Just Sharing This My Channel Master 1.8 project.

[a33]

as soon as the weather improves (today I have a very cold fog) I will take some pictures to show how my actuator is set.
I made a solid clamp to let the actuator move away from the polar axis when it goes east (the cylinder is on the west side)
when the actuator is fully retracted (west) it is perpendicular to the south

with actuator like this the parabola sweeps faster to the east than to the west for the same actuator travel
a very good solution here !! but more complex !!

https://www.satellites.co.uk/forums/attachments/mont4-jpg.140637/

I looked a bit more into the actuator mount, as in the picture. It is interesting.

As long as B+C = A, the big advantage seems to be the the reduced risk of flopping the dish, by generating a theoretical >180 degree rotation range, similar to here: 180 Degree Rotation with Linear Actuator | Home CSP, Inc.
The bigger C is, the more the risk of flopping is reduced.
The range of higher accuracy then also shifts a bit to the extended side of the actuator, but it would do that even more when A > B+C , if I'm not mistaken. So no need to stick to A=B+C with this setup, I would say: length A could be longer.

Another effect (advantage) of spreading the accuracy more towards the extended side of the actuator would be, that at the extended side less motor power is needed for retracting the dish again, as the actuator can take a longer length for retracting a rotational degree.
I've read that some people had trouble with retracting because of the the dish weight, but I did not read this approach.


NB In setups where C is small, the maximum (theoretical) actuator stroke length for the setup is never more than 2B (when B<A), or 2A (when A<B ); so maximum twice the shortest triangle side length, as we called it earlier in this thread.
When C is greater, as in this case, the maximum (theoretical) actuator stroke length for the setup increases to 2B + C when (A = B+C), or even to A+B when (A > B+C).
Knowing the maximum possible stroke length for the actuator, could help designing the proportions of the triangle side lengths.
Added: For instance: increasing the already longer leg of the triangle sides, does not imply that the actuator stroke becomes larger. That is not mentioned very often.....


I hope that I've described this somewhat understandable.
It does look like till now, this is a bit under-developed area in our satellite dish hobby....

Greetz,
A33

 

[Channel Hopper]

That sort of "advice" prompts the thought that the controller manufacturer didn't have a very good grasp of good EMC design and construction methodologies and knew that the unit has a somewhat "fragile" EMC performance, but didn't know how-to/want-to-try to fix it, and thus wanted to hand over responsibilty any EMC-related problems to the installer/end-customer!

Since the manufacturer is US based, the formula for grounding and earth loops may differ with two pin electrical supplies and or double insulated (two square) equipment.

 

[7mdish]

So what about the best connection in Europe?
Based on your advices it seems connecting shield at both sides would be the best solution. What do you think? Thanks.

 

[jeallen01]

So what about the best connection in Europe?
Based on your advices it seems connecting shield at both sides would be the best solution. What do you think? Thanks.

That would be my advice to start with - and then "see what happens" in terms of whether you have any "issues" such as possible interference with the correct operation of the motor.

OTOH, if none, then you are good to go; if not, then you should probably try disconnecting one or other of the shields at the motor(s) end. OTOH, I rather doubt that you will if the controller is as "good" as most people seem to claim that it is

Edited:
However, it might also be worth checking if there if is an external direct "ground" connection between the motor mount and the controller - in reality, the presence or absence of such a connection should not make any difference, but if there is then I would suspect the continuity of the grounding connections in the controller between the sensor circuits and the chassis ground - and also see below.

In that respect, in many older "traditional" US designs there was relatively (by European/EN/IEC standards) poor general continuity between the various sections of the chassis. That meant that the overall screening efficiency of such cases was often poor ( but could often be considerably improved by cleaning the mating surfaces between those sections and tightening the securing screws/bolts). In addition, US FCC Part 15 legal requirements don't have any real requirements for protection against incoming radiated and conducted interference - unlike the EN/IEC standards and EU legal susceptibility requirements!

Thus, if the controller is a very old design and has not been "updated" to meet the latter then such a US design might be notably more susceptible to external interference!

 

[Manikm909]

Is the 36" actuator now fitted and arc increased to 55.5W and 58.0W?

