High voltage arc gap design

[Tom Bruhns]

On Jun 1, 7:58 pm, "Michael A. Terrell" <[email protected]>
wrote:
....

[USA television] Ch 1 was lost
over 50 years ago to land mobile fire and police radio VHF High band
service.

You're quite sure about that, are you?

Cheers,
Tom

 

[Jamie]

On Jun 1, 7:58 pm, "Michael A. Terrell" <[email protected]>
wrote:
...

[USA television] Ch 1 was lost
over 50 years ago to land mobile fire and police radio VHF High band
service.

You're quite sure about that, are you?

Cheers,
Tom

I don't think it was lost, They just didn't use it because it
falls on the IF freq of the receiver or close to it.

But then again, I could be incorrect there.

http://webpages.charter.net/jamie_5"

 

[Tom Bruhns]

On Jun 1, 7:58 pm, "Michael A. Terrell" <[email protected]>
wrote:
...

[USA television] Ch 1 was lost
over 50 years ago to land mobile fire and police radio VHF High band
service.

You're quite sure about that, are you?

Cheers,
Tom

I don't think it was lost, They just didn't use it because it
falls on the IF freq of the receiver or close to it.

But then again, I could be incorrect there.

http://webpages.charter.net/jamie_5"

There's a nice, though I don't know how accurate, history of USA's
Channel 1 at http://www.anarc.org/wtfda/channel1.htm. Back that
early, I don't know if there were any TVs using a 45MHz IF; early ones
used 21MHz, or thereabouts, much to the consternation of amateur
operators wanting to transmit on the 15 meter band.

Now how did we get to this from "high voltage arc gap design"??

Cheers,
Tom

 

[[email protected]]

| "Michael A. Terrell" wrote:
|>
|> Robert Baer wrote:
|> >
|> > From reliable soft failure analog to crappy on/off digital.
|> > TV is the first frontier...
|>
|> That spectrum had value for other uses. A 1 Mhz slice at the bottom
|> end is fairly useless for anything other than local radio service. It
|> also has very different propagation, and is reserved for radio by
|> international agreement, because it can easily cross multiple borders.
|> With the high background noise in most areas you need a kilowatt or more
|> to cover a small town. The only time I've had clear reception in years
|> was when the whole region was without electricity for 30 miles or more,
|> right after the hurricanes a few years ago.
|
| What spectrum is that?
|
| I read a thread some time ago on an hdtv group about what TV stations
| would be doing after the date for dropping analog. Some stations will
| keep their secondary UHF frequencies as their new primary broadcast
| frequencies. But many plan to switch their digital broadcasts to the
| frequency they now use for analog. In other words, it appears that TV
| stations will be spread across the VHF/UHF bands more or less as they
| are today.

More UHF and less VHF. But the big point is they are juggling around. Some
people will need UHF antennas where VHF sufficed (viewers of only the major
networks in most big cities). Others will need VHF antennas where UHF was
once all they needed. The government needs to set up an antenna coupon
program, too.

 

[[email protected]]

|
| "Paul Hovnanian P.E." wrote:
|>
|> "Michael A. Terrell" wrote:
|> >
|> > Robert Baer wrote:
|> > >
|> > > From reliable soft failure analog to crappy on/off digital.
|> > > TV is the first frontier...
|> >
|> > That spectrum had value for other uses. A 1 Mhz slice at the bottom
|> > end is fairly useless for anything other than local radio service. It
|> > also has very different propagation, and is reserved for radio by
|> > international agreement, because it can easily cross multiple borders.
|> > With the high background noise in most areas you need a kilowatt or more
|> > to cover a small town. The only time I've had clear reception in years
|> > was when the whole region was without electricity for 30 miles or more,
|> > right after the hurricanes a few years ago.
|>
|> What spectrum is that?
|
|
| 700 Mhz to 800 Mhz. In other words, everything above Ch 52.
|
|
|> I read a thread some time ago on an hdtv group about what TV stations
|> would be doing after the date for dropping analog. Some stations will
|> keep their secondary UHF frequencies as their new primary broadcast
|> frequencies. But many plan to switch their digital broadcasts to the
|> frequency they now use for analog. In other words, it appears that TV
|> stations will be spread across the VHF/UHF bands more or less as they
|> are today.
|
|
| Not likely. They already lost channels 70 to 83, and Ch 14 in some
| areas ( Chicago?) for UHF land mobile service. The DTV conversion is
| shaving 17 more channels for the original UHF TV spectrum. Ch 1 was lost
| over 50 years ago to land mobile fire and police radio VHF High band
| service.
|
| In less that a year there will only be 51 of the 83 channels assigned
| over the years.

Except not channel 37.

 

[[email protected]]

| Unfortunately, the lightning arresters consist of three 20 kV units per
| phase, stacked in series. When this station had been used with a 12 kV
| input, the bottom two sections of each phase were jumpered to ground.
| Nobody noticed this (there's a whole story behind the problems at this
| utility that lead up to this f*k-up worthy of another post.

Technically, configured wrong. That and inadequate checklist/testing.

I'll look forward to the "another post" some day.


| It was quite an event. I was standing about 100 feet away. After the
| initial fault, the system breaker (about 20 miles away) de-energized the
| entire line. We stood there for a few seconds and, just as a few people
| were thinking about walking up to it, someone shouted, "Wait for the
| reclose!" Sure enough, the system operators had neglected to disable the
| reclose operation. About 15 seconds later, another fireball.

How long did it take to make the repairs and reschedule the substation
maintenance?

 

[Richard The Dreaded Libertarian]

Channel 37 is reserved for the alien invasion forces communications
network.

They learned their lesson after the Independence Day fiasco. That's when
they tried to piggyback their signals on our satellite system. Jeff
Goldblum managed to intercept and hack their command and control
infrastructure.

I wonder why, when they had that captured alien in the cage, and the
guy asks, "What do you want us to do", and the alien says, "We want
you to die!", the guy didn't ask, "Why?"

Maybe they were emulating CheneyBush and the Ayrabs:
"They want us all to die!"

Has anybody asked them "Why?" Could it be because they think we want
them all dead, because of the CheneyBush actions?

Thanks,
Rich