Laser C/KU Dish

[Magic Static]

I've assembled and older 10' mesh dish. It's supposedly good with KU band as well as C-Band. Not having fun with Ku right now. I'm wondering if anyone is familiar with this dish? I'm looking for specifications like focal length and FD ratio. I'm not finding much info at all on the net. The company quit making these in 1987 and I don't think they sold very many.

 

[mikekohl]

Actually quite a few of these were sold in the Western and Central U.S., I believe as late as 1990.
Distributed by R S & I, who had branches in every major city in the Rockies and West Coast,
headquartered in Idaho (Recreational Sports and Imports). You may have more luck tagging RS&I's name
to a search for info on the Laser private label line of antennas.

 

[Magic Static]

I finally went and measured the dish. the parabolic shape is 115" in diameter and 18.5" deep. So..
115 x 115 = 13225
18.5 x 16 = 296
13225 ÷ 296 = 44.679 (focal length inches)
44.679 ÷ 115 = .388 (.39 F/D ratio)

Which makes the quad legs a little too long and I have to bring the scalar closer to the dish.
That made an improvement

Also moved the actuator to the east side as recommended by Satellite AV. The actuator now has no problem handling this dish from 50.0°W ~ 139.0°W

 

[Magic Static]

Well they say "Practice makes perfect". Time to redo this setup. I have been trying to tweak this dish and finding a lot of little "I should have done that different" things about this setup. This is the dish for my DVB card in the PC. And I find I need to change everything but the PC. New DVB card and Software, reposition the feed supports on the dish, rewire it, strengthen the pole assembly. The dish really is a POS. The design is OK but the craftsmanship is horrible. There is NO place on this dish to accurately measure the elevation angle because of the craftsmanship. I figure the closest is about 2° off. This makes setting a declination angle trial and error. But I still may get the results I want in the end. It's just going to be a lot more hobby time

 

[Babadem]

I finally went and measured the dish. the parabolic shape is 115" in diameter and 18.5" deep. So..
115 x 115 = 13225
18.5 x 16 = 296
13225 ÷ 296 = 44.679 (focal length inches)
44.679 ÷ 115 = .388 (.39 F/D ratio)

Which makes the quad legs a little too long and I have to bring the scalar closer to the dish.
That made an improvement

Also moved the actuator to the east side as recommended by Satellite AV. The actuator now has no problem handling this dish from 50.0°W ~ 139.0°W

Good to layout the calculations the way you did. Good job on getting your installation done.

 

[Magic Static]

This dish has been in my shed disassembled since summer of 2006. I was looking for something with Google Earth and ran across the original location of the Laser C/Ku. I don't think this area has ever been updated. I didn't think to take pictures when I picked up the dish, but I have one now

 

[Magic Static]

Replacing the Actuator

The PMA24 that I bought for the WSI 6' special and transferred to the Laser C/KU is too worn and I'm replacing it. I got about a year of use out of it. So out to the Satellite Junkyard I went. I wanted to get a 3 footer and translate the extra length into more accuracy. But there were none to be found. The was an impressive Saginaw 4 footer, wow that's a long stick. So I looked for some suitable two foot jacks and came out with three to choose from. A later model Von Weise, an older Eagle (OEM Von Weise?),and a Venture Maxi (ball screw).

The PMA24 had a 48ppi sensor and was very accurate while it lasted. When I put it on the Laser I whoops reversed the motor and sensor wires and put an end to the reed switch in the PMA24. I looked for a new switch at digikey. There are only 700 to choose from, yikes! So I found a junk motor with a similar looking switch and used it. It worked very well, I was suprised.

 

[Magic Static]

Venture Maxi

The first jack I looked over was the Venture. The paint had been UV'd right off the arm. I discovered this unit had a ballscrew and I was excited. This would make a fine one I thought. But the sensor is only 32ppi, and not good enough for a C/KU rig.


I really liked the motor on this one too. So I rehabed it for later consideration.

 

[Magic Static]

Wesbar Eagle

This was an older jack and the motor is identical to the Von Weise. Maybe an OEM version? I didn't spend any time with this one as it has an Hall Effect Sensor.

 

[Magic Static]

Von Weise

The last one I looked at was the Von Weise. This one didn't look all that old and has a 48ppi sensor. The big attraction for me was the almost silent operation.
Yes I think we have a winner!

 

[Magic Static]

I guess I'm done I've been useing this dish as my main one for awhile now. I would like to put some better LNBs on it. But it's good for now. I see 55.5W~139.0W with it.

 

[Anole]

Congrats. I enjoyed the saga.
One thing you mentioned early on, that's well worth repeating:
Never trust stock focal length on old dishes! -

All these things change with time:
- value of a dollar
- global temperature
- MPG of new cars
- magnetic North
- how far you had to walk to school when you were a kid
- the size of the last fish you caught
- and..the wavelength of C-band
- not to mention the math for focal length!


iPhone 4

 

[Cham]

"and..the wavelength of C-band"
I always thought of that as a constant...