YES!!!

Actuator fitted - I can now get from 54e to 58w and maybe then some.

I tried without the plate, but dish fowled itself on the PM - so that plate was needed in the end...

I have also now fitted @RimaNTSS arms, mainly so that i could use a proper CBAND holder (forgot colllar width)

some pics attached

however, im getting hit and miss results from CBAND on 55w....

there are some variables which im unsure of - firstly, where exactly should i fit the scalar ring - ive tried various positions, with different channels pulling in, depending where i put it

also, channels fade in and out a lot - interference maybe? or just weak? not sure if the LNB is particularly high gain, i doubt it.

also, the skew seems very important.

i also dont know whether to adjust elevation or not this far west - i will take a signal meter to it, rather than in and out of house, checking, back out altering and hoping etc.

could just be 1.8m aint cutting it...i dont think i have obstruction to line of sight

i have an OSACRS feed (3897 - H - 6110) tonight, but a lot of the POWERVU channels i currently cannot get.

What is the relevance of these numbers on the LNB? (circled blue)

Thanks All

 

[Channel Hopper]

What is the relevance of these numbers on the LNB? (circled blue)

Thanks All

That is to level the scalar ring at the correct f/d ratio of the dish. It requires careful addition of washers, or changes to the feed arms to get correct.

 

[moonbase]

YES!!!

Actuator fitted - I can now get from 54e to 58w and maybe then some.


What is the relevance of these numbers on the LNB? (circled blue)

Thanks All

As indicated by CH above, those numbers are scalar ring positions for various F/D dishes.
The position of the scalar ring along the LNBF barrel and the distance of the LNBF throat from the dish can impact on signal levels in C-Band.

'ere, cop for this picture, it presents my findings on the impact of changing the feed distance from the dish in conjunction with movement of the scalar along the feed barrel.
The test was carried out on 43.1 West using a prime focus dish with a flat scalar on the feed. The same logic might apply to an offset focus dish with hooded scalar.

The values of 745, 750 and 755 are the distances of the feed opening to the centre of the dish in millimetres.
The values of 0 to 40 are the distances in millimetres of the scalar ring along the feed barrel, 0 being flush with the open end of the feed.

43.1 West is a good test for dish and LNB alignment in C-Band. It is not an easy catch for a UK location and needs things to be reasonably well aligned.

.

 

[moonbase]

also, the skew seems very important.

To be expected, 55.5W is linear polarity so no dielectric plate required and the skew needs adjusting to maximise the signal level.

 

[Manikm909]

i didnt realise there was some stuff at 43w too - i'll have a look - will get signal meter on it re 55w - i get different channels come in depending on which way the wind blows

its funny - i thought the 24" actuator was a beast until i saw and fitted the 36!! the24" looks small in comparison

 

[moonbase]

i didnt realise there was some stuff at 43w too

Try checking out Lyngsat, Flysat and the C-Band section of the forum, plenty of info there.


You might get lucky with 43.1W in C-Band but with a 1.8m offset dish I think it will need to be aligned fairly accurately.

'ere, cop for the picture below, it shows the two different C-Band frequencies I locked on 43.1 West last time I checked it some time ago.
I actually locked four different frequencies but two of them are no longer listed as being active so I excluded them from the table.

If you can get the two bad boys listed in the table below with your 1.8m dish you are doing well.
However, if you are struggling with 55.5 West I think you are up against it with 43.1 West unless your arc is getting worse the more extreme West you go?

If your arc is bitched up, you might find it easier to grab 150 channels from 40.5 West in C-Band as it is less extreme and one of the easiest to get.
The kids round 'ere are pulling in signals from 40.5W using the inside surface of a wheely bin lid coated with bacofoil and a broomshank for elevation adjustment.

.

 

[a33]

Actuator fitted - I can now get from 54e to 58w and maybe then some.

I tried without the plate, but dish fowled itself on the PM - so that plate was needed in the end...

