE operating your amplifier into the antenna. Once confirmed it’s OK, you can then leave the amplifier in the operate mode while QSY’ing up and down the band. We have had customers who did not make this quick check only to find out later that a gopher chewed through the coax or a tree branch destroyed some elements on the antenna, thereby exposing the amplifier to a damaged antenna system.


(Q)
What other operating aids do you recommend?

(A) A high quality PEP reading meter placed at eye level will eliminates all the guesswork out of your antenna system. A quick glance will quickly show that everything is “A OK”. This is invaluable in trying to troubleshoot your antenna system when the amplifier faults due to a problem with the antenna.



(Q) Why does my amplifier seem to only work in CW mode?

(A) The amplifier is transparent to what mode the radio is operating. The amplifier is simply an RF pump, unconcerned of what type of RF it’s processing. If the amplifier works in CW mode, it will work in RTTY mode, SSB, AM, digital, etc. The reason why the meter on the amplifier only moves in CW mode is because it is not a peak reading meter. When using the amplifier’s output meter all measurements should be read with the radio in a continuous mode, such as RTTY, CW, etc.



(Q) I heard that ALC is not necessary, should I connect it?

(A) Absolutely YES, it is mandatory! ALC in all our amplifiers is not for output power regulation. It is simply for Ultimate Overdrive Protection of the finals. Once properly set and adjusted it never has to be adjusted again unless the radio is changed. Power output is regulated through the radio’s RF drive control. The less you drive the amplifier, the less it’s output will be.



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