Just Sharing This Something to make dish skew possible on zone 2 dishes

jeallen01

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Afternoon.

I seem to remember, but can't find ATM, a thread where someone is/was trying to get 30W on a Zone 2 dish and questioned how get to the appropriate skew angle - which is nearly 30 deg according to dish pointer - when the existing SKY LNB can't be skewed more than around 20 deg (without mods). Then someone else suggested that it would be better to skew the entire dish so that the LNB skew can be set to around 0 deg and it can better cover the Zone 2 dish face. Thought about that and what would be needed to skew the dish - and that would normally probably mean skewing the whole dish mount on the wall, etc.

Then "wandering through" the garden, I remembered that my previous neighbour (now moved) had given me some of the steel tubes that were going to be trashed when he took down the kids' old and decrepid garden trampolene - which had a surrounding safety net supported by a ring of sloping and curved tubes. Dug one of those out of the "pile", had a look and concluded that one could probably replace the mounting pole/tube for many Zone 2 dishes (certainly the two I have down the garden) with part of one of those curved tubes because they are made of 25mm diameter steel tube - more than adequate to support a Zone 2 dish, or possibly even a slightly bigger "normal" dish.

So, did a couple of rough estimations (not calculations!) using an angle gauge to see how much "angular" deviation one would get if that tube was used - and it worked out at up to nearly 30 deg (or maybe even more) if the whole (nearly 1m long) tube was used (see photos). Thus, using that approach, one could probably skew the whole dish by up to that amount by simply replacing the existing mounting tube by a suitable length of one of these tubes.

Maybe I'll try that sometime (although not right now) - but it might be worth anyone with similar issues keeping an eye out for something similar being scrapped, or even in the skips at recycling centres as a lot of those trampolines are probably going to get scrapped as Winter approaches.

PS: normal straight steel tubes from scrapped things like trampolines/exercise bikes/etc., can make very cheap (like "free") shortish dish masts for the smaller dishes - used a few from skips like that already
 

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RustySpoons

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Great work!

I've never understood why the LNB skews on the Sky dishes, having a skewing bracket would be better due to the focal shape of the feedhorn.
However I have a Maxview Omnisat dish here (Camping Dish, based on a Zone2) that has a dish skew function.
 

jeallen01

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@RustySpoons

Why? - Money of course!

Making the LNB able to skew in the holder (just like most "normal" dishes) is probably a whole LOT cheaper/easier for SKY & its suppliers than building the dish mount so that it can skew - also a lot easier\quicker (and thus cheaper also) for SKY "engineers" to adjust when installing the dishes :rolleyes:
 

2cvbloke

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I remember back when I had my indoor dishes, and using a Zone 1 dish to pick up Hispa back when it still carried Analogue channels, and it needed the whole dish to be skewed, which to (I think) Raven's credit, they did put in that feature on the back of the dish, but that was on the stamped-out steel arms rather than pole-mounts as per the Zone 2 dishes...

But, minidishes made solely for sky use are built to be used for Astra 2 use, rather than anything else, so just like their receivers, the dishes are hobbled so they're limited in how you can use them...
 

jeallen01

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PS: to Thread title and Post #1

I forgot to mention that this mod would obvious only work for dishes on poles, and not for those on pressed/stamped steel arms!
 

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@RustySpoons

Why? - Money of course!

Making the LNB able to skew in the holder (just like most "normal" dishes) is probably a whole LOT cheaper/easier for SKY & its suppliers than building the dish mount so that it can skew - also a lot easier\quicker (and thus cheaper also) for SKY "engineers" to adjust when installing the dishes :rolleyes:
Yes but that completely negates the point of it being an oval dish with a matched feed horn, as soon as you skew the LNB that benefit is being lost.
If you look at the oval VSAT dishes, the dish is skewed.
 

jeallen01

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Yes but that completely negates the point of it being an oval dish with a matched feed horn, as soon as you skew the LNB that benefit is being lost.
Yup, but intended for footprints where the signal levels are high and there is, or is likely to be, a large take-up from paying customers who want "cheap" and cheaply-installed, or FTA services, (and, Yup again like @2cvbloke said), they don't want those customers to have the choice of using other sats at all easily)
If you look at the oval VSAT dishes, the dish is skewed.
Possibly just the opposite - relatively low signal levels (by comparison with those from the major DTH package providers) but probably need to keep the dishes small and cheap nevertheless, and so make them more tunable by including features like dish skew adjustment.
 

