Alpha 86 1.5 KW No Time Limit Amp
Specifications (Per manual):
Frequency Coverage: 1.8 to 30 Mhz (as modified with ham license)
This is one of the great amps I have owned. In fact I liked it so much, I had two of them; each being driven by an Icom 775. I directly keyed them with the 775 relay output with no problem as relay current requirements were small. It took about 60 watts to drive to full output. I used them in FSK mode with full output and 80% duty cycle (Contest CQ mode). They do get warm but air flow is quiet and tubes never seem to have a problem. Only operational challenge is to keep SWR below 2:1 or protection circuit will trip and you have top reset. This is sometime challenging on 40/80 and 160 when you want to QSY quickly and your antennas have small 2:1 SWR bandwidth. There is a 3 minute warm-up period with these tubes when you first turn the amp on. Standby/operate switch put to standby when not using. If you try and transmit into the wrong antenna or no antenna, you may blow the pin diode protection fuse in which case the amp will work but you can't receive in operate, only standby mode. Solution is to take cover off and replace fuse - about a ten minute job if you have the fuse (1/4 amp, 125 volt axial - looks like small diode and available special order from Radio Shack or Alpha). This amp only works on 240, there is no provision for 208, 220, 240 taps as on Alpha 89 and Alpha 91B. I ran on 208 for a year and could only get about 1200 watts output. Then switched to 240 and got full 1500 watts output on all bands. I never used the ALC or the QSK keying circuit (key the amp which keys the exciter) as the QSK on the Icom 775 worked just fine. I also never experienced any Icom 775 spike problems even with 775's with serial numbers in the 11xx range (early models). My only reason to change amps was to go to automated band change model for quicker contest operation. These amps also work from the WARC bands where permitted.
Note: The Alpha 86 amp was reviewed in the April 1989 QST and is available as an Adobe Acrobat(R) file from the Members Only section at the ARRL Website (www.arrl.org). Current used prices for this amp are in the $2,000 to $2,400 range. Some models don't have the optional fan on the back or the adjustable ALC pot on the rear panel.Typical Settings and Power Input verses Power Output: