Bruce in Bangkok wrote in
:

However, the recommended length of the "Cantenna" seems to be one wave
length. Which is about 8 inches. Because of what I welded together to
make the tube mine ended up 12 inches long, about 1.5 wave length. Dom
you think cutting the tube to 1 wave length improve signal strength?

Anything over a wavelength doesn't increase the directivity much from our
experience. We did get more signal by adding a cone to the end, about a 45
degree angle out to a larger feedhorn to collect the signal. It also
reduced our sidelobe. I'm not sure it really made any difference in signal
quality, though. The sun noise bouncing around all over gets in the tube,
anyways, some.


Secondly, I am now getting greedy. Since the Cantenna and the dish
each worked very well, thank you, I'm now thinking of combining the
two. If I do that I am assuming that the mouth of the tube should be
at the focus point of the dish? right?



That would be fun to try. Make the mount out of stiff wire so you can play
with bending the mount to adjust the position of the cantenna. ANYTHING
you do to collect the signal and concentrate it on the antenna really makes
a difference. Notice how huge commercial satellite antenna dishes are?
The bigger the better because it is like a big telescope mirror, collecting
and focusing more signal on the detector.....

http://www.astro.cornell.edu/academi.../ao_scheme.htm
(The ultimate collector)



--
Creationism is to science what storks are to obstetrics...

Larry

On Wed, 23 Jun 2010 16:53:55 +0000, Larry wrote:

Bruce in Bangkok wrote in
:

However, the recommended length of the "Cantenna" seems to be one wave
length. Which is about 8 inches. Because of what I welded together to
make the tube mine ended up 12 inches long, about 1.5 wave length. Dom
you think cutting the tube to 1 wave length improve signal strength?

Anything over a wavelength doesn't increase the directivity much from our
experience. We did get more signal by adding a cone to the end, about a 45
degree angle out to a larger feedhorn to collect the signal. It also
reduced our sidelobe. I'm not sure it really made any difference in signal
quality, though. The sun noise bouncing around all over gets in the tube,
anyways, some.


Secondly, I am now getting greedy. Since the Cantenna and the dish
each worked very well, thank you, I'm now thinking of combining the
two. If I do that I am assuming that the mouth of the tube should be
at the focus point of the dish? right?



That would be fun to try. Make the mount out of stiff wire so you can play
with bending the mount to adjust the position of the cantenna. ANYTHING
you do to collect the signal and concentrate it on the antenna really makes
a difference. Notice how huge commercial satellite antenna dishes are?
The bigger the better because it is like a big telescope mirror, collecting
and focusing more signal on the detector.....

http://www.astro.cornell.edu/academi.../ao_scheme.htm
(The ultimate collector)

Got a 36 inch dish given to me today. Am planning on making a mount
for a cantenna and see how that goes. I think if I paint it with
flowers, or something, my wife will let me keep it in the room - if it
doesn't block the wind coming in through the window :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Bruce in Bangkok wrote in
:

Got a 36 inch dish given to me today. Am planning on making a mount
for a cantenna and see how that goes. I think if I paint it with
flowers, or something, my wife will let me keep it in the room - if it
doesn't block the wind coming in through the window :-)

Cheers,


The flowers may also disguise it from the government security services
worried about the insurgent takeover of the country, a real concern in
Thailand, these days....(c;]

Just don't get caught with it pointed at satellites or out to sea....hee
hee.



--
Creationism is to science what storks are to obstetrics...

Larry

On Fri, 25 Jun 2010 14:00:01 +0000, Larry wrote:

Bruce in Bangkok wrote in
:

Got a 36 inch dish given to me today. Am planning on making a mount
for a cantenna and see how that goes. I think if I paint it with
flowers, or something, my wife will let me keep it in the room - if it
doesn't block the wind coming in through the window :-)

Cheers,


The flowers may also disguise it from the government security services
worried about the insurgent takeover of the country, a real concern in
Thailand, these days....(c;]

Just don't get caught with it pointed at satellites or out to sea....hee
hee.


It will be pointed at the Marina and if they catch me I'll just say
I'm stealing from the foreigners - a traditional Thai custom :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Bruce in Bangkok wrote in
:

It will be pointed at the Marina and if they catch me I'll just say
I'm stealing from the foreigners - a traditional Thai custom :-)


And they'll say, "Wait a minute! You ARE a foreigner!"


--
Creationism is to science what storks are to obstetrics...

Larry

On Sat, 26 Jun 2010 02:59:43 +0000, Larry wrote:

Bruce in Bangkok wrote in
:

It will be pointed at the Marina and if they catch me I'll just say
I'm stealing from the foreigners - a traditional Thai custom :-)


And they'll say, "Wait a minute! You ARE a foreigner!"


NO, I just say "I live here - see I got a driving license :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Bruce in Bangkok wrote in
:

On Sat, 26 Jun 2010 02:59:43 +0000, Larry wrote:

Bruce in Bangkok wrote in
m:

It will be pointed at the Marina and if they catch me I'll just say
I'm stealing from the foreigners - a traditional Thai custom :-)


And they'll say, "Wait a minute! You ARE a foreigner!"


NO, I just say "I live here - see I got a driving license :-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)


That didn't work in Bahrain....

They said, "Anyone can get a driving license in Bahrain, even me!", with
a big smile on their face.

They did like it when I wore the custom-tailored Arab dress I had made
with the Nehru collar and sleeves with big pockets in the ends.
Bahraini women used to stop me on the street to compliment me, an
American, on looking very nice in traditional dress. Then, they'd
correct my headwear to get the proper gullwing crease under the fan
belts....

The tailor I bought the clothes from insisted I wear it back to my
hotel. I was afraid the locals would be upset as if I were making fun
of them, but the exact opposite was true. I had grown a nice goatee and
moustache before coming over on that trip, which seemed to even please
the customs agent at Bahrain's airport. But my lilly white skin was a
dead giveaway in an Arab country.

I got many compliments. My own co-workers from the Charleston Naval
Shipyard didn't recognize me, though. I opened my hotel room door when
one of them knocked and he backed out apologizing profusely because he
though he had the wrong room....(c;]

The other Americans refused to eat with me in the restaurant when I wore
it. Americans are so queer in foreign countries. They were the same in
Tehran in the late 70's. They shied away from the Iranians, staying
pretty much to themselves. I wouldn't eat in a restaurant where they
spoke English. I was learning Farsi and needed the practice.

Do you speak and read the Thai language. That would be as hard as Farsi
or Arabic to me. My fav Chinese restaurant here keeps trying to teach
me Mandarin. They all laugh at my stumbling. "You just ordered a
girl!", she said to me blushing and laughing. I knew what I ordered.
She would do, the little tiny thing....(c;]

I used to get away with saying all kinds of horrible things in Farsi in
Iran, just because I was a "dumb American"....hee hee.

Whenever I had to sign something in the Iranian Air Force I worked for,
I signed my name in Farsi. "No, no!", the Iranians would say, "You must
sign in ENGLISH or they think I signed it!" I'd act all indignant as I
was signing in English. Iranian AF officers are terrified of being
blamed for something. That's what foreign contractors are for...(c;] I
spent millions of Rials on all kinds of stuff. It was like owning the
bank! I had my eye on a Gulfstream II to fly home on leave, but that
might have been going too far....unless I made a deal with the General
to come home, too...

--
Creationism is to science what storks are to obstetrics...

Larry