few questions about Channel Master dish 1.8

[samoloko]

Dear Channel Master 1.8 dish owners
would you please measure distance between 4 dish hole centres that hold dish to mount
are there 2 types of the dish back az /el mount - Rx only type Is like 1.2 CM and Rx/Tx type 183 Is like 2.4 CH - what Is the width of the dish back plate that mounts between az /el mount profiles
can someone give some measurments of an original polar mount for Channel Master 1.8 dish

 

[archive10]

the distance from the centra of each hole is 610 mm.
they are arranged in a aquare.
the holes are 12,5 mm wide (diameter).
there are two type of mounts, just as you say.
the most common by far is the RxO, which is the three steel tube arms that affix to the dish rim at each side, and one at the bottom
the Tx version is much heavier, based, as you say on a "back plate", which extends to the bottom of the dish, and the feedarm holder is affixed to that.
Unfortunately I only have the Rx version of the mount, so I can't tell you the width of that back plate.

 

[samoloko]

st1 thank you for reply
what do you recommend Skyware 1.8 Rx and Tx type 180 dish or 183 type which Is with 2.4 Skyware type az /el mount
I guess that 183 type az /el got to be more stable and It Is announced as a class 3 dish
http://www.skywareglobal.com/images/pdf/Prod.sheets 2012/Type 183 Kuband VST014.3.pdf
http://www.skywareglobal.com/images/pdf/Prod.sheets 2012/Type 180 VST011.2.pdf

 

[archive10]

st1 thank you for reply
what do you recommend Skyware 1.8 Rx and Tx type 180 dish or 183 type which Is with 2.4 Skyware type az /el mount
I guess that 183 type az /el got to be more stable and It Is announced as a class 3 dish

Well, I have a 180 Rx sitting in the garden for just over 3 years, and it has survived multiple storms and takes in 28.2E just fine.
It was orignallly optimised for Astra 2D reception (10773 being the key transponder to receive).
Never had to readjust - the mount seems to be well-dimensioned and well-engineered to maintain alignment properly.
Perhaps I can eek out another 0.2 dBuV of strength by careful alignment to 2F - but TBH it's not necessary. So no point in trying.

So to choose would require knowing what the intended use is. If you are Rx only, then a type 180´will do just fine.
If you are at a mountain top (exposed) location, or need to accomodate transmitter electronics on the feed arms, then a 183.
Otherwise it's not necessary.

 

[samoloko]

st1
where did you point out exactly your 1.8 dish as there are 28.2, 28.3, 28.5 positions
My motorized PFA 1.8 separate parts from degree leading to better SNR

 

[archive10]

The difficult one was 2D.
AFAIR 2D was at 28.2.
This meant that some transponders on 28.5 did not work properly (Ocean Finance TV comes to mind) - but that was a compromise I had no probs with!)

 

[RimaNTSS]

Last summer (in Latvia) I pointed 1,8m antenna to Eutelsat28a @ 28,5*E, scanned all 59 available transponders and put data in the table. Then pointed antenna West where Astra2F located @28,28E, scanned same transponders again and put data in the same table. Then, in last column of the table calculated difference between 2 measurements. My conclusion: For bigger antennas, to be able to receive maximum signals, we should make difference between positions 28,2*E and 25,5*E

 

[samoloko]

anybody please tell me size / thickness of l profiles of az / el mount that hold reflector to mount
what Is thickness of tube
Is there a space between pole and mount tube when you put mount to tube 114 mm od

 

[archive10]

I think the L-profiles are about 4 mm. I will configrm this later.
The original mount is designed to fit a pipe mast (pole) with outside diameter of 4.5 inches, or 114 mm.
The actual mount diameter is something like 5 inches, to allow some room for the bolts that holde the mount to the pole.
As the bolts are only in two places on the mount, there is a gap between pole and the mount.

 

[Archived-1]

A couple of pictures from my mount if it helps, like st1 says it looks around 4mm.

 

[samoloko]

I think the L-profiles are about 4 mm. I will configrm this later.
The original mount is designed to fit a pipe mast (pole) with outside diameter of 4.5 inches, or 114 mm.
The actual mount diameter is something like 5 inches, to allow some room for the bolts that holde the mount to the pole.
As the bolts are only in two places on the mount, there is a gap between pole and the mount.

thank you st1
5 mm gap Is too much I think
did you saw SSS shim trick

Martin
from your pics looks like l profiles are dismountable Is that correct
BTW what Is going on with your project

 

[Archived-1]

Martin
from your pics looks like l profiles are dismountable Is that correct
BTW what Is going on with your project

Yes its all dismountable, I will take a few more pictures of what's left of it tomorrow if needed ?.

Its just on temporary hold at the moment, I wanted to leave the concrete a good 3 weeks to cure with it being cold, then I moved on to doing my drive and fence in my spare time, I will try and grab a day next week, and order an actuator over the weekend

 

[archive10]

thank you st1
5 mm gap Is too much I think
did you saw SSS shim trick

No, not seen this, but here's a pic of my mount - there's not that much need for a shim.
And, in any case, it's been there for 4 years now, and works great.

View attachment 73074

Martin
from your pics looks like l profiles are dismountable Is that correct

The upper and lowe bar are dismountable (as shown taped to main part in Martin's pic), but the main square bit is welded together.

I've measured the rest of the steel, and part of the mount sitting on top of the 5" tubular section is made from 6mm steel.
The top half welded to the main square L-profile bit is 5mm steel.

 

[Archived-1]

I wish I would have not chopped mine up, its very easy to convert this mount to a motorised dual axis AZ/EL mount.

View attachment 73077

 

[samoloko]

Martin
look at original channel master polar mount and Laminas polar mount - they are simple and easy you have skills you can diy polar mount from your az /el mount

 

[archive10]

I wish I would have not chopped mine up, its very easy to convert this mount to a motorised dual axis AZ/EL mount.

Maybe. But you'd need an advanced antenna control, much like your Research Concepts device.
It would not work with a simple DiSEqC-type (v-)box driving it...

Nevertheless, I agree that the an Az/El style mount would be mechanically preferable to the polar mount once we get to this size of dish...
(Just eyeing the potential in my Prodelin 1241 mount... (picture from gdsatcom.com))

 

[Archived-1]

I have all my plans in place for the polar mount, but i butchered the mount in question, I do have to now make a az/el dual axis mount for my controller to work correctly, but my above drawing is what I would have done to the mount, but like I say I have all my plans in mind but thanks.

 

[RimaNTSS]

Martin! Is that rust (circled blue) ? It is terrible!

 

[Archived-1]

Martin! Is that rust (circled blue) ? It is terrible!

To be honest Rimants that rust does not bother me one bit .



















Its not my dish

 

[RimaNTSS]

rust does not bother me one bit

You mean, it does not change signal quality?!

Its not my dish

Ow, I see, it really does not matter then