power supply

Ouch!

The way I remember it the product used standard relays. The key was that in the off/relaxed position everything was shunted together to common ground point. Lightning could still jump the relay but it would be greatly reduced with everything shunted/grounded together. It was a pretty ambitious scheme if I remember correctly. The antenna lines were all disconnected, shunted too. Depending on the frequency, antenna switches can be pretty expensive too...

One of the radios I used to work on was the Motorola Micor series. They had an interesting antenna relay in them. They used two magnetic reed-switches encased in an aluminum (I think it was aluminum) housing. One switch had a magnet shrink wrapped to it keeping it in the closed position (receive side). A small coil (12vdc) went around the metal case. To transmit they applied 12vdc to the coil which in turn closed the open reed and opened the one with the magnet affixed... For an overall image:

They made a great lightning arrester. Many, many times that is the only part I would have to replace after a tower lightning strike. If you took one apart, quite often the two reed-switches would be completely obliterated, just blown to bits... Motorola had a lifetime guarantee on those relays. Sent many of them back in for warranty replacement. You couldn't tell what happened to them without taking them apart :)

The Ph.Ds at Mitre let me design a couple of diode T/R switches that worked well enough but I don't have the education to design the more complex versions like duplexers or circulators. I never saw anyone still using coaxial relays in digital radios, and they aren't cheap enough at ham fests to buy one to play with.

Except for GPS the stuff I worked on operated below 1 GHz, what they called "DC".

Thanks, I went with this one, you just saved me $100.

Karl

I had a friend in the Dallas area that had a heavy hit - very strong - come down and burn the side of his house at the utility lead. It killed every electrical or electronic item that was attached to the wall or power...

His insurance man laughed at first - until he started making a list.

Mart> >

That's why I LOVE underground electrical distribution. Storms don't take down the lines, and lighting can't find the wires to deliver a direct hit. I use on-line (dual conversion) UPS for my sensitive electronics (computers)

External hard drives!

Bullcrap. There are plenty of times that underground cables were struck by lighting, too. Lloyd should just tell the power company to put surge arrestors in before service is supplied to the property.

You bring up a good point for the future. This box has 6 USB. They are full - mouse, keyboard, camera, memory stick, two hard drives.

Any big deal to add more USBs?

Also can you beat the 2Tb limit on USB hard drives. I've had no luck here.

FWIW, this is the box you helped pick out with a MB replacement. I'll give you the old MB if you can use it.

Karl

Karl Townsend fired this volley in news: snipped-for-privacy@4ax.com:

For whatever reason, drives past 1TB are still fairly short-lived. Although I own (and fairly frequently replace) some of the larger drives (staying well backed-up), I still buy 1TB drives when I need some off- line storage.

Adding more USB? Just use an active hub to run the lower-bandwidth devices off a single physical port. At the least, you could 'hub' the mouse and keyboard, and probably the stick, too.

Lloyd

I'm at 15Tb, making plans to go to 30Tb of storage. USB is of marginal use in this case.

karl

There may be some degrdation in bandwidth with USB 2.0, but USB hubs are widely available (external power supply better) For example

Heres a 5T USB 3.0 drive

You may want to evaluate high capacity HDDs for the computer.

I'm seeing a 5 TB Seagate Expansion as size = 4.54 TB and I can open the folders and play a video with 32 bit XP SP3 on a Pentium M laptop made in 2005.

Low-power devices like a mouse, keyboard and memory stick can be combined on an unpowered hub. AC-powered external drives can use a hub too, but when I copy between drives I put them on different Mobo ports.

"Portable" USB drives take operating power from the USB port and need to be plugged in directly or into a powered hub.

The 2007-vintage Dell D820 laptop beside me can host 10 USB ports; 2x USB3 on an ExpressCard, 4x USB2 on the Mobo and 4 more on a CardBus expander. With 1 TB drives in the boot drive and CD bays it can have over 20 TB plugged in directly.

There are PCI adapter cards for USB3, like this, if you don't have PCI-E slots left:

They won'r run at full USB3 speed because the PCI bus is too slow, but neither will external hard drives. I've seen a little over 100 MB/S from the USB3 ExpressCard which also won't meet the full spec.

-jsw

If the tower was not properly grounded lightning will cause damage. Good grounding will carry off the charge and prevent it from doing damage. Our towers would get hit almost every lightning storm and no damage to the electronics. Most all of the telecommunications towers can withstand a direct hit with no damage. The power has to have some place to go and the best place is directly into the ground with the proper grounding system.

John

Get an external USB hub and connect the four ports up and use one on the computer. The first 4 could be 1 and you have 3 more disk drives.

I've seen 3T USB's at Sams. They are coming. Slow. Certain disk drive user sucks drives like drops of water...

Mart>

You have all the eggs in one basket. I too have a lot of video but it's distributed over a number of computers on the network. None of the computers are "first flight" and they have a couple of external USB drives hanging off of them. The one computer on the TV then plays the video from wherever it is, I have all the drives listed on the desktop, all running XP. I think active UPS's give good electrical protection but I just have MOV's. I prefer 1TB drives for price and reliability.

Psst... John, wake up, you're dreaming...

I worked in two-way radio communication most of my career. Several of the towers I serviced equipment at were grounded to R56 spec, which was very ambitious and the best at the time. The equipment still took hits that caused considerable damage...

And other towers that had little to no grounding and got hit regularly, had very little equipment damage. Go figure...

Maybe our lightning had more oomph than your lightning ;-)

My backup scheme for valuable files is one port-powered 1 TB or 2 TB portable drive to copy to immediately plus two AC-powered ones that I save to when the internal drive approaches full. The USB drives are plugged in only when I'm using them.

Fairly valuable files go on pairs of 2 TB externals, stuff I wouldn't care too much about losing goes on the 5 TB drives which I bought to free up filled pairs of smaller backup drives.

I've had one WD backup drive degrade to complete failure before I could copy all the files off it, and a drive with a reallocated sector count rising fast enough that Seagate replaced it without arguing, although it passed their fitness test.

Here is a large user's comparison of drive reliability. Notice that they may choose cheaper over better, and Seagates vary wildly by model.

Elsewhere they point out that their 24/7 environment doesn't imitate the average user.

-jsw

On Sunday, March 8, 2015 at 8:22:14 AM UTC-4, Leon Fisk wrote in rec.crafts.metalworking:

No. John is spot on. Leon, maybe its just that you haven't been through three or four years of electrician school.

Lightening or surge arresters have been in use for years (here in the 21 century). Why do you think aircraft hardly ever get electrical equipment damage, though they get struck more often than the ground experience you claim above?

Look up what an surge arrestor (or lightning arrestor) actually is:

On Sunday, March 8, 2015 at 8:22:14 AM UTC-4, Leon Fisk wrote in rec.crafts.metalworking:

Leon Fisk

Psst... John, wake up, you're dreaming...

I worked in two-way radio communication most of my career. Several of the towers I serviced equipment at were grounded to R56 spec, which was very ambitious and the best at the time. The equipment still took hits that caused considerable damage...

And other towers that had little to no grounding and got hit regularly, had very little equipment damage. Go figure...

Maybe our lightning had more oomph than your lightning ;-)