ND2E's Blog

Even after I bonded the antenna and house grounds together, I suspect that there will still be a significant voltage spike on the ground during a lightning event. There are only a couple of ways to isolate the computer from the radio and in most cases it is not real isolation but using something that is relatively cheap as a consumable to isolate the spike effects.

So I had originally decided to use external usb to serial converters and cheap passive hubs to isolate the equipment. A little testing yesterday showed me that (at least using the PCMCIA card as a USB source) the USB ports can not provide enough power for the USB-Serial interface and a hard drive. Once the Gx270 is finished I will see if it can source enough current to handle the drives, USB adapters, and soundcard. If not I will have to introduce yet another variable-a powered USB hub. Who knows how that will affect the isolation.

Life is just not fair…it keeps getting in the way of play time. I’ve actually been on the air a couple of times since the last post but only long enough to make a couple of QSOs before I had to do something else.

I have replaced the Dell Dimension 8400 that died. I have a new used Optiplex GX270 that I picked up from one of the refurb dealers. Back in the day we would have called them salvage dealers but I guess that isn’t PC anymore.

In any case, I am waiting on PATA to SATA power connector adapters before I add the big disks to the system. It came with a 40 Gig hard drive and 512 M of RAM. I purchased another 1 Gig stick from Crucial so I should have enough RAM for radio and server operations. The GX270 is evidently 2003 vintage because it uses DDR not DDR2 sticks. That caught me by surprise, especially since I didn’t have DDR memory in stock…I completely skipped that era.

The new computer should be on line sometime late next week after I install the SATA drives, operating system, and programs.

I will install HRD V5 (I will keep V4 on my laptop) as well as a host of other programs including Dx Keeper and all of its subprograms. Others will include:
• XAMPP so I can have a test machine for the web sites I control
• Firefox
• GIMP
• OpenOffice
• Eraser
• CCleaner
• AdAware
• PDF Maker

Oh yes, I almost forgot, I need Creative’s package since I use an external soundcard.

In an effort to keep the system from being destroyed again, I have tied the antenna and house ground systems together. I really don’t think that it will actually do any good because the two ground points are about 100 feet apart. My understanding is that 35 feet of just about any economic size of copper wire will have enough inductance to make the two grounds appear to be separate during a lightning event. (The rise time of the lightning pulse being so quick that the inductance plays a significant role in the voltage difference.)

I am hoping that the big UFER otherwise known as the patio will help but I really don’t know nor do I know of any tool that might model the effect. So to meet code I have bonded the grounds.

So hopefully I will get some operating time this weekend and next week.