1.1 triax gives better results than my 1.3 aluminium primsat dish

[Spiff]

Good evening from Mullion Cove Cornwall : )
I have just installed a recently purchased Primesat 1.3m aluminium dish.
I removed the 1.1m Triax steel dish and mounted the Primesat 1.3m on the same Technomate TM-2600 M2 motor, same receiver a Technomate TH-5402HD C1 +.
Peak up horizontal vertical and all the LNB settings.
The LNB is an Inverto Black Ultra twin output.
All satellites in the arc have been logged with the station number and quality with the Triax .
Comparisons show the Primesat to be several points down on all 27 satellites.
The Triax readings were logged on lots of occasions on our Samsung 65 inch UHD TV.
No amount of tweaking will bring the levels up to the smaller dish.
Nilesat is even more iffy than with the Triax as it was borderline before.
Anyone has similar problems ?
One thing I noted was that the steel mounting bracket did not fit the back of the ally dish correctly.
If I remember correctly there was a quarter inch or maybe larger gap which pulled to shape or the dish did on tightening up the bolts.
The company did not except that their dish was at fault saying that they has tested both dishes ?
I did not mention the bracket problem as I had forgotten about it at the time.
I prefer the appearance of the Primsat dish as it has steady arms for the LNB, which is also simpler to change due to a bolted clamp rather than the Triax plastic clamp.

Thank you for your time.
Kind Regards Spiff ( Allen )

 

[Captain Jack]

Prime Sat dishes as sold by satellite super store? Aren't these prime focus? Can you post a few pictures of the dish?

 

[sonnetpete]

Prime Sat dishes as sold by satellite super store? Aren't these prime focus?

CJ, I've checked and the 1.3M is an offset dish. The dish mount is designed for a ground stand (similar to the Gibi 1.25) and as such wouldn't fit on a Technomate motor without modifying in some way. I just wonder if this is part of the OP's problem. As you say, some photos of the installation are required...

 

[Analoguesat]

Try stringing the dish (running threads across the face in 3 or 4 places. Chances are the face is warped - the threads should meet in the middle within a mm or so.

 

[Spiff]

Good morning Captain Jack your fame proceeds you : )
Pictures of installation, note the angle readings on the dish bracket are different from the settings with the Triax which set up at 26.7.
Nothing else was altered, the motor bracket was left as it was with the Triax.
Thank you to the other gentlemen who replied.
Both dishes are off set.
Kind Regards Allen

 

[sonnetpete]

Initially, the only difference i can see from how it looks on the suppliers website, is that you've taken the rear dish bracket off, turned it through 180 degrees and bent up the lug so that it will fit on the motor stub. Is that correct? Can't really see that having an undue effect on the dish surface or it's mounting bracket but you never know. I'd also recheck the verticality of your elbow mount just in case the extra weight has had an effect. I assume you've tried the Black Ultra in differing positions towards and away from dish focus?

 

[Spiff]

Initially, the only difference i can see from how it looks on the suppliers website, is that you've taken the rear dish bracket off, turned it through 180 degrees and bent up the lug so that it will fit on the motor stub. Is that correct? Can't really see that having an undue effect on the dish surface or it's mounting bracket but you never know. I'd also recheck the verticality of your elbow mount just in case the extra weight has had an effect. I assume you've tried the Black Ultra in differing positions towards and away from dish focus?

Good Morning thank you for your reply, you are correct in all my modifications. I have rotated and The Black Ultra and moved it forward and back. The dish weights 2kg more than the Triax, I will check the pole again. I had to mount it high up the motor pole because of the webcam pointing at the scale. Regards Spiff.

 

[aceb]

Did you just get very lucky with the declination adjustment as it looks like the back of the dish is hard against the motor stub pole?

 

[Analoguesat]

Spiff is this supposed to be in the Ka band section or are you referring to Ku?

No prob if its in the wrong section I can move it easily enough

 

[dxsat]

I could be wrong, but it looks as though you've installed the dish upside down, with the result the LNB is in the wrong place. The six fixing bolts are in the upper part of the dish face, when they should be in the lower. The side arm holes are not usually exactly halfway between top to bottom so if you flip the dish they'll be in the wrong place.
Did you drill a new hole for the bottom arm?
The dish is a 1.25m. The effective area is probably 1.2metres.

 

[sonnetpete]

I could be wrong, but it looks as though you've installed the dish upside down, with the result the LNB is in the wrong place

Yes agreed. I completely missed that one. You can confirm it's upside down by referring to the photos on the suppliers website. Probably explains why there was a gap when assembled.

 

[Spiff]

Yes agreed. I completely missed that one. You can confirm it's upside down by referring to the photos on the suppliers website. Probably explains why there was a gap when assembled.

Good evening thank you all for the suggestions : )
I have checked the pole and it is still plumb.
There is only one hole for the bottom support for the LNB.
The dish bracket fixing bolts are so spaced so that it can only be mounted one way up.
I thought it looked odd as the bracket looks closer to the top of the dish.
The image on their website looks the same I remember checking it, but will now check it again.
The dish bracket is against the pole, if it had been further down there should be more clearance, however flexing the dish up and down from this position reduced the signal quality.
It is at the top of the motor pole due to the webcam mounting.
The first thing I will try is removing the camera and moving the dish down the motor pole so that there is room to tilt the dish further down.
Will post tomorrow as soon as this is done.
Kind Regards Spiff.

