Posted on: 4th February 2010
THE MAX limit of power is always 400Watt in the Netherlands.
There is no amplifier that hold 400watt max. You have to build it yourself. Even then filtering will be worse.
Is just as driving a car to the limit. It will collapse after a while. So you need a bit overkill to save your equipment.
** note ** Pictures are from the internet.!! not provided by myself. I’m not responsible if anything is read in a wrong way.
Fred Astaire – Winston Churchill – Apollo 11 – the Collins KWM-2. The best performers always set new standards and raise the bar for those who follow. New standards for style, charisma and integrity. But most of all, when the eyes of the world were on them, they always delivered reliable rock-solid performance. Just like the Alpha 87A. As the Alpha 87A enters into retirement, history is already awarding it a place on a pedestal as a true benchmark for linear amplifier performance. And the engineers at Alpha are preparing to raise the bar yet one more time.
Alpha has delivered over 1,500 Alpha 87A amplifiers over the period from 1990 to 2005. Most are now worth more today than when they were originally purchased – another hallmark of a classic – becoming more loved by your audience with the passage of time. So why retire? And what comes next?
We want the 87A to retire at the top of its game. The original design was groundbreaking for the late 1980s when it was introduced. Technology marches on however, opening up exciting new possibilities that could not have been cost-effectively addressed at that time. Like using multiple microprocessors. The 87A uses a single Motorola processor to run the entire amplifier. The new Alpha will use no fewer than five micros. Automobiles made in the 1980s might have utilized only one processor to run the engine, whereas today they will probably have more than a dozen. This cuts down on the wiring harness, eases code development, improves manufacturability and increases reliability.
Frequency coverage: All amateur frequencies from 1.8-29.7 MHz
Power output: 1500 Watts minimum
3rd Order IM: <-30 dBc
SWR tolerance: 3:1
Drive power: 65 Watts nominal
Tube: Eimac 8877
Cooling: Forced air
Antenna outputs: 4xSO-239 connectors
Antenna selection: 1 or 2 outputs per band/segment
Input: SO-239 connector
Tuning/Band switching: Automatic. Manual override possible
Power: 100,120,200,220,240V ac, 50/60 Hz
Power tap selection: Automatic
Interface: Serial port. Full remote control capability
Protection: Protected against all common faults
Display: Bar graphs as well as digital panel meter
T/R switching: Vacuum relays; QSK (full break-in)
Bypass capability: 1500 Watts
Wattmeter and antenna selector active in “ON1” to allow use with exciter. HV and tube come on in “ON2” for linear use.
On the other hand, the basic mechanical parts that perform the auto-tune magic in the 87A are just as good today as when the design was originally put into production. To this day, the use of external-anode ceramic tubes is still the most cost-effective way to develop 1.5kW (with margin) of RF power in the HF range. Alpha is frequently asked why we don’t use solid-state devices. The answer is that tubes continue to be more cost effective. Remember, Alpha amplifiers deliver 1.5 kW key-down into a 2:1 load. With margin. You can unscrew the output coax while transmitting and the amp will quietly shut down. You can push a nail into the coax, and the amplifier will again quietly shut down. The IM performance into a 2:1 load is the same as into a 1:1 load. If lightning strikes, you may have to replace a fuse and an output relay, but the tube will very likely survive. If you must change the tube, this task is well within the reach of most amateurs. Even in the field. Changing 16 or even 32 large soldered-in power transistors with all the associated thermal concerns is probably not something you would want to attempt in most home workshops, let alone in a tent on a Dxpedition! Add to that, tubes are more efficient, lighter and quieter to cool. After all, what matters most is not what particular technology is inside, but how the amp performs as part of a system – your station. And, whether it can be maintained at peak performance for many years. The 8877 tube, which will be used in our new Alpha, has been in continuous production for 35 years. How many power transistors can make a similar claim?
Thus the new amp will use the most reliable RF power source and tank circuitry ever devised, it will use state-of-the art technology to deliver performance and features never before seen in an HF linear, and it will proudly carry the name ALPHA 9500.