RV mobile auto dish with support for 101, 99, 103

DIY modding ?
replace legacy LNB to new SL3; IMO controlling by 101W LNB should works same way and 99/103 will be just a bonus signal in same coax
what STB you have ?

 

Not trying to be a "Debbie downer" here, but I can envision at least a few issues with trying to do a mod like that. I and many others would love to have a carryout dish that can do all 3 DirecTV sats at once.

So let's assume that the current Ku LNB being used inside the dome was a standard LNB used on other dishes and that a larger SL3 would be able to be mounted securely to the "arm" inside the dome and have sufficient clearance as well to move inside the dome. Then what about having to "tilt" the entire carryout to get alignment on 99 and 103? That would have to be done manually each time so that alone removes at least some of the "automatic" alignment as well as being able to make sure the "tilted" carryout didn't move in wind/weather once aligned. Then there is the question on whether the reflector in the carryout would be big enough to collect enough Ka band signal strength from any of the sats, especially 99 and 103 to give a reliable signal on even a cloudy day. I guess the only way to find out is to get someone to do the mod but I have not seen or read about anyone even trying it. My guess is that it's a LOT more problematic than just swapping an LNB or the manufacturers would have already done it. A Winegard tech told me that to currently produce such a "portable" Ka capable device would not only need to be much larger than the current iterations, but would be cost prohibitive as well.

Right now, the only automated 3 sat dish setups are the Winegard Travl'er or the RF Mogul Eagle 2 dishes which are both roof mount devices (around 50 lbs) which also use an SL3 and a slimline reflector. I have seen a couple of write-ups where someone mounted a Winegard Travl'er dish on a picnic table top using C clamps and another fashioning a plywood base attached to an appliance dolly, but at 1500.00+, it's not something I think most would want to hassle with, or feel comfortable in making "portable".

 

it's a matter of heavy rainy days, otherwise it should works OK
as to the tilt - I would use average value what suppose to be at middle of traveling area

 

DIY on that level is way beyond even the typical dbstalk poster. This isn't like suggesting that someone install their own dish or SWM16, it is at least an order of magnitude more involved and would require the commitment of many hours of work. Suggesting it is pure folly unless the poster says they're willing to build their own solution and are handy with tools, welding, etc.

 

Also, as grover517 points out ...

Is the dish of the Winegard carryout even large enough to receive the Ka band signals sufficiently to make the such a modification worthwhile?

And won't the shorter focal length cause the wrong angular separation between the 99 and 103° focal points for reception by the SL3's feedhorns?

Sent from my LG-H918 using Tapatalk

 

no worry,a focal point is geometrical parameter of the _reflector_, not wavelength

 

But isn't the physical spacing of the feedhorns on a multisat LNBF related to a constant f/D ratio?

That is to say, the larger the reflector diameter the further apart the feedhorns on the LNBF?

(Notice the wider spacing of the 99, 101, 103 feedhorns on the LNBF of the 1.2m AK/HI dish).

So if the SL-3 Slimline LNBF was designed for a larger diameter reflector, wouldn't the 99, 101, 103 feedhorns all have to be clustered closer together in proportion to the smaller diameter used for the Winegard carryout dish?

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while you're correct on the spacing for different focal length of a reflector, a size of it is not the matter, it's all about geometry; bigger surface just collecting more energy to LNBF reflected from it ;
to the concern about space between LNBFs - the reduced focal length of Ku dish vs Ka will slightly affect a performance of the DIY model... I'm sure you wouldn't see dramatic decrease of SS while clear sky.

 

Imagine the dish was a mirror aimed towards the sun. The distance from the mirror of the focal point where you can catch stuff on fire depends only on the curvature of the mirror.

Now imagine three suns at 2* spacing (talk about global warming!) The distance of the focal points is still determined by the curvature of the mirror. Therefore, so would the spacing of those focal points. Making the mirror a little larger (while keeping the curvature constant) isn't going to move the focal points further away and therefore it wouldn't increase the distance between them. It would simply concentrate more sunshine at each of the three focal points.

Now obviously there's a practical concern here - you can't use the curvature of the Slimline on a gigantic dish. Well before it could reach say 10 meters the curvature would be such that it would close in on itself. To achieve such a size you'd need to use a dish with much less curvature, and therefore locate the LNBF much further away from it since reducing the curvature would push the focal points out. That in turn would increase the distance between the three focal points.

I don't know what the AK/HI LNBF looks like, but if the feedhorns are spaced further apart either the dish is less curved, the LNBF is located further from the dish than on a Slimline, or both.

 

The curvature of the Slimline may have been chosen due to the need to spread all the way out to 119. The fact that it is wider than it is tall almost certainly was. If Directv ever abandons 110/119, I wonder if they might introduce a new round or almost round dish, possibly with different curvature and different focal length. They'd want to keep using the same SL3 LNBs, I'm sure.