Friday, November 14, 2008

HF capability, AM boatanchor, NEARFest, etc

A lot has changed since I last posted. I got hired by Intel for the Itanium Platform Validation Engineering team, I spent two weeks in California for training (Santa Clara area), I moved to Worcester, and most importantly... I got more radio stuff. (you can see where my priorities are!)

Radio stuff:
* NA1C no longer needed his old Tempo 2020, a clone of the Uniden 2020. I bought it from him at a bargain price as the bandswitch wafers are having problems and need repairing or replacing and he didn't really want to deal with it. Still haven't fixed it... haven't decided if I will replace them with banks of relays or re-tension the wipers properly and see if that helps. It covers 80, 40, 20, 15, and 10 meter bands, and has receive support on 15MHz. It's got a dual 6146 final amplifier and seems very well constructed, except for the bandswitch.
* I bought an old Globe Electronics VHF-62 Hi-Bander for $20 at a hamfest, guessing that it would be something interesting. I was not disappointed - it turns out it's a 2-meter and 6-meter all-tube AM transmitter capable of approximately 50 watts on both bands, plus CW! I haven't powered it up yet, as I do not know the multiplication factor for the local oscillator, have no receiver to match it with, and haven't figured out what repairs it will need. Still an awesome deal, it seems very well constructed though it was a kit.
* I went to fall NEARFest in Deerfield, NH with KC2EMA, KB1MSH, AB1JD, and now-KB1RGK. We had a much, MUCH better time than this spring - I was far overprepared, bringing a full tent (with stakes this time), a tarp and posts/stakes/rope to put it up, a grill, enough food for four days, plenty of dry clothes, etc etc. We didn't have to sleep in the van this time, we bought much cooler stuff, and AB1JD did not get hit on by creepy fat old hams. A good time was had by all.
* I'm building a 1kW linear amplifier, capable of operation from 40 meters to 10 meters with the possibility of adding some more inductance and capacitance for 80 meter operation. It only produces about 500 watts up toward 10 meters, but that's to be expected, as it uses a pair of 813s in grounded grid. The input matching network is apparently
the magic that makes it so powerful, most people I have talked to tell me I am insane to expect anything more than 600 watts out of a pair of 813s but several people say ZL1AXB (the designer) is definitely right about it. Almost all my parts are at least 100% overrated for the job, so I am not too worried about magic blue smoke.

EDIT: I almost forgot!
* The aforementioned NA1C and I are setting up a ghetto colocation facility in the basement of his apartment. Routers are kept off the floor using cement blocks, our cooling consists of a set of ventilation fans stuck in a broken window, and the power for the room was run while the fuse panel was fully live. Racks are out, stacking the equipment up one box on top of the next is in - just make sure to put the longest boxes at the bottom. We're running point to point links to various friend's apartments in the area using a 12dBi omnidirectional 12cm whip antenna and a pile of old 30dBi parabolic dishes... in general, it's going to be interesting. and cheap. And a perfect example of how NOT to run a datacenter.