[ExI] antennas and cell phones

[hkhenson]

At 08:11 PM 6/30/2008, Bryan wrote:
>On Monday 30 June 2008, Tom Nowell wrote:

snip

> > Well, in Burma the cyclone took the telecoms network down. Telecoms
> > Sans Frontieres offered to send in telecoms engineers to put up a
> > temporary network and offer every refugee a phone call to someone, so
> > they could let relatives know what was happening. The temporary
> > network would also allow aid agencies on the ground to co-ordinate
> > better. The Burmese government rejected this, and kept aid agencies
> > out. In Burma, your cell phone IS just a paper weight. As to Bryan's
> > point - a cellular network requires a fair amount of technology,
> > you're not likely to knock this up in your backyard. Without a
> > certain degree of civilisation, it's hard to rebuild a downed
> > network.
>
>Go read some of the antenna documents I linked to Keith.

I have a story related to antennas I tell that I have meant to write 
up for a long time.

In the summer of 1961, between freshman and sophomore years, I could 
not find a summer job so I studied up for a first class commercial 
radio telephone licence, something that doesn't even exist any more, 
but in those days was needed to operate a transmitter.

I took the test, got it and moved to Tucson where I had been going to 
school.  Went to work for KVOA-TV which was that summer building a 
new transmitter on top of the Catalina mountains north of Tucson.

The building construction was mostly finished.  What we were doing 
was to put in the transmitter, the controls, the microwave link up 
from the studio and such.  There were 5 or 6 of us and we worked both 
at the studio and on the mountain depending on what needed to be 
done.  Among other things I picked up the skill of brazing 4 inch 
wide grounding strips that were placed in all the cable troughs.

One of my co-workers was from Turkey.  His family was well off.  He 
was bright enough to have a MS degree from MIT and was 6-8 years 
older than me.  He showed me photographs of his master's project, a 
high gain Yagi antenna.  From the dimensions of it, it was up in the 
current 2.4 GHz cell phone band.  His family's intent was for him to 
go back to Turkey and eventually become the head of the national 
telephone company.  He was working this physical level job to gain 
experience.  Man did he need it.

I have never run into a person so inept at the kind of skills I took 
for granted.  A 6-32 tap isn't that sturdy.  I have broken a few of 
them tapping holes, but this guy managed to break 6 of them in a day.

One of the days we were working out of the studio I went into the 
shop area and found him tangled up like a kitten with a ball of 
string.  He had been given the task of making a cable that ran from 
the transmitter to the control console.  The cable was to be (as I 
recall) 30 wires each 30 feet long with lugs soldered on the ends.  I 
found him trying to measure out these cables with a one foot 
ruler.  He had about 6 cut and when the wires were made into the 
cable, the wires randomly varied by a few feet.

I showed him the obvious way of turning over a chair and putting a 
pipe through the cable spool then marking off a distance on the floor 
by counting the one foot floor tiles.  Then it was a matter of 
pulling a wire out and cutting it to length.  This obvious stratagem 
did not occur to him.  I was fascinated and spent some time when we 
were making the hour and a half drive up the mountain drawing him out 
about his childhood.  He had never touched at tool nor even watched 
someone working on a car, this simply being below the social place of 
his family.

>It is not
>impossible to do communications in your backyard. In the case of wired
>communication, go get a string and place it between two cups and
>whisper in one cup, listen through the other, over a suitable distance
>that I sadly forget the mathematical definition of.

Ah, yes, the string telephone length function.

Without new cell phones, how long would the cell network be useful?

Keith