Advice Needed KA and KU LNB"s for motorised dish ?

[sat-tv-fan]

I presume with a add on holder for the KA band LNB such a setup would work fine with all sats or not so good ? I wish I could find someone to get to my dish in the local area without any call out charges, still have my apparently immoveable LNB which I very much wat to replace...so if I ever do I wonder if the above idea would work ?

 

[Terryl]

All this would depend on the dish your using, a round dish will have a prime focus that is round, as it is mostly used for one satellite.

When adding a second LNB off to one side (or both sides) the dish used will have an elliptical shape, this allows more signal for the outside LNB's.

You can try the add on to a round dish but you will have to offset the dish 5 to 10 degree for that LNB to get enough signal.

Example: if the satellite was at 100 degrees for the Ku LNB then you will have to move it (buy it's motor) 5 to 10 degrees left or right (depends on what side the LNB is mounted off center) to get the best signal on Ka band.

 

[sat-tv-fan]

Thanks for the reply, interesting, just a standard 1m dish here

 

[archive10]

All this would depend on the dish your using, a round dish will have a prime focus that is round, as it is mostly used for one satellite.

When adding a second LNB off to one side (or both sides) the dish used will have an elliptical shape, this allows more signal for the outside LNB's.

You can try the add on to a round dish but you will have to offset the dish 5 to 10 degree for that LNB to get enough signal.

Example: if the satellite was at 100 degrees for the Ku LNB then you will have to move it (buy it's motor) 5 to 10 degrees left or right (depends on what side the LNB is mounted off center) to get the best signal on Ka band.

Does Ku and Ka have different focal points?
I noticed in the Prodelin technical documentation, that the feed-arms for the Ku and Ka band models using the same reflector does indeed have different length feed-arms.
Is this a design-thing, or does the focal point vary with wavelength?
(Don't remember physics in College covering this...)

 

[sat-tv-fan]

I presume this LNB is no good for Ka and Ku band here ? http://www.ebay.co.uk/itm/NEW-OUT-o...498?pt=LH_DefaultDomain_0&hash=item35e3e30452

 

[hairybadger]

I presume this LNB is no good for Ka and Ku band here ? http://www.ebay.co.uk/itm/NEW-OUT-o...498?pt=LH_DefaultDomain_0&hash=item35e3e30452

Ka and Ku are different frequency bands and thus require different antenna lengths, so I'm not sure how this LNB can support both unless I'm missing something obvious (dual antennae?).

 

[Captain Jack]

These have a number (3?) of ports behind the cap, each channelling down specific bands. So yes, this does both.

Have a read a long and comprehensive neighbouring thread on this LNB.

 

[Llew]

I presume this LNB is no good for Ka and Ku band here ? http://www.ebay.co.uk/itm/NEW-OUT-o...498?pt=LH_DefaultDomain_0&hash=item35e3e30452

These LNBs are fine for experimenting on the Ka bands, but are somewhat restricted for use on Ku, as the Ku LNB only covers 12.2 - 12.7 GHz (the NA DirecTV frequencies).
More info on how we have used this LNB can be found here - https://www.satellites.co.uk/forums/threads/the-directv-sl3k4nr1-03.162534/

Ka and Ku are different frequency bands and thus require different antenna lengths, so I'm not sure how this LNB can support both unless I'm missing something obvious (dual antennae?).

I've used Ka and Ku LNBs including the LNB mentioned on my dishes (Triaxes and Gibertini) with no significant need to adjust for focal length.

 

[sat-tv-fan]

OK I see thanks for the info, so limited for KU then, if only someone would produce a full band version, anyway we are half way there it seems

 

[John]

@ Llew, the XMW R9216DF & feed turned up the other day. Quite impressed with the speed of delivery from South Korea via FedEx. If anybody is interested in importing one themselves and would like to see the tracker just shout up.
If of any interest to others re: Ka reception, i decided to go for the slightly cheaper option of a DRO type lnb instead of the more expensive PLL type. Slapped it on my temp Channel Master 1.2 set-up this afternoon where it was overcast here but not raining and i couldn't see diddly squat of any Ka signals on my Televes siggy from either 16E , 7E or 4.8E. Going to swap out the XMW feed for a bit of waveguide + horn to see if any change. Iv'e got a Precision 1.2 PF solid stood idle in the lock-up , i'm going to do a comparison between the two when time permits.
Iv'e still got my cheap modded SL3 Ka unit & sup2400 for band A though .

 

[Llew]

Hi John. With your 1.2 dish, you should have no problem getting something from 16E or 7E.

I presume you have aligned the rectangular ports of the feed and LNB correctly, i.e H-H?
My FD9000 is off ATM, and with the label as shown in your pic, if it was attached to the LNB as you have it, the ports would be diametrically opposed.
But perhaps my label is affixed differently...

 

[John]

... , it was a thing i double checked Llew when i mated the two together initially but i had to whip the cap off just to double check.

It draws about 89mA and shows gain on the analyser, i know you have the PLL version which might be different current draw, would you please put your Promax on it & see what yours draws under no signal.

 

[Llew]

Mine draws around 250mA John. Extra PLL circuitry (Xtal oscillator etc) would account for some extra current draw, but yours seems way down.

I can't find any specs online for XMW Ka LNBs, but typical Norsat versions all come in at 175 - 250mA roughly.

May be wrong, but it seems to be yours isn't performing as it should.

 

[John]

.... Thanks, i suspect you could be right Llew, iv'e just checked the current draw on another Televes meter here and that is saying 92mA, so both analysers in the same ball park.

I'll shoot Jin a message off for his opinion & a bit more info on what nominal current draw to expect.

 

[Llew]

Good idea John. Expensive enough without having to worry about a possible faulty unit.

 

[John]

... message gone, await response with interest

 

[John]

... update re: XMW Ka lnb, clear sky at one point this afternoon so decided to re-try. Not very pleasant to do as we have had a fair bit of snow in the last day and i was paddling around in the stuff trying to keep the siggy from getting wet through etc. Saw good levels from 16E, a bit down from 7E due mainly i think to obstruction. This is only a temp dish location at ground level for initial tests.
So, it would seem that this DRO type lnb really does only draw around 90mA.
Not heard anything back from Jin as yet but i'll drop him a line to assure him the unit appears to be ok.
I meant to mention before but forgot .... how inspirational VS is when it comes to going the extra mile as far as experimental tinkering / fabrication etc for Ka feeds/waveguides etc, iv'e been catching up on his exploits on this and other sites recently and have learned a lot from it. I thought i was a bit of a fabricator but him ... well , on another level.

 

[Llew]

Good to hear that it seems OK John. Confirmation from Jin will settle it I suppose.
Still less current draw than, say, an Inverto BU single (125mA), so our PLL version really does seem to suck up the power.
Most of my Ka reception is done with the Triax TD88 at ground level. Perhaps you will have better results when you have your dish in the clear.
Yes, VS and his projects are a thing to behold - wish I had the nous like him to initiate and develop stuff in a similar fashion.