By using a plate like that, you determine where the theoretical rotation range of 0-180 degrees around the mount's axis begins (so: where the zero degree is).
As the actual range you can reach is not 0-180, but maybe something like 25-155 degrees (very much depending on the mount build), you can use that 25 degree position for the lowest satellite at the retracted side that you wish to receive. Thus you can reach at the extended side to about 155 rotational degrees, in this example.
Hence my previous answer: "That could be dependent on which is the most easterly satellite (max. retracted) that you want to receive, and which is the most westerly satellite (max. extended)?"

The location of the plate does not necessarily have to be on the pole-part of the mount (edit: at the base of the actuator), it can just as well be on the dish-part of the mount (edit: at the top of the actuator), or even a plate at both locations. What happens is that you manipulate the dish aiming angle, relative to the (theoretical) 0-180 axis rotational angle. There is no need whatsoever, to have due south/north at exactly 90 degrees or so; you can have it as you wish....

Greetz,
A33

Edited

 

[Manikm909]

just been outside to peak signal on 55w.
my results are pretty great but i have a strange issue, which i cannot work out - even on strong signals i get signal dropout sporadically.
not sure if its interference or a faulty LNB
i will try and capture it in a video

does the same outside with signal meter, using a short cable direct from lnb to meter

 

[moonbase]

just been outside to peak signal on 55w.
my results are pretty great but i have a strange issue, which i cannot work out - even on strong signals i get signal dropout sporadically.
not sure if its interference or a faulty LNB
i will try and capture it in a video

does the same outside with signal meter, using a short cable direct from lnb to meter

Any cross polarisation from a strong signal on the opposite polarity with similar frequency?
Sniff the culprits to see if there is a pattern.

What LNBF is it, a Titanium PLL or some other LNBF?
Some of the Tit's have a wifi and 5G filter in the circuitry that supposedly improved things.
I found an extra 1dB+ when I tried one compared to a non "filtered" LNBF.

 

[Manikm909]

Any cross polarisation from a strong signal on the opposite polarity with similar frequency?
Sniff the culprits to see if there is a pattern.

What LNBF is it, a Titanium PLL or some other LNBF?
Some of the Tit's have a wifi and 5G filter in the circuitry that supposedly improved things.
I found an extra 1dB+ when I tried one compared to a non "filtered" LNBF.

its a cheapie for sure - from aliexpress...
i literally cannot watch a single channel without it stuttering, even if the signal remains strong - its such strange.
i will get a video to show what im on about...

some comparative signal readings would be good for channel pictured above. (TNT Sports)

 

[Manikm909]

this is what im faced with -- just constant stuttering and dropouts - across all channels it seems...

Dropbox

www.dropbox.com

 

[moonbase]

this is what im faced with -- just constant stuttering and dropouts - across all channels it seems...

Dropbox

www.dropbox.com

Something not reet there, it looks like you have signal margin but it is in % so not easy to tell.
If you get the signal readings in dB you can assess the margins better.
An Octagon SF8008 or any E2 receiver suitably loaded will give you the signal levels in dB and pour Poop.

It could be the LNBF but you need another one to try as a comparison.
I got spare Tits over 'ere you can buy for huge wad.

Have you tried adjusting the feed/scalar distances to see if it makes any difference?

 

[Manikm909]

i will see what the octagon does - however the signal meter has TV viewing and did the same...

yes i tried without the scalar hood - maxed it, then slid the scalar over which gained a bit more signal and clamped into place...

btw - i whizzed over to 43w to chance my luck, the only TP that worked was the Playboy ` Venus one, signal was around 38% and doest have the issues 55w does - it gives pixelation but not the stuttering.

 

[ozumo]

C-band at 40°E is strong, I get most of it with a 1.2m, though it's mostly T2MI.

 

[nelson_b]

this is what im faced with -- just constant stuttering and dropouts - across all channels it seems...

Dropbox

www.dropbox.com

Hmm - Odd problem ... just been having a look at that channel .... and others on 55.5 West ... No issues here - channels are running smooth with no dropouts on DRHD F15 receiver .

 

[Manikm909]

just run it through my Octagon SF8008 - it read 10db approx - i deffo think the LNB is faulty or interference.....

i will post another video...

anyone got a spare @moonbase i can borrow just to see if it is the LNB...?


VIDEO HERE:

Dropbox

www.dropbox.com