Specifications

Introduction
Many hams have never heard of this particular model of ETO Alpha amplifier. A few have
heard of it, but have never seen one, even fewer own one.
I happen to be one of those very few who owns an 86. I'll elaborate on how I came to
acquire it later.
Only 274 of these jewels were built between December 1987 and October 1989. The last 74
units being what is known as "export" models, meaning they covered 1.8-30MHz
continuously. The unit I have falls into this final group. I personally know the person who
owns the last unit ever made, and he loves it (no, it's not me).
The picture of the front panel on the first page of this article shows a "domestic" model, on
which the band-switch positions are marked in ham bands, except for the 10meter band,
which is left blank and disabled from the factory.
The "export" model, has the same number of positions (9 total), but are marked in frequency
segments, including 22-30MHz position, which is enabled from the factory.
The picture of the interior, on the first page, is of a "factory-stock" domestic unit.
Some specifications:
The 86 weighs in at a healthy 66 Lbs.= 30Kg.
The box measures 7.5" H x 17"W x 15"D.
A pair of EIMAC
3CX800A7 triode tubes do the amplifying in a class AB
2,
grounded-grid
configuration.
A tape-wound Hipersil® 3.5kVA CCS transformer provides the power (not a Peter Dahl,
more about this later).
The 86 is able to produce 1500 watts of RF output in any mode, with no time limit.
Two plate voltages are available, 2.5kV & 1.6kV, SSB & CW respectively.
All front panel indicators are LED or LED bar-graph type.
The RF power output bar-graph full scale is 2.3kW, the grid current graph is 150mA. and the
reflected RF power reads up to 250 watts.
The Plate current graph reads up to 1.5A, and when switched, reads plate voltage up to
3.0kV
The plate current graph also can display the "tune" feature (more on this later).
The 86 uses a Pi-L output network, with a Pi type input network.
The T/R system uses PIN diode switching for high speed, silent change-over (more on this
later).
With the proper connections made, the 86 is capable of full QSK operation (more on this
later).
86 to 89
The Alpha 89, is a direct descendent of the 86, and has much of the same designs.
The similarities between the old 86 and the later 89 are many. The most obvious difference
is the outside color. The 86 is dark bluish-gray, and gray, the 89 is textured satin-black. The
basic hardware is the same, such as the cabinet, power transformer, tubes, RF tank circuit,
blower, power supply.