QRO – Alpha 78

Posted on June 5, 2011 in Ham Radio by KG2V
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The shack upgrade is basically complete

About 2 weeks ago, I purchased a freshly retubed Alpha-78, which I installed today in place of my SB-230

Now, there are some things I actually LIKE about my SB-230, and I think I’m going to keep it around, as it’s still outputting rated power from it’s admittedly rare tube. It’s SMALL, it’s silent, as the tube is conduction cooled to the heatsink – oh, and did I mention it’s small?

The Alpha is actually a BIT too large for where it has to go, and I’m having to put a fan on the airspace on top of the amp to make SURE things stay cool there as I don’t have the recommended 4 inches

Other worries is that it can actually put out more watts (WAY more watts) than my LDG AT-1000 is rated to handle (1000w SSB, 750 CW, 500 RTTY/Digital), but I switched the MkV Field over to ‘Class A’ drive, and I’m finding that 30-40 watts or so drives the amp to 800watts peak or so in ‘bandpass’ tuning mode (heck, I’m lazy – yes, the amp is less efficient, and you can’t get max power out that way, but, as I said, I can’t push it anyway)

I made my first 2 ‘QRO’ (sort of – The SB-230 could, in theory put out 600 Watts CW – on a good day, plus I only pushed to 800 or so watts) today, and busted 2 pileups on the first call – Kinda nice, Chile and Haiti both on 40ssb

The big thing I DON’T like about the Alpha? It’s physically LARGE – a tad larger than is really ‘comfortable’ for my desk (might have to build some new stuff)

Big things left to do in the shack? Get the Digital wattmeter (vs the tuners built in analog meter set for peak mode) setup, and get RTTY/PSK31 setup (it’s been setup in the past, just isn’t right now)

It’s been an interesting month, to think I went from an Alpha Delta DX-EE at 30ft to a Force 12 C3SS and D-140 at circa 40ft, and from 400-600 watts to “how much wattage to I dare dump through the tuner” (I guess I could totally bypass the tuner for 10-15 and 20, but it’s needed on 12,17 and 40)

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