2cvbloke

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While devouring some reduced-to-clear chicken wings from tesco, I was having a think about this, it got me to think of how dish motors & actuators are set up so that as the dish swings from one direction to the other, the skew is sorted by the angle that the motor arm is set at, so replicating that for a fixed Z2 dish shouldn't be too hard with access to a suitable pipe bender to bend the existing (or replacement) pole mount to the appropriate angle... :)

But of course it's been a while since I even put up a dish, so, haven't the foggiest how that'd actually work in practice... :confused
 

jeallen01

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@2cvbloke
"shouldn't be too hard with access to a suitable pipe bender" is probably an "over estimate" of what's possible for most of us - we have to work with what we've got/can afford and use!

PS: Although @Channel Hopper did a great job of setting up the steerable Gibertini, it seems that some of the very carefully tweaked fixed dishes get better signal levels/quality on their particular sats than does the steerable dish - so I'm not sure that the latter is the "ultimate solution" ????

BTW: it seems "about time" you got around to puting up ANOTHER sat dish :D
 
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2cvbloke

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BTW: it seems "about time" you got around to puting up ANOTHER sat dish :D

Nah, I had more fun with analogue satellite television back in the day, digital's a bit tedious to play with, not as fun as picking a frequency and waving the dish about 'til something happened on the screen, like when I had my indoor dishes looking for various satellites that I could get via my west-facing windows at the time... :lol:

I still have my Pace MSS300 from back then too (Still set to the last channel it tuned into, which was Cuatro on Hispa), presently only used to boost the height of my TV/Monitor, heck, I rarely even watch TV these days anyway, so sat hunting is something that lost my interest when the fun stuff went byebye... :(
 

jeallen01

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Nah, I had more fun with analogue satellite television back in the day, digital's a bit tedious to play with, not as fun as picking a frequency and waving the dish about 'til something happened on the screen, like when I had my indoor dishes looking for various satellites that I could get via my west-facing windows at the time... :lol:

I still have my Pace MSS300 from back then too (Still set to the last channel it tuned into, which was Cuatro on Hispa), presently only used to boost the height of my TV/Monitor, heck, I rarely even watch TV these days anyway, so sat hunting is something that lost my interest when the fun stuff went byebye... :(
The digital sat era is just "different" in many ways (as I have sort-of realised over the last few years!) - so could you not "reaclimatise" and "enjoy" (as I have had to!)?
 

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Nah, my hobbies changed over the years, I like things where I can see the effects of immediately, rather than waiting for scans of transponders for digital stuff that may not even be visible owing to encryption, stuff like tuning carbs on small engines, repairing rotary dials on old telephones, or just faffing about with soldering LEDs to things and making them glow... :lol:

It's why I liked analogue stuff, it was fun to experiment with, like when I managed to get "a" signal on my BSB Squarial (wish I still had that!) when sat on the mount for my Attisat FL500 squarial (also wish I still had that!!!), given that the BSB kit was made for circular polarised signals rather than linear, it was fun to capture it in the way I did... :)

With digital, no such things, not enough signal = no channels = no fun, it's either On or Off, nothing in between... :(
 

Channel Hopper

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The answer might be a combination of that non penetrating ground mount languishing in the garage, plus a selection of Ross' choicest tyre mounts.

With the correct combination of air pressure settings, one could adjust both a fair amount of dish skew and elevation for those pesky inclined orbit birds.

With the correct apparatus ( connectors/adapter so/rubber tubes/other hosiery), one could potentially pump away from the comfort of ones armchair. :-wow
 

jeallen01

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@2cvbloke

Life's like that for many of us (and "them") - we enjoy what we can do, and don't feel "comfortable" with that with which we are not (I'm the same with the "online scene"!). Anyway, be happy with whatever works for you :D.

BTW: this thread has "deviated" far beyond what I had initially imagined!
 

jeallen01

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The answer might be a combination of that non penetrating ground mount languishing in the garage, plus a selection of Ross' choicest tyre mounts.

