USING THE AVANTEK AWP-64100 6 GHZ LINEAR ON 5.7 GHZ

The Avantek AWP-64100 has seen wide use over the years as AT&T point to point microwave links as part of an early communications system. As fiber optics and satellites have taken over much of the communications load, these 6 GHz microwave links have been decommissioned. Many of these amplifiers have found their way to the surplus market and from there into Amateur Radio applications.

There are a total of six stages in the amplifier with the first stage being an adjustable attenuator. The next two stages are high gain, low power devices followed by a 1/2 watt IMFET driving a 3 watt IMFET which in turn drives a pair of 6 watt IMFET devices. The linear operates in Class A so it is very linear lending itself to modes such as SSB.

They are easy to put on 5760 other then DC power. Since these replaced older TWT amplifiers in very early microwave point-to-point links, they were designed to operate from the same DC power source that originally powered the older TWT amplifiers. They accept an input of a nominal -24 VDC and draw a about 3 amps. The -24 VDC drives an internal DC/DC converter that in turn generates +10.5 VDC for the IMFET drains and -12 VDC bias for the IMFET gates. This power supply can easily be removed and power supplied by some other DC power supply. The 10.5 VDC drain supply by far provides the largest amount of current (approximately 5-6 amps) while the -12 VDC gate bias is fairly low current (< 1 amp). The power distribution and regulation components are built along the side of the amplifier.

The AWP-64100 has two very large heatsinks, one on top and one on the bottom. Keep in mind that these amplifiers ran 24 hours per day, 365 days per year in remote locations and had to be up and running in any temperature extreme. The heatsink also dissipates heat from the DC/DC power supply. If the power source is an external supply then that portion of the heat load goes away. When we factor in the significantly lower duty cycle for Amateur microwave operation, not a lot of the original heatsink is "required." That is not to say that you don't want to be careful to provide sufficient heatsinking. If the amplifier in its original form consumes about 75 watts, and provides 10 watt of RF then at minimum 65 watts of heat needs to be removed. That is almost 230 BTU's of heat! So make certain you allow enough of the original heatsink to remain, especially if you utilize the on-board DC/DC switching power supply.

Here are some specifications on the amplifier provided by Jeff Kruth, WA3ZKR

If you are interested in converting one of these and want to see what I have done with mine go HERE: I will be offering another amplifier for sale once I have completed the conversion and tested the amplifier. Contact me if you are interested in obtaining a nice 10 watt linear for 5760. Contact me at: nr6ca@sbcglobal.net