[CQ-Contest] Alpha 87A Alpha Max
Dick Green WC1M
wc1m73 at gmail.com
Wed Oct 5 16:36:31 EDT 2016
The usefulness of Alpha Max depends on your antenna system. If you have only one antenna per band, it's really not necessary. The base design of the 87A includes precise tuning for enough frequency segments to ensure optimum tuning for one antenna per band. I don't think AlphaMax adds much value in this scenario, except perhaps to deal with small impedance changes that might occur if you use switchable stubs or filters, or to deal with impedance changes that result from unusual weather conditions, snow cover, etc. You can probably live with somewhat less than optimum tuning in those cases. If the amp is on your operating desk (as opposed to located remotely, in another room, etc.), then you can reach over and quickly peak the tuning when necessary.
AlphaMax really shines when you have multiple antennas per band. With the base amp you can only store the tuning parameters for one antenna on each band, so tuning will not necessarily be optimum for other antennas on that band. AlphaMax deals with this really well (though sometimes it needs a brief steady carrier to compensate for the impedance changes.) I'm a serious contester with multiple antennas per band in my station (as many as four per band with switchable stubs and filters), so I find AlphaMax absolutely necessary to ensure rapid optimization of power output and grid current when I switch antennas. I can immediately tell if I happen to have AlphaMax tuning switched off -- grid current is high and power is usually lower than max on all but one antenna per band.
Note that If your 87A is remote from the operating desk, you're not necessarily out of luck. In theory you can use AlphaRemote to peak the tuning. There's also the free program Alpha 87A CAT, which has a lot more features, a better display and complete access to the front panel functions.
[As an aside, the Acom 2000A solves the problem differently. Each frequency segment can contain tuning parameters for up to 10 antennas -- more than enough for most stations, even if you use switchable stubs or filters. It's interesting how the approaches differ: the 87A requires you to manually tune your one antenna per band, but then AlphaMax can peak the tuning. The 2000A will automatically tune a given antenna and store the parameters, but it won't autotune on the fly. This makes it easy to quickly retune your antennas, which takes a lot more time on the 87A -- even for one antenna per band. But it's odd that the 2000A doesn't have offer autotune for peaking the amp on the fly. Although it's relatively easy to tell the 2000A which antenna you're using, you do have to remember which antenna corresponds to which antenna number in the 2000A. I solved the problem by driving the 87A frequency segment and antenna selection from homebrew antenna switching software.
As for duplicating AlphaMax, I can't answer the question with authority, but I have some thoughts. The upgrade consists of two chips, a PAL and an EPROM. It should be possible to copy the EPROM data from another AlphaMax EPROM in order to create a new one. I found one email online where KK2ED had a bad AlphaMax EPROM and was looking around for one to copy. The PAL chip may be more problematic. I don't know if you can copy the code from one of those or what type of programming device you would need. RKR Designs should be able to advise on that. If Glen AE0Q is still there I'm sure he can answer the questions. For a long time the world's expert on the 87A was Brad, who I think worked for the company from the time the amp was originally developed. If he's still at RKR, he'll know.
Hope this helps.
73, Dick WC1M
From: Jim Brown [mailto:k9yc at audiosystemsgroup.com]
Sent: Tuesday, October 4, 2016 4:47 PM
To: cq-contest <cq-contest at contesting.com>
Subject: [CQ-Contest] Alpha 87A Alpha Max
I'm about to buy an Alpha 87A, early production, without the Alpha Max Firmware. That's the feature that provides auto tuning (as opposed to auto recall of saved settings, which was how the amp was originally built).
1) How useful is the Alpha Max auto-tune feature?
2) The new owner of Alpha says the upgrade kit is no longer available.
Is there an easy way to add it? That is, are the chips generic? I'm guessing that at least one of the two chips is an EPROM. Is it practical to buy the chips and copy the firmware from another 87A?
3) Is it worth going to the trouble? I would use it for my high dipoles for 80 and 40M.
Thanks and 73, Jim K9YC
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