With the correct combination of air pressure settings, one could adjust both a fair amount of dish skew and elevation for those pesky inclined orbit birds.

With the correct apparatus ( connectors/adapter so/rubber tubes/other hosiery), one could potentially pump away from the comfort of ones armchair. :-wow
Possibly! But I'm not "going there" - would probably mean a lot more than one ground mount, pump and whatever! Also I don't have the time, budget, OR the space (or the "incentive") :)
 

moonbase

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@2cvbloke
... it seems that some of the very carefully tweaked fixed dishes get better signal levels/quality on their particular sats than does the steerable dish - so I'm not sure that the latter is the "ultimate solution" ????


Absolutely correct, and to be expected.


With a motorised dish it may be down to the resolution of the motor moving the dish across an arc and the accuracy of the polarity skew and declination.

For example, a v-box powering a Jaeger 1224 H-H motor generally gives just under 12 pulse counts per degree with a resolution of 1/12th of a degree per click. If a fixed dish has some type of threaded rod for adjustment of azimuth it is easily possible to get a more accurate resolution down to 1/20th of a degree depending of the TPI of the threaded rod and its securing points on a mount.

The same logic applies to azimuth and polarity skew. A fine manual adjustment mechanism should generally provide more accuracy than that automatically allocated by a dish traversing an arc powered by a motor.

I am not familiar with the resolution available using DiSEqC motors so cannot comment on their accuracy.

Does such accurate dish pointing matter, possibly not? It might only come into play when signals being received are extreme fringe and the extra accuracy might get an increase of a few tenths of a dB and achieve a lock.

Where the motorised dish comes into it's own after initial setup is the convenience, all done with a remote control or the press of a button on a receiver/controller. No messing about in the dark and rain with a spanner and a meter.
 
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2cvbloke

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@2cvbloke

Life's like that for many of us (and "them") - we enjoy what we can do, and don't feel "comfortable" with that with which we are not (I'm the same with the "online scene"!). Anyway, be happy with whatever works for you :D.

BTW: this thread has "deviated" far beyond what I had initially imagined!

Well, it wasn't the can & can't do, it was just the excitement of getting signals via somewhat silly means, like my Lidl 70cm dish with an upside-down LNB with a sock over it, the BSB Squarial receiving Linear signals, my BSB Minidish modified to take a modern 40mm LNB, and seeing how my old Ferguson TV coped with going between PAL and SECAM analogue sat channels (not always well!!), I miss those days... :(

Today I don't even have the minidish outside hooked up to anything, mostly cos the landlord stuffed the cables away into somewhere I can't presently open up, but also cos, well, I can't be arsed... :lol:

But back on topic, maybe bashing a straight pole into the ground at an appropriately jaunty angle to mount the Z2 dish onto might work? Of course the angle would need to be calculated based on their Lat. & Long. position, but that way they could push the dish back & forth if they felt like switching satellites... :confused
 

jeallen01

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This thread is getting far more "technical" than I ever intended/envisaged!:( - please don't "excerbate" that further

BTW: as for the DiSEqC positioning issues with steerable dishes - regardless of what the dish motors are capable, some receivers have 0.1 degree resolution whilst other manage 0.01 resolution, but that does not affect the azimuth/elevation issue, where the adjustment is on an axis at 90 deg to DiSEqC-controlled motion (unless, of course, one has a 2-axis positioner system). From recent experience, BOTH adjustments have a substantial effect on SS/SQ.

PS: Night, night, folks - off to bed soon (proves how old I am getting now :( )
 
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2cvbloke

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That's the trouble with things that seem simple, they open up a can of worms and it just goes everywhere... :-rofl2
 

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...BTW: as for the DiSEqC positioning issues with steerable dishes - regardless of what the dish motors are capable, some receivers have 0.1 degree resolution whilst other manage 0.01 resolution...



For a DiSEqC motor I would be surprised if it had gearing or a drive mechanism capable of anything finer than a tenth of a degree, perhaps someone can measure the number of steps a DiSEqC motor counts when moved from the peak point of two closely adjacent satellites?
 
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