UPDATE Please have a look at these two images, one of my dish the other from the sellers website.
Have they drilled the holes for the bracket in the wrong place.

http://www.satellitesuperstore.co.uk/fixed-dishes.htm#primesat130

I am begining to doubt my sanity : )

 

[archive10]

The bracket placement is defo different on the two pics.
Nevertheless, the actual position of the bracket shouldn't affect the reception. (It's just the means of holding the dish to the pole).

What I think you should be worried about this:

One thing I noted was that the steel mounting bracket did not fit the back of the ally dish correctly.
If I remember correctly there was a quarter inch or maybe larger gap which pulled to shape or the dish did on tightening up the bolts.

If the bracket "pulls in" the reflector - it may be the reflector deforming.
If the holes are drilled in the wrong place, so that the bracket is shaped to go on a different part of the paraboloid, then you would likely experience a "mistfit" of the mount and reflector.
Difficult to say the effect of this - depends on dish design, degree of misfit etc.

I think you should post the two pics to SSS, and ask them if they changed the design of the dish...

Edit: In fact, I think the images on SSS site looks different from yours in other ways - notable the feed support arms. They seem to be attached about half-way up your dish, whereas the images on SSS are clearly lower, about 1/3 from the bottom of the dish. The angle of the arms also seems differerent.
This may be due to a design changes at the mfg, or even swtiching mfg, SSS should be able to confirm this.
I also note that their images for the 1.3 and the 1.1 metre models are the same.
Can you confirm that your reflector measures 1.3 meter horizontally on the widest bit?

 

[archive10]

Actually, you should string the dish as AS suggests, to see if it's in good shape.

 

[Spiff]

The bracket placement is defo different on the two pics.
Nevertheless, the actual position of the bracket shouldn't affect the reception. (It's just the means of holding the dish to the pole).

What I think you should be worried about this:



If the bracket "pulls in" the reflector - it may be the reflector deforming.
If the holes are drilled in the wrong place, so that the bracket is shaped to go on a different part of the paraboloid, then you would likely experience a "mistfit" of the mount and reflector.
Difficult to say the effect of this - depends on dish design, degree of misfit etc.

I thkn you should post the two pics to SSS, and ask them if they changed the design of the dish...

Thank you for your reply, a heavy steel bracket and an ally dish, I have felt uneasy about the way it had to pull in.
The setting for the dish scale worked out as 26.7 this was fine with the Triax, but was a mile out for the Primsat dish, would this not confirm that the bracket is in the wrong place ?

 

[hvdh]

The bracket placement is defo different on the two pics.
Nevertheless, the actual position of the bracket shouldn't affect the reception. (It's just the means of holding the dish to the pole).

A bracket like this is designed and suited for just one particular part of the dish.
If holes in the dish are drilled in the wrong place, the bracket indeed will deform the dish while tightening the screws!
(Edit: if dish was redesigned, could also be a wrong bracket supplied)

Spiff, maybe you can still try if the bracket would fit better at the lower place.

 

[aceb]

The LNB appears to be looking far to high on the reflector, regardless of whether they've changed the design of the dish.

 

[Spiff]

A bracket like this is designed and suited for just one particular part of the dish.
If holes in the dish are drilled in the wrong place, the bracket indeed will deform the dish while tightening the screws!

Too true I have as suggested emailled with both images attached as below.

Hallo Dave has the design of the dish changed since the picture on your website ?
Please see attached mine and yours.
When I fitted the dish bracket it did not match the shape of the dish but pulled in as the bolts were tighten, I assume bending the dish, steel against ally.
The reading on the dish bracket scale on the Triax worked out at 26.7 on the Primsat it is completely different.
I have been on Satellite & Digital TV Support forums trying to sort the problem out, when the suggestion of the differences came to light.
Kind Regards Allen and Alanna

http://www.shopingathome.com/Military%20Wireless.htm[/code

 

[rolfw]

Looking at your installation picture, there only appears to be minimal elevation (declination when installed on a DiSEqC motor) adjustment on the dish as it's not designed for DiSEqc motor mounting when the motor has a downward arm, I would guess that extended bolts and a couple of inches spacer would be necessary to offer enough movement.

It certainly does appear that your backplate on the dish is located much higher than on the S S picture which I have removed and left the link.

 

[Spiff]

Good morning I am going to move the mounting down the motor pole today

Too true I have as suggested emailled with both images attached as below.

Hallo Dave has the design of the dish changed since the picture on your website ?
Please see attached mine and yours.
When I fitted the dish bracket it did not match the shape of the dish but pulled in as the bolts were tighten, I assume bending the dish, steel against ally.
The reading on the dish bracket scale on the Triax worked out at 26.7 on the Primsat it is completely different.
I have been on Satellite & Digital TV Support forums trying to sort the problem out, when the suggestion of the differences came to light.
Kind Regards Allen and Alanna

http://www.shopingathome.com/Military%20Wireless.htm[/code

Looking at your installation picture, there only appears to be minimal elevation (declination when installed on a DiSEqC motor) adjustment on the dish as it's not designed for DiSEqc motor mounting when the motor has a downward arm, I would guess that extended bolts and a couple of inches spacer would be necessary to offer enough movement.

It certainly does appear that your backplate on the dish is located much higher than on the S S picture which I have removed and left the link.

Good morning I have moved the dish bracket down the motor pole so that there is more room to adjust the elevation.
Have adjusted the elevation but no improvement in signal.
So will be moving it back up as there is less leverage on the motor if the dish is wind blown with the bracket higher up. Kind Regards Spiff